Seismic Sleuths

Earthquakes

A Teachers Package for Grades 7-12

Introduction

Produced by
The American Geophysical Union
2000 Florida Avenue, NW.
Washington, DC 20009

Supported by the
Federal Emergency Management Agency
Washington, DC 20472

This product was developed by the American Geophysical Union (AGU) with 
financial support from the Federal Emergency Management Agency (FEMA) under 
Cooperative Agreement EMW-92-K-3892. AGU is solely responsible for the accuracy 
of statements and interpretations contained herein.

Funding for this publication was allocated to FEMA by The United States 
Congress, under the Earthquake Hazards Reduction Act of 1977, as amended. FEMA 
maintains a royalty-free, nonexclusive and irrevocable right to reproduce, 
publish or otherwise use and to authorize others to use, the work for public 
education purposes. FEMA hereby authorizes and encourages the educational 
community to reproduce this product in its entirety and to disseminate it at no 
cost to the recipient.

Single copies of this publication may be obtained from FEMA at no cost by 
contacting the FEMA Warehouse:
Toll free number: 1-800-480-2520, Fax: 301-497-6378
Mailing address: P.O. Box 2012, Jessup, MD 20794-2012

AGU/FEMA EARTHQUAKE CURRICULUM
Project Director:
M. Frank Watt Ireton, Manager of Pre-college Education, American Geophysical 
Union

Associate Project Director:
Karen Lee Spaulding, Manager of Professional and Continuing Education, American 
Geophysical Union

Project Editor:
Mary Liston Liepold, Washington, District of Columbia

Copy Editor:
Pam Knox, Senior Copy Editor, American Geophysical Union

Authors and Reviewers:
Roy Q. Beven, Science Teacher, San Juan Capistrano, California
Jane Nelson Crowder, Science Teacher, Bellevue, Washington
Jo Ellen Dodds, Science Teacher, Twin Falls, Idaho
Lynda Vance, Science Teacher, Boise, Idaho
James F. Marran, Social Studies Teacher, Wilmette, Illinois
Ronald H. Morse, Science Teacher, Cicero, New York
Walter L. Sharp, Science Teacher, Camillus, New York
James D. Sproull, Science Teaching Consultant, Kirkland, Washington

Consultants and Reviewers:
Charles Ault, Science Educator, Lewis and Clark College, Portland, 
Oregon
Robert A. Christman, Geologist and Science Educator, Western 
Washington University, Bellingham, Washington
Henry J. Lagorio, Architectural Engineer, Orinda, California
Sue J. Nava, Seismologist, University of Utah, Salt Lake City, Utah
Martin Stout, Engineering Geologist, Whittier, California
Keith A. Sverdrup, Seismologist, University of Wisconsin, Milwaukee, 
Wisconsin
Diana Todd, Structural Engineer, National Institute of Science and 
Technology, Gaithersburg, Maryland
Monte D. Wilson, Geologist, Boise State University, Boise, Idaho

Design by:
Auras Design, Washington, District of Columbia

Illustrators:
Susie Duckworth, Falls Church, Virginia
Max Karl Winkler, Silver Spring, Maryland

Graphic Artist:
Gregg Sekscienski, Albuquerque, New Mexico

Project Officer:
Marilyn P. MacCabe, Mitigation Directorate, Federal Emergency 
Management Agency

ACKNOWLEDGMENTS
The American Geophysical Union (AGU) and the Federal Emergency Management Agency 
(FEMA) acknowledge with gratitude the many individuals who provided technical 
experience, teaching knowledge, and classrooms for field testing in the 
development of this project. Along with the authors and consultants, they 
provided continuous feedback in the development of these materials. Without the 
assistance of these individuals and the students who participated in the field 
test this volume would not have been possible.

Technical Reviewers:
William Chavez, Geological Engineer, New Mexico Institute of 
 Mining and Technology, Socorro, New Mexico
Lucy Jones, Seismologist, United States Geological Survey
David Love, Environmental Geologist, New Mexico Bureau of Mines 
and Mineral Resources, Socorro, New Mexico
Mary Ellen Williams, Earthquake Program Specialist, United States 
Geological Survey, Woods Hole, Massachusetts

Curriculum Reviewers:
Allen Bone, Science Teacher, Butte, Montana
William Krayer, Science Teacher, Gaithersburg, Maryland
Sharon Stroud, Science Teacher, Colorado Springs, Colorado

Field Test Teachers:
Roger Alsup, Jim Anderson, Richard Arrington, Joann Ball, Allen Bone, 
Gail Chaid, Linda Dudley, Jo Dodds, Elizabeth Ellis, George Foley, John 
Gallagher, Melody Green, Paul Grogger, Kay Kidder, Paul Jamerson, 
Larry Madden, Lloyd Magnuson, Gay Ann Masolo, Sue Ayn Moore, 
Becky Orahood, Doyle Orrell, Nancy Sallee, Sandy Shutey, Jack Staker, 
Ann Sullivan, Edith Thurman, Maris Ward, Leslie Wehner, Ronald 
Wieland, and Walt Woolbaugh.

Teachers who participated in the two 1994 Seismic Sleuths Leadership Institutes 
also conducted field testing and review of the lessons during the institutes. 
The suggestions and additions by the initial field test and institute teacher 
participants have contributed to a stronger curriculum package.

A special note of thanks to Katharyn E. K. Ross, whose comprehensive Fourth 
Edition of Earthquake Education Materials for Grades K - 12 contributed greatly 
to the unit resource lists in this package, and to Sean Cox, teacher, Salem High 
School, New Hampshire, who provided the appendix to Unit Six.

Introduction
Earthquakes are mystifying events. They are as unpredictable as they are 
powerful, and not even seismologists fully understand the forces within the 
Earth that set them in motion. As an educator, you can capitalize on that 
mysterious appeal to engage your students interest.

Ultimately, however, the purpose of these lessons is to demystify earthquakes, 
and to counter the fatalism that frequently accompanies ignorance about natural 
phenomena. Interactive lessons invite students to discover what is known 
about quakesthe considerable body of knowledge that deals with their causes, 
the patterns of their occurrence, and what human beings can do to minimize their 
catastrophic effects on themselves and their communities.

The units in this package follow a pattern of zooming in and out, beginning with 
concerns closest to home, moving to general principles and global perspectives, 
then homing in again to engage students in evaluating their personal 
preparedness and that of their families, schools, neighborhoods, and 
communities. Look for the magnifying glass symbols opposite the text, which 
indicate essential vocabulary and helpful hints (Teaching Clues and Cues).

Units 1 and 6 deal most specifically with the personal and 
local, but every unit contains a mixture of general information 
and specific, local applications. A healthy respect for the 
power of earthquakes requires both kinds of understanding. 
Units 4 and 5 feature interactive lessons in architecture and 
engineering, topics seldom dealt with in grade 7-12 curriculum 
materials.

You may not find time to teach every lesson in this package. 
For teachers who must pick and choose, most of the lessons 
are designed to stand on their own. Take time to familiarize 
yourself with the outline, however. Read the unit 
introductions; take advantage of the background readings 
provided and of the unit resource lists. The Teacher 
Preparation section in each lesson outlines things you need to 
do before class begins, in addition to assembling the items on 
the materials list. Plan ahead now for the cooperation you 
will need in Unit 1, the 
materials you will need in Unit 4, and the field trips you will 
make in Unit 5. Youll see a burst of learning to reward your 
efforts and a wealth of ideas to enrich your science and social 
studies teaching.

Theory takes a back seat to hands-on experience in most of 
these lessons. As its name implies, this Seismic Sleuths 
package focuses on discovery. Ideally, the process of 
discovery will ripple through the town or city outside your 
classroom. Beginning in Unit 1, students will be interacting 
with a wide range of public officials. Please initiate and 
encourage these relationships. They will benefit the students, 
the school, and the community.

Through interacting with adults in positions of responsibility, 
students will develop a realistic sense of how their community 
functions day to day and how it would function in the 
aftermath of an earthquake or other natural disaster. Most will 
find it enormously reassuring to learn that emergency plans are 
in effect. Moreover, they will be empowered by the 
knowledge that their individual and collective actions can 
make a difference. Cultivating relationships within their 
community will also expose students to a variety of careers 
they might never have considered and provide a motivation to 
stay in school. In the long range, these activities will prepare 
todays students to be tomorrows concerned and informed 
participants in democracy.

The school will benefit from these relationships by widening 
the pool of local adults who take an active interest in 
education, share their expertise and experience, and serve as 
role models for students. The community at large will benefit 
greatly, whether or not it is in an area known to be seismically 
active. Most of the kinds of emergency planning that students 
will learn about, and model in Unit 6, would be appropriate 
not only in the event of an earth- quake but also in case of 
flood, hurricane, or other large-scale disaster. In just the last 
few years, almost every section of the country has experienced 
destructive natural events.

Overview of the Units
Unit 1. This three-part introductory unit sets the stage for 
what follows. Every teacher should take time to include some 
of the materials contained in this unit. The introductory lesson 
assesses students knowledge of earthquakes. In lesson two 
students describe their own experiences and tell how they 
would prepare for an earthquake. Lesson three requires 
students to make contact with emergency personnel in their 
community to ascertain emergency preparedness plans. 
Lessons in this unit are referred to in future units.

Unit 2. This five-part unit moves students beyond their 
personal survival into the causes of earthquakes. This unit 
sketches the big picture, building on students knowledge 
from earth science or other science classes. The unit begins 
with students modeling stress buildup in the crust, followed 
by lessons on how earthquakes and other evidence tell 
scientists about the structure of the Earth. In the third lesson, 
students contrast historic time with the vastness of geologic 
time and simulate techniques of paleoseismology. The unit 
concludes with lessons on some potential side effects of 
earthquakes, such as tsunami, liquefaction, and landslides. 
Students study how the geology of an area influences the 
destructive effects and how high population density at unsafe 
sites can increase the amount of damage during an 
earthquake.

Unit 3. In this four-part unit, students learn about the different 
wave motions during an earthquake and how these motions 
are studied. A historical piece on the development of 
seismology adds background to students knowledge. 
Students study and simulate the measurement of earthquakes 
using the Richter and Mercalli scales to find out how 
seismologists arrive at earthquake measurements.
This unit concludes with activities that plot the distribution of 
earthquakes worldwide, then focuses in on local earthquakes, 
first in Japan, then in the United States. It offers a variety of 
lessons in science, mathematics, and social studies.

Unit 4. This five-part unit is designed to allow students to 
construct an understanding of how buildings respond to 
earthquakes. Lessons on building design and how earthquake 
forces act on various designs provide students with 
information on how to build earthquake resistant structures. 
Students then apply this knowledge by constructing testing 
devices and testing their designs. This unit is critical for 
developing students understanding of why buildings collapse 
and what can be done to make buildings safer.

Unit 5. This five-part unit focuses students attention on what 
to do before, during, and after an earthquake. By studying 
historical earthquakes as reported in the press, students learn 
how people have responded to earthquakes in the past. 
Students then learn what their response should be during an 
earthquake by planning and practicing earthquake drills. 
Students conduct safety assessments of their home, classroom, 
and community and see how secondary disasters associated 
with earthquakes can also be alleviated.

Unit 6. This concluding four-part unit offers a variety of 
summing-up and assessment activities. Writing activities, a 
fast paced quiz game, and a high pressure simulation allow 
students a chance to show off what they have learned in this 
curriculum. An extensive resource list provides detailed 
instructions for conducting a community-wide disaster 
simulation that becomes realistic and dramatic with the 
involvement of community disaster officials.

Seismic Sleuths Matrices for the National Education Standards
A Seismic Sleuths development team has put together the 
matrices on the following pages to use in correlating the 
Seismic Sleuths materials with the National Science Education 
Standards. The National Science Education Standards, under 
development by the National Research Council since 1993, will 
be released in late 1995. The Standards have been developed 
through consensus building among K-12 teachers, teacher 
education faculty, scientists, and other education specialists. 
Through this process a document that represents the broad 
thinking of the science education community is being 
developed as to what students should know, how they should 
be taught, and how they should be assessed. The Standards are 
meant to be descriptive rather than prescriptive and designed 
to be a tool to strengthen science education.

Using the Seismic Sleuths Standards matrices
The development team, working with the November 1994 
draft of the National Science Education Standards, examined 
Seismic Sleuths section by section identifying correlations to 
the Science Content areas listed in the Standards. Two criteria 
were used: the section made a strong and direct connection to 
that content area, or the section made an indirect connection. 
A strong, direct connection is shown in bold faced type.

The following matrices are provided. Below is a summary of 
Seismic Sleuths and the content areas listed in the Standards. 
This page shows at a glance the correlations between Seismic 
Sleuths and the Standards. The next six pages describe more 
detailed correlations between Seismic Sleuths and the 
Standards using wording from the Standards. In some cases 
the development team felt that where a particular concept was 
not listed in the wording of the Standards a possible 
connection could be shown in parentheses.

When using the matrices it should be kept in mind the 
descriptive nature of the Standards. The connections shown in 
these matrices are suggested connections based on the 
development teams experience working with Seismic Sleuths. 
Many other correlations can be made and will become evident 
as the curriculum materials are used. Additionally, connections 
can also be made between Seismic Sleuths and Benchmarks for 
Science Literacy, (AAAS, 1993), Content Core, (NSTA, 
1992), and Earth Science Content Guidelines Grades K-12, 
(AGI, 1991). The user is referred to these documents for 
further connections.

UNIT 1: 
Whats It All About? Pre-assessment of students knowledge of earthquakes and 
hazards preparedness. 

UNIT 2: 
What Happens When The Earth Quakes? An exploration of earthquake processes, 
including causes and measurement.

UNIT 3: 
How Do People Learn About Earthquakes? Students explore the science and history 
of seismology. 

UNIT 4: 
Can Buildings Be Made Safer? Students construct an understanding of how ground 
shaking during an earthquake can damage buildings and how buildings can be made 
better able to 
withstand this shaking.

UNIT 5:
What Should People Do Before, During, and After An Earthquake? 

UNIT 6: 
Now You Know It, Can You Show It? A variety of summing-up and assessment 
activities that showcase students knowledge.

SEISMIC SLEUTHS CURRICULUM PACKAGE
Unit 1. Whats It All About?	2
1. What Do You Know about Earthquakes?	3
2. It Could Happen Here	11
3. Investigating Community Preparedness	17
Unit Resources	25

Unit 2. What Happens When the Earth Quakes?	38
1. Stick-Slip Movement	39
2. Shifting Plates and Wandering Poles	45
3. Earthquakes in Geologic Time	67
4. Earthquake Hazards	89
5. Quake-Smart Siting	127
Unit Resources	137

Unit 3. How Do People Learn about Earthquakes?	142
1. The Waves of Quakes	143
2. Pioneering Ideas	151
3. Sizing Up Earthquakes	161
4. Distribution of Earthquakes	193
Unit Resources	221

Unit 4. Can Buildings Be Made Safer?	226
1. Building Fun	227
2. Structural Reinforcement: The Better Building	232
3. The BOSS Model: Building Oscillation Seismic Simulation	247
4. Earthquake in a Box	257
5. The Building Challenge	263
Unit Resources	270

Unit 5. What Should People Do Before, During, 
and After an Earthquake?	272
1. Predicting Earthquakes	273
2. Starting Here, Starting Now	289
3. Find and Fix the Hazards (Wood Frame Homes)	299
4. Rapid Visual Screening (RVS) in the Community	311
5. Are the Lifelines Open? Critical Emergency 
Facilities and Lifeline Utility Systems	319
Unit Resources	327

Unit 6. Now You Know It, Can You Show It?	330
1. Preparing for the Worst: A Simulation	331
2. Earthquake Simulation: Putting Plans into Action	341
3. Whats Your E.Q. I.Q.?	345
4. Hey, Look at Me Now!	353
Unit Resources	355

Appendix: Earthquake Drill	356

Earthquake Glossary		360

Seismic Sleuths

Earthquakes

A Teachers Package for Grades 7-12
 
Unit One

Whats It All About?

Every teacher, no matter how busy, should take time 
to cover some of the material in this three-part 
introductory unit. Through brainstorming and new 
contacts within the community, students move from 
planning for their own safety to learning firsthand 
about critical facilities and lifeline systems that serve 
large numbers of people.

Please read through all the lessons well in advance, 
especially noting the Teacher Preparation section at 
the beginning of each Procedure. In this unit you will 
build a foundation for the units and lessons ahead by 
enlisting the cooperation of your schools 
administrators, your fellow teachers, and emergency 
personnel throughout the community and even 
beyond. Take time to scan the rest of the units too. 
You may want to let parents know now that you will 
be asking for their help in the Unit Five field trips and 
home safety activities. If you plan to involve the 
school community and outside experts in the 
culmination of Unit Four, also include this information 
in the initial contacts you make during this unit.

Lesson one, which students may complete either 
individually or in small groups, provides an 
assessment of what students already know about 
earthquakes plus experience with both scientific and 
popular ways of describing them. The worksheets 
provided will make this activity easier for students 
who arent thoroughly comfortable with writing. In 
lesson two, students distinguish between luxuries and 
necessities, describe their own experience with natural 
hazards and how they and their families obtained the 
necessities, and come to see how preparedness can 
help individuals and families cope effectively in the 
event of an earthquake or other natural disaster. In the 
following units, students will learn some strategies for 
risk reduction.

Lesson three, which requires the cooperation of a 
number of emergency personnel in the community at 
large, calls for some extra effort on the part of your 
students. Teachers who have tried it report that the 
outcome is worth the effort. The contacts you and your 
students make now will be vital through the units that 
follow and even after this curriculum is completed. 
Your students, their families, and your entire 
community will be empowered to prepare wisely for 
the possibility of an earthquake or other destructive 
natural phenomenon.

1.1 What Do You Know About Earthquakes

TEACHING CLUES AND CUES
At the end of this activity, collect the assignments and hold onto 
them until you have done the last lesson you plan to teach from this 
curriculum before the postassessment activity. You will use them 
again in postassessment.

RATIONALE
This preassessment activity is designed to focus your students on what 
they are about to learn, assess their current knowledge, and later 
provide them and you with a gauge of what they have learned from 
this earthquake curriculum.

FOCUS QUESTIONS
What do you know about earthquakes and earthquake preparedness?
What would you like to learn from these lessons?

OBJECTIVES
Students will:
1. Use various writing styles to describe a hypothetical earthquake.
2. Anticipate what they will learn in this study of earthquakes.

MATERIALS
 Writing paper and pens
 Student copies of Master 1.1a, Writing Outlines (three pages)
 Classroom computers (optional)
 Pictures or slides of earthquake damage (optional: See Unit Resources.)

PROCEDURE
A. Introduction
Show a selection of images to familiarize students with the kind of 
damage earthquakes can cause. Tell students that they are going to 
draw on the knowledge they already have about earthquakes to invent a 
specific quake and imagine themselves in it. Distribute copies of the 
writing outlines, Master 1.1a, and ask each student to note the date and 
time of their quake, its location, how much damage it caused, and other 
basic information at the top of page 1.

TEACHING CLUES AND CUES
The newspaper accounts on Master 5.1a are examples of how 
news articles are written.

This activity is purely diagnostic. Explain to students that you do not 
expect professional scientific writingonly their best try on the basis of what 
they already know.

B. Lesson Development
Now tell students that each of them is going to write about his or her 
hypothetical earthquake from three different points of view: that of a 
news reporter, a scientist, and an individual directly affected by the 
quake. Each of the three accounts will describe the same earthquake, 
but the styles of the three will vary.

News Reportera short, concise article describing the who, what, 
where, and when of the earthquake and providing information the 
public needs.

Scientista scientific account stating what is objectively known about 
the earthquake: its causes, its effects, its magnitude and/or intensity, 
and the likelihood of its recurrence, if known.

Eyewitnessa personal letter to a friend telling about being in an 
earthquake. This will describe what happened to the student, to the 
building in which the student was, to family members and pets, and to 
the family home during the earthquake. Have students describe what 
they had done before the earthquake to be prepared, how effective 
their preparations were, what life was like in the two weeks following 
the earthquake, and what they would do differently in preparation for 
the next earthquake.

Tell students to feel free to make up information, quotations, etc., but 
to keep the basic facts consistent from one essay to another. Since, in 
real life, compositions of the second and third type are likely to be 
written later than news accounts, however, some discrepancies in 
details are to be expected.

C. Conclusion
Ask students to talk about the experience of writing the accounts. Ask:
 Did you feel you had enough information to do the job in each 
case?
 Did some of you wish you knew more? Is there anything specific 
youd like to find out?
 Was one point of view more comfortable than the others? Were 
some accounts easier to write?

Discuss the validity of the different points of view. Emphasize that 
each kind of account is valuable in its own right.

ADAPTATIONS AND EXTENSIONS
1. If time is short, form groups of three students each. Have each 
student develop one point of view and share it with the group.
2. If this assessment reveals that students have very little basic 
information about earthquakes, you may want to spend class time with 
some of the books or videos in the Unit 2 resource list before 
proceeding.
3. Invite students to write about an earthquake from a premodern point 
of view, such as that of a Native American in North America before 
Columbus. Alternatively, students may write from the viewpoint of a 
traditional culture with which they are familiar.
4. Invite students to bring in samples of writing about earthquakes and 
classify them as journalistic, scientific, or informal. This could make a 
long-term bulletin board display.

TEACHING CLUES AND CUES
If you have access to enough computers, encourage students to 
compose their accounts on a classroom computer and save 
the files. This will make it easy to rewrite them later as a postassessment 
activity.

1.1a Writing Outlines

Name

Date

Just the facts:
Date and time of the hypothetical 
earthquake
Location (city, state, country)
Estimated strength and impact
	Richter magnitude
	Deaths
	Injuries
	Property damage $
	Maximum Mercalli intensity if known (I-XII)
	Date of last earthquake in this region

Use these same facts in each of the three variations that follow.

1. Newspaper account: intended for the general public, who need practical 
information. May appear immediately 
after the quake, while aftershocks are still occurring and emergency conditions 
are still in effect.
Dateline (place and time of filing story)
Lead sentencemust be catchy, attention-grabbing. May be a particularly 
startling fact or a quotation (make it 
up) from a person in authority, an expert, or an eyewitness.
Rest of lead paragraphmust answer what, where, when, who was affected, and how. 
(May use quotations.)
One or more body paragraphsprovide background. Add more details on effects, 
quotations from more people, 
possible explanation, analysis. (Think of what people need to knowwhat to do, 
where to go, what to watch for.)
Final sentencethe clincher; ends story with a punch. (Possibly a warning about 
aftershocks?)

2. Scientific account: intended for specialists; will probably appear well after 
the dust has settled.
Lead paragraphmust answer what, where, when, who was affected, and how. Likely 
to be heavy with data 
instead of quotations. (Make them up too, but keep them consistent with the 
basic data at the top of page 1.)
One or more body paragraphsprovide background and analysis, more details on 
effects, maybe quotations from 
experts, scientific explanations, and hypotheses. (Will probably compare 
original and revised estimates of severity 
and effects, compare earthquake to other quakes.)
Final paragraphsummarizes what scientific knowledge has been gained or what 
plans are underway to gather 
information as a result of the earthquake.

3. Informal account: intended for a friend, usually also written after the worst 
is over; may include humor or 
exaggeration.

[inside address]
Name
Street no., Apt. no.
City/State/Zip
Date
Dear [name],
Your friend,

1.2 It Could Happen Here

VOCABULARY
Earthquake: a sudden shaking of the ground caused by the passage of seismic 
waves. These 
waves are caused by the release of energy stored in the Earths crust. Natural 
hazard: any of the range of natural Earth processes that can cause injury or 
loss of life to human beings and damage or destroy human-made structures.
 
RATIONALE
Students will consider the range of their needs and the state of their 
personal preparedness for an emergency.

FOCUS QUESTIONS
What do people need to survive?
What kinds of natural events can prevent people from meeting their 
basic needs?
How does society cope with these events?

OBJECTIVES
Students will:
1. Distinguish between luxuries and necessities.
2. Describe their own experience with severe weather or natural 
disasters, and how they and their families fared.
3. Explain why preparedness can help individuals and families cope 
effectively in the event of an earthquake or other natural disaster.

MATERIALS
Chart paper
 Felt markers
 Student copies of Master 1.2a, Three-Day Survival Pack
 Transparency made from Master 5.5b, A Chain of Disasters (optional)
 Overhead projector (optional)
 Materials for assembling the Three-Day Survival Pack (optional)

PROCEDURE
A. Introduction
Ask students to consider which of all the things they use and consume 
every day are really essential to their survival. Discuss, and develop a 
class listing on chart paper. (Answers may include variations on water, 
food, clothing, and shelter.)

Ask: How do you meet these needs? (Answers will include faucets, 
restaurants, grocery stores or parents refrigerators, school cafeterias, 
clothing stores, parents homes.) Now ask students to name some 
natural occurrences that could cut them off from these sources, and 
describe their own experiences with snowstorms, hurricanes, floods, or 
earthquakes. Beyond their own experience, what events of this type 
have they heard or read about in the last two years? Develop a list of 
events.

TEACHING CLUES AND CUES
Please save the lists students develop in this 
lesson. You will use them again later in this
lesson and in Unit 5, lesson 5.

To help students understand why electricity, 
natural gas, and other services would be
disrupted by an earthquake, you may 
want to project a transparency made 
from Master 5.5b, A Chain of Disasters.

Many scientists prefer the term natural hazard 
to natural disaster because proper 
preparation can avert disaster, 
preventing or minimizing injury and 
damage. This curriculum encourages 
students to take a proactive role in 
preparing themselves and their 
community to survive destructive 
natural events.

B. Lesson Development
1. Elicit a definition of natural hazards from the class. Emphasize that 
earthquakes, volcanoes, floods, hurricanes, tsunami, and similar events 
are the result of natural processes in the life of our dynamic Earth. 
These processes have shaped our Earth and created the beauty of 
mountains, valleys, lakes, and rivers. Be sure students understand the 
difference between natural events and those caused by human activity.

2. Ask: If an earthquake occurs in an uninhabited region, and has no 
impact on human beings or human property, is it a disaster?  (Not for 
human beings, though it may be for other life forms.) Are we able to 
control natural events, or accurately predict when they will occur? (No, 
but students may be aware of instances in which human activity has 
influenced natural events, as in the relationship between dams and 
floods, and of our relative success in predicting some meteorological 
events.) Lead students to the conclusion that because our ability to 
control natural events, or even predict when they will occur, is still 
very limited, people have a responsibility to plan how they would cope 
if an earthquake or other destructive event struck their community.
 
3. Ask students how they and their families coped with any destructive 
events they have experienced. Were their homes equipped with 
everything they needed? Did they have to leave their homes? Were the 
roads open? Were the stores open? Who provided help? (If personal 
experiences are lacking, discuss recent news accounts of earthquakes, 
floods, and storms.) 

4. Look again at the list of vital necessities and widen the discussion to 
include the needs of communities as well as individuals. Ask: If a 
major earthquake occurred in or near your community, what 
necessities would have to be added to the first list? (Answers may 
include medical care, electrical power and other utilities, and essential 
transportationfor hospital workers, police, firefighters, and people 
who supply food, water, and other necessities.)

Emphasize that a damaging earthquake would disrupt all or most of the 
communitys lifelinesits supplies of water and power and its 
transportation and communications systems. Emergency services, such 
as police, fire departments, and emergency medical technicians, would 
be severely taxed and unable to answer all calls for assistance. For this 
reason, individuals, families, and neighborhoods must be prepared to 
be self-sufficient for at least 72 hours.

TEACHING CLUES AND CUES
In assembling the survival pack, group can 
openers and other utensils in one container so 
theyll be easy to find.
 
Suggest that families assemble a smaller version of the pack to keep in the 
trunk of the car.

C. Conclusion
Distribute student copies of Master 1.2a, Three-Day Survival Pack. 
Explain its purpose. The Federal Emergency Management Agency 
(FEMA) and law enforcement authorities recommend that every family 
assemble a pack like this and keep it handy in their home for 
emergencies, checking it periodically to keep it up to date. (Batteries 
may need replacing, family needs may have changed.) Compare this list 
with the lists students have developed. If your school is in a high-risk 
zone, you may want to prepare a variation of the survival pack to keep in 
your classroom.

Ask students to take the sheet home and encourage the members of their 
household to cooperate in filling a clean trash can or other suitable 
container with these supplies. Make sure that everyone knows its 
location.

Tell students that in the following lessons they will learn more about one 
type of natural hazard, earthquakes. They will also research their own 
communitys potential to survive destructive natural events, especially 
earthquakes.

ADAPTATIONS AND EXTENSIONS
1. In section A., Introduction, instead of a class discussion, you might 
ask individuals or small groups to develop lists of essentials they would 
need to survive 72 hours without access to power, running water, roads, 
stores, and so on. Then challenge each student or group to justify the 
items on their list, and develop a class list from the items that most 
students agree are essential. Compare this list with Master 1.2a when it is 
distributed.

2. Make a list of the daily activities that involve electricity, water, natural 
gas, telephone, and transportation. Then enlist the cooperation of parents 
in an at-home recovery simulation. For a period of 24 hours (representing 
72 hours), ask students to do without things that would not be available 
after an earthquaketelephone or other communication, nonessential 
transportation, electricity, gas, and running water. Alternatively, consider 
involving the administration and the other teachers in an in-school 
simulation. With preplanning, heat or cooling could be turned down, 
lessons in every subject could be earthquake-related, and lunch could 
feature emergency rations.

1.2a Three-Day Survival Pack

TOP OF THE BARREL
Flashlight and radio with batteries
First aid kit, including:
 
Medicines
Antibiotic ointment
Aspirin, acetaminophen, or ibuprofen
Ipecac (to induce vomiting)
Kaopectate
Prescription medications 
(insulin, heart tablets)

Dressings
Adhesive tape, 2 wide roll
Sterile bandage, 2 and 4 rolls
Large triangular bandages
Band-aids
Cotton-tipped swabs
Sterile absorbent cotton
Ace bandage
Butterfly bandages
Gauze pads, 4 x 4
Latex gloves

Other Supplies
Scissors
Tweezers
Thermometer
Petroleum jelly
Rubbing alcohol
Tissues & toilet paper
Pocketknife
First-aid handbook

Emergency instructions
Waterproof page with phone
numbers, when & how to
turn off utilities, meeting
places, etc.

MIDDLE OF THE BARRELL
Water (4 liters [about 1 gal] per person)
Three-day supply of food
 Choose food that does not require refrigeration.
 Date all food items.
 Write out a menu for each day.

Suggested foods (1/2 lb. per person):

Canned tuna
Graham crackers
Canned beans
Dried apricots
Nonfat dry milk
Peanut butter
Powdered juice mixes
Pet food if necessary
Canned juices

BOTTOM OF THE BARREL
Bedding
Sleeping bags or blankets 
Plastic sheet or tarp

Personal supplies
Toiletries
Towel
Books
Paper and pencil
Cash

Infant supplies, if necessary

Fuel and light
Matches
Candle
Signal flare
Canned heat (Sterno)
Extra batteries

Equipment 
Can opener
Dishpan
Disposable dishes
Disposable utensils
Ax
Shovel
Bucket and plastic bag liners

Other
Water purification 
tablets
Chlorine bleach
Eye dropper 

Clothing
One change per person

 Place pack in convenient place known to all family members. Keep a smaller 
version in the trunk of your car.
 Keep items in airtight bags.
 Change stored water every three months. Check and rotate food every six 
months. Mark dates on your calendar.
 Rethink kit once a year. Update supplies and replace batteries, outgrown 
clothing, and perishables.


1.3 Investigating Community Preparedness

TEACHING CLUES AND CUES
The other early lessons in Unit 1 will be revisited 
in Unit 6. This one will culminate in a major 
simulation in Unit 6, but it will also be 
woven throughout Units 2 to 5. The 
classroom map will play a major role 
in this continuing development, so it 
is worth the time you spend on it now.

RATIONALE
Now that students have thought seriously about individual survival in 
the event of a natural disaster, it is time for them to learn about their 
communitys survival plans.

FOCUS QUESTIONS
How would your community cope in the event of an earthquake or 
other natural disaster?
Who are the people responsible for your communitys survival and 
recovery?

OBJECTIVES
Students will:
1. Adopt and begin to research individual roles in community 
earthquake planning, management, and follow-up.
2. Set up a classroom map for further elaboration.
3. Begin a process of learning through and with the community that 
continues throughout this entire curriculum.

MATERIALS
 Master 1.3a, Preparedness People
 Local map
 Transparency made from Master 1.3b, U.S. Earthquake Hazard Map
 Extra transparency sheets
 Overhead projector
 A square of sturdy paper, 1 m x 1 m or larger
 Paper, pens, envelopes, and stamps for writing letters
 Markers in a variety of colors


PROCEDURE

TEACHING CLUES AND CUES
If you and your class determine that the seismic risk for your area is 
very low, you may want to expand your focus to include 
hazards of greater local concern, such as tornadoes or other storms or 
flooding. Keep earthquakes in focus as well, however. Remind students 
that most of them will move several times in the course of their lives and 
that earthquakes can happen anywhere.

Outside of class, write or call the preparedness 
people in your community to let them know
that students will be contacting them and why and to enlist their 
cooperation.

Teacher Preparation
1. Look at Master 1.3a, Preparedness People, and add or subtract items 
as necessary to fit your community and the number of students in each 
class. Make a transparency from your list.
2. Find a map, or a portion of a map, that includes your students 
homes and one or more local governments. Copy the map onto a 
transparency sheet.
3. Decide whether to assign roles, allow students to choose them, or 
hold elections, at least for the major roles. If the class is very large, 
you may want to assign more than one student for some roles.
4. Find out who is responsible for emergency response in your school 
building. Notify this person of your plans to teach about earthquakes. 
Notify the administration and fellow teachers as well, and enlist their 
cooperation for the long term.

A. Introduction
Ask students if they have ever heard the emergency broadcast system 
go into effect on radio or TV. Do they know who is responsible for 
emergency response in their school? If they dont know, tell them, and 
briefly describe the procedures that would be followed during an 
earthquake. (In most schools, students would drop, cover, and hold 
until the shaking stopped, following their classroom teachers 
directions. Then the principal would direct an evacuation similar to 
that during a fire drill. See Unit 5, Lesson 2 for more details.)

Remind students that an earthquake or other natural disaster in their 
own area would impact large numbers of people. Tell them that in 
Unit 6 each of them will play the role of someone with responsibility 
for the communitys emergency planning and survival. In this unit 
they will adopt that role and begin to learn about it.

B. Lesson Development
1. Project the U.S. Earthquake Hazard Map, Master 1.3b, and deter-
mine how great a seismic hazard is shown for your state or region.
2. Project the Preparedness People master, and go over the list of roles 
students could assume throughout this curriculum. Incorporate student 
suggestions in developing the final list, then distribute the roles.
3. Assign students to contact their mentors and set up interviews. Each 
student will interview one individual to learn what the person does 
and what role he or she plays in the communitys earthquake 
preparedness plan. Students may tailor their questions to the person, 
but every interview should include these questions:

 What are the current emergency plans for this area?
 Have they ever been implemented?
 What is your role during an emergency?
 How many people answer to you?

This map is drawn along state lines for ease of 
use. A map drawn along geological boundaries 
would look quite different and might 
put parts of some states in another 
hazard category.

TEACHING CLUES AND CUES
If more than one class is doing this activity, consider sending a group for each 
interview (for example, one mayor from each 
class to interview the mayor together).

 What are the lines of communication during an emergency?
 What is the budget of this department or organization?
  How much of this is dedicated for emergency preparedness and 
actual emergencies?
 May I call you again if I have additional questions?
 Would you be willing to speak to my class?

Encourage students to take notes, to review their notes after the 
interview, and to make follow-up calls if they find they are missing any 
information.

4. Assign students to write letters thanking their mentors for the 
interviews. Review the format of a business letter, if necessary. Tell 
students that each letter must include details from the notes taken 
during the interview, so that both the recipient and you, the teacher, 
will know the time was well spent. Collect the letters and mail them 
from the school.

5. Fasten the large, sturdy sheet of paper to the wall and project the 
map transparency onto the paper. Move the projector away from the 
paper until the image reaches the desired size, then trace the image on 
the paper.

6. With the class, work out a way to represent all of the following on 
the large area map you have prepared:

 Hospitals and nursing homes
 Fire and police stations
 Power, sewage, and water plants
 Gas, water, electric, and sewage trunk lines
 Railroads and other mass transit systems
 Major roads and highways
 Telephone systems and other communications systems
 Schools

All of these are considered critical facilities or lifeline utility systems. 
Schools are important both because they may house large populations 
to be evacuated and because they frequently serve as centers for 
emergency shelter and the distribution of supplies.

C. Conclusion
Display the local map prominently in the front of the classroom. 
Students will add to this map, and to their role knowledge, as they gain 
information throughout these lessons.

ADAPTATIONS AND EXTENSIONS
1. If your city or metropolitan area is a large one, divide it into regions 
and assign one to each of several classes. If it is small, extend your 
investigation into the surrounding communities.

2. Assign students to learn as much as they can about disasters that have 
impacted their town or area in the past. They can begin by interviewing 
long-time residents and searching the newspaper archives.

3. If you do not plan to teach all the units in order, you may want to 
introduce Unit 5, Lesson 5 at this time.

1.3a Preparedness People

All these people and more may play a role in your 
communitys disaster preparedness planning and 
response.
 Mayor or City Administrator
 City Manager
 Public Information Officer
 Chief of Police
 Fire Chief
 Emergency Services Coordinator
 Superintendent of Schools
 School District Risk Manager
 City Building Code Inspector
 City Council Members
 City Geologist
 City Planner
 Coordinator of Roads and Transportation
 Director of Public Health
 Director of Public Works
 Superintendent of the Sewage Plant
 Superintendent of the Water Department
 Electric Company Emergency Officer
 Gas Company Emergency Officer
 Telephone Company Emergency Coordinator
 Hospital Safety and Security Manager


BIBLIOGRAPHIES
National Center for Earthquake Engineering Research 
(NCEER) Information Service. (1995). Teachers 
Packets, 9-12. Buffalo, NY: State University of New 
York at Buffalo.

Seismology Resources for Teachers. Seismological 
Society of America, 21 Plaza Professional Building, 
El Cerrito, CA 94530; 415-525-5474. Includes 
software, databases, and video listings.

World Amateur Seismological Society. Reference 
List for Amateur Seismologists. A list of references 
intended to serve as an introduction to the literature of 
seismology.

BOOKS
American Red Cross, Los Angeles Chapter. (1985). 
The Emergency Survival Handbook. In English and 
Spanish. A simple, practical, and easy-to-use guide.

Federal Emergency Management Agency/National 
Science Teachers Association. EarthquakesA 
Teachers Package for K-6 (Tremor Troop). (FEMA 
159, 1992). Washington, DC: FEMA/NSTA. (FEMA 
Publications, 500 C St. SW, Washington, DC 20472.)

The Homeowners Guide to Earthquake Safety. 
Sacramento, CA: California Seismic Safety 
Commission (1900 K Street, Sacramento, CA 95814).

Kimball, Virginia. (1992). Earthquake Ready: The 
Complete Preparedness Guide. Malibu, CA: 
Roundtable Publishing, Inc., A practical, nontechnical 
guide to preparation and survival.

Movers and Shakers. An educational program for 
grades K-12 that includes a video and a two-sided 
classroom poster. Available free to educators by 
writing to Movers and Shakers (E-8), State Farm 
Insurance Companies, One State Farm Plaza, 
Bloomington, IL 61710-0001.

Plafker, George, and Galloway, John P., eds. (1989). 
Lessons Learned from the Loma Prieta Earthquake of 
October 17, 1989. Denver, CO: U.S. Geological 
Survey, Circular # 1045. Excellent photographs, maps, 
and illustrations.

Yanev, P. (1991). Peace of Mind in Earthquake 
Country. How to Save Your Home and Your Life. 
San Francisco, CA: Chronicle.

PAMPHLETS AND PERIODICALS
American Red Cross, Los Angeles Chapter. 27 Things 
to Help You Survive an Earthquake. Los Angeles, CA: 
American Red Cross. (2700 Wilshire Blvd., 
Los Angeles, CA 90057; 213-739-5200.) Poster in 
English and Spanish lists 4 things to do during an 
earthquake, 6 to do afterwards, 14 survival items to 
keep on hand, and 3 essential things to know.

Earthquakes and Volcanoes. An attractive, 
nontechnical magazine published bimonthly by the 
U.S. Geological Survey to provide current 
seismological information. Washington, DC: U.S. 
Government Printing Office; 202-783-3238; $8/yr.

Federal Emergency Management Agency pamphlets. 
Family Earthquake Drill and Home Hazard Hunt, 
FEMA 113; Earthquake Safety Checklist, 
FEMA 46.

Harris, J.W. (1980). Building a Firm Foundation
Educating about Geologic Disasters. The Science 
Teacher 47, 9: 22-25.

May 18th, 1980: Eyewitness Accounts by 
Cobblestone Readers. Cobblestone (May 1981): 
pp. 20-23. By and for readers 8-14. This issue has 
several good features on earthquakes.
Scientists Predict: Big Quake Will Strike Eastern 
U.S. Current Science (Jan. 6, 1989): p. 7. For readers 
10-16.

Teachers Packet of Geologic Materials. A collection 
of leaflets, booklets, and reference lists provided free 
by the U.S. Geological Survey, Geologic Inquiries 
Group, 907 National Center, Reston, VA 22092. Send 
request on school letterhead, indicating the subject and 
grade level you teach.

Westrup, H. Giant Quake: When Will It Strike? 
Current Science (Sept. 7, 1990): pp. 45. For readers 
1016.

NON-PRINT MEDIA
Earthquake Slides. Photographs of earthquake effects, 
copies of seismograms, and seismicity maps can be 
obtained from the National Geophysical and Solar 
Terrestrial Data Center, Code D62, NOAA/EDS, 
Boulder, CO 80302.

Earthquake Sound Cassette Tape. Emergency 
Preparedness Committee, Utah State PTA, 1037 East 
South Temple, Salt Lake City, UT 84102; 801/359-
3875. A one-minute tape available for $2, including 
postage.

EERI Videotapes and Slide Sets. Oakland, CA: 
Earthquake Engineering Research Institute. For 
information, phone 510-451-0905, or fax 510-451-
5411.

National Earthquake Information Center Seismicity 
Maps. Full-color maps available from USGS/NEIC, 
PO Box 25046, Federal Center, MS 967, Denver, CO 
80225-0046; 303-273-8477. $5$15 plus $2 shipping.
Nur, Amos, and MacAskill, Chris. (1991). The Walls 
Came Tumbling Down: Earthquakes in the Holy Land. 
Stanford, CA: ESI Productions. Video provides a tour 
along an active fault from the north of Israel to 
Jerusalem.

Steinbrugge Collection. Richmond, CA: Earthquake 
Engineering Research Center. Over 10,000 
photographs and 5,000 slides of earthquake damage. 
The library will provide copies to teachers and 
researchers. Call 510-231-9401 for information.

USGS posters plus seismicity maps for most of the 
states. USGS Map and Book Distribution, PO Box 
25286, Federal Center, Building 10, Denver, CO 
80225; 303-236-7477.

World Seismicity Map. Large 48" x 36" wall map 
shows epicenters, depths of foci, and dates and 
magnitudes of large quakes. Wards Natural Science 
Establishment, Inc., 5100 W. Henrietta Road, PO Box 
92912, Rochester, NY 14692-9012; 800-962-2660.

Note: Inclusion of materials in these resource listings 
does not constitute an endorsement by AGU or FEMA.


Earthquake Information Resource List

State Geological Survey Offices
Geological Survey of Alabama 
420 Hackenberry Lane 
P.O. Box O 
Tuscaloosa, AL 35486-9780 
205-349-2852

Alaska State Geological Survey 
794 University Avenue 
Suite 200 
Fairbanks, AK 99709-3645 
907-474-7147 
FAX: 907-479-4779

Arizona Geological Survey 
845 North Park Avenue 
Suite 100 
Tucson, AZ 85719 
602-882-4795

Arkansas Geological Commission 
Vardelle Parham Geology Center 
3815 West Roosevelt Road 
Little Rock, AR 72204 
501-324-9165

California Division of Mines & Geology 
801 K Street 
Mail Stop 14-33 
Sacramento, CA 95814-3532 
916-323-5336

Colorado Geological Survey 
1313 Sherman Street 
Room 715 
Denver, CO 80203 
303-866-2611 
FAX: 303-866-2115

Geological Survey of Connecticut 
Dept. of Environmental Protection 
Natural Resources Center 
165 Capitol Avenue 
Room 553 
Hartford, CT 06106 
203-566-3540

Delaware Geological Survey 
University of Delaware 
Delaware Geological Survey Building 
Newark, DE 19716 
302-831-2833 
FAX: 302-831-3579

Geologist of Washington, DC 
Univ. of the District of Columbia 
Dept. of Environmental Science 
4200 Connecticut Avenue, NW 
Washington, DC 20008-1154 
202-282-7380 
FAX: 202-282-3675

Florida Bureau of Geology 
Florida Dept. of Natural Resources 
903 West Tennessee Street 
Tallahassee, FL 32304 
904-488-9380

Georgia Geologic Survey 
Georgia Dept. of Natural Resources 
Environmental Protection Div. 
19 M.L. King Jr. Drive, Room 400 
Atlanta, GA 30334 
404-656-3214

Hawaii Geological Survey 
Div. of Water/Land Development 
Dept. of Land & Natural Resources 
P.O. Box 373 
Honolulu, HI  96809 
808-587-0230 
FAX: 808-587-0219

Idaho Geological Survey 
University of Idaho 
Morrill Hall, Room 332 
Moscow, ID 83843 
208-885-7991 
FAX: 208-885-5826
Illinois State Geological Survey 
Natural Resources Building 
615 East Peabody Drive 
Champaign, IL 61820 
217-333-5111 
FAX: 217-244-7004

Indiana Geological Survey 
Dept. of Natural Resources 
611 North Walnut Grove 
Bloomington, IN 47405 
812-855-9350 
FAX: 812-855-2862

Iowa Dept. of Natural Resources 
Geological Survey Bureau 
123 North Capitol Street 
Iowa City, IA 52242 
319-335-1575 
FAX: 319-335-2754

Kansas Geological Survey 
University of Kansas 
1930 Constant Avenue 
Campus West 
Lawrence, KS 66047 
913-864-3965 
FAX: 913-864-5317

Kentucky Geological Survey 
University of Kentucky 
228 Mining & Minerals Resources Bldg. 
Lexington, KY 40506-0107 
606-257-5500 
FAX: 606-257-1147

Louisiana Geological Survey 
Louisiana State University 
P.O. Box G 
Baton Rouge, LA 70893 
504-388-5320 
FAX: 504-388-5328

Maine Geological Survey 
Dept. of Conservation 
State House Station #22 
Augusta, ME 04333 
207-287-2801 
FAX: 207-287-2353

Maryland Geological Survey 
Maryland Dept. of Natural Resources 
2300 St. Paul Street 
Baltimore, MD 21218 
410-554-5504

Massachusetts Office of the State Geologist 
Commonwealth of Massachusetts 
100 Cambridge Street, 20th Floor 
Boston, MA 02202 
617-727-9800 
FAX: 617-727-2754

Michigan Dept. of Natural Resources 
Geological Survey Div. 
Box 30028 
Lansing, MI 48909 
517-334-6923 
FAX: 517-334-6038

Minnesota Geological Survey 
University of Minnesota, Twin Cities 
2642 University Avenue 
St. Paul, MN 55114-1057 
612-627-4780 
FAX: 612-627-4778

Mississippi Office of Geology 
Mississippi Dept. of Environmental Quality 
P.O. Box 20307 
2380 Highway 80 West 
Jackson, MS 39289-1307 
601-961-5500 
FAX: 601-961-5521

Missouri Dept. of Natural Resources 
Division of Geology & Land Survey 
P.O. Box 250 
Buehler Bldg/111 Fairgrounds Road 
Rolla, MO 65401 
314-368-2100 
FAX: 314-368-2111

Montana Bureau of Mines & Geology 
Montana Coll. of Min. Sci. & Tech. 
West Park Street 
Main Hall 
Butte, MT 59701 
406-496-4180

Nebraska Geological Survey 
University of Nebraska  Lincoln 
Conservation and Survey Division 
901 North 17th Street 
113 Nebraska Hall 
Lincoln, NE 68588-0517 
402-472-3471

Nevada Bureau of Mines & Geology 
University of Nevada, Reno 
Mail Stop 178 
Reno, NV 89557-0088 
702-784-6691 
FAX: 702-784-1709

New Hampshire Geological Survey 
University of New Hampshire 
Dept. of Earth Science 
117 James Hall 
Durham, NH 03824 
603-862-3160 
FAX: 603-862-2030

New Jersey Geological Survey 
New Jersey Division of Science & Research 
CN 029 
Trenton, NJ 08626 
609-633-6587 
FAX: 609-633-1004

New Mexico Bureau of Mines & Mineral Resources 
N.M. Inst. of Mining & Technology 
Campus Station 
Socorro, NM 87801 
505-835-5420 
FAX: 505-835-6333

New York State Geological Survey 
3136 Cultural Education Center 
Albany, NY 12230 
518-474-5816 
FAX: 518-473-8496

North Carolina Geological Survey Dept. of Environment, Health & Natural 
Resources 
Box 27687 
Raleigh, NC 27611 
903-733-3833

North Dakota Geological Survey 
600 East Boulevard 
Bismarck, ND 58505-0840 
701-224-4109 
FAX: 701-224-3682

Ohio Dept. of Natural Resources 
Division of Geological Survey 
4383 Fountain Square Drive Building 
Columbus, OH 43224-1362 
614-265-6576 
FAX: 614-447-1918

Oklahoma Geological Survey 
University of Oklahoma 
100 East Boyd 
Energy Center, Room N-131 
Norman, OK 73019-0628 
405-325-3031 
FAX: 405-326-3180

Oregon Dept. of Geology & Mineral Industries 
800 NE Oregon Street, #28 
Suite 965 
Portland, OR 97232 
503-731-4100 
FAX: 503-731-4066

Pennsylvania Geological Survey 
Box 2357, 9th Floor 
Harrisburg, PA 17105 
717-787-2169 
FAX: 717-783-7267

Geological Survey of Puerto Rico 
Dept. de Recursos Naturales 
Munoz Rivera Ave., Stop 3 
San Juan, PR 00906 
809-724-8774

Geological Survey of Rhode Island 
University of Rhode Island 
Geology Dept. 
315 Green Hall 
Kingston, RI 02881 
401-792-2265

South Carolina Geological Survey 
South Carolina Mapping Services 
5 Geology Road 
Columbia, SC 29210-9998 
803-737-9440

South Dakota Geological Survey 
University of South Dakota 
Dept. of Water & Natural Resources 
Science Center 
Vermillion, SD 57069-2390 
605-677-5227 
FAX: 605-677-5895

Tennessee Division of Geology 
Dept. of Environment & Conservation 
Dept. of Geology 
701 Broadway, Suite B-30 
Nashville, TN 37243 
615-742-6689 
FAX: 615-742-6594

Texas Bureau of Economic Geology 
University of Texas, Austin 
University Station, Box X 
Austin, TX 78713-7508 
512-471-1534 
FAX: 512-471-0140

Utah Geological Survey 
Utah Dept. of Natural Resources 
2363 South Foothill Drive 
Salt Lake City, UT 84109-1491 
801-467-7970 
FAX: 801-467-4070
Vermont Geological Survey 
Agency of Natural Resources 
103 South Main Street 
Center Building 
Waterbury, VT 05671-0301 
803-244-5164 
FAX: 802-244-4528

Virginia Division of Mineral Resources 
Dept. of Mines, Minerals & Energy 
Alderman & McCormick Roads 
Charlottesville, VA 22903 
804-293-5121 
FAX: 804-293-2239

Washington Dept. of Natural Resources 
Geology/Earth Resources 
Mail Stop PY-12 
Olympia, WA 98504 
206-459-6372 
FAX: 206-459-6380

West Virginia Geological & Economic Survey 
P.O. Box 879 
Morgantown, WV 26507-0879 
304-594-2331

Wisconsin Geological & Natural History Survey 
University of Wisconsin - Extension 
3817 Mineral Point Road 
Madison, WI 53705 
608-262-1705 
FAX: 608-262-8086

Geological Survey of Wyoming 
State of Wyoming 
P.O. Box 3008, University Station 
Laramie, WY 82071 
307-766-2286 
FAX: 307-766-2605

Selected Regional & Other USGS Offices
Albuquerque 
Earth Data Analysis Center 
University of New Mexico 
Albuquerque, NM 87131-6031 
505-227-3622

Anchorage 
Room 101 
4230 University Drive 
Anchorage, AK 99508-4664 
907-786-7011

Fairbanks 
Box 12, Federal Building 
101 12th Avenue 
Fairbanks, AK 99701 
907-456-0244

Lakewood 
MS 504, Room 1813 
Building 25, Federal Center 
Denver, CO 80225-0046 
303-236-5829

Menlo Park 
MS 532, Room 3128 
Building 3 
345 Middlefield Road 
Menlo Park, CA 94025-3591 
415-329-4309

Reston 
US Geological Survey 
507 National Center 
Reston, VA 22092 
703-648-6045

Rolla 
MS 231 
1400 Independence Road 
Rolla, MO 65401-2602 
314-341-0851

Salt Lake City 
USGS-ESIC 
2222 W. 2300 South 
Salt Lake City, UT 84138-1177 
801-524-5652 

Sioux Falls 
EROS Data Center 
Sioux Falls, SD 57198-0001 
605-594-6151

Spokane 
Room 135 
US Post Office Building 
W. 904 Riverside Avenue 
Spokane, WA 99201-1088

Stennis Space Center 
Building 3101 
Stennis Space Center, MS 39529 
601-688-3541

US Department of the Interior 
Room 2650 
1849 C Street NW 
Washington, DC 20240 
202-208-4047

Eastern Region 
Assistant Chief Geologist 
US Geological Survey 
953 National Center 
Reston, VA 22092 
703-648-6660

Northeastern Regional Hydrologist 
Water Resources Division 
433 National Center 
Reston, VA 22092 
703-648-5813

Southeastern Regional Hydrologist 
Water Resources Division 
Suite 160 
3850 Holcomb Bridge Road 
Spalding Woods Office Park 
Norcross, GA 30092 
404-409-7700

Mapping Applications Center 
12201 Sunrise Valley Drive 
Reston, VA 22092 
703-648-6002

Central Region 
Directors Representative & Assistant Chief Geologist 
Box 25046 
911 Denver Federal Center 
Denver, CO 80225 
303-236-5438

Central Region Hydrologist 
Water Resources Division 
Box 25046 
406 Denver Federal Center 
Denver, CO 80225 
303-236-5920 

Mid-Continent Mapping Center 
1400 Independence Road 
Rolla, MO 65401 
314-341-0880

Rocky Mountain Mapping Center 
Box 25046 
Denver Federal Center 
Denver, CO 80225 
303-236-5825

EROS Data Center 
Sioux Falls, SD 57198-0001 
705-594-6123 
(For map and book orders)

Branch of Distribution 
Box 25286 
Building 810 
Denver Federal Center 
Denver, CO 80225 
303-236-7477

ESIC Open-File Report Sales 
Box 25286, Building 810 
Denver Federal Center 
Denver, CO 80225 
303-236-7476 
(For report orders)

Western Region 
Directors Representative 
MS 144 
US Geological Survey 
345 Middlefield Road 
Menlo Park, CA 94025 
415-329-4002

Western Region Hydrologist 
Water Resources Division 
MS 470 
US Geological Survey 
345 Middlefield Road 
Menlo Park, CA 94025 
415-329-4414

Western Mapping Center 
US Geological Survey 
345 Middlefield Read 
Menlo Park, CA 94025-3591 
415-329-4524

Special Assistant to the Director for Alaska 
4230 University 
Anchorage, AK 99508-4664 
907-786-7001

Alaska Volcano Observatory 
4200 University Drive 
Anchorage, AK 99508 
907-786-7497

Branch of Atlantic Marine Geology 
Gosnold Building 
Quissett Campus 
Woods Hole, MA 02543 
508-548-8700

Cascades Volcano Observatory 
David A. Johnston Building 
5400 MacArthur Blvd. 
Vancouver, WA 98661 
206-696-7693

Center for Coastal and Regional Marine Studies 
600 Fourth St. S. 
St. Petersburg, FL 33701 
813-893-3100

Flagstaff Field Center 
2255 N. Gemini Drive 
Flagstaff, AZ 86001 
602-556-7151

Hawaiian Volcano Observatory 
Volcanoes National Park 
Hilo, HI 96718 
808-967-7328

Hydrologic Information Unit 
US Geological Survey 
419 National Center 
Reston, VA 22092 
703-648-6817

Geologic Inquiries Group 
US Geological Survey 
907 National Center 
Reston, VA 22092 
703-648-4383

USGS Library 
US Geological Survey 
950 National Center 
Reston, VA 22092 
703-648-4302

Minerals Information Office 
Corbett Building, Room 340 
North Sixth Avenue 
Tucson, AZ 85705-8325 
602-670-5544

Minerals Information Office 
Room 133 
W. 904 Riverside Avenue 
Spokane, WA 99201 
509-353-2649

Minerals Information Office 
Mackay School of Mines 
University of Nevada 
Reno, NV 89557-0047 
702-784-5552

Minerals Information Office 
Room 2647 
Main Interior Building 
1849 C St. NW 
Washington, DC 20240 
202-208-5512 
(a joint USGS/US Bureau of Mines office)

National Earthquake Information Center 
MS 967 
Denver Federal Center 
Box 25046 
Denver, CO 80225 
303-273-8500

National Landslide Information Center 
MS 966 
Denver Federal Center 
Box 25046 
Denver, CO 80225 
303-273-8587

National Water Data Exchange 
US Geological Survey 
421 National Center 
Reston, VA 22092 
703-648-5016

Office of Water Data Coordination 
US Geological Survey 
417 National Center 
Reston, VA 22092 
703-648-5016

Source: American Geological Institute

U.S. Department of Agriculture Soil Conservation Service State Offices
State Conservationist 
USDA Soil Conservation Service 
665 Opelika Road 
Auburn, AL 36830 
205-821-8080, x535

State Conservationist 
USDA Soil Conservation Service 
949 E. 36th Avenue - Suite 400 
Anchorage, AK 99508-4302 
907-271-2424

State Conservationist 
USDA Soil Conservation Service 
201 E. Indianola Avenue - Suite 200 
Phoenix, AZ 85012 
602-640-2247

State Conservationist 
USDA Soil Conservation Service 
5404 Federal Building 
700 W. Capitol Street 
Little Rock, AR 72201 
501-324-5964

State Conservationist 
USDA Soil Conservation Service 
21221-C Second Street - Suite 102 
Davis, CA 95616-5475 
FTS-757-8200 
916-757-8200

State Conservationist 
USDA Soil and Conservation 
655 Parfet Street - E200C 
Lakewood, CO 80215-5517 
303-236-0295

State Conservationist 
USDA Soil Conservation Service 
16 Professional Park Road 
Stoffs, CT 06268-1299 
203-487-4013

State Conservationist 
USDA Soil Conservation Service 
1203 College Park Drive - Suite A 
Dover, DE 19901-8713 
302-678-4160

District Conservationist 
Cooperative Extension Service 
901 Newton Street, NE 
Washington, DC 20017 
202-576-6951

State Conservationist 
USDA Soil Conservation Service 
401 SE lst Avenue - Suite 248 
Gainesville, FL 32601 
904-377-0946

State Conservationist 
USDA Soil Conservation Service 
Federal Building, Box 13 
355 E. Hancock Avenue 
Athens, GA 30601 
FTS-250-2272 
404-546-2272

Director, Pacific Basin 
USDA Soil Conservation Service 
602 GCIC Building 
414 W. Soledad Avenue 
Agana, Guam 96910 
671-472-7490

State Conservationist 
USDA Soil Conservation Service 
300 Ala Moana Blvd - Suite 4316 
Honolulu, HI 96850 
808-541-2601

State Conservationist 
USDA Soil Conservation Service 
3244 Elder Street - Suite 124 
Boise, ID 83705 
208-334-1601

State Conservationist 
USDA Soil Conservation Service 
1902 Fox Drive 
Champaign, IL 61820 
217-398-5267

State Conservationist 
USDA Soil Conservation Service 
6013 Lakeside Blvd 
Indianapolis, IN 46278 
317-290-3200

State Conservationist 
USDA Soil Conservation Service 
693 Federal Building 
210 Walnut Street 
Des Moines, IA 50309 
515-284-4261

State Conservationist 
USDA Soil Conservation Service 
760 South Broadway 
Salina, KS 67401 
913-823-4570

State Conservationist 
USDA Soil Conservation Service 
771 Corporate Drive - Suite 110 
Lexington, KY 40503-5479 
606-233-2749

State Conservationist 
USDA Soil Conservation Service 
3737 Government Street 
Alexandria, LA 71302 
318-473-7751

State Conservationist 
USDA Soil Conservation Service 
5 Godfrey Drive 
Orono, ME 04473 
207-581-3446

State Conservationist 
USDA Soil Conservation Service 
301 John Hanson Business Center 
339 Buschs Frontage Road 
Annapolis, MD 21401 
410-757-0861

State Conservationist 
USDA Soil Conservation Service 
451 West Street 
Amherst, MA 01002 
413-256-0441

State Conservationist 
USDA Soil Conservation Service 
1405 S. Harrison Road - Suite 101 
East Lansing, MI 48823-5202 
517-337-6702

State Conservationist 
USDA Soil Conservation Service 
600 Farm Credit Building 
375 Jackson Street 
St. Paul, MN 55101-1854 
612-290-3675

State Conservationist 
USDA Soil Conservation Service 
1321 Federal Building 
100 W. Capitol Street 
Jackson, MS 39269 
601-965-5205

State Conservationist 
USDA Soil Conservation Service 
Parkade Center - Suite 250 
601 Business Loop, 70 West 
Columbia, MO 65203 
314-876-0903

State Conservationist 
USDA Soil Conservation Service 
443 Federal Building 
10 E. Babcock Street 
Bozeman, MT 59715-4704 
406-587-6813

State Conservationist 
USDA Soil Conservation Service 
345 Federal Building 
100 Centennial Mall North 
Lincoln, NE 68508-3866 
402-587-6813

State Conservationist 
USDA Soil Conservation Service 
Bldg. F - Suite 201 
5301 Longley Lane 
Reno, NV 89511 
702-784-5863

State Conservationist 
USDA Soil Conservation Service 
Federal Building 
Durham, NH 03824 
603-868-7581

State Conservationist 
USDA Soil Conservation Service 
1370 Hamilton Street 
Somerset, NJ 08873 
908-246-1662

State Conservationist 
USDA Soil Conservation Service 
517 Gold Avenue, NW - Suite 3301 
Albuquerque, NM 87102-3157 
505-766-2173

State Conservationist 
USDA Soil Conservation Service 
771 Hanley Federal Building 
100 S. Clinton Street 
Syracuse, NY 13260-7248 
315-423-5521

State Conservationist 
USDA Soil Conservation Service 
4405 Bland Road - Suite 205 
Raleigh, NC 27609 
919-790-2888

State Conservationist 
USDA Soil Conservation Service 
278 Federal Building 
220 E. Rosser Avenue 
Bismarck, ND 58502-1458 
701-250-4421

State Conservationist 
USDA Soil Conservation Service 
200 N. High Street - Suite 522 
Columbus, OH 43215-2478 
614-469-6962

State Conservationist 
USDA Soil Conservation Service 
Agriculture Center Building 
Farm Road & Brumley Street 
Stillwater, OK 74074 
405-624-4360

State Conservationist 
USDA Soil Conservation Service 
1640 Federal Building 
1220 SW 3rd Avenue 
Portland, OR 97204 
503-326-2751

State Conservationist 
USDA Soil Conservation Service 
1 Credit Union Place - Suite 340 
Wildwood Center 
Harrisburg, PA 17110-2993 
717-782-2202

Director, Caribbean Area 
USDA Soil Conservation Service 
P.O. Box 364868 
San Juan, PR 00936-4868 
809-766-5206

State Conservationist 
USDA Soil Conservation Service 
46 Quaker Lane 
West Warwick, RI 02893 
401-828-1300

State Conservationist 
USDA Soil Conservation Service 
950 Thurmond Federal Building 
1835 Assembly Street 
Columbia, SC 29201 
803-765-5681

State Conservationist 
USDA Soil Conservation Service 
Federal Building 
200 Fourth Street, SW 
Huron, SD 57350-2475 
605-353-1783

State Conservationist 
USDA Soil Conservation Service 
675 Kefauver Federal Building 
801 Broadway Street 
Nashville, TN 37203 
615-736-5471

State Conservationist 
USDA Soil Conservation Service 
Poage Federal Building 
101 S. Main Street 
Temple, TX 76501-7682 
817-774-1214

State Conservationist 
USDA Soil Conservation Service 
4402 Bennett Federal Building 
125 S. State Street 
Salt Lake City, UT 84138 
801-524-5050

State Conservationist 
USDA Soil Conservation Service 
69 Union Street 
Winooski, VT 05404 
802-951-6785

State Conservationist 
USDA Soil Conservation Service 
9201 Federal Building 
400 N. 8th Street 
Richmond, VA 23240 
804-771-2455

State Conservationist 
USDA Soil Conservation Service 
Rock Pointe Tower II 
W. 316 Boone Avenue - Suite 450 
Spokane, WA 99201-2348 
509-353-2337

State Conservationist 
USDA Soil Conservation Service 
75 High Street - Suite 301 
Morgantown, WV 26505 
304-291-4151

State Conservationist 
USDA Soil Conservation Service 
6515 Watts Road - Suite 200 
Madison, WI 53719-2726 
608-264-5577

State Conservationist 
USDA Soil Conservation Service 
3124 Federal Building 
100 East B Street 
Casper, WY 82601 
307-261-5201

Source: U.S. Department of Agriculture

FEMA Regional Earthquake Program 
Managers
Earthquake Program Manager 
FEMA Region 1 - NT 
442 J.W. McCormack POCH 
Boston, MA 02109-4595

Earthquake Program Manager 
FEMA Region 2 - NT 
26 Federal Plaza 
New York, NY 10278-0002

Earthquake Program Manager 
FEMA Caribbean Office 
P.O. Box 70105 
San Juan, PR 00936

Earthquake Program Manager 
FEMA - Region 3 
105 S. Seventh St. 
Philadelphia, PA 19106-3316

Earthquake Program Manager 
FEMA - Region 4 - NT 
1371 Peachtree Street, NE 
Atlanta, GA 30309-3108

Earthquake Program Manager 
FEMA Region 5 - NT 
175 West Jackson 
Chicago, IL 60604-2698

Earthquake Program Manager 
FEMA Region 6 - NT 
800 North Loop 288 
Denton, TX 76201-3698

Earthquake Program Manager 
FEMA Region 7 - NT 
911 Walnut Street 
Kansas City, MO 64106-2085

Earthquake Program Manager 
FEMA Region 8 - NT 
Denver Federal Center 
Denver, CO 80225-0267

Earthquake Program Manager 
FEMA Region 9 - NT 
Presidio of SF, Bldg 105 
San Francisco, CA 94129-1250

Earthquake Program Manager 
FEMA Region 10, NT 
130 - 228th St., S.W. 
Bothell, WA 98021-9796

State Emergency Management 
Directors and State Earthquake 
Program Managers

Alaska 
Director 
Alaska Division of Emergency Services 
New Anchorage Armory 
Building 49000, Suite B-210 
P.O. Box 5750 
Fort Richardson, AK 99505-5750 
907-428-7000 
(FAX) 907-428-7009

Earthquake Program Manager 
907-428-7022 
(FAX) 907-428-7009

Arizona 
Director 
Arizona Division of Emergency Services 
5636 E. McDowell Road 
Phoenix, AZ 85008 
602-231-6245 
(FAX) 602-231-6231

Earthquake Program Manager 
602-231-6238 
(FAX) 602-231-6231

Arkansas 
Director 
Arkansas Office of Emergency Services 
P.O. Box 758 
Conway, AR 72032 
501-329-5601 
(FAX) 501-327-8047

Earthquake Preparedness Program Supervisor 
Earthquake Preparedness Program 
501-329-5601 
(FAX) 501-327-8047

California 
Director 
Governors Office of Emergency Services 
State of California 
2800 Meadowview Road 
Sacramento, CA 25832-1499 
916-427-4990 
(FAX) 916-427-4215

Deputy Director 
Governors Office of Emergency Services 
1110 E. Green Street, Suite 300 
Pasadena, CA 91106 
818-304-8388 
(FAX) 818-795-2030

Northern/Bay Area/Coastal 
Earthquake Program Manager 
101 8th Street, Suite 152 
Oakland, CA 94607 
510-540-2713

Southern California 
Earthquake Program Manager 
1110 East Green Street 
Suite 300 
Pasadena, CA 91106 
818-304-8383

Colorado 
Director 
Office of Emergency Management 
Camp George West 
Golden, CO 80401-3997 
303-273-1622 
(FAX) 303-273-1795

Connecticut 
State Director 
Office of Emergency Management 
360 Broad Street 
Hartford, CT 06105 
203-566-3180/4338 
(FAX) 203-247-0664

Georgia 
Executive Director 
Georgia Emergency Management Agency 
P.O. Box 18055 
Atlanta GA 30316-0055 
404-624-7000 
(FAX) 404-624-7205

Earthquake Program Manager 
404-624-7000 
(FAX) 404-624-7205

Guam 
Director of Civil Defense 
Guam Emergency Services Office 
Territory of Guam 
P.O. Box 2877 
Agana, Guam 96910 
671-477-9841 
(FAX) 671-477-3727

Earthquake Program Manager 
Civil Defense 
671-477-9841/9842 
(FAX) 671-477-3727

Hawaii 
Vice Director of Civil Defense 
Department of Defense 
3949 Diamond Head Road 
Honolulu, HI 96816 
808-734-2161 
(FAX) 808-737-4150

Earthquake Program Manager 
Hawaii State Civil Defense 
808-734-2161 
(FAX) 808-737-4150

Idaho 
State Earthquake Program Coordinator 
Idaho Bureau of Disaster Services 
650 West State Street 
Boise, ID 83720 
208-334-3460 
(FAX) 208-334-2322

Earthquake Program Manager 
208-334-3460 
(FAX) 208-334-2322

Illinois 
Acting Director 
Illinois Emergency Management Agency 
110 East Adams Street 
Springfield, IL 62706 
217-782-2700 
(FAX) 217-782-2589

Chief, Division of Planning 
217-782-4448 
(FAX) 217-782-2589

Indiana 
Director 
Indiana State Emergency Management Agency 
Indiana Government Center 
Center South, Suite E-208 
302 West Washington Street 
Indianapolis, IN 46204 
317-232-3830 
(FAX) 317-232-3895

Iowa 
Administrator 
Iowa Emergency Management Division 
Hoover State Office Building 
Level A, Room 29 
Des Moines, IA 50319 
515-281-3231 
(FAX) 515-281-7539

Kansas 
Deputy Director 
Division of Emergency Preparedness 
P.O. Box C-300 
Topeka, KS 66601 
913-266-1400 
(FAX) 913-266-1129

Kentucky 
Executive Director 
Kentucky Disaster and Emergency  
   Services 
EOC Building, Boone Center 
Frankfort, KY 40601-6168 
502-564-8680 
(FAX) 502-564-8614

Earthquake Program Manager 
502-564-8628 
(FAX) 502-564-8614

Maine 
Director 
Maine Emergency Management Agency 
State House Station 72 
Augusta, ME 04233 
207-289-4080 
(FAX) 207-289-4079

Earthquake Program Manager 
207-2870-4029

Massachusetts 
Director 
Massachusetts Emergency Management Agency 
400 Worcester Road 
P.O. Box 1496 
Framingham, MA 01701 
508-820-2003 
(FAX) 508-820-2030

Earthquake Program Manager 
Massachusetts Earthquake Hazards Reduction Program  
508-820-2000 
(FAX) 508-820-2030

Mississippi 
Director 
Mississippi Emergency Management 
   Agency 
P.O. Box 4501, Fondren Station 
Jackson, MS 39296-4501 
601-352-9100 
(FAX) 601-352-8314

Earthquake Program Manager 
601-960-9978 
(FAX) 601-352-8314

Missouri 
Director 
State Emergency Management Agency 
P.O. Box 116 
Jefferson City, MO 65102 
314-751-9779 
(FAX) 314-634-7966

Earthquake Program Manager 
314-751-9574 
(FAX) 314-634-7966

Montana 
Administrator 
Montana Disaster and Emergency Services Division 
P.O. Box 4789 
Helena, MT 59604-4789 
406-444-6911 
(FAX) 406-444-6965

Earthquake Program Manager 
406-444-6911

Nebraska 
Assistant Director 
Nebraska Civil Defense Agency 
1300 Military Road 
Lincoln, NE 68508-1090 
402-473-1410 
(FAX) 402-473-1433

Earthquake Program Manager 
402-473-2101 
(FAX) 402-473-1433

Nevada 
Director 
Nevada Division of Emergency Management 
2525 South Carson Street/Capitol Complex 
Carson City, NV 89710 
702-887-7302 
(FAX) 702-887-7246

Earthquake Program Manager 
702-687-4240 
(FAX) 702-887-6788

New Hampshire 
Director 
New Hampshire Office of Emergency Management 
State Office Park South 
107 Pleasant Street 
Concord, NH 03301 
603-271-2231 
(FAX) 603-225-7341

Natural Hazards Program Specialist 
603-271-2231 
(FAX) 603-225-7341

New Jersey 
Deputy State Director 
Office of Emergency Management 
New Jersey State Police 
P.O. Box 7068 
West Trenton, NJ 08628 
609-538-6050 
(FAX) 609-538-0345

New Jersey Office of Emergency Services 
609-538-6012

New Mexico 
Bureau Chief 
New Mexico Emergency Management Bureau 
Department of Public Safety 
4491 Cerrillos Road 
P.O. Box 1628 
Santa Fe, NM 87504 
505-827-3456

Earthquake Program Manager 
505-827-9254 
(FAX) 505-827-3381

New York 
Director 
New York State Emergency Management Office 
Public Security Building 
State Campus 
Albany, NY 12226-5000 
518-457-2222 
(FAX) 518-457-9930

Earthquake Project Coordinators 
518-457-9959

North Carolina 
Director 
North Carolina Division of Emergency Management 
116 West Jones Street 
Raleigh, NC 27603-1335 
919-733-3867 
(FAX) 919-733-7554

Lead Planner, Natural Hazards 
919-733-3627 
(FAX) 919-733-7554

Oklahoma 
Director 
Oklahoma Department of Civil 
Emergency Management 
P.O. Box 53365 
Oklahoma City, OK 73152 
405-521-2481 
(FAX) 405-521-4053

Oklahoma Earthquake Program Officer 
405-521-2481 
(FAX) 405-521-4053

Oregon 
Administrator 
Oregon Emergency Management Division 
Executive Department 
595 Cottage Street, N.E. 
Salem, OR 97310 
503-378-4124 
(FAX) 503-588-1378

Earthquake Program Coordinator 
503-378-2911 ext. 237

Pennsylvania 
Director 
Pennsylvania Emergency Management  
   Agency 
P.O. Box 3321 
Harrisburg, PA 17105-3321 
717-783-8016 
(FAX) 717-783-7393

PMD Chief/Earthquake Program Manager 
Pennsylvania Emergency Management 
Transportation and Safety 
Building B-151 
Harrisburg, PA 17120 
717-783-1048 
(FAX) 717-783-9223

Puerto Rico 
Director 
State Civil Defense Agency  
Commonwealth of Puerto Rico 
P.O. Box 5217 
San Juan, PR 00906

Deputy Executive Director 
Earthquake Safety Commission Commonwealth of Puerto Rico 
P.O. Box 5887 
Puerta de Tierra Station 
San Juan, PR 00906 
809-722-8784

Rhode Island 
Director 
Rhode Island Emergency Management  
   Agency 
State House, Room 27 
Providence, RI 02903 
401-421-7333 
(FAX) 401-751-0827

Earthquake Program Manager 
Rhode Island Earthquake Project 
401-421-7333 
(FAX) 401-751-0827

South Carolina 
Director 
South Carolina Emergency Preparedness Division 
1429 Senate Street 
Columbia, SC 29201-3782 
803-734-8020 
(FAX) 803-734-8062

Earthquake Program Manager 
803-734-8020 
(FAX) 903-734-8062

Tennessee 
Director 
Tennessee Emergency Management Agency 
3041 Sidco Drive 
Nashville, TN 37204 
615-741-0001 
(FAX) 615-242-9635

Earthquake Program Manager 
615-741-4299 
(FAX) 615-741-0498

Utah 
Director 
Utah Division of Comprehensive Emergency Management 
State Office Building, Room 1110 
Salt Lake City, UT 84114 
801-538-3400 
(FAX) 801-538-3770

Epicenter Manager 
801-538-3786

Vermont 
Director 
Vermont Emergency Management Agency 
103 Main Street 
Waterbury, VT 05676 
802-244-8721 
(FAX) 802-244-8655

Earthquake Program Manager  
Vermont Earthquake Program  
802-244-8721 
(FAX) 802-244-8655

Virgin Islands 
Director 
Virgin Islands Emergency Management Agency 
VITEMA 
131 Gallows Bay 
Christiansted, VI 00820 
809-733-2244 
(FAX) 809-778-8980

Chief of Planning 
VITEMA 
2C Este Conte 
A & Q Buildings 
Charlotte Amalie 
St. Thomas, VI 00802 
809-774-2244

Virginia 
State Coordinator 
Office of Emergency Services 
310 Turner Road 
Richmond, VA 23225-6491 
804-674-2497 
(FAX) 804-674-2490

Earthquake Program Manager 
804-674-2442 
(FAX) 804-674-2431

Washington 
Assistant Director 
Washington State Department of  
   Community Development 
Emergency Management Division 
4220 East Martin Way, PT-11 
Olympia, WA 98504 
206-923-4901 
(FAX) 206-438-7395

State Earthquake Program Coordinator 
206-923-4976 
(FAX) 206-923-4991

West Virginia 
Director 
West Virginia Office of Emergency Services 
State Capitol Building, EB-80 
Charleston, WV 25305 
304-558-5380 
(FAX) 304-344-4538

Wyoming 
Coordinator 
Wyoming Emergency Management Agency 
P.O. Box 1709 
Cheyenne, WY 82003 
307-777-7566 
(FAX) 307-635-6017

Source: Federal Emergency Management 
Agency

Seismic Sleuths

Earthquakes

A Teachers Package for Grades 7-12
 
Unit Two

What Happens When the Earth Quakes

 In this unit students will move beyond their own 
personal survival and that of their community, the 
focus of Unit 1, to the big picture of earthquakes in 
space and time. Since the Seismic Sleuths curriculum 
is intended to supplement, and not to replace, your 
schools own syllabus, it sketches this big picture 
without filling in all the basic earth science 
background. Your preparation to teach these lessons 
must begin with an assessment of your students 
readiness. If they have no familiarity with rocks and 
minerals or with faulting and other processes that 
form landscapes, you may need to provide a brief 
introduction from the first few chapters of a high 
school geology or earth science textbook.

Unit 2 begins with a hands-on activity that models 
what happens when the stresses accumulated at a fault 
are released in an earthquake. Using a box, a board, 
sandpaper, and other simple materials, students apply 
scientific method and basic math skills to measure 
movement, calculate averages, and plot their 
information on a graph.

The second lesson includes three activities and an 
overview of what is now known about Earths ever-
shifting surface and its layered inner structure. In the 
first activity, students will reproduce the magnetic 
evidence for the migration of Earths poles in the 
course of tectonic movement. In the second, they see 
how this record is written in the rocks at mid-ocean 
ridges. In the third, they create a map showing the
arrangement of the continents 120 million years ago, 
and compare it with the map of the world today. As 
students consider several alternative explanations for 
tectonic plate movement, remind them that earth 
science, like the Earth it studies, is constantly in 
motion. Scientific knowledge moves forward through 
questioning and the development of hypotheses into 
theories; its goal is never to provide dogmatic 
answers.

The third lesson begins with an exercise in which 
students contrast the small scope of historic time with 
the vastness of geologic time. In the second activity, 
Paleoseismology, they simulate the techniques 
seismologists use to read the record of relatively 
recent earthquakes.

The amount of damage an earthquake causes depends 
on the strength and duration of the earthquake, on 
population density, on methods of construction (to be 
dealt with in Unit 4), and on the geophysical/ 
geological characteristics of the impacted area. 
Lesson 4 progresses to three of the most potentially 
destructive earthquake effects: liquefaction, 
landslides, and tsunami. Each occurs when a seismic 
shock impacts an area with certain physical 
characteristics. Lesson 5 underlines the importance of 
site, as students interpret maps highlighting different 
features of the landscape. They will draw on their new 
knowledge to make additions to the local map they 
began in Unit 1.

2.1 Stick-Slip Movement
 
RATIONALE
Students will operate a model to observe the type of motion that 
occurs at a fault during an earthquake and explore the effects of 
several variables.

FOCUS QUESTIONS
How much energy will a fault store before it fails?
Is this quantity constant for all faults?

OBJECTIVES
Students will:
1. Model the frictional forces involved in the movements of a fault.
2. Measure movement, calculate averages, and plot this information 
on a graph.
3. Explore the variables of fault strength vs. energy stored.

MATERIALS
for each small group
 1 copy of Master 2.1a, Stick-Slip Data Sheet
 4 sandpaper sheets, 23 cm x 28 cm (9 in. x 11 in.), in 60, 120, and 
400 grit (12 sheets)
 Scissors
 Strapping tape
 1-1b box of sugar cubes
 8 thumbtacks
 A box of rubber bands
 2 large paper clips
 Yardstick or meter stick
 At least 2 m of string
 Large dowel or empty tube from a roll of paper towels
 Marking pen
 Scales
 Pine board, approx. 2.5 cm x 30 cm x 1.8 m (1 in. x 12 in. x 6 ft.)
 Several books to support one end of the board
 Protractor for measuring angles
 1 brick (optional)

VOCABULARY
Fault: a break or fracture in Earths crust 
along which movement has taken place.

Friction: mechanical resistance to the motion of objects or bodies that 
touch. Stick-slip movement: a jerky, sliding movement along a surface. It 
occurs when friction between the two sides of a fault keeps them from 
sliding smoothly, so that stress is built up over time and then suddenly 
released.

Variable: in a scientific experiment, the one element that is altered to test 
the effect on the rest of the system.

PROCEDURE
Teacher Preparation
To assure success, construct the model ahead of time and rehearse the 
activity. Then arrange materials for student models in a convenient 
place.

A. Introduction
Elicit a definition of fault from the class, supplementing students 
information as necessary until the essential elements have been 
covered.

Explain to students that when an earthquake occurs and movement 
begins on a fault plane, the movement will not proceed smoothly 
away from the focus. Any change in the amount of friction along the 
fault will cause the fault movement to be irregular. This includes 
changes along the length of the fault and with depth, changes in rock 
type and strength along the fault, and natural barriers to movement, 
such as changes in the direction of the fault or roughness over the 
surface of the fault plane.

Rupture along a fault typically occurs by fits and starts, in a type of 
sporadic motion that geologists call stick-slip. As energy builds up, 
the rock on either side of the fault will store the energy until its force 
exceeds the strength of the fault. When the residual strength of the 
fault is exceeded, an earthquake will occur. Movement on the fault 
will continue until the failure reaches an area where the strength of 
the rock is great enough to prevent further rupture. In this manner, 
some of the energy stored in the rock, but not all of it, will be released 
by frictional heating on the fault, the crushing of rock, and the 
propagation of earthquake waves.

B. Lesson Development
1. Divide the class into working groups of at least four students each. 
Distribute one copy of Master 2.1a, Stick-Slip Data Sheet, to each 
group. Tell students that they are going to model a process, record 
data for each trial, and then vary the process, changing only one 
variable at a time.

2. Allow groups to assemble their materials, then give these 
directions:
a. Fold each piece of 120-grit sandpaper in half lengthwise and cut, to 
produce eight strips of sandpaper, each 11.5 cm x 28 cm (4.5 in. x 
11 in.) in size.
b. Wrap one of the strips around the box and secure it around the sides 
(not the top and bottom) with two rubber bands. (See diagram.) Weigh 
and record box mass.
c. Tape the seven remaining strips of 120-grit sandpaper into one long 
strip. (Be sure to use tape only on the back of the sandpaper.) Now 
attach the sandpaper lengthwise down the center of the pine board, 
using two thumbtacks at each end and being sure the sandpaper is 
drawn tight.
d. Attach one paper clip to one of the rubber 
bands around the box.
e. Tie one end of the string onto another paper 
clip and place a mark on the string about 1 cm 
from the clip. Use one rubber band to join the 
paper clip on the box with the paper clip on the 
string. Tie the free end of the string around the 
dowel or paper towel roll.
f. Tape the meter stick onto the sandpaper strip on 
the board.
g. Position the box at one end of the board so it is centered on the 
sandpaper. Use books to raise the other end of the board 
approximately 10 cm (4 in.). Measure and record the height.
h. Gently roll the string onto the dowel until the string lifts off the 
paper and becomes taut. Note the location of the mark on the string 
relative to the meter stick. Take care to keep the dowel in the same 
position during rolling and measurement.

TEACHING CLUES AND CUES
This part of the activity requires a very steady hand.
 
Controlling the tension on the string works best 
if the string is rolled onto the dowel until the dowel 
rests on the books and is against the 
edge of the board.

i. Continue to roll the string onto the dowel until the box moves. The 
box should move with a quick, jumping motion. Record the new 
location of the mark on the string (the distance the box moved) on the 
data table. Continue rolling up the string and recording jump distance 
until the box hits the meter stick. The meter stick can be pulled 
upwards to allow the box to continue to be pulled.
j. Subtract the beginning measurement from the ending measurement 
or add up the jump measurements to find out how far the box moved. 
Divide by the number of jumps to calculate an average jump distance.

3. Instruct other students in the same group to change one variable, 
repeat the procedure, and average the distance of the jumps. Students 
may vary the model by adding one or more rubber bands, adding more 
books to change the angle of the board, substituting the brick for the 
box, or using sandpaper of a different grit. If time allows, give every 
student a chance to operate the model with each of the variations.

4. Ask students to complete their data sheets.

C. Conclusion
Ask the class:
 What might the different variables represent in terms of earthquakes 
and landscape conditions? (Number of rubber bandsdifferent 
amounts of energy released; angle of the boardsteepness of the 
fault; sandpaper grit sizedifferences in the amount of force
required for a fault to movethe amount of friction.) Emphasize 
that different faults can store different amounts of energy before 
they fail. Some faults have the potential for generating larger 
earthquakes than others.

 Do the rubber band and string go totally slack after each movement? 
(No.) What does this tell you about the release of stored energy on a 
fault when an earthquake occurs? (No earthquake ever releases all 
the energy stored in the Earth at a particular point. It is because 
some stored energy always remains that one quake may have 
numerous foreshocks and aftershocks, and earthquakes recur 
frequently in some active areas.) 

2.2 Shifting Plates & Wandering Poles

VOCABULARY
Paleomagnetism: the natural magnetic traces 
that reveal the intensity and direction of Earths 
magnetic field in the geologic past.

RATIONALE
To understand earthquakes students need to understand the structure 
of the Earth. The theory of plate tectonics has contributed to an 
understanding of how the Earths plates move and how that movement 
can cause earthquakes.

FOCUS QUESTIONS
How does the shape of the continents indicate that they were once 
joined?
What are some of the ways to tell the continents are moving?

OBJECTIVES
Students will:
1. Model magnetic reversal patterns.
2. Use paleomagnetic data to demonstrate plate motion.

MATERIALS
 Master 2.2a, Tectonics Background
 Transparency of Master 2.2b, Earth Cross Section
 Overhead projector
 Master 2.2c, Reading the Patterns
 Master 2.2d, Continental Pieces, two copies for each small group
 Master 2.2e, World Map Grid
 Master 2.2f, World Map Grid, 120 MYA
 Classroom world map for each small group
 Bar or cow magnet
 Large nail
 Paper clips or staples
 Clamp with a handle
 Bunsen burner, cigarette lighter, or other direct heat source
 One 3 x 5 file card and sheets of blank paper
 Twenty 9 can (3-4 in.) lengths of audiocassette tape (Use an old tape.)
 A roll of clear tape
 Scissors and a ruler
 Pens or pencils
 Maps of South America and Africa (optional, but desirable)
 Map of the Pacific Ocean floor (optional, but desirable)

PROCEDURE
Teacher Preparation
Practice the magnetizing demonstration before class. Prepare the nail 
by stroking it with a magnet until it will pick up paper clips or staples 
on one end. Place the nail in a clamp and heat it in the middle until the 
clips drop off.

Read Master 2.2a, Tectonics Background, and decide how much time 
you will need to spend presenting this information to your students. If 
they are already familiar with its outlines, you may just want to 
connect the illustrations with the stick-slip movement students saw in 
the previous activity.

PART ONE
POLES AT PLAY

A. Introduction
Pass out copies of Master 2.2a, Tectonics Background. Project Master 
2.2b, Earth Cross Section, and review the first two major sections of 
Master 2.2a with the students. Point out to students that on a world 
map continental land masses seem to have a jigsaw fit. Early 
mapmakers noted this long ago when drawing the first maps of the 
new world.

TEACHING CLUES AND CUES
You may want to take students through a quick 
review of magnetic properties and the rule of
attraction and repulsion of poles.

B. Procedure
1. Ask the students how magnets work. Some may already know that 
alignment of atomic forces creates the magnetic pull, or force field. 
Tell students that when a magnet is heated it loses its magnetic force, 
and when it cools down it again picks up the faint trace of the Earths 
magnetic field. Demonstrate this with a nail by stroking it with a 
magnet and then heating it, as explained above. Ask students where 
rocks are heated (in volcanoes and deep within the Earth). Tell them 
that in the next two activities they are going to simulate the process of 
using paleomagnetism to study plate tectonics.

2. Tell students that in 1963, two English geophysicists, Vine and 
Matthews, were using extremely sensitive magnetometers to make 
measurements of the seafloor across the Mid-Atlantic Ridge. 
Scientists already knew that over the 4.6 billion years of Earths 
history, its magnetic poles have changed directions more than once, so 
that the south pole and the north pole have actually switched 
places. When a volcano erupts, the volcanic rocks record the direction 
of the poles at that time. The rocks are magnetized in somewhat the 
same way as the nail was by the magnet in your demonstration. What 
Vine and Matthews discovered was a pattern of polar reversal stripes 
on both sides of the ridge. The purpose of this activity is to simulate 
those patterns.

TEACHING CLUES AND CUES
Be sure students understand that it is the magnetic poles that have 
changed, not the physical ends of the Earth.

3. For each group of two or three students, pass out 20 audiotape 
strips, one 3 by 5 card, glue or tape, and a magnet.

4. Give these instructions:
a. Tape 6 or 7 strips of audiotape to the card by one end, so they are 
parallel to each other and about 1 cm apart. One end will be loose, as 
shown on the illustration.
b. Stroke one of the strips with one pole of the magnet. Then stroke 
the next strip with the other pole of the magnet.
When the magnet is passed over the loose, ends of the tape, the strips 
will move. Their direction will depend on which end of the magnet 
they were stroked with.
c. Create patterns of magnetism by mixing up the order in which you 
stroke the strips of tape, then give the cards to other groups to 
interpret.

TEACHING CLUES AND CUES
This activity works best if the card is held upside 
down with the tape hanging down.

Be sure all strokes on the individual strips are 
in the some direction. Do not touch again when 
testing polarity.

C. Conclusion
After they have had a chance to create patterns and share them with 
other groups, ask students if they were able to interpret the other 
groups patterns. How did the tape strips record the direction of the 
magnetism? (Magnetic particles are embedded in the tape.)
This activity was adapted from a workshop on earth science activities 
presented at the Exploratorium in San Francisco, CA.

PART TWO
RECORDS IN THE ROCK

A. Introduction
Review the structure of the Earths interior with the class, drawing on 
Master 2.2a. Remind students that in the last activity they saw how 
patterns of magnetic polarity can be recorded. What Vine and 
Matthews saw, as they explored the Mid-Atlantic Ridge with their 
instruments, was a similar pattern recorded in volcanic rocks. Looking 
at these patterns on one side of the ridge, they noticed that the 
opposite side showed a mirror image of reversals. Their next step was 
to collect rock samples from the sea floor and determine the age of the 
rocks, to find out when the volcanoes that formed the rocks erupted. 
They discovered not only that the patterns of ages were mirrored on 
the two sides, but also that the rocks on both sides were progressively 
older as they moved away from the ridge. The next activity will help 
students understand the process Vine and Matthews followed.

B. Procedure
l. Give each group a copy of Master 2.2c, Reading the Patterns, and a 
pair of scissors. Give these instructions:
a. Cut the reversal pattern off the bottom of the sheet and trim away 
everything outside the dotted outline.
b. Cut the reversal pattern along the dashed horizontal line in the 
center to form two strips. Place the two strips together with the 
patterned bands facing in, making sure that the arrows on both strips 
face the same way. Tape ends together.
c. Insert the scissors at one of the black dots on the map and carefully 
cut a slit along the axis of the mid-ocean ridge, following the broken 
line between the two dots. Insert the open end of the folded reversal 
pattern into the slit from underneath, holding onto the stub, and 
carefully pull the first several centimeters of paper through (up to the 
first dark line). Crease the strip along the dark line so the first pattern 
is showing, bend it flush with the paper on one side of the ridge, and 
label it with a 1 in red ink. Do the same thing on the other side of the 
ridge.
Tell students that this represents a volcanic eruption during which the 
rocks adopt the magnetic field of the Earth at that time. Then, 
announce that a reversal of the poles has occurred.
d. Pull up the second pattern on the strip, bend it over, and label it 2. 
Repeat with the other side. Continue this process until all the patterns 
have been pulled up and labeled.

TEACHING CLUES AND CUES
There should be nine bands on each side of the ridge.

2. When all the bands have been labeled, ask students:
 What does each fold of paper represent as it is pulled up from 
below? (new rock being erupted from inside the Earth by volcanic 
action)

 Which pattern represents the oldest volcanic rock? (Number 1)

 Is the pattern of the reversals and the ages mirrored on the two sides 
of the ridge? (Yes.)

 Why do the pattern bands vary in width? (Their width is deter- 
mined by how much volcanic activity occurred before the reversal 
and how long the reversal of polarity lasted.)

 Can you tell which way the poles were oriented during any given 
age on your model? (Yes.)

C. Conclusion
Conduct a quick drill to be sure students understand how the models 
show what direction the poles were oriented in. Call out a number and 
ask students to answer with a direction. Go on until students can 
respond rapidly.

PART THREE
MAPPING PREHISTORY

TEACHING CLUES AND CUES
To demonstrate paleomagnetic alignment, make large blowups of 
the South American and African continents, or draw their 
outlines on the overhead. Demonstrate the process of alignment and 
distance measurements.

A. Introduction
Tell students that in the last activity they modeled the creation of new 
ocean floor at a spreading mid-ocean ridge. Project the transparency 
of Master 2.2b and review the section of Master 2.2a entitled Three 
Kinds of Plate Movement, Four Kinds of Boundaries, and discuss. 
Then discuss the driving mechanism for plate tectonics, so students 
understand some of the complicated forces and that scientists are still 
exploring how these forces work. Tell the class that in this last 
activity they will look at one more line of evidence that the continents
have been moving. Review the process of magnetism and how rocks 
pick up the polar orientation during their formation. Explain that 
sensitive instruments called magnetometers can analyze samples of 
rock to discover where the north pole was located during their 
formation. In this next activity, students will use magnetic data 
collected from several different locations to establish plate motions.

B. Procedure
1. To each small group, pass out scissors, tape, a ruler, two copies of 
Master 2.2d, Continental Pieces, and one each of Master 2.2e, World 
Map Grid, and Master 2.2f, World Map Grid, 120 MYA. Point out 
that there are two north arrows on each of the continental pieces. The 
N stands for north today and the PN stands for paleonorth, or the 
approximate location of the north pole 120 million years ago (MYA). 
The line that lies across the arrow, labeled G, represents grid north, 
and should always line up so it is parallel to longitude (see example 
on Master 2.2e, World Map Grid.) The numbers in the tables on the 
grid masters tell the distance to the north pole from the tip of the 
arrow point at the time that sample was collected.

TEACHING CLUES AND CUES 
Be sure to pass out two copies of Master 2.2d to each group.

Make sure that the grid north line remains parallel to the longitude 
lines while you complete step 2.b.

2. Give these instructions:
a. Cut out the continents on one copy of Master 2.2d along the dotted 
continental outlines.
b. To place the continents on Master 2.2e, World Map Grid, begin 
with any continent. Place the ruler alongside the present day north 
arrow line (N) on the continent to align it with the intersection of the 
Prime Meridian (O) and the north edge of the map. Next, align the 
grid north line (G) so it is parallel to the nearest longitude. When both 
arrows are aligned, measure the distance from the pole to the point 
where the two arrows cross. Tape the continent in place.
c. Repeat the process until all the continents are in place. This creates 
a map of the world as it appears today.
d. Now repeat the process with a new copy of Master 2.2d, 
Continental Pieces, and a copy of Master 2.2f, World Map Grid l20 
MYA, this time lining up the PN arrows. This creates a map of the 
world as it may have appeared 120 million years ago.

3. When they have completed both tasks, ask students if they could 
tell which continent moved the most. (India) Point out that the continents do 
not fit together perfectly and ask them for some possible 
reasons. (Students may suggest that the scale could be wrong, the 
drawings may not be quite accurate, or our measurements may be 
inaccurate.) Let students discuss the possibilities. If necessary, ask if 
they think the continents have always had the same outline as they do 
today. (No. The sliding, colliding, and converging movement of the 
plates has added new material in some places and worn the edges 
away in others. Point out western North America and the place where 
India collided with Asia to form the Himalayas.)
If a wall chart or map of the oceans is available, point out the continental 
shelves. Explain that geologically each continent extends to the 
edge of its continental shelf. Does the jigsaw puzzle fit together better 
if the edges of the shelves are used as continental boundaries? (Yes.)

TEACHING CLUES AND CUES
You may want to project some of the students completed maps during 
this discussion.

TEACHING CLUES AND CUES
Students will learn more about Alfred Wegener in the next unit, in lesson 
3.2.

C. Conclusion
Review the steps in using magnetism to find the ancient location of 
the continents. Point out to students that this evidence was not 
available during Wegeners time. In this series of activities they have 
experienced some of the ways scientists established the theory of plate 
tectonics. Ask:

 If this information had been available, would it have helped 
Wegeners case? (Yes.)

 How does the last map differ from a map of today? (Discuss.)

 At the rate of drift (5 to 15 cm, or 2-7 inches in a year), about how 
long would it take todays continents to join into one 
supercontinent? (Answers will vary.)


ADAPTATIONS AND EXTENSIONS
1. Challenge students to find out how magnetometers work and how 
scientists use them, then report to the class.

2. On a map of the Pacific Ocean floor, locate the Hawaiian Islands 
and the chain of islands that forms the Emperor Seamounts. Note the 
sharp bend in the line of seamounts. Ask students:
 What could have caused the bend? (a change in the direction of 
plate movement)
 What does this bend, and the long pattern of reversals illustrated in 
the earlier activities, indicate about the possibility of the Pacific 
Ocean closing? (With plates constantly changing directions, it may 
not close.)

3. Scientific American published a series of articles on plate tectonics 
in the late 1960s which were published as a collection in 1970 (see 
Wilson, unit resources). Provide students with copies and ask them to 
prepare a report to the class on the evolution of the theory.

4. Ask volunteers to compare and contrast continental drift, plate 
tectonics, and sea floor spreading, or to show the relationships among 
plate boundaries, earthquakes, and volcanoes.

5. Invite students to build models to demonstrate the four types of 
plate boundaries.

6. A group of students could create giant cardboard models of the 
continental pieces by enlarging them to scale. They or another group 
could perform a Drift Dance, moving in various patterns until the 
pieces lined up more or less as they are today.

7. Ask the class: If earthquakes are only supposed to happen in the 
vicinity of plate boundaries, why did the 1811 and 1812 New Madrid, 
Missouri, earthquakes occur? (New Madrid is located on a failed rift 
zone that tried to split North America apart.) Was it an isolated occurrence, or 
could the same thing happen in other such areas? (There may 
be other such rift zones that have not yet been discovered.)

2.2a Tectonics Background

To understand why earthquakes happen, we need to understand two basic facts 
about the planet we live on: that it 
is made up of layers, and that its surface is broken into irregular pieces 
called plates. Much of what we know 
about the composition of Earth has been learned by studying how earthquake waves 
travel in and through it.

Earths Layers
Just for a moment, imagine the Earth as if it were a hard-boiled egg. It has a 
thin crust (the shell); a thick middle 
layer, or mantle (the white); and a core (the yolk). The crust and the uppermost 
portion of the mantle together 
form the lithosphere. The plates are called lithospheric plates because they 
belong to this region. Scientists divide 
the mantle into zones and the core into an inner and outer core. (See Master 
2.2b.)

Crust and Lithosphere
Earths crust varies in thickness from about 30 km to between 70 and 80 km on 
the continents to only 6 km on the 
ocean floor. Even at its thickest point, the crust is not nearly as thick in 
relation to the whole bulk of the Earth as 
the shell of an egg is in relation to the egg. Remember that the crust is 70-80 
km thick at its thickest point, and the 
radius of the Earth is about 6,371 km.

The oldest rocks of the crust found so far have been dated by radioactive decay 
(isotopic dating) at about 4 
billion years. Earth scientists assume that the Earth was much hotter billions 
of years ago than it is today, and that 
the lithosphere (crust plus upper mantle) broke into plates as it cooled and 
hardened.

The lithosphere extends to an average depth of about 100 km. It is deepest under 
the continents and shallowest at 
the mid-ocean ridges.

Mantle
The mantle contains several zones, or layers with different properties. Its 
upper portion is a region with a plastic, 
semisolid consistency, called the asthenosphere. The thickness of the 
asthenosphere is still a matter of debate. 
Estimates of the distance to the base of the asthenosphere range from about 200 
km to 700 km. The mantle 
accounts for approximately 67% of Earths mass. Information from earthquake 
waves indicates that this region 
generally behaves as a plastic; that is, it will bend and flow in response to 
pressure. Temperature and pressure 
continue to increase as we move through the mesosphere to approach the core, at 
a depth of about 2,890 km.

Core
Both layers of the care are thought to be composed primarily of iron, with 
lesser amounts of nickel and possibly 
silicon, sulfur, or oxygen. Scientists have measured the velocity of earthquake 
waves passing through the core, 
and reason that such movement would be possible through materials with the 
physical properties of these 
elements. The liquid outer core, which might be compared to the outer two-thirds 
of an eggs yolk, reaches from 
a depth of about 2,890 km to 5,150 km. The solid inner core goes the rest of the 
way to the center of the Earth.

Earths core is very hot. Its high temperatures are due to the tremendous 
pressure of the layers above it, heat 
generated by the impact of other bodies during the formation of the planet, and 
radioactive decay. Evidence 
collected from mines and deep wells shows that the average increase in 
temperature is about 1?C for every 40 
meters of depth. If this rate held constant to the center of the Earth, 
theoretically, the temperature of the core 
would be about 150,000?C. According to the evidence we have, however, the actual 
temperature is between 
3,000 and 4,000?C at the core-mantle boundary, and about 5,000?C at the boundary 
of the outer and inner 
coresroughly the same temperature as the surface of the Sun!

Earths Plates
Most earthquakes and volcanoes are associated with large-scale movements of 
Earths plates, and occur at the 
boundaries between plates. There are 12 major plates and a number of smaller 
ones. The plates are named after 
continents (the North American Plate), oceans (the Pacific Plate), and 
geographic areas (the Arabian Plate).

The plates are in very slow but constant motion, so that seen from above by a 
patient observer, Earths surface 
might look like a slowly moving spherical jigsaw puzzle. The plates move at 
rates of 5 to 15 cm (2-7 inches) in a 
yearabout as fast as our fingernails grow. On a human scale, this is a rate of 
movement that only the most 
sophisticated instruments can detect, but on the scale of geological time, it is 
a dizzying speed. The oldest rocks 
in the crust, formed 3.8 billion years ago, could have traveled around the Earth 
14 times at this rate.

Three Kinds of Plate Movement, Four Kinds of Boundaries
Plate movement is generally one of three kinds: spreading, colliding, or 
sliding. Earthquakes can accompany all 
 three kinds of movement, but the most forceful quakes generally result from 
colliding and sliding movements.
When plates are spreading, or separating from each other, earth scientists call 
their movement divergent. The type of 
boundary that results (A) is a ridge, like the Mid-Atlantic ridge system.

When plates are colliding, or pushing against each other, scientists call the 
movement convergent. If an oceanic plate 
converges with a continental plate or another oceanic plate, the oceanic plate 
is forced down into the mantle, creating an 
ocean trench (B). The Alaskan trench and the Aleutian Islands were formed in 
this way; so were the Andes Mountains. If two continental plates converge, 
neither will be forced into the mantle. Instead, their edges will crumple and a 
large mountain chain may result (C). The Himalayas arose when India collided 
with Asia.

Movement in which plates slide past each other is called lateral (or transform) 
plate movement (D). This kind of 
movement is occurring along the San Andreas Fault in California.

Continental Drift: 1910 to 1960
The theory of continental drift originated early in this century, but it did not 
gain general acceptance until the late 
1960s. Between 1910 and 1912, the German meteorologist, geophysicist, and 
explorer Alfred L. Wegener 
formulated the theory called continental drift. He collected evidence from the 
rocks, fossils, and climatic records 
of several continents to show that they had once been joined together. Wegener 
knew little about the oceanic 
crust, which had not yet been explored, and thought that the continents merely 
moved horizontally, plowing 
through the oceanic crust.

Plate Tectonics: 1960 to the Present
In the early 1960s, British geophysicists Fred Vine and Drummond Matthews used 
magnetic data to show that the 
ocean floor is spreading apart at the mid-ocean ridges. As they shared the 
evidence for the process they called 
sea-floor spreading, scientists began to realize that the continents were also 
moving. By 1968, a new explanation 
for the dynamics of Earths surface had been created, combining Wegeners 
hypothesis with evidence from the 
ocean floor. Scientists call it the theory of plate tectonics.

The Mechanism of Plate Tectonics
Although the theory of plate tectonics is generally accepted, no one completely 
understands how the process 
works. Wegener thought that centrifugal force, caused by the rotation of the 
Earth, and tidal forces caused 
continental drift. Modern scientists have rejected this theory and replaced it 
with several others. Three 
mechanisms called convection, ridge push, and slab pull may play a role.

Convection Currents
Convection currents are systems of heat exchange that operate in the mantle as 
it is heated by the core. The 
mantles plastic-like material moves upward as it is heated, and sinks when it 
cools. You can see this kind of 
movement if you boil water in a clear glass pot. Even though the heat on the 
stove is constant, the water on the 
bottom of the pot is the hottest. As it heats, it becomes less dense and rises, 
while relatively cooler water from the 
top of the pot takes its place on the bottom. This continuous exchange creates 
convection currents in the water.

According to this theory, convective movement acts as a drag on the underside of 
the plates. As mantle material 
moves in large convection cells, the plates are rafted along the top of the 
cells, being pulled apart where the cell 
rises and colliding where it sinks.

Ridge Push
The ridge-push mechanism derives from the bulging of the undersea ridge crest as 
the oceanic lithosphere below 
it expands. The lithosphere expands because it is heated by mantle material 
pushing upward from below. As the 
lithosphere is pushed up at the ridge, a large portion of a plate may come to 
rest on an inclined plane. Gravity will 
cause this portion to slide down the inclined plane and push on the rest of the 
plate.

Slab Pull
Once this slab of oceanic lithosphere moves away from the ridge crest (and from 
the heat that is rising at the 
ridge), it will cool and contract, increasing in density. It will also thicken 
as underlying mantle material cools and 
attaches itself to the bottom of the slab. Eventually, the slab of lithosphere 
becomes denser than the underlying 
asthenosphere and sinks into the mantle. As it sinks, it pulls the rest of the 
plate along with it. At about 200 to 
300 km, the difference in density between the descending slab and the mantle is 
at its greatest, so the slab pull 
force is also at its greatest. Below this point, the mantle material becomes 
stronger and the resistance to sinking 
also becomes stronger.

A Natural Cycle
One result of all this slow, steady motion is the gradual opening and closing of 
ocean basins. As tectonic 
processes rearrange the surface of the planet, shifting lands and seas over 
millions of years, they also cause 
earthquakes. Now, and for the foreseeable future, human beings have no way to 
affect these mighty tectonic 
processes. By understanding them, however, we can learn to conduct our own lives 
in ways that minimize our 
risk from any disturbances they may cause.

Seismic Sleuths

Earthquakes

A Teachers Package for Grades 7-12
 
Unit Two (continued)

2.3 Earthquakes in Geologic Time

ACTIVITY ONE
TWENTY CENTURIES

VOCABULARY
Index fossil: a fossil that, because its approximate date is known, 
allows scientists to determine the age of age of the rock in which it is 
imbedded.

Radiometric dating: the process of using natural radioactivity to 
determine the age of rocks.

Strata (s. stratum): layers of rock or other materials formed at different 
periods in geologic time.

RATIONALE
Students have a difficult time comprehending how short the span of 
human history is in relation to Earths geological history. This lesson 
sets the stage for paleoseismology by providing a context in 
geological time.

FOCUS QUESTIONS
If no earthquakes have been recorded in my area since it was settled, 
does that mean earthquakes never happen here?

OBJECTIVES
Students will:
Students will compare the time period of their own lives and that of 
human history to the age of the Earth and events in Earths history.

MATERIALS
 Student copies of Master 2.3a, Centuries Worksheet
 Twelve 500-sheet reams (one case) of standard copier paper
 Student copies of Master 2.3b, Selected Events in Human History
 Student copies of Master 2.3c, Earth History Events
 Scissors

PROCEDURE
Teacher Preparation
1. Obtain 12 reams of standard-size paper and stack them on a desk 
where they will be visible to all students. Unwrap only the top ream. 
On each of the lower reams, cut a strip 7 to 10 cm wide from the side 
of each wrapper so the paper shows through. The results should be a 
column of exposed paper edges 11 reams high. Stack the unwrapped 
twelfth ream neatly on top, and place a copy of the Centuries 
Worksheet on top of the stack.

2. Make a copy of Master 2.3c, Earth History Events, and cut it into 
strips along the dashed lines.

A. Introduction
Ask the students to tell you what they mean when they say that 
something happened a long time ago. (Answers will range from a 
few months to centuries and beyond.) Ask students if it was a long 
time ago that dinosaurs became extinct, and our earliest human 
ancestors first appeared. Then ask them to guess the order in which 
these events occurred. Record their guesses without comment.

Emphasize that scientists seek proof of how long ago different events 
occurred by studying things that record the passage of long periods of 
time, such as the layers in rocks (strata) and index fossils. Index fossils 
represent species that existed only during specific time periods, so 
their presence is an index to the age of the rocks. Radiometric dating 
techniques can also reveal how long ago rocks were formed. The 
dating of events that occurred a long time ago and the sequence in 
which they occurred are among the puzzles scientists must solve. We 
are constantly adding to our knowledge of Earth history.

B. Lesson Development
1. Distribute copies of the Centuries Worksheet (Master 2.3a). Holding 
up the copy you placed on top of the paper stack, tell the students that 
the stack is 12 reams high, and that every single page in it stands for 
the same length of time. Explain that every dot on the sheet stands for 
one year. The first dot on the top line represents this year. Each dot 
after that one is a previous year. The entire sheet contains 2,000 dots. 
Ask the students to circle the dot representing the year in which they 
were born.

2. Distribute copies of Master 2.3b, Selected Events in Human History. 
With these sheets and their Centuries Worksheets in front of them, 
have students place the number of each event on Master 2.3b on or 
near the dot that represents its year.

3. Tell the class that geologic time calls for a different scale than 
historical time. From now on, one dot equals one hundred years. Each 
sheet of paper in the 12-ream stack now represents 200,000 years. The 
farther down the stack a sheet is, the farther back in history the time it 
represents. Ask the students to determine how far down the stack a 
sheet representing one million years ago is located. (It will be five 
sheets down.)

4. Ask students how many dots there would be in a ream of 500 sheets 
of paper if each sheet had 2,000 dots. (1,000,000 dots). If each dot 
represents 100 years, how many years would one ream of sheets 
represent? (100 years x 1,000,000 dots per ream = 100,000,000 years.)

5. Distribute the strips of paper cut from Master 2.3c, having each 
student choose one. Give students these directions:
a. Calculate how many years an inch of paper represents. Look at your 
paper strip and decide if the event it names will fit within the span of 
years represented by the reams of paper (1.2 billion years).
b. If it does, calculate how far down the paper stack to place your 
individual marker, then come forward to place it at the correct depth.
c. If it does not, use the math we have already done to calculate how 
much more paper would be needed. Share your findings with the 
class.

6. Elicit ideas from the class on the age of the Earth. (The answer, 
about 4.54 billion years, is on Master 2.3c.) Ask: How many reams of 
paper like the ones in the front of the classroom would it take to 
represent that many years? (46 reams)

C. Conclusion
Ask the class: Now that you have an idea of the age of the Earth, 
would you describe the human race as young or old? (relatively 
young) Which occurred more recently, the extinction of the dinosaurs 
or the appearance of human beings? (the appearance of humans) 
Compare these facts with the students earlier guesses. Emphasize that 
terms like young and old, long ago and recent can have very different 
meanings in different contexts. Because an event such as an 
earthquake has not taken place in historical time does not mean it is 
impossible, given the great sweep or geological time.

ACTIVITY TWO
PALEOSEISMOLOGY, OR READING THE CLUES

TEACHING CLUES AND CUES
The two parts of this activity use the same materials and take 
approximately the same length of time. It may be convenient 
to do them in sequence. Alternatively, you may want to have half the 
class do the first activity and the rest do the second.

RATIONALE
By using models, students will learn how geologists apply present 
knowledge to understand seismic history.

FOCUS QUESTIONS
How do we know about earthquakes that happened long ago?

OBJECTIVES
Students will:
1. State and explain several basic geologic principles.
2. Model the procedure geologists use to determine earthquake 
recurrence intervals.

MATERIALS
 Transparencies made from Master 2.3d, Sag Pond, 1830 to 1994
 Overhead projector
 Newspapers for covering desks
 Play clay or modeling clay, in red, blue, yellow, and white
 Student copies of Master 2.3e, Sag Pond Template
 15-cm (6-in) lengths of dowel or other small cylinders for rolling 
play dough (optional)
 Knives for cutting the clay (Plastic picnic knives will do.)
 Transparencies made from Master 2.3f, Ditch Creek, 1830 to 1994
 Student copies of Master 2.3g, Ditch Creek Template

PART ONE
SAG POND

VOCABULARY
Paleoseismology: the study of ancient earthquakes.

Peat: a deposit of semicarbonized plant remains in a water-saturated 
environment. Peat is an early stage in the development of coal.

Principle of crosscutting relationships: the principle stating 
that a rock is always younger than any other rock across which it cuts. 
Earthquake faulting illustrates this principle: Faults are always younger 
than the rocks they cut.

Principle of superposition: the principle upon which all geologic 
chronology is based, stating that in any sequence of sedimentary layers 
that has not been overturned or faulted, each layer is younger than 
the one beneath, but older than the one above it.

Principle of uniformitarianism: the fundamental principle stating that 
geologic processes have operated in essentially the same way throughout 
geological time.

Recurrence interval: the actual or estimated length of time between two 
earthquakes in the some location.

Sag pond: a small body of water occupying an enclosed depression 
formed by strike-slip fault movement.

Strike-slip faulting: faulting in which movement is horizontal.

PROCEDURE
A. Introduction
Ask students: Have your parents or grandparents experienced an 
earthquake in their lifetime? Explain: Geologists assume that the 
earthquakes we observe today are similar to those that happened 50 
years ago, 100 years ago, and even before human beings recorded 
history. Their impact may be different because of differences in 
human population patterns, but geologic processes and the natural 
principles that govern them have operated in essentially the same way 
throughout geological time. This assumption is expressed in the 
principle of uniformitarianism. By studying the traces of recurring 
earthquakes, those that have happened numerous times in the same 
area, we can speculate about the history of very old earthquake events 
and even make general predictions about the future. Introduce the 
principle of superposition and the principle of cross-cutting 
relationships. The activity that follows uses a generalized model of a 
strike-slip fault to illustrate these principles.

B. Lesson Development
1. Project the first transparency made from Master 2.3d, Sag Pond, 
1830 to 1993. Tell students that the diagrams they see show the effect 
of faulting in successive earthquakes. Because faulting causes surface 
dislocations, certain types of faulting will form hills and valleys in the 
Earths surface. With strike-slip faulting, if movement occurs as 
shown by the arrows, the following topography can be created:
 Right Lateral Strike-Slip Fault
X = area where ground is being pulled apart or extended, forming a sagpond.

 Left Lateral Strike-Slip Fault
Y = area where ground is being squeezed or compressed, forming a 
hill or ridge.

TEACHING CLUES  
AND CUES
If students have questions at this point, tell them that the activity 
that follows may answer them. Any questions that are not 
answered by the activity can be dealt with in the concluding discussion.

2. As you point to each of the figures, 1 through 6, read the 
accompanying text aloud to the class.

3. Divide the class into working groups of three to five students each. 
Distribute paper for covering desks, clay, knives, rollers (if available), 
and one copy of Master 2.3e, Sag Pond Template, to each group. Give 
these directions:
a. Pat or roll two clay patties, one white and one red, to a thickness of 
about 1 cm (.3 in.). Using the template provided, trim the patties to fit 
within the confines of the circle marked on the grid, then remove them.
b. Now make two sag pond peat deposits, one white and one blue, each 
0.5 cm thick and sized according to the small sag pond template at the 
upper left of the grid.
c. Place the large white layer on the grid template between A-B and 
C-D as outlined. Place the blue clay sag pond deposit on top of this 
first layer, aligning the long axis of the sag pond layer with fault line E-
F, and centering it between A-B and C-D. Out both layers along the 
fault line E-F. Lift the A-B side and raise it to the position marked 
Offset Line.
d. Place the red layer of clay over the offset layers and center a second 
sag pond deposit (the white one), as in the stop above. Cut (or trench, 
as geologists say) all the clay patties along line A-D. Carefully separate 
the sides so you have a good cross-section view and draw a cross 
section of each side. Compare the layers on the two sides of the fault 
A-D.

C. Conclusion
Build a class discussion around these questions:
 How is the principle of superposition applied in this activity?
 How is the principle of crosscutting relationships applied in this activity?
 How is the principle of uniformitarianism applied in this activity?
 What does the difference in thickness and spacing of the peat layers on 
the two sides of the fault indicate? (that the terrain has been disturbed)
In what year do we know an earthquake occurred on this fault? (1857)

PART TWO

DITCH CREEK
PROCEDURE

A. Introduction
Tell students: By using age-dating methods on peat deposits and very 
old stream channels, geologists can determine earthquake recurrence 
intervals dating back several thousands of years. The shorter its recurrence 
interval, the more likely an area is to experience an earthquake in 
your lifetime. This activity is another illustration of the principles you 
saw in the last one. Like the previous activity, it is based on a 
generalized model of a strike-slip fault.

B. Lesson Development
1. Project the first transparency made from Master 2.3f, Ditch Creek. 
Tell students that the diagrams they see show the effect of faulting in 
successive earthquakes. As you point to each of the figures, 1 through 
5, read the accompanying text aloud to the class.

2. Divide the class into working groups of three to five students each. 
Distribute paper for covering desks, clay, knives, rollers (if available), 
and one copy of Master 2.3g, Ditch Creek Template, to each group. 
Give these directions:
a. Make three layers of clay, one white, one yellow, and one red, 
patting or rolling the clay to a thickness of about 1 cm (1/3 in.) and 
trimming it to fit within the confines of Area 1 on the grid. Place the 
white layer on the Area 1 part of the grid and remove the others. Make 
a pencil-thick string of blue clay and lay it along the line marked on 
the grid as Stream Line, running the length of the first layer. With the 
knife, cut along the E-F fault line marked on the grid, which is 
perpendicular to the stream. Now offset the C-D section of the model, 
moving it to the position marked 1857 on the grid. This offset 
represents the movement along the fault of 1857.
b. Now place the yellow layer on top of the white layer and the offset 
stream. Be sure to place this second layer within the grid marks. Make 
another pencil-thick stream out of blue clay and place it on the same 
stream line indicated on the grid. Cut the layers again along the same 
fault line as in the previous step. Offset the C-D section to the position 
marked 1906.
c. Repeat this one more time with the red clay layer and one 
additional blue streamline.

TEACHING CLUES AND CUES
Remind students that arrows placed on fault diagrams show the 
relative direction of the motion.
 
You may want to cover the copy at the bottom of the master (Figure 2, 
p. 85) while you ask students to describe what they think 
has happened to produce the new picture.

C. Conclusion
Build a class discussion around these questions:
 How is the principle of superposition applied in this activity?
 How is the principle of crosscutting relationships applied in this activity?
 How is the principle of uniformitarianism applied in this activity?
 Would you build your home in 1994 or later near this fault?

ADAPTATIONS AND EXTENSIONS
Provide a small-scale map of a seismic area and ask students to locate 
other streams along fault lines and identify offset stream channels. For 
example, on a map of the Grand Canyon, locate Bright Angel Canyon 
and point out the place where it meets the Colorado River. Ask: What 
caused the Bright Angel Creek to cut a canyon where it did? (The 
Bright Angel fault caused a weak place in the rock for the water to 
erode.)

2.3b Selected Events in Human History

1. My great grandmother is born. (Estimate.)

2. 1776U.S. Congress adopts the Declaration of Independence.

3. 1936Inge Lehmann demonstrates the presence of an inner core.

4. 1492Columbus reaches the Americas.

5. 1909Andrija Mohorovicic discovers discontinuity at 
crust/mantle boundary.

6. 1989Loma Prieta quake rocks World Series fans.

7. 1811/1812New Madrid quakes, greatest ever in continental 
U.S., estimated at over 8.0 on the Richter scale.

8. 1755Offshore earthquake near Lisbon, Portugal. Earthquake, 
40-foot tsunami, and fires kill 60,000 people.

9. 132Chinese scholar Chang Heng invents seismoscope to detect 
earthquakes.

10. 1556The most disastrous earthquake on record, at Shen-Shu, 
China, kills 830,000 people.

11. 1889First record of a distant earthquake was received at 
Potsdam, Germany.

2.3c Earth History Events

1. Earth formedapproximately 4.54 billion years ago
2. North and South America joined by the closing of the Isthmus of Panama
approximately 2,800,000 years ago
3. Last trilobites died outapproximately 225 million years ago
4. Earliest known humanoid (our early ancestor) fossils depositedapproximately 
2 million years ago
5. Earliest known animal fossils (jellyfish-like organisms) deposited
approximately 1.2 billion years ago
6. New Madrid rift zone openedapproximately 500 million years ago
7. Earliest known reptile fossils depositedapproximately 290 million years ago
8. Earliest known bird fossils depositedapproximately 160 million years ago
9. Earliest known mammal fossils depositedapproximately 200 million years ago
10. Earliest known flowering plant fossils depositedapproximately 135 million 
years ago
11. Earliest known trilobite fossils depositedapproximately 600 million years 
ago
12. Present day Appalachian Mountains formedapproximately 250 million years ago
13. Rocky Mountains formedapproximately 70 million years ago
14. Mass extinction of dinosaurs and other forms of life occurredapproximately 
65 million years ago
15. Breakup of Pangaea beganapproximately 180 million years ago
16. Earliest known fossils of land animals depositedapproximately 390 million 
years ago
17. Last lee Age endedapproximately 10,000 years ago
18. Oldest known rock on Earth formed in southwest Greenlandapproximately 3.2 
billion years ago
19. Himalayas begin forming as India joined Asian continentapproximately 30 
million years ago
20. Formation of iron, copper, and nickel ores1 billion years ago
21. Much of continental land masses underwater330 million years ago
22. Active volcanoes in New England210 million years ago
23. Earliest microfossils formed in South African chert3.2 billion years ago
24. Algal stromatolites formed in Rhodesian limestones3 billion years ago

Figure 1, Sag pond
In the left-hand side of Figure 1 (X), there is a place where the ground has 
pulled apart. The depression caused by 
this pull-apart basin is called a sag pond. This is a very narrow, long or 
elongated pond or basin. Sag ponds are 
generally aligned with the long axis parallel to the faults. In the right-hand 
drawing, (Y), a ridge is being formed 
by squeezing, or compression.
 
Figure 2, Sag pond 1830
Fault slippage has formed a sag pond, which has filled with water containing 
reeds, cattails, and algae. These 
organic materials die and accumulate rapidly on the bottom of the sag pond in 
the form of peat. Peat can 
accumulate as much as several centimeters per year.
 
Figure 3, Sag pond 1857
Fault moves, offsetting shorelines of sag pond and organic materials (peat) on 
bottom.
 
Figure 4, Sag pond 1994
Shortly after the faulting, a new sag pond forms with more reeds, cattails, and 
algae. Peat continues to 
accumulate. In 1994 the sag pond is pumped dry, and a shallow trench (A-B) is 
dug with excavation equipment 
perpendicular to the fault. A sketch of one side of the trench is reproduced 
below (see Figure 5).

Figure 5, Trench Log 1, 1994

Later that same year, a deeper trench is excavated across the same sag pond, and 
the following trench log is 
obtained:
 
Figure 6, Trench Log 2, 1994
What are your conclusions regarding the pre-1830 seismic history (the 
paleoseismology) of this fault? (The peat 
layer shows that faulting has taken place. The depth of the layers can be 
measured, and the distance between the 
layers can be measured.)

Figure 1 1830
A stream (a) flows across a strike-slip fault.
 
Figure 2 1857
An earthquake with movement along the fault in 1857 causes displacement of 
stream (a) as shown. The amount of 
displacement probably represents the amount of offset the earthquake caused. As 
the years go by, soil and sand 
may bury and cover up parts of the original stream course (b).
 
Figure 3 1906
Another earthquake with movement along the same fault in 1906 causes further 
offset of the course of the stream. 
Soil and sand will continue to bury and cover up parts of the 1857 (b), and the 
1906 (c) offset. A shallow trench 
(line G-H) cut parallel to and south of the fault in 1994 might show the 
following relationship (Figure 4) on the 
southern side of the trench:
SECTION VIEW
Ground surface
 
Figure 4 Trench Log 1, 1994

The rate of movement and timing of earlier earthquakes can be determined from 
the age of the sand and gravel 
deposits in the stream channel.
If a second longer and deeper trench is excavated in the area of trench G-H, the 
following log might be obtained 
(Figure 5):

SECTION VIEW
 
Figure 5 Trench Log 2, 1994

Seismic Sleuths

Earthquakes

A Teachers Package for Grades 7-12
 
Unit Two (continued)

2.4 Earthquake Hazards

ACTIVITY ONE
LIQUEFACTION: THAT SINKING FEELING

RATIONALE
Like other earthquake-related phenomena, liquefaction may cause the 
loss of property and even injury or death. This model allows 
instructors and students to observe the effects of liquefaction and the 
phenomenon of sand boils on a small scale.

FOCUS QUESTIONS
What happens when a damaging earthquake strikes areas prone to 
liquefaction?

OBJECTIVES
Students will:
1. Construct a model to demonstrate liquefaction.
2. Distinguish between soil liquefaction and soil saturation.
3. Assess potential damage to homes, lifelines, and schools.

MATERIALS
for the teacher
 Master 2.4a, Teacher Background Reading: Liquefaction
 Master 2.4b, New Madrid Narrative

for each small group
 226 g (about 8 oz) of well-sorted fine sand [Sandbox sand works well.]
 One .25-1 (9 oz) clear plastic cup
 One pie plate, diameter 23 cm (9 in.)
 225 ml (5 oz) of water in a pitcher
 Sinker or comparable small object weighing at least .06 kg (2 oz)
 One 250-ml beaker
 Newspapers to cover work surface

TEACHING CLUES AND CUES
If possible, substitute a small, hollow, ceramic house, measuring approximately 
5 x 5 x 7 cm, for
the sinker. These are sold at hobby shops for Christmas scenes, and can be 
filled with BBs to add weight.

PROCEDURE
Teacher Preparation
Read Master 2.4a, Teacher Background Reading: Liquefaction, and 
Master 2.4b, New Madrid Narrative. Decide how you will share this 
information with your students. Students who like to read will find 
New Madrid Narrative delightful.
Gather enough materials so you can have two students per station. 
Before class, cover work areas with newspapers, set up the stations, 
and practice each activity at least once to be sure everything works.

A. Introduction
Tell students that an earthquake with a magnitude of 5.0 or greater 
may cause saturated sand or clay soils to liquefy. During the winter 
of 1811 and 1812, a series of earthquakes affected the central portions of the 
United States that we now know as Missouri, Arkansas, 
Kentucky, Illinois, and Tennessee. As the soft sediments along the 
rivers were violently shaken, tremendous volumes of sand were liquefied and 
ejected onto the Mississippi River flood plain. These sand 
boils, as they are called, are still visible in the rural countryside today. 
Fortunately the area of the earthquakes was not heavily populated in 
1811-12, so loss of life, injuries, and loss of property were minimal.

During the 1989 World Series in San Francisco, a 7.1 earthquake 
struck the Bay Area. Millions of people viewed firsthand the fires and 
severe damage to buildings in the Marina District. Some of this 
damage occurred because soil liquefaction caused lifelines to rupture 
and buildings to collapse.

TEACHING CLUES AND CUES
Students may be aware that the flooding of the Mississippi and Missouri Rivers 
in the summer of
1993 caused mud boils in some places. Explain that these eruptions, 
somewhat similar to sand boils, were caused by extreme saturation of 
muddy soils in combination with the force of the torrential rains. Mud 
boils, like sand boils, can also be caused by earthquakes over 
magnitude 5.0.

VOCABULARY
Consolidated: tightly packed, composed of particles that are not 
easily separated.

Ground water: subsurface or underground water.

Lifeline: a service that is vital to the life of a community. Major lifelines 
include transportation systems, communication systems, water 
supply lines, electric power lines, and petroleum or natural gas pipelines.

Liquefaction: the process in which a solid (soil) takes on the 
characteristics of a liquid as a result of an increase in pore pressure and 
a reduction in stress.

Sand boil: a forcible ejection of sand and water from saturated soil, 
caused by an earthquake or heavy flooding.

Saturated: having absorbed water to the point that all the spaces between 
the particles are filled, and no more water can enter.

Unconsolidated: loosely arranged, not cemented together, so particles 
separate easily.

B. Lesson Development
1. Write the word liquefaction on the board, and ask student to 
identify its root work (liquid). Emphasize that liquefaction does not 
cause an earthquake, but is the result of an earthquake. Liquefaction 
occurs only in highly saturated sand or clay soils. An earthquake with 
a magnitude of 5.0 or greater is usually needed to cause liquefaction. 
Earthquake vibrations cause soil particles to lose contact with each 
other, so the soil takes on the characteristics of a liquid.

2. Assign a partner to each student and designate a work station for 
each team. Give these directions:
a. Cut off about 5 mm from the bottom portion of the plastic cup.
b. Invert the cup and place it in the middle of the pie pan.
c. Holding the cup firmly, slowly pour the sand into the bottom of the 
cup to a level of 10-20 mm from the top. (One student may hold while 
another pours.) Level the sand with your fingers. Do not shake the cup 
to settle or level the sand.
d. Lightly place the sinker, model house, or other weight onto the 
leveled surface of the sand.
e. Again holding the cup, slowly pour the entire 225 ml of water into 
the pie pan around the outside of the cup and sand.
f. Observe what happens and record the time it takes for the soil to 
reach saturation.
g. Once the soil is saturated, one student win hold the cup firmly in 
place while the other gives the side of the cup several sharp taps to 
simulate earthquake shaking. Observe what happens to the weight.

C. Conclusion
Help students to clean up and then initiate the discussion. Ask: If the 
weight in our experiment were an occupied building, and liquefaction 
occurred over a large inhabited area, as it did in the San Francisco Bay 
Area in 1989, what would be the effect on:
 People?
 Private homes?
 Schools?
 Buried lifelines (gas, water, electrical, oil, sewage)?
 Agricultural lands?
 Medical facilities, fire stations, police stations?
 Large urban areas (Memphis, San Francisco, Boston)?
 Industrial areas?
 Materials that had been discarded in old sand boils? (These could 
range from dead cows to old refrigerators to poisonous waste.)

ADAPTATIONS AND EXTENSIONS
1. Make sand of various particle sizes and objects of different masses 
available for student experiments. Investigate the degree of 
liquefaction each will exhibit and the effects on the structures that rest 
upon them. (A layer of diatomaceous earth under the sand will bubble 
up when the table is rapped. Try it!)

2. Invite students to find ways to vary the amount of force they apply 
to the sand and water mix in the model.

3. Provide an aquarium or plastic gallon jars so students can 
experiment with larger models. Use transparent containers of any 
sizeeven a plastic sandwich boxfor an interesting side view.

4. Bury objects in the sand and observe the results.

5. Develop models of overhead power lines, pipelines, sewage lines, 
light posts, and highways, and observe how liquefaction affects them.

6. Challenge students with this question: If a building has already 
been constructed on soil that has a potential to liquefy, what can be 
done to reduce the likelihood of damage? Invite them to design and 
test model structures that would reduce structural damage during 
liquefaction.

ACTIVITY TWO
LANDSLIDES: SLIP-SLIDING AWAY

RATIONALE
Earthquakes dramatically increase the potential for landslides in areas 
where landslides are common, such as those where sedimentary rocks 
lie just under the soil. Structures on cliffs and ridges need to be 
designed to the highest earthquake standards, and should be fully 
insured.

FOCUS QUESTIONS
How can an earthquake trigger a landslide?
What factors affect the probability of an earthquake-related landslide?

OBJECTIVES
Students will:
1. Construct a model to simulate an earthquake-related landslide.
2. Investigate the variables that affect an earthquake-related landslide, 
such as the strength of the slope materials, the steepness of the slope, 
and the intensity of ground shaking.
3. Explain why the steepness of a slope determines how the force of 
gravity acts on an area of ground and how it is related to frictional 
forces.

MATERIALS
for the teacher
 Slides or photos of landslide damage (in your geographic area, if 
available)
 Slide projector and screen or blank wall space (optional)
 Pasteboard or cardboard arrows in three colors, cut to the correct 
lengths to illustrate the 30 angle (optional)

for each small group
 A pine board, approx. 2.5 cm x 25 cm x 1.0 m (1 in. x 10 in. x 3 ft.)
 A meter stick
 Two plastic dishes, approx. 19 cm in radius, with sides 3.5 cm high
 Enough dry sand to fill the two dishes
 500 ml of water in a beaker or other suitable container
 Newspapers to cover work surfaces
 A sensitive bathroom scale that can register weights as low as 1 
Newton (less than 2 lbs)
 Paper towels for cleaning the board between trials
 Master 2.4c, Landslide Data Table
 Master 2.4d, Landslide Activity Sheet
 Pencils or pens
 Transparency made from Master 2.4e, Components of the Force of Gravity
 Overhead projector
 Soil, gravel, or other materials for the extension (optional)

TEACHING CLUES AND CUES
The width of the board can vary, but it must be 1 m long.

The inexpensive clear plastic dishes sold to put under potted plants will 
be ideal. The dish must be a little smaller than the board.

VOCABULARY
Friction: mechanical resistance to the motion of objects or bodies that 
touch.

Gravity: the force of attraction between any two objects with mass. 
Gravity is especially noticeable when an object of great mass, such as 
Earth, attracts an object of lesser mass.

Landslide: an abrupt movement of soil and bedrock downhill in 
response to gravity. Landslides can be triggered by earthquakes or other 
natural causes.

Loess: an unstratified, windblown mixture of clay, sand, and organic 
matter usually crumbly and buff or yellow-brown in color.

Mass movement: the movement of surface material caused by gravity.
Variable: in a scientific experiment, the one element that is altered to test 
the effect on the rest of the system.

PROCEDURE
Teacher Preparation
Assemble slides and/or photos. Assemble the other materials ahead of 
time and experiment with them to get a feeling for how various angles 
will affect their movement. Cover work surfaces with newspapers.

A. Introduction
Ask the students: Can an earthquake cause a landslide? Promote a 
discussion of their experiences and ideas. Show any images you have 
gathered of earthquake-related landslides, especially those that have 
affected your local environment.

Explain to the students that not all landslides are earthquake related; 
many are caused by other natural factors. Landsliding, or mass movement, occurs 
when the forces that hold materials in place are exceeded 
by the force of gravity in the direction of motion. The forces that hold 
sand, soil, rocks, and buildings in place are related to the strength of 
the materials. The balance of these forces may be affected by the 
intensity of ground shaking during an earthquake. The steepness of the 
slope on which the materials rest determines how much the force of 
gravity acts in the direction of motion.

B. Lesson Development
1. Divide the class into cooperative groups of three or more students. 
Distribute one copy of Master 2.4c, Landslide Data Table, to each 
group. Ask one member from each group to collect a dish of sand and 
the other materials.

2. Tell the students they will be conducting this investigation in a 
scientific manner. That is, they are to control the variables, manipulate 
only one, and measure or observe the response. When students have 
completed the experiment, it is very important that they use only their 
results to develop an explanation and that their explanation relates only 
to this particular model. Point out that the questions toward the end of 
the Landslide Activity Sheet relate to the scientific process they are 
employing.

3. Instruct students to set up a ramp, as illustrated on Master 2.4c, and 
begin to explore the effect of the ramps angle on the weight the scale 
reads. Explain that the less weight the scale records, the greater the 
force of gravity parallel to the ramp and the weaker the force of 
friction that holds the material in place. Give these instructions:
a. Place the scale at the bottom end of the ramp and place a dish of 
sand right side up on top of it.
b. Raise one end of the ramp to the height corresponding to the first 
angle indicated on the Landslide Data Table. As you move from one 
angle to another, record the scale readings in the Landslide Data Table.

TEACHING CLUES AND CUES
If you do not have enough scales you may do this section as a 
demonstration. You may also choose to simply describe the 
forces and use the factors in the data table below to describe how the 
measured weight of the material changes as the angle of the ramp 
changes. Whether you do the weighing or the students do, be sure 
to convert pounds into the metric unit Newtons (2.2 pounds = 9.8 
Newtons).

4. Stop the groups when they have completed the scale measurements 
and explain that the ramp breaks the force of gravity up into two 
components. Project the transparency of Master 2.4e, Components of 
the Force of Gravity, to illustrate. One of the components operates in 
a direction perpendicular to the ramp; that is the force they just 
measured. The other force operates along the ramp. That is the force 
of gravity, which will cause the landslide. These two components of 
gravity form two sides of a right triangle. Depending on the angle of 
the ramp, the force of friction may or may not cancel the force of 
gravity.

TEACHING CLUES AND CUES
If you made the arrows listed in the materials section, use them now to 
help students visualize these angles. Explain that the science of trigonometry 
deals with 
the mathematics of right triangles. Here you will simply measure and 
calculate the forces.
 
From 0-20 degrees not much will happen, but above 20 degrees, the 
students should begin to see some distinct motion.

5. To investigate the effect of slope on material with and without a 
simulated earthquake, ask the students to remove the scale. Show 
them how to place the dish of sand upside down at one end of the 
board without spilling the sand. First, place the board on top of the 
dish. Then, while holding the board down over the dish, carefully flip 
the board over. The dish should be upside down on the board with all 
the sand still in the dish.

6. When all the groups have accomplished this, ask students to vary 
the angle of the ramp as they did before, this time by slowly raising 
the end of the board with the dish of sand. Instruct students to record 
the height at which the sand starts to slide, then lower the ramp by 
about 5 cm and tap on the ramp to simulate an earthquake.

7. Give these instructions to test the effect of water on the sand:
a. Again cover the dish with the board, flip the dish right side up, and 
add 225 ml of water to the sand.
b. Flip the dish of wet sand back onto the ramp and repeat step 6 to 
see the effect each new angle of the ramp has on the wet sand.
c. Continue to record your data and observations in the Landslide Data 
Table. Use the transparency of Master 2.4e, Components of the Force 
of Gravity, and Master 2.4d, Landslide Activity Sheet to answer the 
questions about force.

C. Conclusion
Allow time for students to respond to the last questions on the 
Landslide Activity Sheet, which ask them to develop an explanation 
for what they have observed. When they have finished, ask the groups 
to share their explanations, being certain to justify their explanations 
by citing their data.

Ask the class if they think the work they have just done is similar to 
what scientists do. Ask them what the scientific community would do 
with a variety of explanations and varying data for the same 
procedure. Impress upon students that their investigation is one aspect 
of science and their reporting is another. Explain that it would take a 
great deal of time and many replications for any of their explanations 
to be accepted as a landslide theory. If they try the extension activities 
and want to carry their investigation of landslides still further, they 
will have to connect this model to real landslide data.

Finally, review and summarize the forces involved in landslides, 
referring to the illustrations on the handouts. Show the photos or 
slides again, and ask students to explain what they observe in terms of 
physical forces.

ADAPTATIONS AND EXTENSIONS
Invite students to test the effect of the material by repeating steps 6 
and 7 above with dishes of potting soil, gravel, and other materials.

ACTIVITY THREE
TSUNAMI: WAVES THAT PACK A WALLOP

VOCABULARY
Amplitude: a measurement of the energy of a wave. Amplitude is the displacement 
of the 
medium from zero or the height of a wave crest or trough from a zero point.

Period: the time between two successive wave crests. Run-up elevation or height: 
the 
highest attitude above the tide line, in meters, that the water reaches as it 
is forced up on land by a tsunami. Seismic sea wave: a tsunami 
generated by an undersea earthquake.

Tsunami: a potential destructive ocean wave created by an earthquake or other 
large-scale 
disturbance of the ocean floor. This Japanese word has the some form in 
both the singular and the plural.

Wave crest: the highest point a wave reaches. The lowest point is called its 
trough.
Wave height: the vertical distance in meters from a waves crest to its 
trough. (This measurement will be twice the amplitude measured for the 
some wave.)

Wavelength: the horizontal distance between two successive crests, often 
measured in meters.

RATIONALE
Underwater earthquakes can cause very powerful seismic sea waves 
commonly called tsunami or (incorrectly) tidal waves. These waves 
can devastate a coastal community because of the tremendous amount 
of energy they carry.

FOCUS QUESTIONS
How do earthquakes cause seismic sea waves?
What kinds of energy transfers are involved?
What precautions can people take to limit tsunami damage?

OBJECTIVES
Students will:
1. Prepare and present a class report that reflects their own research 
on seismic sea waves.
2. Describe the characteristics of an average seismic sea wave in 
terms of speed, wavelength, and period, and predict its effects on a 
coastal community.
3. Calculate the energy of the disturbance (sea floor motion) that 
causes an average seismic sea wave.

MATERIALS
 Master 2.4f, Teacher Background Material
 Student copies of Master 2.4g, Tsunami Event Reports
 Student copies of Master 2.4h, Seismic Sea Waves Activity Sheet
 Transparency of Master 2.4i, Wave Characteristics and Energy
 Overhead projector
 Student copies of Master 2.4j, Seismic Sea Waves Energy Analysis
 Copies of Master 2.4k, Seismic Sea Waves Research and Report 
 Form, one for every two students
 A large coil, telephone cord, or hose for demonstrating wave action
 Numerous student copies of Master 2.41, Grading Matrix
 Poster board or chart paper, markers, and audiovisual equipment as 
available
 Video camera (optional)

PROCEDURE
Teacher Preparation
Read the teacher background information on tsunami. Locate some 
before and after photos of tsunami, and either make transparencies or 
have them available to pass around the room.

Check your school and community libraries for the periodicals listed at 
the end of this lesson and in the Unit Resources. Also look for beginning 
oceanography textbooks and back issues of Scientific American.

TEACHING CLUES & CUES 
You may want to review scientific notation before handling the large 
numbers in this activity.

A. Introduction
If you have photos, share them with the class. Then pass out copies of 
Master 2.4g, Tsunami Event Reports. Have students take turn reading 
the accounts aloud. Ask students what they think causes tsunami.

B. Lesson Development
1. To provide the students with some common language, pass out 
Master 2.4h, the Seismic Sea Wave Activity Sheet, and help the class 
work through it. Project the upper half of Master 2.4i, Wave 
Characteristics and Energy. Ask students to tell you what belongs in 
each blank, and label the wave form accordingly. Point out that waves 
never stand still, so we have to be very clever to measure their 
characteristics.
2. Pose this question: How can a fault movement of only one meter in 
the depths of the ocean cause a huge wave to strike land? Promote 
student discussion until someone mentions the energy involved. At 
that point, project the lower half of Master 2.4i, and show students 
how the uplift of one meter actually involves lifting a column of water 
the same size as the area of seafloor uplifted.
3. Pass out copies of Master 2.4j, Seismic Sea Waves Energy 
Analysis. Work through the activity as a class or have students 
complete the worksheets in pairs, depending on their previous 
preparation.

TEACHING CLUES & CUES
You may want to videotape the presentations by setting the camera up 
on a tripod very close to the presenters. If you film your first 
class, you can use the footage to show other classes what you are 
looking for.

4. Challenge students to explain how a wave that is only one meter 
high in the ocean can grow so high as to overwhelm the land. Again 
direct their attention to the lower half of 2.4i, and point out the energy 
involved. (As the wave nears shore, in shallow water, the energy is 
forced upward, or refracted. See Master 2.4f for more detail.)

5. Invite students to do some research on actual tsunami drawn from 
the table of Notable Tsunami (below) or from other sources. Hand out 
one Seismic Sea Waves Research and Report Form (Master 2.4k) to 
every two students, explaining that each team is to research a specific 
topic and report what they learn to the class. Two students will report 
on tsunami warning systems; the others will report on a particular 
tsunami drawn from the list below. Set a due date and establish how 
you are going to evaluate the report. If you will use the matrix 
provided, explain it now.

Notable Tsunami by Place Reported

November 1, 1755	Lisbon, Portugal
April 2, 1868	Hilo, Hawaii
June 15, 1896	Sanriku, Japan
August 13, 1868	Arica, Peru
August 27, 1883	Java, eruption of Krakatau (also spelled Krakatoa)
March 2, 1933	Sanriku, Japan
April 1, 1946	Hilo, Hawaii
March 9, 1957	Hilo, Hawaii
May 23, 1960	Southern California
March 28, 1964	Crescent City, California
November 29, 1975	Hilo, Hawaii
May 26, 1983	Minehama, Honshu, Japan
July 12, 1993	Aonae, Japan

6. Invite discussion of preventive measures that can be taken to 
minimize seismic sea wave damage. As students progress in their 
research, they may be able to suggest guidelines. The presentations on 
early warning systems will address this topic directly.

7. When the due date for presentations is near, review how you will 
evaluate the presentations and specify the time limit for each. Provide 
poster board or chart paper and markers, overhead transparencies and 
pens, and slide or video apparatus if available.

C. Conclusion
Have the students present their reports. Before each presentation, 
distribute copies of the grading matrix. Ask students to use one matrix 
sheet for each presentation, taking notes in the space allotted and 
evaluating their peers presentations on the same criteria by which 
theirs will be graded. A respectful classroom atmosphere will ensure 
the success of these presentations.

ADAPTATIONS AND EXTENSIONS
Challenge one pair of students to research and describe the compressional waves 
that have been associated with underwater earthquakes in 
terms of the waves characteristics and its effect on ships.

2.4a Teacher Background Reading
Liquefaction

How Liquefaction Occurs during Quakes
Liquefaction happens during an earthquake when vibrations cause the pressures to 
build up in the ground water 
that occupies the pore spaces between the grains of sand, silt, or loess. The 
longer the duration of the earthquake, 
the more likely that liquefaction will be induced. The only solid strength of 
such a deposit is provided by the 
friction between grains touching each other. When the pressure in the water that 
fills the pore space between the 
grains is sufficient to spread them apart, the solid nature of the sand, silt, 
or loess deposit is changed into that of a 
viscous liquid: quicksand or quickclay.

Because it takes time for the pressures that produce liquefaction to build up 
underground, and because quicksand 
is a heavy, thick fluid that moves slowly, conditions of liquefaction, sand 
boiling, and associated phenomena may 
not he apparent during the shaking. In fact, they often do not manifest until 
after the shaking has already passed, 
sometimes not until 10-20 minutes later. The quick conditions or boiling of the 
sand can persist for hours or even 
days after the quake, sometimes as much as a week.

How Big Does It Take & How Near to the Quake?
A natural question regarding seismically induced liquefaction is how big an 
earthquake is required to induce 
quick conditions and how close it has to be for such effects to be possible. 
With regard to size, several technical 
publications suggest that liquefaction does not occur for earthquakes less than 
Richter magnitudes of 5.2. 
However, minor liquefaction effects in areas underlaid by particularly ideal 
predisposing conditions (loose sand 
deposits saturated with a near-surface water table) have been observed for 
earthquakes as small as 4.7 on the 
Richter scale in the New Madrid Seismic Zone. Minor damage to vulnerable 
structures has occurred in such 
areas.

With regard to distance, an earthquake in June of 1987 of magnitude 5.2 in 
southeastern Illinois caused 
liquefaction phenomena near Bell City, Missouri, 150 miles (240 km) from the 
epicenter. A swimming pool, two 
large grain bins, a carport, and three houses were damaged (one severely). There 
was also fissuring and lateral 
spreading. At the same time, points nearer the epicenter of that quake did not 
experience such ground failures. 
Three years later in 1990 this same area experienced no liquefaction phenomena 
when a 4.7 earthquake struck 
only 20 miles (32 km) away.

Nearness to the epicenter implies greater amplitudes of ground motion, but 
distance implies a longer duration of 
shaking, since the wave train consists of many waves traveling at a variety of 
speeds. The epicenter of the 
magnitude 8.1 earthquake that struck Mexico City in 1985 was 240 miles (384 km) 
away and induced 
liquefaction that severely damaged some buildings. Although lasting less than a 
minute at its distant source, that 
quake lasted several minutes in Mexico City. Ground shaking amplitudes within 
the city, were never large, yet 
400 buildings collapsed, resonating with the long-lasting wave train (or 
sequence of waves) amplified by 
underlying clays.

The New Madrid earthquakes of 1811-12 induced extreme examples of liquefaction, 
manifesting as sand boils 
and explosion cratering in the area of St. Louis, Missouri, and across the river 
in the flood plain of Illinois. 
Liquefaction also occurred from those quakes as far as Cincinnati, Ohio, more 
than 300 miles (480 km) away.

Three Ways to Induce Liquefaction
Liquefaction in soils can be stimulated three ways: seismically, mechanically, 
and hydrologically. Seismically-
induced liquefaction is caused by seismic waves. Mechanically-induced 
liquefaction is caused by vibrations that 
come from railroad trains, motor vehicles, tractors, and other mechanical 
sources of vibratory ground motion. 
Hydrologically-induced liquefaction occurs when ground-water pressures increase 
due to rising stream levels 
during flooding conditions. This type of liquefaction most commonly occurs on 
properties protected by levees, 
where rivers can rise to levels above the land surface without actually flooding 
the land. Most of the New Madrid 
Seismic Zone falls into this category, being surrounded by levees that flank the 
rivers and drainage ditches 
throughout the area. Because of this, seismically-induced sand boils became 
hydrologically active during river 
flood stages, and can turn into quicksand and boil again, just as they did 
during the earthquakes that formed them. 
Similarly, tractors, trains, and trucks crossing over sand fissures during times 
of high water table can 
mechanically induce liquefaction, causing highways to sag, railroad tracks to 
get out of parallel, and farm 
equipment to sink into the ground.

Note: Adapted from Stewart, David, and Knox, Ray, The Earthquake That Never Went 
Away: The Shaking Stopped in 1812, 
but the Impact Goes On, Marble Hill, MO: Gatlinburg-Richter Publications, 1993.

2.4b New Madrid Narrative
(A 1912 Account of the 1811-1812 Earthquakes)

The First Day
At 2:30 on the morning of December 16, 1811, a tremendous earthquake occurred 
whose epicentral region is thought to have 
been just west of the location of present day Blytheville, Arkansas, a city that 
did not exist at the time. Had it been there, it 
would have been devastated totally, as evidenced by the numerous earthquake 
boils and fissures that visibly surround the city 
today. The Richter surface wave magnitude is thought to have been 8.6. President 
James Madison, 800 miles (1280 km) away 
in the White House in Washington, DC, was shaken out of bed by the quake.

Many aftershocks immediately followed, some probably magnitude 6.0 or greater. 
At least two more of the December 16 
shocks are thought to have equaled 8.0 on the Richter scale.

Then, some time around 11:00 a.m., another great shock occurred in the vicinity 
of present-day Caruthersville, which to the 
residents there at the time seemed worse than the first. This one is thought to 
have been another magnitude 8.0. However, 
present-day Caruthersville wasnt there at the time. It was not founded until 
1857. In 1811 another village occupied that site. 
It was called Little Prairie, Missouri.

The River Rampages, and Towns Disappear
The Mississippi River was churned into a virtual maelstrom, with miles of banks 
caving in, boats being swamped and sunk, 
and even entire islands disappearing along with their human occupants.

Two towns disappeared at this time. One settlement to disappear on December 16, 
1811, was Big Prairie, Arkansas. At the 
confluence of the Mississippi and St. Francis Rivers, the town site liquefied 
and sank, but slowly enough for all residents to 
safely escape. There were about 100 people there at the time. The Mississippi 
River now occupies that site.
Another community destroyed that day was Little Prairie, Missouri, near present-
day Caruthersville. Eyewitness accounts of 
the horror tell us of people being violently thrown from their beds in the 
middle of the night. It had been a bright full moon, 
but shortly after the shock everything became pitch black because of the dust. 
People were injured and bleeding, and some 
were even knocked temporarily unconscious.

The earth continued to jerk and rumble through the darkness until daylight, 
when, around 8:00 a.m. the second hard shock hit 
the area. Throughout the morning more shocks continued, with the ground heaving 
and cracking, sometimes opening and then 
suddenly slamming shut, spewing ground water over the tops of tall trees. In 
some places the ground literally exploded, 
blasting debris high into the air, raining sand and carbonized wood particles 
down upon the heads of those nearby, while 
leaving a deep crater in the ground where smooth land had been before. Sometimes 
the earth formed spreading crevasses 
beneath the bases of large trees, splitting their trunks from their roots 
upwards beyond the levels of their limbs. At one point 
during the morning a great fissure began to form within the town. The 
townspeople stood around that pit and watched, 
horrified, as dark, viscous fluids gurgled from beneath the earth while gaseous 
fumes and the smell of sulfur and brimstone 
filled the air.

Many were thinking that the end of the world was at hand and that the very gates 
of hell itself were opening up to take their 
village. Amidst the terror, after the third great shock around 11:00 a.m., the 
soils of their settlement began to turn into 
quicksand, with dark waters oozing from the pores of the earth. As their whole 
town began to sink their streets and cabins 
were flooded, not from the river, but from the ground itself.

Escape from Little Prairie
Hastily, the residents of Little Prairie gathered what meager possessions they 
could hold, lifted small children to their 
shoulders, and waded westward. Looking ahead of themselves, they could see the 
rising waters far off on the horizon. For 
eight miles (12.8 km) they waded through waist-deep waters, never knowing from 
one step to the next if they were going to 
plunge headlong into an unseen crevasse or trip over a buried stump, all the 
while surrounded by snakes, coyotes, and other 
wild creatures swimming for their lives in that turgid flood. During their 
escape, they did not know if they would live through 
the day or not, but all did survive.

The First Day Was Over, but the Worst Was Yet to Come
What has been described, thus far, was only the first day of the Great New 
Madrid Earthquake series. More and bigger 
tremors were yet to come. At about 9:00 a.m. on January 23, 1812, another of the 
really big ones hit. This was probably 
centered north of Little Prairie and south of Point Pleasant, a small settlement 
there at the time. It is thought to have been an 
8.4 magnitude earthquake.

The Mississippi River bank, on which the village of Point Pleasant was situated, 
collapsed during the January 23 event. 
Fortunately, the residents had all evacuated the site prior to that catastrophe 
so that none were injured. The town, however, 
was lost forever.

The January 23 event also caused several huge sand boils in Tennessee that 
created a dam across Reelfoot Creek. This created 
Reelfoot Lake.

On February 7, 1812, came the largest quake of all. At about 3:15 in the morning 
the region was rocked by an 8.8 magnitude 
shock. Outside of Alaska, that is the largest earthquake in American history and 
one of the largest in the world.

This is the quake that caused the Mississippi River to run backwards. It caused 
such towering waves of water to be thrown 
over the banks that thousands of acres of trees were shattered into splinters 
and stumps. It threw boats up on dry land along St. 
Johns Bayou at New Madrid. And it created two temporary waterfalls. These falls 
had a vertical drop of about six feet (2 m) 
followed by a mile (2 km) or so of shallow rapids.

During the largest of the New Madrid earthquakes, the river is said to have 
boiled, whirled, and heaved with massive waves 
bashing from one bank to the other, sweeping boats and debris into oblivion. 
Some eyewitnesses from the banks said they 
actually saw the river open up in yawning chasms, into which the swirling waters 
disappeared, drawing hapless flat boats and 
their passengers into the maelstrom, never to be seen again. Others said water 
spouts would shoot upwards from the waters 
surface, like tall fountains.

The earthquakes had literally destroyed the landscape with sand deposits, 
crevasses, and permanent flooding. Most residents 
of the region abandoned their properties and moved away. The boot-heel portion 
of Missouri was nicknamed Swampeast 
Missouri sometime after the quakes.

Two More Towns Gone Forever
The February 7 quake destroyed two other towns, wiping them forever from the 
face of the earth. One was Fort Jefferson, 
Kentucky, swept away by landslides. These slumps are still visible today along 
Highway 51 leading into Wickliffe. The other 
lost town was New Madrid itself. What was left of the settlement slumped 
downward 15-20 feet (5-10 m) into the waters 
edge and was washed away by the spring floods of 1812.

The throbs and throes of terra firma wrought by the Great New Madrid Earthquakes 
of 1811-12 trouble us no more. Though 
the motions of these gargantuan ground vibrations ceased in 1812, their impact 
goes on. Permanent traces of their violence lie 
scattered over a 5,000 square mile (12,000 sq km) area spanning five states.

Note: This account was adapted with only minor changes from Fuller, Myron L., 
The New Madrid Earthquakes of 1811-
1812, A Scientific Factual Field Account, USGS Bulletin 494, Washington, DC: 
Government Printing Office, 1912; reprinted 
by Southwestern Missouri University Center for Earthquake Studies, 1990. Please 
keep in mind that the numerical Richter 
magnitudes quoted in this book were not determined by instrumental measurements 
as they are today, because these events 
predated the invention of reliable seismographs.

2.4c Landslide Data Table

2.4c Landslide Data Table (key)

2.4d Landslide Activity Sheet

Name

Group Names/Roles

1. Why do you think the scales measure less weight as one end of the ramp is 
raised?

2. At what height or what angle does the dry sand slide?

Why do you think it slides then, in terms of forces?

3. What effect does the simulated earthquake (knocking on the ramp) have on the 
dry sand?

Why do you think the simulated earthquake has that effect?

4. Before testing wet sand, what effect do you think wetting the sand will have 
on the slide angle? Why?

5. What effect did wetting the sand have on its slide angle? Why?

6. What effect does the simulated earthquake (knocking on the ramp) have on the 
wet sand?

7. How did you control the following variables?
a. height or angle
b. quantity of material
c. amount of moisture
d. surface condition
e. other

8. How did you insure that only one variable was changed at a time?

9. From your data, try to explain how earthquakes affect landslides in as much 
detail as possible.

10. How could you test your explanation?

11. What was interesting or unexpected in the investigation? Why?

2.4d Landslide Activity Sheet (key)

Date:

1.	Why do you think the scales measure less weight as one end of the ramp is 
raised?
	Some of the weight is acting along the ramp. The scale doesnt record that 
weight.	 
		
2.	At what height or what angle does the dry sand slide?
	40-50 cm, or about 30 degrees.	
	Why do you think it slides then, in terms of forces?
	The force of gravity along the ramp is greater than the frictional forces.
	 
		
3.	What effect does the simulated earthquake (knocking on the ramp) have on 
the dry sand?
	The sand slides a bit with each knock.	
	Why do you think the simulated earthquake has that effect?
	It must reduce the frictional forces because gravity remains constant.	  
		
4.	Before testing wet sand, what effect do you think wetting the sand will 
have on the slide angle? Why?
	It will probably slide more easily because the water reduces the friction.
	 
		 
5.	What effect did wetting the sand have on its slide angle? Why?
	The sand seemed to stick to the ramp, so it required a sharper angle to 
make it slide.	 
	Surface tension causes the sand to adhere to the ramp.	 
		
6.	What effect does the simulated earthquake (knocking on the ramp) have on 
the wet sand?
	It slid further with each knock.	 
	
7.	How did you control the following variables?
	a.	height or angle
	Used a meter stick according to the table.	
	b.	quantity of material
	Filled the dish full each time.	
	c.	amount of moisture
	Measured 225 ml.	
	d.	surface condition
	Used only one type of sand.	
	e.	other
			
8.	How did you insure that only one variable was changed at a time?
	We carefully observed and recorded after each change.	 
			
9.	From your data, try to explain how earthquakes affect landslides in as 
much detail as possible.
	An earthquake will cause a slidable piece of material to move a certain 
amount for each jolt.	 
			
10.	How could you test your explanation?
	Repeat the investigation. Compare our explanation to others. Look into 
real landslide data.	 
			
11.	What was interesting or unexpected in the investigation? Why?
	The addition of water did not lower the angle required for the sand to 
slide.	 
		 
2.4e Components of the Force of Gravity		

2.4f Teacher Background Reading
Seismic Sea Waves
 
A seismic sea wave is created when a fault in the ocean floor moves vertically. 
The energy of the lifted or 
lowered water radiates outward as very long shallow water waves commonly (and 
erroneously) called tidal 
waves. Because these waves have nothing to do with the attraction of the Moon 
or the Sun, scientists prefer the 
Japanese word tsunami, which means wave in the harbor, or the English term 
seismic sea wave.

Most seismic sea waves, like most earthquakes, occur around the Pacific Ocean, 
but there have been great 
seismic sea waves in most regions of the Earth.

The great destructive power of these waves comes from the huge energy imparted 
to the water by fault 
movement. To equate this energy to mechanical work, we can imagine the work 
needed to lift an average volume 
of ocean water a distance (d) of 1 meter. The average depth of the ocean (h) is 
3.8 km. The average surface area 
(A) of the ocean floor moved up or down by such an event, according to seismic 
sea wave research, is 20,000 
square kilometersa 200 km x 100 km piece of seafloor about the size of New 
Jersey. The volume (V) of 
seawater lifted would then be 76,000 cubic kilometers. If we take 1.03 kg/m3 as 
the density (D) of seawater, the 
mass (m) of that seawater would be about 78 billion metric tons. To lift this 
much water by 1 m would take 7.6 x 
1014 Joules, the energy of 183 kilotons of TNT. See Master 2.4j for a complete 
quantitative analysis.

This energy radiates outward from the epicenter as a wave train of low waves, 
not as a single large wave. Each of 
these seismic sea waves has an average amplitude of 1 meter, wavelengths over 
100 km, and periods of 7-15 
minutes (for short-period tsunami) or over 40 minutes (for long-period tsunami). 
These waves travel at speeds 
between 550 and 800 kilometers per hour before encountering land.

Seismic Sea Wave Characteristics
Seismic sea waves are very different from wind-generated sea waves. Normal wind 
waves rarely have 
wavelengths over 300 meters, and generally travel under 100 km/hr. A medium-
sized tsunami can have 
wavelengths of 150 km and travel at 550800 km an hour. Tsunami are like tides 
in that a low tide is followed by 
a high tide, but in the case of a tsunami dramatic high and low tides can be 
only tens of minutes apart. This may 
be the origin of the expression tidal wave.

As seismic sea waves encounter land, they cause rapid tide-like motion. The 
trough of the waves causes very low 
tides, while the wave crests may cause a run as high as 32 meters. Sometimes 
seismic sea waves can cause 
enormous breaking waves. The mechanism for these waves is very similar to that 
of wind waves; the friction of 
the ocean bottom slows the troughs and the crests move over them and break. Thus 
the characteristics of seismic 
sea waves when they hit land, like those of wind waves, are very much related to 
the characteristics of the near-
shore ocean bottom and the shoreline.

The depth of the ocean water also controls the speed of seismic sea waves. As 
the depth changes, the waves 
speed and direction change, resulting in the phenomenon we call refractionthe 
change in direction of a wave as 
it moves from one medium to another.

Extensive international cooperation has developed a tsunami early warning system 
for the Pacific Islands. A 
system for the U.S. Pacific Coast is being developed. The older system is 
centered at the Pacific Tsunami 
Warning Center in Honolulu, where data are collected from seismic observatories 
across the globe. The Center 
evaluates the potential of a tsunami and institutes special observations at 
various tsunami watch stations. All 
these data are verified and emergency preparation procedures are put into effect 
when necessary.

Causes Other Than Earthquakes
Not all destructive sea waves are caused by earthquakes. Some are caused by 
landslides and volcanic eruptions 
and some are artificially created by events like underwater nuclear explosions. 
In 1883, the Krakatoa Island 
volcano erupted, blowing the island away down to a depth of about 43 m below sea 
level. This event caused giant 
waves that killed some 36,000 people in Java and Sumatra.

2.4g Tsunami Event Reports

1. On July 12, 1993, the Hokkaido-Nansei-Oki earthquake of magnitude 7.8 
produced one of the largest seismic 
sea waves in Japans history. The tsunami hit the Okushiri coast within five 
minutes after the main shock, 
causing waves at the shoreline between 15 and 30 m high. The town of Aonae on 
the island of Okushiri suffered 
extensive damage. At least 185 people were killed, with property damage 
estimated at $600 million.

2. The Prince William Sound, or Anchorage, Alaska, earthquake of March 27, 1964, 
caused seismic sea waves 
generated by an underwater landslide. At Valdez, the earthquake triggered a 
landslide that deepened the harbor 
by as much as 100 m in one place and caused a tremendous tsunami. In addition, 
the earthquake uplifted the sea 
floor by as much as 4 meters. The tsunami killed 119 people in Alaska, Hawaii, 
and California and caused over 
$282 million in damage.

3. On April 1, 1946, at 53.5 north and 163 west, 130 km southeast of Unimak 
Island, Alaska, a large earthquake 
occurred 4,000 m below the ocean surface in the Aleutian Trench, causing an 
undersea landslide. Four and one 
half hours later, a tsunami reached Oahu, Hawaii, after traveling 3,600 km at 
800 km/hr. Water rose 12 m above 
the high tide line on Oahu and 18 m on Hawaii (the Big Island). This seismic 
sea wave demolished 488 homes 
and damaged 936 others, with property loss estimated at $25 million and 173 
people killed.
4. An earthquake on the ocean floor may also cause a compressional wave that can 
severely damage ships close 
to the epicenter of the event. Even though we consider fluids as non-
compressional in systems like automobile 
brakes, compressional waves can travel in seawater under the tremendous 
pressures and accelerations of the 
water in underwater seismic events. Ships struck by these waves report an 
experience similar to running aground 
or striking another vessel.

In 1969, a magnitude 8.0 earthquake west of Gibraltar caused compressional waves 
that struck the 32,500-ton 
tanker Ida Knudsen, sailing in 4,900 m of water. The tanker was 35 km from the 
epicenter of the seaquake and 
suffered so much damage that at first it was declared a total loss. The ship was 
later extensively rebuilt.

2.4h Seismic Sea Waves
Activity Sheet

Name
Date
Characteristics of a Seismic Sea Wave
Label the following characteristics and state the average values.
 
A Possible Tsunami Scenario
Imagine that a magnitude 6.8 earthquake occurs 1,625 km from a coastal town on a 
strike-slip fault in the ocean 
floor, where the water is 3.8 km deep. A wave train is generated with a speed of 
650 km/hr and wavelengths of 
150 km. The National Tsunami Warning Center alerts the townspeople.

1. How long will it take the tsunami to hit the coastal town?

2. The first wave hits at 2:00 p.m. Does Jen have time to rescue the boom box 
left on the beach before the next 
wave hits? Calculate the period of the waves. (Period is wavelength divided by 
speed.)

3. Describe what might happen when this seismic wave encounters the coastal 
town.

4. What could be done to prepare for this tsunami?

2.4h Seismic Sea Waves
Activity Sheet (key)

Characteristics of a Seismic Sea Wave
Label the following characteristics and state the average values.

A Possible Tsunami Scenario
Imagine that a magnitude 6.8 earthquake occurs 1,625 km from a coastal town on a 
strike-slip fault in the ocean 
floor, where the water is 3.8 km deep. A wave train is generated with a speed of 
650 km/hr and wavelengths of 
150 km. The National Tsunami Warning Center alerts the townspeople.

1. How long will it take the tsunami to hit the coastal town?
Time = Distance / Speed =	1,625 km = 2.5 hours
	650 km / hr

2. The first wave hits at 2:00 p.m. Does Jen have time to rescue the boom box 
left on the beach before the next 
wave hits? Calculate the period of the waves. (Period is wavelength divided by 
speed.)
Period = Wavelength / Speed =	150 km = .23 x 60 = 13.8 min
	650 km / hr

3. Describe what might happen when this seismic wave encounters the coastal 
town.
There would be very high and very low water with only minutes in between.

4. What could be done to prepare for this tsunami?
People could be warned to move to high ground.

2.4i Wave Characteristics and Energy
 
2.4j Seismic Sea Waves
Energy Analysis
 
Name
Date

To calculate the minimum energy needed to cause an average seismic sea wave, we 
can calculate the work 
needed to give a particular volume of ocean water some gravitational potential 
energy. In essence, this means 
calculating the product of the force needed to lift a particular volume of water 
and the height to which it is lifted. 
Using the average values from tsunami research to carry out the following steps, 
calculate the energy released 
by an earthquake on the sea floor that starts a seismic sea wave.

1. What is the average sea floor area that moves in an earthquake that results 
in a seismic sea wave?

2. Knowing that the average ocean depth (h) is 3.8 km, what volume (V) of water 
is moved in the disturbance that 
causes a seismic sea wave? (Use the formula V = Ah.)

3. This volume of ocean water has a certain mass. Knowing the density (D) of 
ocean water to be 1.03 kg/m3, 
calculate the mass (m) of the water moved by the quake. (Use the formula m = 
DV.)
(note: 1 km3 = 1 x 109 m3)

4. To lift that mass of ocean water requires a force that is at least equal to 
waters weight. Using 9.8 m/s2 as the 
acceleration due to gravity (g), calculate the force (F) needed to lift that 
much ocean water.

5. Supposing that volume of ocean water is lifted an average height (d) of one 
meter, how much work (W) is 
done? This value represents the energy imparted to the seismic sea wave by the 
earthquake.

6. How much energy is this in equivalent tons of TNT? 1 Ton TNT = 4.18 x 109 
Joules

7. Imagine this much energy spreading over a great area, but then being applied 
to say only 3.8 meters of water 
instead of 3.8 kilometers. How high might the 3.8 meters of water be lifted?

2.4j Seismic Sea Waves
Energy Analysis (key)

1. What is the average sea floor area that moves in an earthquake that results 
in a seismic sea wave?

A = 20,000 km2

2. Knowing that the average ocean depth (h) is 3.8 km, what volume (V) of water 
is moved in the disturbance that 
causes a seismic sea wave?

Volume of seawater: V = Ah = (20,000 km2)(3.8 km) = 7.6 x 104 km3
= 76,000 km

3. This volume of ocean water has a certain mass. Knowing the density (D) of 
ocean water to be 1.03 kg/m3, 
calculate the mass (m) of the water moved by the quake. To convert km3 to m3, 
multiply by 10 m3/km3.

Density of seawater: D = 1.03 x 103 kg/m3
Mass of seawater lifted:
m = DV = (1.03 x 103 kg/m3)(7.6 x 104 km3) = (1.03 x 103 kg/m3) (7.6 x 104 km3) 
(109 m3/km3)
7.8 x 1016 kg or 78 trillion metric tons
(note: 1 km3 = 1 x 109m3)

4. To lift that mass of ocean water requires a force that is at least equal to 
waters weight. Using 9.8 ms2 as the 
acceleration due to gravity (g), calculate the force (F) needed to lift that 
much ocean water.

Acceleration due to gravity: g = 9.8 m/s2
Force due to gravity or weight of seawater:
F = mg = (7.8 x 1016 kg)(9.8 m/s2) = 7.6 x 1017 Newtons

5. Supposing that volume of ocean water is lifted an average height (d) of one 
meter, how much work (W) is 
done? This value represents the energy imparted to the seismic sea wave by the 
earthquake.

Distance lifted: d = 1 m
Work done against gravity:
W = Fd = (7.6 x 1017N)(1 m) = 7.6 x 1017 Joules.

6. How much energy is this in equivalent tons of TNT?

Conversion factor: 4.18 x 109 Joules = 1 Ton TNT
W = Energy = (7.6 x 1017 Joules) (1 Ton TNT/4.18 x 109 Joules)
Energy = 1.8 x 108 Tons TNT or 180 Megatons TNT

7. Imagine this much energy spreading over a great area, but then being applied 
to say only 3.8 meters of water 
instead of 3.8 kilometers. How high might the 3.8 meters of water be lifted?

If all the energy were applied to only 3.8 meters of water (1/1,000th), then the 
water would rise 1,000 meters 
instead of only one meter. The energy spreads out very rapidly, so maybe only 
1/100th of the energy reaches the 
3.8 meters of water. In this case the water would rise 30 metersquite a 
sizeable wave.

2.4k Seismic Sea Wave Research and Report Form

Name

Date

Event

Cause

Characteristics of the tsunami

Damage

What could have been done to prevent the damage?

Information Source 
Title:
Author: 
Publisher and place of publication:
Date:

2.4j Grading Matrix

Score 4 points 
Students clearly communicate all the facts about their event, covering each of 
the categories on the Seismic Sea 
Wave Research and Report Form. While reporting the waves characteristics and 
energy, students connect the 
Wave Characteristics and Effects activity sheet and the Energy Analysis activity 
to their event. The students 
employ logical thought processes and a knowledge of todays safety practices in 
their discussion of damage 
prevention. They use some visual method of communicating their ideas, such as 
the board, an overhead, a video, 
a poster, or a demonstration.

Score 3 points 
Students clearly communicate all the facts about their event, covering each of 
the categories on the Seismic Sea 
Wave Research and Report Form. They do not effectively connect the Wave 
Characteristics and Effects activity 
sheet and the Energy Analysis activity to their event. The students discussion 
of preventive measures is good. 
They use the board, an overhead, a video, a poster, or a demonstration in their 
report.

Score 2 points 
Students clearly communicate all the facts about their event, covering each of 
the categories on the Seismic Sea 
Wave Research and Report Form. They superficially mention wave characteristics, 
wave energy, and preventive 
measures, or they cover one of these three, but not the others. They rely mainly 
on the spoken word to 
communicate their information and ideas.

Score 1 point 
Students report the facts of their event by reading directly from the Seismic 
Sea Wave Research and Report 
Form. They hardly mention wave characteristics and energy. The discussion of 
preventive measures, if any, is 
incomplete. They do not use any visual communication aides.

Score 0 points 
Students report incorrect information. The Seismic Sea Wave Research and Report 
Form was poorly completed 
and the presentation to the class is poor. Statements about the waves 
characteristics, its energy, and damage 
prevention are missing or inaccurate.

2.5 Quake-Smart Siting

RATIONALE
City planners, developers, builders, and buyers need information 
about soil and subsoil geology in order to choose sites and design 
structures that will best withstand ground shaking and other 
earthquake hazards.

FOCUS QUESTIONS
What are the important geologic considerations when choosing a 
building site and designing or reinforcing a building for earthquake 
survivability?
Have these considerations been taken into account in the planning of 
towns and cities?

OBJECTIVES
Students will:
1. Interpret soil- and earthquake-related geologic maps.
2. Apply these interpretations in choosing a building site and an 
earthquake-resistant building design.
3. Locate information about the soils and geology of their local 
community and apply the same process to interpret it.

TEACHING CLUES AND CUES
Sample maps are provided so students can do this activity without any 
special preparation. However, the activity will be most meaningful to students 
if they can 
relate it to their own area. Master 2.5b, Soil and Geologic Maps and 
Map Sources, suggests types of maps that would be appropriate and 
where to get them. The Unit 1 resource list suggests many other. 
sources. if you have trouble locating maps, call your county or state 
geology office or the USDA Soil Service and ask for help.

MATERIALS
 Student copies of Master 2.5a, Background Reading: Site Characteristics
 Unit 1 Resource List
 Master 2.5b, Soil and Geologic Maps and Map Sources
 Student copies of Master 2.5c, Surface Map, Soil Map, Geologic 
Map, and Hazard Map (4 pages)
 Transparencies made from Master 2.5c, Surface Map, Soil Map, 
 Geologic Map, and Hazard Map (4 pages)
 Overhead projector
 Local map prepared in Unit 1

VOCABULARY
Fault: a break or fracture in Earths crust along which movement 
has taken place.

Landfill: a site where soil has been deposited by artificial meansoften, 
where garbage or rubbish has been disposed of, then covered with dirt 
and compacted.

Landslide: an abrupt movement of soil and bedrock downhill in 
response to gravity. Landslides can be triggered by an earthquake or 
other natural causes.

Liquefaction: the process in which a solid (soil) takes on the 
characteristics of a liquid as a result of an increase in pore pressure and 
a reduction in stress.

Sedimentary deposits: accumulation of solid particles that originated 
from the weathering of rocks and that have been transported or deposited 
by wind, water, and ice.

Seismic: of or having to do with earthquakes.

Slump: a type of landslide in which a block of rock or soil moves along a 
curved surface and rotates.

Tsunami: a potentially destructive ocean wave created by an 
earthquake or other large-scale disturbance of the ocean floor; a 
seismic sea wave. This Japanese word has the same form in both the 
singular and the plural.

PROCEDURE
Teacher Preparation (optional but highly recommended)
If at all possible, gather a selection of local geologic and soil maps in 
advance. Make student copies of these maps or the appropriate 
portions of them. If you are not familiar with maps of this type, invite a 
local geologist or soil scientist to explain them.

A. Introduction
Have students read Master 2.5a, Background Reading: Site 
Characteristics, as homework, or read it with them in class. Explain 
and amplify any unfamiliar terms. Discuss the relationship between 
soils, subsoil geology, and the suitability of a site for building. Explain 
that the locations of roads, utility lines, reservoirs, and other facilities 
also involve seismic considerations.

B. Lesson Development
1. Divide students into small groups. Give each group one copy of 
Master 2.5c, Surface Map, Soil Map, Geologic Map, and Hazard Map 
(4 pages). Use the map keys to review the special symbols and 
markings on each map. Instruct students to interpret the information 
shown on the specialized maps and transfer it to the surface map.

2. As a class, discuss what type of building would be most earthquake 
resistant in each area of the maps the groups have developed. Ask: Are 
there some areas where construction is not advisable no matter what 
the building materials? Instruct students to add these notations to the 
maps.

3. When all the maps have been completed, site hazards have been 
noted, and construction recommendations have been made, regroup 
students into three or four large groups. Within each large group, stu-
dents can quiz each other about the potential of various sites on their 
maps.

4. Ask for a volunteer from each large group to report on the groups 
findings and recommendations. Ask students: What would be the best 
way to share your recommendations if these maps represented your 
own area of the country?

C. Conclusion
Stack the three specialized maps on the projector at the same time so 
the various kinds of information are all displayed simultaneously. 
Discuss the conclusions that students have drawn and answer any 
questions. Extend the discussion to the geologic history and hazard 
potential of your own region.

(optional but highly recommended) 
Direct students attention to the local map they prepared in Unit 1. 
Have them follow the process they used above to transfer information 
from local soil maps to the classroom map, noting any implications for 
building and the location of critical facilities. If this process arouses 
concerns about safety during an earthquake, ask students to contact the 
local officials they interviewed in Unit 1 to express their concerns and 
find out if these concerns have been taken into consideration. Ask 
these students to report back to the class on what they learn.

2.5a Teacher Background Reading
Site Characteristics

Earthquakes dont kill people, buildings do.
Architects and engineers consider this a fair one-sentence summary of 
earthquake-related deaths, injuries, and 
damage. Yet, underneath every building is the Earth, which can shake and damage 
or destroy the building. In the 
final analysis, the cause of the death and destruction may not be the earthquake 
or the building, but rather 
someones lack of knowledge about the soil and subsoil under the building. Much 
of the scientific study 
surrounding earthquakes is focused on the geological characteristics of building 
sites, the relationship of building 
sites to earthquake damage, and how buildings respond to ground shaking induced 
by earthquakes. Location is 
just as important as building design for making sure that a building can survive 
an earthquake. Geological site 
considerations include the location and history of faults, sedimentary deposits, 
landfill, liquefaction, steep slopes 
and landslides, tsunami, and human-made hazards.

Faults: Displacement and Ground Shaking
Earthquakes happen when two sides of a fault are displaced, releasing energy in 
waves. Buildings can be 
damaged either by direct displacement on the fault or by ground shaking.

Geologists have mapped the locations of many of the most dangerous fault zones 
in the U.S., yet many faults are 
not yet recognized. A building within a fault zone can be severely damaged by an 
earthquake on that fault, but 
this kind of damage is rare. Most buildings are not in fault zones, and the 
recurrence interval for any particular 
fault may be hundreds or thousands of years. The most common cause of damage in 
earthquakes is the ground 
shaking caused by the earthquake waves. These attenuate, or die off, with 
distance, so the two most important 
factors controlling the amount of shaking are the magnitude of the earthquake 
and the distance of the building 
from the fault.

The distance from the fault, not from the epicenter, determines the amount of 
damage. Energy is produced by all 
the parts of the fault that move in an earthquake. Because in big earthquakes 
the fault can be hundreds of miles 
long, a structure may be hundreds of miles from the epicenter and still be on 
top of the quakes impact zone.

Several other factors can affect the amount of shaking. Waves do not travel 
evenly in all directions from the fault, 
so the orientation of the fault and the way in which displacement on the fault 
occurs can change the 
characteristics of the waves. Even more important are variations in local 
topographythe lay of the land
including the subsoil layers, which may trap or amplify seismic energy, and the 
type of rock and soil that underlie 
buildings.

Sediments and Landfill
Ground shaking is greatest on soil that has arrived in place fairly recently, 
whether it was put there by natural 
processes (in which case, geologists call it sediment) or by artificial ones (in 
which case, it is called landfill). 
Unfortunately, most of the worlds urban centers are sited on relatively young, 
loose, sedimentary deposits. 
Sediment age and particle size are important in predicting how soil will respond 
to shaking during an earthquake. 
Areas near the shores of rivers and oceans are especially likely to contain 
young sediments washed there by the 
water.

Structures located on former watercourses (such as old river beds) or on sites 
that have been artificially filled 
with sand dredged up from the bottom of a body of water are among the worst 
locations for construction in 
earthquake country because the soil can shift so easily. In Mexicos devastating 
1985 earthquake, Mexico City, 
320 km (200 miles) from the epicenter, suffered far more damage than the 
shoreline towns closer to the epicenter. 
The shoreline is made of solid rock, but Mexico City is built on the sediments 
of an ancient lakebed.

Old watercourses are usually low and wet, so they are frequently filled when 
someone wants new land to build on 
and sell. Landfill is usually a mixture of soil, rock, and decaying organic 
material in particles of varying sizes.

Because it is not natural to the area where it has been put, landfill in one 
spot is likely to be of a different 
composition from landfill in another spot nearby. When seismic waves are 
transmitted through landfill, they are 
amplified and their period is lengthened. Long earthquake waves are particularly 
destructive to some types of 
surface structures. Landfills commonly will settle and sink during a strong 
earthquake.

Liquefaction
Whenever poorly consolidated soil or fine sand becomes saturated, an earthquake 
is likely to cause soil 
liquefaction. Earthquake vibrations compact the soil, causing water mixed with 
sand to flow upward. Structures 
may settle several feet or even topple, causing considerable damage. In a 
related phenomenon, sandy or muddy 
soils may behave like liquids, flowing out onto the surface as sand boils or mud 
boils.

Slopes and Landslides
Structures on cliffs and ridges are also at high risk for earthquake damage, 
even if they are built on strong 
bedrock. Earthquake waves appear to be reflected and amplified by topographic 
highs like cliffs and ridges. 
Earthquakes also dramatically increase the potential for landslides in areas 
where landslides are common, such as 
those where sedimentary rocks lie just under the soil. The probability of an 
earthquake-related landslide depends 
on the strength of the slope materials, the steepness of the slope, and the 
extent and duration of ground shaking. 
Structures on cliffs and ridges need to be designed to the highest earthquake 
standards, and should be fully 
insured.

Tsunami
Tsunami are caused by faulting and the abrupt movement of the ocean floor during 
an underwater earthquake. A 
wave generated by this movement can travel as fast as 640 km/hr (400 mph) on the 
open ocean, where it may not 
be much above normal height. When it approaches the shore, however, it may 
attain a height of 15-20 m (50 
feet)in some cases, even 32 m. Tsunami present a distinct hazard to low-lying 
coastal areas, particularly the 
west and northwest shorelines along the western North American coast and the 
northerly facing coast of Hawaii. 
Low-lying waterfront properties in these areas are at high risk from tsunami.

Human-Made Structures
Human-made structures, such as dams, reservoirs, water tanks, and tall 
buildings, can present special earthquake 
hazards, and need to be considered during site selection. Every building 
decision needs to consider the exposure 
to geologic hazard and the probability of an earthquake, bearing in mind that 
earthquakes are possible anywhere 
in the world at any time.

2.5b Soil and Geologic Maps and Map Sources

 USGS topographical maps of your area

 Detailed USGS seismic maps that specifically identify earthquake fault traces 
(available only for areas of high 
seismic risk)

 Maps issued by state departments of geology or natural resources

 Land use policy or development maps, available from county or city zoning 
offices. The use of these maps is 
mandatory for all nonresidential and large-scale residential construction. They 
may be referred to as special 
studies zones maps

 Seismic risk maps. These are based on the location, number, and magnitude of 
historic earthquake events that 
have taken place and been recorded during the last 200 years

 Maps indicating areas of structurally defective grounds, generally developed 
by state or local agencies to 
include (a) poor soils and (b) landslide areas

 Landslide susceptibility maps, available from USGS for specific regions in the 
U.S. The U.S. Department of 
Housing and Urban Development also has data and maps of landslide problems.

 Maps noting geologic hazards; may he included in your local building codes

 Microzonation maps include data on the anticipated maximum earthquake 
intensity, active faults, geologic 
units, special studies zones, ground response, liquefaction susceptibility, 
landslide susceptibility, and zones of 
potential tsunami inundation. Available from zoning offices.

 Soil studies of the area produced for agricultural purposes, either by USDA or 
local agencies

 Soil maps produced by the Soil Conservation Service


BOOKS FOR YOUNG READERS
Asimov, I. (1978). How Did We Find Out about 
Earthquakes? New York: Walker.

Aylesworth, T.G., and Aylesworth, V.L. (1983). 
Moving ContinentsOur Changing Earth. Hillside, 
N.J.: Enslow.

Eicher, D.L. (1976). Geologic Time. Englewood 
Cliffs, NJ. Prentice Hall.

Eicher, D.L. (1984). The History of the Earths Crust. 
Englewood Cliffs, NJ: Prentice Hall.

Fodor, R.V. (1978). Earth in Motion: The Concept of 
Plate Tectonics. New York: William Morrow.

Iacopi, R. (1974). Earthquake Country. Menlo Park, 
CA: Lane Book Company.

National Geographic Society. (1982). Our Violent 
Earth. Washington, DC: National Geographic Society.

Poynter, M. (1990). Earthquakes: Looking for 
Answers. Hillside, NJ: Enslow.

Walker, B. (1981). Earthquake. (Planet Earth series) 
Alexandria, VA: Time-Life Books.

BOOKS
Adams, M. W., editor. (1970). Tsunamis in the Pacific 
Ocean. Honolulu, HI: East-West Center Press.

Bolt, Bruce A. (1993). Earthquakes. New York: W. H. 
Freeman and Co. General information on earthquakes 
in a readable style. Probably the best single source 
currently available.

Bolt, Bruce, A. (1982). Inside the Earth. San 
Francisco: W.H. Freeman and Co. More technical than 
the later Earthquakes, but highly readable for adults 
and advanced students. Includes excellent historical 
information; portraits of Beno Gutenberg, Inge 
Lehmann, and other pioneers of seismology; plus 
challenging activities and exercises.

Bonini, W.E., and Bonini, R.R. (1986). Andrija 
Mohorovicic: Seventy Years Ago an Earthquake 
Shook Zagreb. In History of Geophysics, Vol. 2, 
edited by C. Stewart Gillmor. Washington, DC: 
American Geophysical Union, pp. 83-88.

Earthquake National Research Council. (1986). Active 
Tectonics. Washington, DC: National Academy Press. 
An anthology of technical discussions, part of the 
Studies in Geophysics series.

Eiby, G.A. (1980). Earthquakes. Auckland, New 
Zealand: Heineman.

Georgi, Johannes. (1934). Mid-Ice: The Story of the 
Wegener Expedition to Greenland. London, England: 
K. Paul, Trench, Trubner, and Co., Ltd.

Gere, J.M., and Shah, H.C. Terra Non Firma: 
Understanding and Preparing for Earthquakes. New 
York: W.H. Freeman.

Gubbins, David. (1990). Seismology and Plate 
Tectonics. New York: Cambridge University Press. An 
undergraduate textbook. Readable, with useful 
illustrations, many advanced math activities, and some 
60 seismograms.

Levin, H.L. (1978). The Earth through Time. 
Philadelphia, PA: W.B. Saunders.

Moore, Gwendolyn B., and Yin, Robert K., 
(November 1984). Innovations in Earthquake and 
Natural Hazards Research: Determining Soil 
Liquefaction Potential. Washington DC: Cosmos 
Corporation (202-728-3939).

Nance, John J. (1989). On Shaky Ground: Americas 
Earthquake Alert. New York: Avon Books.

National Academy of Sciences. (1985). Liquefaction 
of Soils during Earthquakes. Washington, DC: 
National Academy Press.

Federal Emergency Management Agency/National 
Science Teachers Association (NSTA)/FEMA. 
(1988). EarthquakesA Teachers Package for K-6. 
FEMA 159. Washington, DC: FEMA Publications 
(500 C St. SW, Washington, DC 20742).

Oakeshott, G.B. (1976). Volcanoes and Earthquakes: 
Geologic Violence. New York: McGraw Hill.

Pakiser, Louis. (1989). Earthquakes. Washington, DC: 
U.S. Government Printing Office. An illustrated 
pamphlet of general information, prepared for the U.S. 
Geological Survey, Department of the Interior.

Scholtz, Christopher H. (1990) The Mechanics of 
Earthquakes and Faulting. Cambridge, England: 
Cambridge University Press. A technical reference for 
teachers interested in exploring further.

U.S. Department of Commerce, Coast and Geodetic 
Survey. (1965). Tsunami! The Story of the Seismic Sea 
Wave Warning System. Washington, DC: U.S. 
Government Printing Office. An exciting story with 
fine illustrations, at a students reading level.

Wegener, Alfred (1966). The Origin of Continents and 
Oceans. New York: Dover.

Wegener, Else. (1939). Greenland Journey: The Story 
of Wegeners German Expedition to Greenland in 
1930-1931. London and Glasgow: Blackie and Son 
Ltd.

ARTICLES AND PAPERS
Evaluating Earthquake Hazards in the Los Angeles 
RegionAn Earth Science Perspective. U.S. Geologic 
Survey Professional Paper #1360, 1985, pages 
375-413, Evaluating Tsunami Potential.

Gore, R. (1985). Our Restless Planet Earth. National 
Geographic 168: 142-181. Includes map, Earths 
Dynamic Crust.

Lowman, P.; Wilkes, Y,; and Ridky, R.W. (1978). 
Earthquakes and Plate Boundaries. Journal of 
Geological Education 26: 69-72.

Matthews, Samuel, W. (1973) This changing Earth. 
National Geographic 143: 1-37.

McCredie, Scott. (March 1994). Tsunami: The Wrath 
of Poseidon. Smithsonian Magazine 24, 12:28-39.

Peterson, Ivars. (Oct. 12, 1985). Liquid Sand. 
Science News.

U. S. Geological Survey, 904 National Center, Reston, 
Virginia, 22092; 703/648-6078. See especially 
Pacific Tsunami Warning System, Volume 18, 
Number 3, 1986, and Devastating Tsunami Inspires 
Efforts to Reduce Future Tsunami Destruction, 
Volume 19, Number 2, 1987.

Wilson, J.T., ed. (1970). Continents Adrift: Readings 
from Scientific American. New York: W.H. Freeman 
and Co.

NONPRINT MEDIA
California Earthquake Education Project. Earthquake 
kits and group materials. Lawrence Hall of Science, 
University of California, Berkeley, CA 94720; 
415/327-6017.

The Drift Globe. Burlington, NC: Omni Resources, 
Inc. (919/227-8300). A 12"-diameter globe with velcro 
fasteners and velcro continents. Instruction guide is 
illustrated with cartoons.

The Earthquake Connection. A live-action video in 
two parts. Available from Wards Natural Science 
Establishment, Inc., 5100 W. Henrietta Road, PO Box 
92912, Rochester, NY; 800-962-2660. Wards also has 
earthquake filmstrips and slides.

Earthquake Effects: A Computer Animation and Paper 
Model. U.S. Geological Survey Open-File Report 
92-200B, by Tau Rho Alpha, Robert A. Page, and 
Leslie C. Gordon. Order from U.S. Geological Survey, 
PO Box 25425, Denver, CO 80225; 303-236-4476.

Earthquake Simulator. A program for the Apple II 
series. Available from Wards Natural Science 
Establishment, Inc., 5100 W. Henrietta Road, PO Box 
92912, Rochester, NY; 800-962-2660.

Earthquake Slides. Photographs of earthquake effects, 
copies of seismograms, and seismicity maps can be 
obtained from the National Geophysical and Solar 
Terrestrial Data Center, Code D62, NOAA/EDS, 
Boulder, CO 80302.

Earthquake Sounds. A cassette tape of sounds 
recorded in various earthquakes, available with a 
catalog from Seismological Society of America, 201 
Plaza Professional Building, El Cerrito, CA 94530; 
415-525-5474.

Earthquakes: Environments and Effects. A 15-minute 
interactive videotape available from CALEEP, 510-
642-8718.

EERI Videotapes and Slide Sets. Oakland, CA: 
Earthquake Engineering Research Institute. For 
information, phone 510-451-0905, or fax 510-451-
5411.

Steinbrugge Collection. Richmond, CA: Earthquake 
Engineering Research Center. Over 10,000 
photographs and 5,000 slides of earthquake damage. 
The library will provide copies to teachers and 
researchers. Call 510-231-9401 for information.

Note: Many of the references for Unit 3 may also be useful 
for teaching this unit. Inclusion of materials in these 
resource listings does not constitute an endorsement by 
AGU or FEMA.

Seismic Sleuths

Earthquakes

A Teachers Package for Grades 7-12

Unit Three
How Do People Learn about Earthquakes?

In the first lesson, students will learn about the 
movement of earthquake waves in our Earth and on its 
surface. It was the study of this movement, by 
Mohorovicic, Lehmann, and others, that developed 
our current understanding of the interior of the Earth. 
Activities illustrate the movement of P and S waves. 
Background material on Love and Rayleigh waves is 
also provided.

The second lesson in Unit 3 is built around 
biographical sketches of three individuals who made 
major contributions to our knowledge of the Earths 
inner structure: the German meteorologist Alfred 
Wegener, who amassed evidence for the controversial 
theory of continental drift; the Croatian seismologist 
Andrija Mohorovicic, who demonstrated the existence 
of the discontinuity between crust and mantle that 
bears his name; and the Danish seismologist Inge 
Lehmann, who demonstrated the existence of the inner 
core. A timetable of other relevant discoveries is 
included as teacher background material.

Lesson 3 begins with a pair of activities that contrast 
the two systems most commonly used to characterize 
earthquakesthe Modified Mercalli scale, which 
assigns a number on the basis of observed effects, and 
the Richter scale, which assigns a number on the basis 
of instrument readings. Students draw isoseismals on 
a map in the first activity. In the second they compare 
Richter magnitudes from several seismograph stations 
for the same earthquake. In the third activity, they 
practice reading seismograms.

Lesson 4 has three parts, moving from the worldwide 
distribution of earthquakes to one seismically active 
area of Japan and then home to the United States. At 
all three stages, students plot actual earthquake data in 
order to gain an experiential understanding of where 
earthquakes occur. In the second activity they 
construct a plot in three dimensions. Most students 
will be surprised to learn that earthquakes are 
everyday occurrences on a global scale, and that they 
may originate from foci as deep as 700 km inside the 
Earth1/9 of the way to its center.

Like the previous unit, this one offers a variety of 
experiences in scientific observation, computation, 
and the application of social science principles. It also 
presents factual information that will stand students in 
good stead as consumers of media information and as 
future property owners.

Social studies teachers may be especially interested in 
the second lesson of this unit. Mathematics teachers 
will find applications of algebra and geometry in many 
of the others. The lessons in this unit can stand on 
their own, but taken together, they provide an 
excellent preparation for learning to mitigate the effect 
of earthquakes on the human environment, in Unit 4.

3.1 The Waves of Quakes
 
RATIONALE
To understand earthquakes and their effects on Earths surface, and to 
understand how scientists have learned about Earths interior, students 
must begin to understand the properties of waves.

FOCUS QUESTIONS
How does matter transmit energy in the form of waves?

OBJECTIVES
Students will:
1. Compare and contrast the two main types of earthquake waves and 
draw sketches to illustrate them.
2. Describe the manner in which each of the two types transfers 
energy and moves Earth particles.

TEACHING CLUES AND CUES
Metal Slinkies will be more effective than plastic ones for this 
activity. If you use plastic Slinkies, tape two together, with 
about 7.5 cm of overlap, for each pair of students.

It will be helpful to refer to Master 2.2b, Earth 
Cross Section, as you talk about waves moving 
through the Earth. You may want to project the transparency.

PART ONE
PRIMARY WAVES (P WAVES)

MATERIALS
 Student copies of Master 3.1a, Earthquake Wave Background
 Slinky toys (One for every two students is ideal.)
 White plastic tape
 String
 Unlined paper
 Pencils

PROCEDURE
Teacher Preparation
Put the Slinky toys and the tape in a central location where they will 
be available to students. Students will mark the coils so they can see 
the movement of energy along their length.

VOCABULARY
Body waves: waves that move through the body (rather than the 
surface) of the Earth. P waves and S waves are body waves.

Compression: squeezing, being made to occupy less space. P waves 
are also called compressional waves because they consist of alternating 
compressions and expansions.

Longitudinal waves: waves that move particles back and forth in the 
some line as the direction of the wave (P waves).

P waves: primary waves, arrive at a station first because they travel faster 
than S waves, or secondary waves. These waves carry energy through 
the Earth in the form of longitudinal waves.

S waves: secondary waves; waves that carry energy through the Earth in 
the form of very complex patterns of transverse waves. These waves 
move more slowly than P waves (in which the ground moves parallel to 
the direction of the wave). In an earthquake S waves are usually 
bigger than Ps.

Transverse waves: waves that vibrate particles in a direction 
perpendicular to the waves direction of motion (S waves).

A. Introduction
Explain: It is the energy from earthquakes that puts human beings and 
human structures in danger. This energy is transmitted through the 
Earth in the form of waves. Distribute copies of Master 3.la, 
Earthquake Wave Background. Go over the Body Waves section of 
the background material with the class.

B. Lesson Development
1. Ask students:
 Where is the energy of an earthquake released? (along the fault 
plane where tectonic stress is released)
 In what form is the energy from an earthquake released? (in the 
form of waves)

2. Divide students into pairs or groups of even numbers, depending on 
the number of Slinkies available. Direct students to pick up their 
Slinkies and mark two spots on each, near the center of the coil, with 
white plastic tape. The two pieces of tape should be at the tops of 
adjacent loops.

3. Two students will hold each Slinky, one on either end. Instruct 
them to stretch it out to a length of approximately three meters on the 
floor or a long counter. Have students take turns compressing between 
10 and 20 coils and then releasing them rapidly while they continue to 
hold the Slinky.

TEACHING CLUES AND CUES
Activity 3 in lesson 2.4 deals with tsunami, destructive water waves 
often caused by earthquakes. If you have not taught this 
lesson, refer to it now.

4. After several repetitions, ask students to describe what they saw 
happen with the coil and the tape. Then ask:

 What kind of earthquake waves does this movement resemble? 
(longitudinal body waves, or P waves)

 How is the movement of the spring like the movement of the 
waves? (It moves by contracting and expandingby compression 
and expansion.)

 In what direction does the energy move? (It moves out from the 
point at which the energy is releasedthe focus.)

 What happens within the body of the Earth when energy moves 
through it in this way? (Energy is transmitted from any material 
near the focus to particles away from the source in the form of 
waves.)

TEACHING CLUES AND CUES
Point out that in a P wave the movement of each coil of the Slinky is 
parallel to the wave motion (the length of the Slinky). In 
an S wave, the movement is perpendicular to the length of the 
Slinky. This difference may be easier for students to see than compression 
and dilation.

C. Conclusion
Challenge pairs of students to decide what a P wave would look like 
and draw one on the top half of a sheet of paper. Tell them to use 
pencil, so if they change their minds later they can revise the drawing. 
(There are several acceptable ways to do this.)

ADAPTATIONS AND EXTENSIONS
1. With students who show special interest, assign all of the reading 
on Master 3.1a and add Rayleigh waves and Love waves to your 
discussion.

2. Research and discuss (a) the intermolecular forces that provide the 
means of transmitting energy in longitudinal waves and (b) the speed 
of P waves traveling in the Earths crust. Ask:

 How does the density of materials affect the speed of P waves? 
(The more dense the material, the faster the waves move.)

 As P waves travel deeper into the Earth, does their speed change? 
(P waves, like S waves, move faster in the mantle than in the crust, 
because the mantle is more dense. The rocks that compose the 
Earth at great depths, however, are plastic, so they slow down the 
waves.)

 Why can P waves travel through liquids, while S waves cannot? (P 
waves travel by compression, and S waves travel by shearing at 
right angles to the direction of motion. Water cannot spring back 
after it is sheared, so the S waves die out in water.)

 How are P waves similar to sound waves? (A sound wave in the 
ground is a P wave; a P wave in the air is a sound wave. Both are 
compressional waves.)

PART TWO
SECONDARY, OR SHEAR WAVES (S WAVES)

MATERIALS
 7.6 m (25 ft) of coiled telephone cord, available at electronics or 
phone stores and some discount stores
 Two different colors of plastic tape, about 1 cm (.5 in.) wide
 Masking tape
 Two empty soda cans

TEACHING CLUES AND CUES
Students may be confused by the array of synonyms for P waves 
and S waves. Help them to understand that each term provides additional 
information about 
one type of wave. P waves, or primary waves, are also called compressional waves 
and longitudinal waves. S waves, or secondary waves, are also called shear waves 
and 
transverse waves. Both P and S 
waves are body waves.

PROCEDURE

A. Introduction
Ask students:

 What type of body wave did the Slinky exercise illustrate? (P 
waves, also known as compressional waves or longitudinal waves)

 What is the other type of body wave? (S waves, also known as 
waves or transverse waves)

B. Lesson Development
1. Give these instructions for demonstrating single shear waves (S 
waves).
a. Place a band of bright colored tape halfway along the coiled 
telephone cord. Place another band close to one end. Lay the cord 
straight along a smooth surface. Have two students hold the ends of 
the cord firmly so it will not move.
b. With plain masking tape, mark a 50-cm line perpendicular to one 
end of the cord. Mark another line of the same length at the cords 
halfway point, directly under the center band of tape. This will 
provide you with a reference line.
c. Pick up the end of the rope at the center of the first perpendicular 
tape line, then move your hand back and forth quickly along the 
masking tape. As you expected, a wave travels down the rope (or 
transmitting medium). Observe the motion of the colored tape while 
waves are moving by. Students may take turns holding the ends of the 
cord.
d. Place two empty soda cans upright on either side of the cord on the 
center tape line. Both cans should be the same distance from the 
cordabout 30 cm (1 ft). When a wave of sufficient amplitude is sent 
along the cord between these cans, what will happen? (The same 
piece of cord, as indicated by the colored tape marker, will knock over 
both cans.)

2. Point out that although students may only see motion in one 
direction, the transverse wave they have just observed vibrates in a 
direction perpendicular to its direction of motion. Remind students 
that S waves within the Earth are not just in one plane, and dont all 
have the same frequencies and amplitudes. In an earthquake, a jumble 
of S waves passes through a particular volume of Earth at the same 
time. Since S waves reach the surface from below, a special pendulum 
seismograph would show ground motion for S waves as a very 
complex, seemingly random pattern of horizontal (back and forth) 
motions.

C. Conclusion
Ask students:

 Which type of wave does this activity illustrate? (S waves)

 What are some differences between P waves and S waves? (P 
waves are longitudinal and S waves are transverse. P waves can be 
transmitted through solids, liquids, and gases, while S waves can 
only be transmitted through solids.)

Now ask students, working in the same pairs as for part one, to decide 
what a diagram of an S wave would look like and draw one on the 
other half of the page they used in part one. They may want to revise 
their drawings of a P wave at this time. When they have finished, ask 
each pair of students to exchange their drawings with another pair and 
discuss the similarities and differences.

ADAPTATIONS AND EXTENSIONS
1. If students have also discussed Rayleigh waves and Love waves, 
ask them to draw these on the backs of their pages at this time and 
follow the procedure for exchanging diagrams as above.

2. Invite students to research and discuss the intermolecular forces 
that provide the means of transmitting energy in transverse waves, and 
why S waves can not be transmitted through liquids, including Earths 
outer core.

The major types of seismic waves are classified as 
body waves and surface waves. The two have 
different shapes and properties. All waves in matter 
depend upon the interaction of forces among the 
particles of some material. These forces transmit 
movement of one particle to movement in adjacent 
particles.

Body Waves
Body waves, so called because they travel through 
the body of the Earth, consist of two types: primary 
(P) and secondary (S). S waves are also called shear 
waves and transverse waves.

Primary (P) waves consist of alternating 
compressions and expansions (dilations), so they are 
also referred to as compressional waves. P waves 
are longitudinal; they cause particle motion that is 
back and forth, in the same linear direction as 
energy transfer. These waves carry energy through 
the Earth, usually at the rate of 3.57.2 km/sec in the 
crust and 7.88.5 km/sec in the mantle.

Secondary (S) waves are transverse; the particle 
motion they cause is perpendicular to the direction 
of energy transfer. Their usual speed is 2.04.2 
km/sec in the crust and 4.54.9 km/sec in the 
mantle.

Longitudinal (P) waves can be transmitted through 
solids, liquids, and gases, while transverse (S) waves 
(with the exception of electromagnetic waves) can 
only be transmitted by solids. Waves can be 
reflected and refracted (bent) when they move from 
material of one density to that of another density. 
Wave energy can also be changed to other forms. As 
they move through the Earth, the waves decrease in 
strength, or attenuate. Waves attenuate more slowly 
in solid rocks than in the basins full of sediment so 
common in the West. Because of this, an earthquake 
in the crust of the eastern United States is felt over a 
wider area than a quake the same size in the rocks of 
the western states.

Surface Waves
Seismograph stations detect surface waves from 
many, but not all, quakes. Whether a station detects 
them or not depends on the strength of the quakes 
energy release, the depth of the quake, and the 
stations distance from the focus.

Unlike body waves, which travel through the Earth, 
surface waves travel around it. The two main types of 
surface waves are called Rayleigh waves and Love 
waves. These surface waves travel more slowly than S 
and P waves, and attenuate more quickly.

Within Rayleigh waves, Earth particles move in 
elliptical paths whose plane is vertical and set in the 
direction of energy transfer. When an Earth particle is 
at the top of the ellipse, it moves toward the energy 
source (seemingly backwards), then around, 
downward, and forward, away from the source. It then 
moves around and upwards back to its original 
position. This produces a ripple effect at the Earths 
surface that is similar to ripples on a pond. The orbits, 
or paths, of these particles become smaller and finally 
die out at a certain depth within the Earth.

Love waves move particles in a back and forth 
horizontal motion as the energy moves forward. If you 
could see a Love wave inside the Earth, you would 
notice a zigzag horizontal motion.

Putting Them Together
Since these four types of waves shake a location on 
Earths surface in various ways and directions, a 
seismic station needs at least three seismographs to 
glean a reasonably good image of ground shaking at 
that location. One seismograph is built to measure 
vertical motions, and two others, aligned perpendicular 
to each other, measure horizontal motions. Although 
P, S, and Rayleigh waves may be recorded on all three 
seismographs, P waves are best recorded on the 
vertical component and S waves on the horizontal. 
Love waves are only recorded on the horizontal 
components, but Rayleigh waves are recorded on all 
three.

3.2 Pioneering Ideas

VOCABULARY
Continental drift: the theory, first advanced by Alfred Wegener, that 
Earths continents were originally one land mass, split off and 
gradually form the continents we know.

Epitaph: an inscription on a tombstone, often intended to sum up 
the achievements of a persons life.

Meteorology: the study of Earths atmosphere.

Pioneer: a person who moves into new and uncharted territory.

Plate tectonics: the theory that Earths crust and upper mantle (the 
lithosphere) are broken into a number a more or less rigid, but 
constantly moving, segments, or plates.

Seismology: the scientific study of earthquakes.

Topography (adj. topographic): the shape of the land; the contours and 
the arrangement of surface features that characterize a region.

RATIONALE
The people who have shaped our idea of the Earth are pioneers, just as 
truly as those who struck out in new directions across its surface. This 
idea may be new to students.

FOCUS QUESTIONS
Could a person be a pioneer without leaving home?

OBJECTIVES
Students will:
1. Read a biographical sketch about a pioneer of earth science.
2. Identify the characteristics of a pioneer.
3. Be able to tell why Wegener, Mohorovicic, and Lehman were 
pioneers.

MATERIALS
 Student copies of Master 3.2a, Three Pioneers (3 pages)
 Master 3.2b, Chronology: The Beginnings of the Seismological Age
 Overhead projector and transparencies (optional)
 Reference books for research (See Unit Resources.)
 Paper and pens

PROCEDURE
Teacher Preparation
Assemble a classroom reference shelf of biographical encyclopedias, 
studies on continental drift and plate tectonics, and books on earth- 
quakes. (See Unit Resources.)

A. Introduction
Tell students that you would like them to explore the notion of 
pioneer. Write the word on the chalkboard or overhead projector and 
ask the class to brainstorm about the meaning of the word and its 
implications. Be prepared to accept any reasonable suggestion. Such 
ideas as risk-taker, adventurer, initiator, innovator, frontier person, 
and explorer are likely to come forward. You may want to use these 
terms to build a concept map.

During the course of the brainstorming, remind the class that in a 
historical sense, we tend to think of pioneers as men and women who 
have moved beyond the edge of settlement. Daniel Boone was such a 
person, and so were Lewis and Clark and Matthew Henson, the polar 
explorer. There are other types of pioneers, howeverthose who are 
willing to advance new ideas and suggest new theories to explain 
physical or cultural phenomena. Albert Einstein, with his theory of 
relativity, is a good example of this kind of pioneer. So is Marie 
Curie, who worked to develop radium therapy and conducted some of 
the earliest experiments with radiation.

B. Lesson Development
1. When the brainstorming session has ended, ask each student to 
write a one-sentence definition of the term pioneer, using the list 
generated by the class as a reference. Then have students share their 
responses to learn if a consensus has developed about the meaning of 
the term. From the collection of definitions presented by class 
members, write what seems to be a representative definition on either 
the board or the overhead. Here are some likely definitions:

A pioneer is a person who is on the cutting edge, someone with the 
courage and the vision to try something new.

A pioneer is the first person to suggest a new idea or to try something 
that has never been tried before.

A pioneer is a person who prepares the way for others because of 
his/her courage and foresight.

2. Divide the class into groups of three students each. Provide each 
group with one copy of Master 3.2a, Three Pioneers. Each of the 
students may read one essay. When students have finished reading, 
ask them to give the essay a title and to write a two- or three-sentence 
summary of the essay in the space provided.

3. With this as context, remind students that when each of these 
discoveries was first published, it created discussion and even 
controversy. To understand the kind of excitement each advance in 
science causes, have half of the students who read about each scientist 
research the evidence that person offered to support the new theory 
and the other half research the views of his or her critics or the 
reasons why it may not have been accepted immediately. Later in the 
same period or the next day, invite the groups to present and discuss 
opposing points of view culled from their reading.

TEACHING CLUES AND CUES
Use Master 3.2b, Chronology: The Beginnings of the 
Seismological Age, for your own reference and to help 
students place the work of these three scientists in the context of 
other disciplines.

C. Conclusion
Return to the consensus definition of pioneer that the class developed 
and ask students to apply that definition to these three individuals. To 
do this, they should write epitaphs for the tombstones of the three 
scientists. Remind students that the purpose of an epitaph is to 
summarize a persons life in a brief and pithy fashion. Post the 
epitaphs on the bulletin board to present the variety of impressions 
class members have about Wegener, Mohorovicic, and Lehmann.

ADAPTATIONS AND EXTENSIONS
1. Make a time line from the information on Master 3.2b, Chronology: 
The Beginnings of the Seismological Age. You could do this either 
before class or during class with student participation.

2. As a class, brainstorm suitable epitaphs for some of the other 
pioneers mentioned in this lesson and those students know about from 
other areas of study.

3. Encourage students to read biographies of intellectual explorers and 
learn about some of the challenges pioneers have faced. ?

3.2a Three Pioneers

Name
Date

1. In 1912, when Alfred Wegener proposed in print that Earths 
continents floated on denser and more stable material below, he 
was openly ridiculed and even scorned by his colleagues. Not until 
several decades later did his ideas receive any acceptance. Today 
he stands as the forefather of modern plate tectonics because of his 
theory of continental drift. His widely accepted theory of land 
displacement holds that Earths continents have been in motion 
throughout geological time.

Wegener believed that there was once a single supercontinent, 
which he called Pangea (or Pangaea). He said that Pangea broke 
apart millions of years ago to form two large continents. He called 
the one in the northern hemisphere Laurasia and the one in the 
southern hemisphere Gondwanaland. After a very long span of 
centuries, Wegener said, Laurasia split to form North America, 
most of Asia, Greenland, and a large section of Europe. 
Gondwanaland became Africa, South America, Australia, India, 
and Antarctica. Wegener believed that the land masses drifted for 
millions of years before assuming their present shapes and arriving 
at their present locations. He was led to this notion by the 
congruity he observed in the shorelines of the lands bordering the 
Atlantic Ocean and several other kinds of evidence. Further, he 
said, the process of continental drift is still going onthe 
continents are still on the move.

Alfred Wegener, who was educated to be a meteorologist and an 
Arctic climatologist, insisted that his theory was correct because of 
the evidence he saw. To support his ideas about continental drift, 
Wegener pointed to the similarities in the fossils of the southern 
continents. Fossils of the same sort from ferns and freshwater 
reptiles had been found in all of the southern continents. He saw 
this as evidence that all the lands south of the equator has once 
been part of a single land mass. He argued that such land-based 
life forms could never have crossed the thousands of miles of open 
ocean that now separate these land masses. His critics scoffed 
because the physical model that Wegener proposed to explain the 
movement of continents did not fit what was then known about the 
physics of the Earth.

For the next 30 years or so, scientists paid little attention to 
Wegeners theory. In the 1960s, however, geologists discovered 
that the ocean floors had been spreading, thus influencing the 
shapes and sizes of the continents. This new theory, called plate 
tectonics, provided a mechanism that made sense in physical terms 
to account for Wegeners idea of continental drift.

Although the continents themselves do not drift, as Wegener 
proposed, he was correct in his thesis that Earths surface is not 
fixed. He was a man well ahead of his time whose insight went 
beyond safe and conventional thinking. So important is Wegener 
to our current understanding of plate tectonics that in the 1970s a 
crater on the dark side of the moon was named for him, to honor 
his courage and vision.

Tragically, Alfred Wegener never lived to see his ideas accepted 
by the scientific community. He perished while attempting to cross 
Greenland from a camp on the ice cap in the winter of 1930. His 
purpose was to learn more about atmospheric conditions in the 
Arctic in order to better predict world weather patterns.

What title would you give this essay?

Write a two- or three-sentence summary of the essay, then add a one-sentence 
comment.

Name
Date

2. In the earths interior, where seismic waves travel invisibly and inaudibly, 
they can be followed only by mathematical equations.
Dragutin Skoko, Mohorovicics biographer

The boundary separating Earths crust from its upper mantle is 
called the Mohorovicic discontinuity, or the Moho, for short, in 
honor of the Croatian seismologist Andrija Mohorovicic. In 1909, 
he used data on the travel tame of earthquake waves to 
demonstrate that their velocity changes at about 50 km beneath the 
surface. Others later refined the study of crust and upper mantle 
and applied new, methods, but Mohorovicic paved their way.
Mohorovicics father, also named Andrija (or Andrew), was a 
maker of anchors. The young Mohorovicic loved the sea, and 
married a sea captains daughter. He taught for nine years at the 
Royal Nautical School in Baka. After becoming director of the 
Meteorological Observatory in Zagreb, in 1891, he studied and 
wrote primarily about clouds, rainstorms, and high winds. After a 
severe earthquake in 1901, however, Mohorovicic and his 
colleagues petitioned their government to establish a seismic 
station in Zagreb. In 1910, Mohorovicic published his account of 
the earthquake of November 9, 1880. In it, he plotted a now- 
standard transit time graph-arrival time versus epicenter distance to 
recording station-using the data for 29 stations that ranged to a 
distance of 2,400 km from the epicenter.

After plotting data for a large number of earthquakes over a wide 
area, he had begun to notice that the P wave arrivals required two 
curves on his graph. Because it was not possible to have P waves 
traveling in the same medium at different velocities, and the earlier 
P arrivals were only seen at some distance from the epicenter, he 
reasoned that the two (different arrival times represented two 
different phases of P waves traveling different paths. After 
working out the refraction equations and tests to determine optimal 
values for the depth of the focus, the ray paths of the two P waves, 
the corresponding two S phases, and their reflection paths, he 
concluded that at approximately 50 km there must be an abrupt 
change in the material that composes the interior of the Earth, 
because he observed an abrupt change in the velocity of the 
earthquake waves. Although this conclusion was not accepted 
immediately, Beno Gutenberg was able to confirm it with his own 
research as early as 1915.

Even after earthquakes became one of his primary interests, as 
chief of the observatory, Mohorovicic was responsible for 
recording all the meteorological data for Croatia and Slovenia
precipitation, tornadoes, whirlwinds, thunderstorms, and more
with only an occasional assistant. He was responsible for all the 
mathematics involved in keeping records and for answering 
hundreds of letters and requests for assistance, as well as teaching 
classes at the University. He was patient and precise in his 
collection and analysis of data, but he loved good scientific 
instruments, and was frequently frustrated at the inadequacy of the 
instruments available and the difficulty of obtaining new ones. An 
accurate clock was particularly important to his research, because 
in studying earthquakes, an error of one second in the time of 
arrival means an error of 5.6 km in estimating the length of its 
travel making it impossible to accurately locate the focus of an 
earthquake. By 1913 he had finally obtained a crystal clock with a 
radio receiver that allowed him to synchronize with the Paris 
Observatory, but in 1914, during World War I, the army 
commandeered it for military use. When the dock was returned to 
him after the war, he also received a new radio receiver that took 
two railroad cars to transport.

Mohorovicic published a paper in 1909 on the effect of 
earthquakes on buildings that described periods of oscillation (see 
lesson 4.3). In this he was at least 50 years ahead of the times both 
in his own country and elsewhere. Croatias first national 
Provisional Engineering Standards for Construction in Seismic 
Areas were published in 1964.

During his lifetime, Mohorovicic maintained contacts with 
seismologists all over the world. He retired in 1922, but remained 
active until shortly before his death in 1936. His only grandchild, 
Andre, remembers that he was always good natureda kind and 
peaceful man. Mohorovicic, like Alfred Wegener, received the 
honor of having his name given to a crater on the dark side of the 
moon.

What title would you give this essay?

Write a two- or three-sentence summary of the essay, then add a one-sentence 
comment.

Name
Date

3. By 1936, scientists had learned from the study of earthquake 
waves that the Earth has three layers, crust, mantle, and core. 
Denmarks Inge Lehmann was the first to demonstrate the 
existence of a change in composition midway through the core, 
dividing it into an inner core and an outer core. This division is 
now known as the Lehmann discontinuity.

As a girl, at the turn of the century, Lehmann attended the first 
coeducational school in Denmark, which was founded and run by 
Hanna Adler. (Adlers nephew, Neils Bohr, was the first to 
describe the physical makeup of the atom.) At that school, 
Lehmann wrote many years later, No difference between the 
intellect of boys and girls was recognizeda fact that brought me 
disappointments later in life when I found that this was not the 
general attitude.

Lehmann studied at Oxford, earned a masters degree in 
mathematics from the University of Copenhagen, and went to work 
as an actuary, calculating life expectancies and statistical risks for 
insurance companies. Beginning in 1925, however, she also served 
as a staff member of the Danish Geodetic Institute, helping to 
establish seismological stations in Greenland and in 
Copenhagena part of the world not noted for its seismicity. 
Seismology soon became her life work, and for 25 years, until just 
before her retirement, she was the only Danish seismologist.

As early as 1910 scientists had noticed a shadow zone in the 
Earths interior, but seismographs had not been refined enough to 
explain this observation. In the course of the 1930s more and more 
sensitive seismographs were being developed. At the Copenhagen 
Seismological Observatory, Lehmann studied waves reflected 
through the core from earthquakes in Japan. In 1936, after 10 
years of studying seismograms, she interpreted the newly revealed 
data to confirm the existence of a relatively small inner core in 
the center of the Earth. The paper in which she reported her 
findings has one of the shortest titles in the history of seismology, 
if not of all science: It was called P.

Lehmann was among the founders of the Danish Geophysical 
Society in 1936, and served as its president from 1941 until 1944. 
She helped to formulate the constitution of the European 
Seismological Federation and was elected its first president in 
1950. She found time to attend most of the meetings of the 
International Union of Geodesy and Geophysics, and served on 
the executive committee of the International Seismological 
Association from 1936 to 1944, from 1951 to 1954, and from 
1957 to 1960. International cooperation in the sciences was one 
of her passions. She was active in national and international 
scientific organizations, and traveled in France, the Netherlands, 
Belgium, and Germany, where she worked with some of the 
leading seismologists of the day. In Canada, she worked at 
Ottawas Dominion Observatory, and in the United States she 
conducted research at the Seismological Laboratory, California 
Institute of Technology; the University of California at Berkeley; 
and the Lamont-Doherty Geological Observatory, Columbia 
University, New York.

She loved hiking, skiing, and mountain climbing. Her favorite 
place indoors, aside from her own cottage in Denmark, was an art 
gallery. She loved to visit galleries and look at paintings 
whenever she traveled, and she traveled widely, especially after 
her retirement in 1953. She also loved music and gardening. Inge 
Lehmann died in February, 1993, at the age of 105, leaving a 
worldwide network of friends.

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Write a two- or three-sentence summary of the essay, then add a one-sentence 
comment.

3.2b Chronology: The Beginnings of the Seismological Age

1883: The English seismologist John Milne hypothesized that with the proper 
equipment, it should be possible to detect seismic waves from a large earthquake 
occurring anywhere on Earth.

1889: Milnes 1883 hypothesis was proven correct when E. von Rebeur 
Paschwitz used delicate pendulum seismographs to record the April 18, 1889, 
Tokyo earthquake in Potsdam and Wilhemshaven, Germany.

1897: Richard Dixon Oldham noticed that seismograms from earthquakes 
consistently showed three different disturbances, the first and second 
preliminary tremors (now known as P waves and S waves, respectively) and 
the large waves that followed the preliminary tremors, and that the difference 
in arrival time between the large waves and the preliminary tremors 
increased in a predictable fashion with increasing distance from the earthquake.

1900: Oldham established that the preliminary tremors (P and S waves) have 
travel paths that take them through the body of Earth (we now call them body 
waves), and that the large waves (now called surface waves) travel along 
Earths surface.

1906: Oldham used evidence from earthquake waves to demonstrate the 
existence of a large central core at a depth of about 3,821 km beneath the 
surface.

1909: Andrija Mehorovicic, a Croatian seismologist, used seismic waves to 
discover a discontinuity at a depth of about 50 km beneath the surface. This 
marks the boundary between what we now call the Earths crust and the 
underlying mantle. In his honor, we call the boundary separating the crust from 
the mantle the Mohorovicic discontinuity, or the Moho for short.

1914: Beno Gutenberg used an extensive data set of earthquake wave travel 
times to compute the average distance to the top of the core at about 2,900 km.

1926: Harold Jeffreys measurements of tides in the solid Earth suggested that 
the Earth was less rigid than had been previously assumed. This led to the 
assumption that the core is fluid.

1936: Inge Lehmann, Danish seismologist, demonstrated the presence of an 
inner core.

3.3 Sizing Up Earthquakes

VOCABULARY
Epicenter: the point on Earths surface directly above the focus of an 
earthquake.

Focus (pl. foci): the point within the Earth that is the origin of an 
earthquake where stored energy is first released as wave energy.

Intensity: a subjective measure of the amount of ground shaking an 
earthquake produces at a particular site, based on geologic effects, 
impact on human structures, and other human observations. Mercalli 
intensity is expressed in Roman numerals.

Isoseismal line: a line on a map that encloses areas of equal earthquake 
intensity.

Magnitude: a number that characterizes the size of an 
earthquake by measuring the motions on a seismograph and 
correcting for the distance to the epicenter of the earthquake. 
Magnitude is expressed in Arabic numbers.
 
ACTIVITY ONE
THE MERCALLI SCALE: CALLING STATION KWAT

RATIONALE
Students need to know how seismologists establish earthquake 
intensity in order to understand how much damage earthquakes can 
cause and how building codes are developed.

FOCUS QUESTIONS
How do seismologists determine the intensity of an earthquake?

OBJECTIVES
Students will:
1. Interpret the Modified Mercalli scale and assign values on the basis 
of descriptions by citizen observers during and after a quake.
2. Use the assigned values to construct an isoseismal map.

MATERIALS
 Overhead projector
 Student copies of Master 3.3a, Modified Mercalli Intensity Scale
 Transparency made from Master 3.3a, Modified Mercalli Intensity Scale
 Back of Master 3.3a, Teacher Background Reading: Richter vs. Mercalli
 Student copies of Master 3.3b, Wattsville Map
 Transparency made from Back of Master 3.3b, Wattsville Map Key
 One copy of Master 3.3c, KWAT Television Script, cut into strips
 Student copies of Master 3.3c, KWAT Television Script
 Colored pencils and lead pencils

VOCABULARY
Modified Mercalli scale of 1931: a qualitative scale of earthquake 
effects that assigns an intensity number to the ground 
shaking for any specific location on the basis of observed effects. 
Mercalli intensity is expressed in Roman numerals.

Qualitative: having to do with perceived qualities; subjective. 
Examples: large, cold.

Quantitative: having to do with measurable quantities; objective. 
Examples: 10 m long, 5 C.

PROCEDURE

A. Introduction
Ask students on what basis scientists classify earthquakes. Many 
students may be aware of the Richter Scale and some may be aware of 
the Mercalli Scale. Explain that the Richter Scale is a quantitative 
measure of the energy released by an earthquake, while the Mercalli 
Scale is a qualitative measure of the amount of damage it does. The 
Richter rating is referred to as a quakes magnitude, and the Mercalli 
rating is referred to as its intensity. The original Mercalli Scale was 
developed in 1902 by the Italian geologist Giuseppi Mercalli. Wood 
and Neumann adapted it to U.S. conditions and introduced the 
Modified Mercalli Scale in 1931. Both the Richter and the Mercalli 
scales have their uses. Have students give other examples of 
quantitative vs. qualitative measurements.

B. Lesson Development
1. Project the transparency of the Modified Mercalli Scale and 
distribute student copies. Share the background information about the 
two earthquake scales (back of Master 3.3a) with the class and discuss 
the importance of intensity in establishing building codes. Briefly 
discuss each of the values assigned on the Mercalli scale. If some 
students in the class have experienced an earthquake, ask them to 
estimate its intensity from the scale.

2. Have the students compare and contrast the differences between the 
two types of measurements. Ask: Why do you think magnitude is 
more often reported than intensity? (Most earthquake-prone areas 
have equipment already in place to determine magnitudes, so this 
measurement can be quickly established. Mercalli ratings are 
sometimes not arrived at until several days later, when a full estimate 
of the damage can be made.) Point out to students that the lack of 
news accounts reporting intensity does not diminish its value to city 
planners and engineers.

TEACHING CLUES AND CUES
Have students listen carefully for significant phrases in the callers 
reports. They will be found in the Mercalli scale (Master 
3.3a).

It may take class discussion to reach agreement 
on the values for some of the reports. Have 
students read the descriptions on the Mercalli scale carefully, and reread 
them as necessary, checking with the script as they proceed.

3. Tell students that in this activity they will be using data adapted 
from reports of an earthquake that struck California in 1971.
Distribute copies of Master 3.3b, Wattsville Map. Appoint one 
student to be Jake Wilde, the television news anchor, and tell the 
other students that they are citizens of Wattsville and the surrounding 
area. The town has just been struck by an earthquake.

4. Distribute the strips cut from Master 3.3c and have students take 
turns reading them in order, starting with the news anchors report. 
Distribute student copies of the script as well.

5. As each student reads a part, have the other students locate the site 
of the report on their maps, scan the Modified Mercalli Intensity 
Scale, and mark a Mercalli intensity in pencil next to the location.

6. After the last student has read, have students draw blue lines 
enclosing areas with equal intensity ratings to develop an isoseismal 
map. (They will be drawing a series of concentric lines.)

7. Project the transparency of Master 3.3b, Wattsville Map, and have 
students take turns giving you the values to draw on the transparency. 
Then draw in the isoseismals according to their interpretation of the 
data.

C. Conclusion
Ask students to find the area where the damage was most intense and 
color this area red. Then build a class discussion around these 
questions:

 Where do you think the epicenter of the earthquake is located? 
(Most students will think that the area with the most damage is the 
epicenter. In certain cases this is a false assumption. Damage may 
be related to siting or construction practices. An example of this is 
the 1985 Mexico City earthquake in which the fault was over 350 
km away.)

 Why did some buildings near the epicenter withstand the shocks 
better than others? (perhaps because their structures were sounder 
or the soil under them was more firm)

 What are some advantages of the Mercalli rating procedure? (In 
ideal conditions, it can be done quickly, and it doesnt require any 
instruments. It describes the impact in human terms: on human 
beings and their structures.)

 What are some disadvantages to this procedure? (It requires human 
observers, so it could not assign an intensity to an earthquake in the 
middle of an ocean or in a deserted place. It also requires the 
exchange of information over a fairly wide area. To arrive at 
Mercalli ratings today, an official survey is conducted through the 
U.S. mail. It is not as precise or objective as instrument readings; 
different people might describe the same situation differently.)

Now place the answer key transparency on the overhead so it overlays 
student data. If there is a discrepancy between the isoseismals shown 
on the master and those students produced, they will see one of the 
drawbacks to this system of measurement. Ask students for 
suggestions to solve this problem.


ADAPTATIONS AND EXTENSIONS
1. Write a modern-day version of the 1931 Mercalli Intensity Scale.
2. Go to the library and search newspapers for qualitative information 
on an earthquake in your area. Construct an isoseismal map for the 
earthquake.

ACTIVITY TWO
RICHTER MAGNITUDE

VOCABULARY
Amplitude: a measurement of the energy of a wave. Amplitude is the 
displacement of the medium from zero or the height of a wave crest or trough 
from 
a zero point.

Duration: the length of time that ground motion at a given site shows 
certain characteristics. Most earthquakes have a duration of less than 
one minute in terms of human perceptions, but waves from a large 
earthquake can travel around the world for hours.

Lag time: the difference between the arrival time of P waves (Tp) and S 
waves (Ts).

Magnitude: a number that characterizes the size of an earthquake by 
recording ground shaking on a seismograph and correcting for the 
distance to the epicenter of the earthquake. Magnitude is expressed 
in Arabic numbers.

Richter magnitude: the number that expresses the amount of energy 
released during an earthquake, as measured on a seismograph or a 
network of seismographs, using the scale developed by Charles Richter 
in 1935.

Seismogram: the record of earthquake ground motion recorded by a 
seismograph.

RATIONALE
To determine Richter magnitude, we need to know both the maxi- 
mum wave amplitude as recorded on the seismogram and the distance 
between the seismograph station and the earthquake, which can be 
calculated by finding the lag time.

FOCUS QUESTIONS
How do scientists determine the size of an earthquake?

OBJECTIVES
Students will:
1. Interpret seismograms to calculate Richter magnitude.
2. Compare Richter magnitudes from several seismograph stations for 
the same earthquake.

MATERIALS
 Transparency made from the first page of Master 3.3d, Five Seismograms
 Overhead projector
 Transparency marker
 Copies of Master 3.3d, Five Seismograms (simplified) (3 pages), 
one set for every two students
 Copies of Master 3.3e, Distance, Magnitude, Amplitude, one for 
every two students
 Paper and pencils or pens
 Rulers or straightedges
 Transparency made from Master 3.3e, Distance, Magnitude, 
 Amplitude
 Transparency made from back of Master 3.3d (page 2), Richter 
 Data Table, Answer Key


PROCEDURE
A. Introduction
Tell students that Richter magnitude is a quantitative measure that is 
related to the amount of energy released during the earthquake and is 
not attracted by factors such as population, building materials, or 
building design. Ask them to name some other kinds of quantitative 
measures (minutes, hours, centimeters, dollars). Be sure they under-
stand the distinction between quantitative and qualitative description.

B. Lesson Development
1. Divide students into pairs. Give each pair a ruler and copies of 
Master 3.3d, Five Seismograms, and Master 3.3e, Distance, 
Magnitude, Amplitude. Tell students that they are going to be working 
with five seismograms, all recorded for one earthquake on September 
2, 1992, with its epicenter at St. George, Utah. Explain that the 
seismographs have been enlarged and simplified for their use but that 
this has also changed the scale, so they must use the vertical scale for 
all measurements. You will be demonstrating the steps to determine 
magnitude by using the first seismogram on Master 3.3d. They will 
record their data on the bottom of the third page of seismograms.

2. Project a transparency of Master 3.3d, page 1, and demonstrate how 
to measure amplitude. (See vocabulary definition.) Using the scale on 
the left side of the graph (the y axis) determine the greatest deflection 
in millimeters above or below zero of the largest seismic wave. 
Record this measurement in the amplitude column on the data table.

3. After all students have measured amplitude, start the next part of 
the activity by asking them which earthquake wave travels fastest and 
therefore should be the first wave recorded on the seismogram. Most 
of them should be aware from previous lessons that it is the P wave. 
On the transparency of Master 3.3d, page 1, point out the arrival of 
the P and S waves. Ask students what the difference between the 
arrival of the two waves is called (lag time (Ts-Tp). Ask students what 
should happen to the lag time recorded at stations farther from the 
earthquake. Offer a hint by comparing the progress of the waves to a 
race between the family car and a race car. The longer the race is, the 
more of an advantage the race car will have.

4. Using the projection of Master 3.3d, page 1, demonstrate how to 
determine distance to the earthquake recorded by the first 
seismogram. Using the scale at the top of the graph (the x axis), 
measure the difference between P wave and S wave arrival times in 
seconds. Use the formula
          Distance = (Ts-Tp) x (8 km/sec) or (4.96 mi/sec)
to convert time to distance. Have students record this in their data 
tables. Give students time to calculate the distances for the other four 
seismograms, following the procedure you have modeled.

5. Project the transparency of Master 3.3e and demonstrate how to 
find the magnitude of the earthquake. To do this, place the left end of 
the ruler on the left scale at the distance calculated in step 4. Holding 
the left edge of the ruler in place, move the right edge of the ruler to 
the correct point for the base-to-peak amplitude. Read the Richter 
magnitude on the center scale where the ruler crosses the graph and 
record it in the data table. Have students repeat this process on their 
own for the other stations. Average the magnitudes from the five 
locations to determine the final magnitude for this earthquake, and 
record it in the data table.

TEACHING CLUES AND CUES
The seismograms on Master 3.3d are seismograms that have 
been simplified and enlarged for classroom use. The 
printed millimeter scale has also been enlarged proportionately.
 
Do not use rulers for this step or the measurement will be 
inaccurate. (Be sure they make all their measurements on the same wave 
cycle, not the crest from one and the trough from another. The diagram on 
p.116 will be helpful.)
 
To measure the amplitude, have students lay a piece of paper across 
the wave and mark the high and low peaks, then use the 
scale on the y axis or the scale printed at the bottom of the seismogram to 
measure the amplitude or 
distance.

C. Conclusion
Project the back of Master 3.3d, Richter Data Table, Answer Key, and 
allow students to compare their calculations with the actual data. Ask 
students how a more accurate magnitude could be calculated. (by 
collecting more data points or by averaging the class averages of the 
calculated magnitude)

ADAPTATIONS AND EXTENSIONS
Seismologists today use a variety of magnitude scales and many types 
of instruments to record precise information on earthquakes. Interested 
students can read about P wave or body wave magnitude (called Mb), 
surface wave magnitude (Ms), moment magnitude (Mw), as well as the 
concept of seismic moment, drawing on materials in the unit resources 
list and others from local libraries.

ACTIVITY THREE
FIND THE EPICENTER: DECODING SEISMOGRAMS

VOCABULARY
Epicenter: the point on Earths surface directly above the focus of an 
earthquake.

Focus (pl. foci): the point within the Earth that is the origin of an 
earthquake, where stored energy is first released as wave energy.

Seismogram: the record of earthquake ground motion recorded 
by a seismograph.

Seismograph: an instrument that records vibrations of the Earth, 
especially earthquakes.

Triangulation: using data from three or more known points to locate an 
unknown point, in this case the epicenter of an earthquake.

RATIONALE
Students can find the location of an earthquake by triangulation if 
they know the distances from at least three seismograph stations.

FOCUS QUESTION
How do seismologists use seismograms to locate the epicenter of an 
earthquake?

OBJECTIVES
Students will:
1. Calculate the distance from an earthquake to a seismograph station.
2. Use five calculated distances to triangulate the location of the 
earthquakes epicenter.

MATERIALS
 Student copies of Master 3.3f, Several Seismographs
 Student copies of Master 3.3g, Sample Seismograms
 Student copies of Master 3.3h, Map of Station locations
 Transparency made from one page of Master 3.3g, Sample Seismograms
 Overhead projector
 Transparency made from Master 3.3h, Map of Station Locations
 Student copies of Master 3.3i, Time/Distance Reference Table
 Drawing compasses
 Metric rulers with millimeter scales

PROCEDURE
Teacher Preparation
Make one copy of each of the masters (3.3f through 3.3i) for every 
two students in your class.

A. Introduction
Ask students chosen at random to explain the difference between an 
earthquakes focus and its epicenter and between a seismograph and a 
seismogram. Review these distinctions if necessary.
Distribute copies of Master 3.3f, Several Seismographs, then project a 
transparency of Master 3.3f and describe their operation.

B. Lesson Development
1. Divide the class into pairs of students. Distribute a set of 
seismograms (Master 3.3g, 3 pages), one map (Master 3.3h), and 
copies of the Time/Distance Reference Table (Master 3.3i) to each 
pair. Tell students that all the seismograms are from the same 
earthquake, a quake that occurred on January 14, 1993, with a 
magnitude of 3.3, but each was recorded by a different seismograph in 
the seismograph network.

2. Project transparencies of one seismogram and the map. Model the 
procedure for students as necessary.

3. Give these directions for finding the epicenter of the earthquake 
recorded on the five seismograms:
a. On the first seismogram, use the second scale to measure the time- 
distance from the nearest 10-second mark to the P wave arrival of the 
earthquake. Record the P wave arrival times in the table to the nearest 
second.
b. Repeat for the S wave, measuring from the same minute mark.
c. Find the Ts-Tp time by subtracting the arrival time of the P wave 
from the arrival time of the S wave. Record this time in the table.
d. Use the time/distance table on Master 3.3i to determine the distance 
to the epicenter.
e. Repeat this procedure for all of the stations.
f. For each seismogram, draw a circle on the map with the compass, 
using the distance you calculated as the radius of the circle. Place the 
point of the compass at zero on the map scale and adjust the compass 
width to the calculated distance. With the distance set, place the point 
of the compass on the station and draw a circle. Mark the outer edge 
of each circle with a letter to identify the station.
g. Repeat, setting the compass and drawing circles for 0 five stations.

4. Instruct students to circle the area where all the circles intersect. 
Ask: What is this area called? (It is the epicenter of the earthquake.)

TEACHING CLUES AND CUES
Emphasize the importance of accurate measurement, particularly 
the need to set the compass accurately for distance. 
Dont worry if the circles dont intersect perfectly, however. Remind 
students that an earthquake actually occurs along a fault, not at one single 
point.

C. Conclusion
Build a class discussion around these questions:

 What information can be obtained from one seismogram? (The 
distance from that seismograph in a 360 circle.)

 After the arcs for stations TRYN and FGTN were drawn, where 
was the epicenter of this earthquake? Explain. (We dont know yet. 
It could be at either place where the two arcs cross. They are the 
common points.)

 After all the stations were drawn, where was the actual epicenter of 
this earthquake? Where was its focus? (In the area where the arcs 
cross just south of station BHT. Directly under the epicenter.)

Why is it necessary to have measurements from at least three 
different stations to locate the epicenter of an earthquake? 
(Answers will vary but should relate to the above questions.)

 Why dont all of the arcs pass through the same point? (Answers 
will vary. Accuracy in measurement and drawing should be two 
most common. Also, an earthquake does not occur at one point but 
along a fault surface. Have students speculate as to the location and 
strike of the fault.

 Which station was closer to the earthquakes epicenter, BBG or 
FGTN? Cite two kinds of evidence from the seismograms to 
support your conclusion. (BBG. Evidence: amount of lag time and 
amplitude difference.)

 Would it be possible for an earthquake at this location to be felt 
where you live? Why or why not? (Answers will vary; will depend 
on distance from the focus and the magnitude of the quake.)

 P waves travel at an average velocity of 6 km/sec in the Earths 
crust. How long would it would take for the P waves from this 
quake to reach a seismic station in your city, if they continued to 
travel at a constant speed? (Answers will vary. Multiply 6 km/sec 
times the distance to your city.)

ADAPTATIONS AND EXTENSIONS
1. Challenge students to research these questions:

 Would a seismograph work on the moon?

 Have scientists placed seismographs on the moon and other planets?

 If so, which planets? Have quakes been detected there?

2. Interested students may research several types of seismographs and 
build their own models.

Seismic Sleuths

Earthquakes

A Teachers Package for Grades 7-12

Unit Three (continued)

3.3a Modified Mercalli Intensity Scale

Intensity Value & Description

I. Not felt except by a very few under especially favorable 
circumstances.

II. Felt only by a few persons at rest, especially on upper 
floors of buildings. Delicately suspended objects may swing.

III. Felt quite noticeably indoors, especially on upper floors of 
buildings, but many people do not recognize it as an earthquake. 
Standing automobiles may rock slightly. Vibration like passing of 
truck. Duration estimated.

IV. During the day felt indoors by many, outdoors by few. At 
night some awakened. Dishes, windows, doors disturbed; 
walls make creaking sound. Sensation like heavy truck striking 
building. Standing automobiles rocked noticeably.

V. Felt by nearly everyone, many awakened. Some dishes, 
windows, and so on broken; cracked plaster in a few places; 
unstable objects overturned. Disturbances of trees, poles, and 
other tall objects sometimes noticed. Pendulum clocks may 
stop.

VI. Felt by all, many frightened and run outdoors. Some heavy 
furniture moved; a few instances of fallen plaster and damaged 
chimneys. Damage slight.

VII. Everybody runs outdoors. Damage negligible in buildings 
of good design and construction; slight to moderate damage in 
well-built ordinary structures; considerable in poorly built or 
badly designed structures; some chimneys broken. Noticed by 
persons driving cars.

VIII. Damage slight in specially designed structures; considerable in 
ordinary substantial buildings, with partial collapse; great in poorly built 
structures. Panel walls thrown out of frame structure. Chimneys, factory 
stacks, columns, monuments, walls may fall. Heavy furniture overturned. 
Sand and mud ejected in small amounts. Changes in well water. Persons 
driving cars disturbed.

IX. Damage considerable in specially designed structures; well-designed 
frame structures thrown out of plumb; great in substantial buildings, with 
partial 
collapse. Buildings shifted off foundations. Ground cracked conspicuously. 
Underground pipes broken.

X. Some well-built wooden structures destroyed; most masonry and frame 
structures destroyed with foundations; ground badly cracked. Rails bent. 
Landslides considerable from river banks and steep slopes. Shifted 
sand and mud. Water splashed, slopped over banks.

XI. Few, if any (masonry) structures remain standing. Bridges destroyed. 
Broad fissures in ground. Underground pipelines completely out of service. 
Earth slumps and land slips in soft ground. Rails bent greatly.

XII. Damage total. Waves seen on ground surface. Lines of sight and 
level distorted. Objects thrown into the air.

When an earthquake occurs, we often hear news 
reporters describing it in terms of magnitude. Perhaps 
the most common question at a news conference is 
What was the magnitude of the quake? In addition 
to calculating the magnitude of an earthquake, 
however, we can describe the effect it had at a 
particular location by measuring its intensity. 
Magnitude and intensity are both measures of an 
earthquake, but they describe different characteristics. 
Each measurement has its uses.

Magnitude is a measurement of the amplitude of the 
earthquake waves, which is related to the amount of 
energy the earthquake releases. Magnitude is 
calculated from the size of the earthquake waves 
arriving at a seismic station. The most commonly used 
scale for magnitude is the Richter scale, developed by 
Charles Richter in 1935. The Richter scale is a 
logarithmic measurement of the maximum wave 
amplitude recorded at a seismograph station, corrected 
for distance from the epicenter. It is theoretically 
open-ended, although the largest quakes recorded in 
this century had a magnitude of 8.9. Each whole 
number increase in Richter magnitude indicates an 
increase in the severity of the ground shaking by a 
factor of 10. Thus a magnitude 6 earthquake will pro- 
duce shaking 10 times more severe than that produced 
by a magnitude 5 earthquake. Magnitude can also be 
related to the amount of energy an earthquake 
releases. Each whole number increase in Richter 
magnitude indicates an increase in the amount of 
energy released by a factor of roughly 30. Thus a 
magnitude 6 earthquake releases about 30 times more 
energy than a magnitude 5 earthquake, and roughly 
900 times as much as a magnitude 4 earthquake. 
These factors are seldom described correctly in news 
accounts.

Each earthquake has a single magnitude that is independent of the location of 
the observer. If a magnitude 
6.0 event strikes some location in the South Pacific, 
then that event will be described as a magnitude 6.0
by observers all over the world. Because magnitude is 
independent of observer location, it is a convenient 
measure to use in reporting the occurrence of an 
earthquake. No matter where it happened, or where 
you are, you get a feeling for the relative size of the 
earthquake by simply knowing its magnitude. This is 
why the press is so quick to report this number.

Intensity is a measure of the effect that the vibration 
had on natural and human-made structures. The most 
common measurement of intensity is the Modified 
Mercalli Intensity scale, originally developed in 1902 
by Giuseppi Mercalli, an Italian geologist. Wood and 
Neumann adapted it to modern conditions in 1931. 
The intensity scale ranges from I, the lowest 
perceptible intensity, to XII, the greatest intensity. 
Intensity is a function of many variables, including 
magnitude, depth of the earthquake, distance from the 
earthquake, local geological conditions, and local 
construction practices. Generally speaking, the 
intensity felt at a given location will increase with 
increasing magnitude, decreasing depth, decreasing 
distance from the earthquake, and a decrease in the 
quality of construction. If an earthquake is shallow, its 
intensity will be greater. If it affects an area built on 
soft sediments, such as landfills or sedimentary basins, 
the intensity will also be greater. A single quake will 
produce a range of intensities that typically decrease 
with increasing distance from the earthquake. An 
isoseismal map illustrates this range.

Intensity is more useful than magnitude as a measure 
of the impact that an earthquake had at any given 
location. Consequently, it is important to the 
professionals who establish building codes and 
insurance rates. If the maximum expected intensity in 
a given area is VII, for example, the building codes 
should specify construction practices that make 
buildings able to withstand this intensity, and property 
insurance rates will probably be high. If the maximum 
expected intensity is only III, the area can relax its 
building codes, and property insurance rates will be 
moderate.

3.3b Wattsville Map

3.3b Wattsville Map (key)

3.3c KWAT Television Script

Jake Wilde: We interrupt our regularly scheduled programming on KWAT to bring 
you a special bulletin. This 
is KWAT news anchor Jake Wilde, and moments ago the town of Wattsville was 
shaken by a strong earthquake. 
Residents in the KWAT broadcast area are invited to call our emergency response 
number, 324- KWAT, and give 
us your name, your location, and a brief summary of what you experienced during 
the quake. Stay tuned for the 
latest reports of what your neighbors saw and felt. To report your observations, 
again, call 324-KWAT. We have 
caller number 1 on the line.

Caller 1: Hi, this is Charles from the hospital. Everyone ran outdoors and we 
only had moderate damage thanks 
to a well-built building.

Caller 2: Hello my name is Roy, and Im calling from RQB Ranch. Everything that 
wasnt nailed down in our 
tack room got turned upside down by the shaking. Some plaster is cracked too.

Caller 3: Hi, this is Bob at Long Valley Mercantile, and we have a mess here. 
When the quake struck, it 
knocked over all of our displays, and broke windows out of the store. All the 
trees and poles were moving.

Caller 4: Hi Jake, Im Jane calling in from West Side Subdivision. Damage was 
slight hereonly some plaster 
shaken off the walls and the heavy furniture moved around.

Caller 5: Hi. This is Jo. Im calling from the north end of town and we need 
some help down here. The water in 
our well has changed its level and we are trying to put out fires with buckets.

Caller 6: Hello Jake, Lynda from Southside City Junior High School. Students 
felt it and did the drop, cover, 
and hold drill. We only had slight damage to the building, with some fallen 
plaster.

Caller 7: Hi, this is Hank and Im calling on my car phone. I just heard the 
news and thought I would report that 
right after I turned south into town off the Interstate, I felt a big bumpbut 
there were not any potholes in the 
road. It was disturbing.

Caller 8: Hello, this is Mary, and Im calling from the basement of the First 
Bank in the center of Wattsville. 
The building has partially collapsed and people are trapped down here. Please 
send help.

Caller 9: Hi this is Jim. We were at the mall when the quake struck. Everyone 
panicked and ran outside. Luckily 
no one was hurt, and damage was slight.

Caller 10: Hi, this is Ron. I work at the MacBest Castle. Many of the tourists 
were frightened and ran outdoors, 
and our chimneys were damaged.

Caller 11: Hello Jake. My name is Sue and Im calling from the Big Bear Lumber 
Camp. The walls of our house 
were swaying and creaking during the earthquake.

Caller 12: Hi. This is Len. We were picnicking at the Great Bend Park. Shortly 
after the quake struck we saw 
trees, telephone poles, and the flagpole swaying back and forth.

Caller 13: Hi. This is Jim out at the Roundup Truck Stop. When the quake hit, 
our chimney broke and fell 
over.

Caller 14: Hello, Jake. This is Marty up at Big Bear Ski Resort. The quake 
rattled our dishes and windows, and 
the walls made creaking sounds.

Caller 15: Hi Jake. This is Keith in River City. Our chimney is damaged and 
some plaster has fallen.

Caller 16: Hi. This is Diana calling from the Lucky Strike Mine. Over here, we 
thought that a big truck had 
struck the building.

Caller 17: Hi Jake. This is Monte from Wattsville University. Everyone in our 
class felt the quake, and some of 
the older, more poorly built buildings have suffered considerable damage.

Caller 18: Hello. My name is Marilyn, and Im calling from Hot Springs Ranch. 
The strangest thing happened! 
Our big pendulum clock stopped dead when the quake struck.

Caller 19: Hi Jake, this is Karen. When the quake hit, I was in White Water 
visiting a friend. Nearly everyone 
felt it and we had a lot of windows broken. They were frightened, and I was 
too!

Caller 20: Hello Jake. This is Frank. I was at Blue Lake Resort when all the 
cars in the parking lot started 
rocking back and forth.

Caller 21: Jake, this is Gene at White Water Manufacturing. All of the heavy 
furniture in the showroom was 
moved by the quake, and some of the plaster fell off the walls.

3.3d Five Seismograms
Simplified

3.3d Five Seismograms (key)

3.3e Distance, Magnitude, Amplitude
 
3.3f Several Seismographs
 
Chinese seismoscope, 132 A.D. The direction 
in which the first ball fell was thought to 
indicate the direction of the epicenter.
 
Inside view

Modern seismographs

3.3g Sample Seismograms

3.3g Sample Seismograms (key)

3.3h Map of Station Locations
 
3.3h Map of Station Locations (key)

3.3i Time/Distance Reference Table

Seismic Sleuths

Earthquakes

A Teachers Package for Grades 7-12

Unit Three (continued)

3.4 Distribution of Earthquakes

ACTIVITY ONE
WHERE IN THE WORLD?

VOCABULARY
Epicenter: the point on Earths surface directly above the location 
(focus) of the earthquake below the surface.

Focus (pl. foci): the point within the Earth that is the origin of an 
earthquake, where stored energy is first released as wave energy.

Latitude: the location of a point north or south of the equator, expressed in 
degrees and minutes. Latitude is shown on a map or globe as east-
west lines parallel to the equator.

Longitude: the location of a point east or west of the prime meridian, 
expressed in degrees and minutes. Longitude is shown on a map or 
globe as north-south lines left and right of the prime meridian, which 
passes through Greenwich, England.

RATIONALE
Knowing where earthquakes occur will allow students to formulate 
theories about what causes earthquakes and why earthquakes occur 
more commonly in particular locations.

FOCUS QUESTIONS
Where have earthquakes been known to occur?
Do earthquakes occur randomly, or mainly in specific areas?

OBJECTIVES
Students will:
1. Locate and plot the epicenters of earthquakes by latitude and 
longitude.
2. Recognize a pattern in the distribution of most earthquakes.
3. Postulate how the occurrence of earthquakes may be related to plate 
tectonic activity.
4. Postulate how deep earthquakes may be related to plate tectonic 
activity.

MATERIALS
 Student copies of Master 3.4a, Earthquakes of the Day, Tables 1-8 
(one set of eight, plus extras as needed)
 One copy of Master 3.4b, Notable World Earthquakes, 1900-1992
 Eight copies of Master 3.4c, World Map (2 pages)
 Scissors and transparent tape
 Atlases, globes, or geography textbooks with detailed maps
 Pencils or pens, both black and red
 Four transparencies made from each page of Master 3.4c, World Map
 Three black transparency markers and three red ones
 Overhead projector
 Student copies of Master 2.2e, World Map Grid (key)

TEACHING CLUES AND CUES 
If your class is very large, you may want to give each group more 
than one copy of the tables and the map so students can 
work in smaller subgroups.

TEACHING CLUES AND CUES 
Do not reduce the map to one page. The scale will be too small to be of 
use.

PROCEDURE
Teacher Preparation
Borrow a number of globes and/or atlases in addition to the ones you 
keep in the classroom, so students can locate cities and countries as 
they plot latitude and longitude.

A. Introduction
Briefly review the system of latitude and longitude and how these 
coordinates are used to pinpoint geographic locations. Ask the 
students what country or region of the world they think has the largest 
number of earthquakes in any given year. Note their answers on the 
chalkboard or on poster paper, but do not comment. Tell them that in 
this activity they will be working with real earthquake data.

B. Lesson Development
1. Divide students into eight roughly equal groups. Distribute one of 
the eight tables in Master 3.4a, Earthquakes of the Day, to each group. 
Explain that each of the tables lists the earthquakes that occurred 
around the world on one day; all were recorded on the monthly listing 
from the U.S. Department of the Interior/U.S. Geological Survey, 
Preliminary Determinations of Epicenters. Give Master 3.4b, Notable 
World Earthquakes, to the group with Table I (1/1/90), along with one 
blank transparency.

2. Give each group a copy of Master 3.4c, World Map. Have students 
cut and tape the two pages together. Do not reduce to one page. 
Students in each group may take turns finding the epicenters and 
marking the maps.

3. Instruct students to distinguish the locations of earthquakes below 
40 km from the more common shallow earthquakes by drawing rings 
around the dots that represent them with the red pencil or pen.

4. Distribute the other three transparency maps and markers to the 
three groups that complete their work first. Instruct students in each 
group to transfer the positions on their maps onto the transparency, 
using the black and red markers as above, and write the dates of the 
earthquakes depicted on the map. As each group completes its work it 
may pass the transparency on to another group until all the 
earthquakes from all nine tables have been recorded on the three 
transparencies.

5. Instruct the group working with Master 3.4b to plot those 
earthquakes on their separate transparency and label it.

6. Collect the transparency maps. Stack the three depicting 
earthquakes of the day (Tables 1-8) on the projector so that they are 
displayed simultaneously. Then distribute copies of Master 2.2e, the 
key to the World Map Grid from lesson 2.2.

7. Ask students to compare the world map you have just distributed 
with the stacked transparencies. Ask:

 Can you detect any relationship between the locations of 
earthquakes below 40 km and the outlines of Earths plates? (These 
earthquakes occur under the continents on the landward side of 
plate boundaries.)

 Do all the earthquakes occur at or near plate boundaries? (Some 
earthquakes occur in places that seem unrelated to plate 
boundaries.)

 Were any of the students correct in judging where earthquakes 
occur most frequently, at the beginning of class?

8. Ask students to note how earthquakes are distributed among the 
four geographic areas: north latitude/west longitude, north 
latitude/east longitude, south latitude/west longitude, and south 
latitude/east longitude. Ask them to speculate on the reasons for this 
distribution. (The northeast quadrant has the highest concentration of 
quakes. The main portion of the Ring of Fire is in this quadrant.)

9. Remind students that the eight tables represent earthquakes that 
occurred on just eight days. Ask them to count the total number of 
quakes and estimate how many earthquakes occur each year. 
(Students should calculate that more than 15,000 significant 
earthquakes occur each year.)

10. Ask students where the worlds most powerful earthquakes have 
occurred. Record their hypotheses, then place the transparency of 
Master 3.4b on top of the others as a check. Ask students to predict 
where major earthquakes will occur in the future.

TEACHING CLUES AND CUES
Dont tell students how to calculate the total; challenge them to find a 
way. One procedure is for each group to report the numbers on its map (Tables 1 
through 8), then for students to add the numbers and average them. The 
average of 42 quakes a day, multiplied by 365, yields a figure of 
15,630.

C. Conclusion
Sum up in a discussion. Ask the class:

 Are people who live near the boundaries of major tectonic plates 
the only ones who have to worry about earthquakes? Why or why 
not? (No. The majority of earthquakes occur along plate 
boundaries, but some quakes do occur within the plates.) Invite 
students to speculate about the causes of intraplate earthquakes and 
faulting.

 Does the amount of damage an earthquake does depend only on its 
magnitude? (No. Population density, soil conditions, building types, 
and other factors determine the amount of damage. Students will 
learn more about these factors in subsequent units.)

ADAPTATIONS AND EXTENSIONS
1. Obtain copies of Preliminary Determinations of Epicenters and have 
students plot other kinds of data on fresh copies of the map, such as:
a. Earthquakes having magnitudes greater than magnitude 5 for (1) the 
world; (2) a particular region of the country, or (3) a particular state or 
local area.
b. Earthquakes that have caused the greatest damage or loss of life.

ACTIVITY TWO

THE PLOT THICKENS: PLOTTING EARTHQUAKE  
FOCI IN THREE DIMENSIONS

VOCABULARY
Epicenter: the point on Earths surface directly above the focus of an 
earthquake.

Focus (pl. foci): the point within the Earth that is the origin of an 
earthquake, where strain energy is first released as wave energy.

Magnitude: a number that characterizes the size of an 
earthquake by recording ground shaking on a seismograph and 
correcting for the distance to the epicenter of the earthquake. 
Magnitude is expressed in Arabic numbers.

RATIONALE
This activity graphically illustrates the patterns in the distribution of 
earthquake foci in one relatively small area.

FOCUS QUESTION
What would the pattern of earthquakes in one region look like if it 
could be observed in three dimensions over a period of time?

OBJECTIVE
Students will plot location and depth for one group of earthquakes and 
observe their relationships.

MATERIALS
for the teacher
 One copy of Master 3.4d, Central Japan (2 pages, left and right)
 Stiff cardboard, 30 cm x 60 cm (1 ft. x 2 ft.)
 Phillips screwdriver to punch holes for hanging
 Four pieces of cord or other support (See Teacher Preparation.)
 Glue or transparent tape
 Wall map of Japan or student atlases for each small group
 One copy of Master 3.4d, Central Japan (2 pages, left and right)
 One copy of Master 3.4e, Selected Earthquakes Since 1980, Japan
 Pencils, pens, and metric rulers
 Transparent tape
 Small craft beads such as 12 mm or 8 nun
 Dental floss or other strong, fine string
 Scissors
 One size 8-d nail

PROCEDURE
Teacher Preparation
Use a copier to enlarge the two-part map until it can cover most of the 
cardboard. Glue or tape the map to the top side of the cardboard. 
Attach cord to the four corners and hang it from the ceiling, or rest it 
on supports above the floor at a height that will be about eye level for 
most students. Make standard-size copies of the two-part map for desk 
use.

TEACHING CLUES AND CUES
Deep-focus earthquakes produce seismograms 
very different from those produced by shallow-focus earthquakes. EPIC and some 
of the other non-print media sources listed in the resources for Units 2 and 
3 can provide examples of both for you to show your students.

A. Introduction
Tell students that earthquakes occur in many locations and at different 
depths. The study of earthquakes has provided most of what we now 
know about the Earths structure. The patterns of their locations 
provided much of the evidence that led geologists to hypothesize the 
existence of plates.

B. Lesson Development
1. Divide the class into the same groups as for Activity One of this 
lesson. Give each group one copy of Master 3.4d, Central Japan (two 
pages, left and right) and Master 3.4e, Selected Earthquakes Since 
1980, Japan. Instruct students to cut the left page of Master 3.4d along 
the dotted line and tape it to the right page.

2. Divide the list of earthquakes into as many equal sections as you 
have student groups, and assign one section to each group. It is not 
necessary to use all the earthquakes. (If you have eight groups, each 
will be responsible for 10 quakes.) Instruct students to begin plotting 
their assigned quakes from Master 3.4e on the map of Japan by 
latitude and longitude, then mark each epicenter with its reference 
number, depth, and magnitude. Point out that 10 small squares on 
their maps represent one degree of longitude and one degree of 
latitude.

3. When the first group has located all the quakes on its own section 
of the list, it can transfer those locations to the hanging map. Other 
groups can follow as they complete their sections. Give these 
instructions for transferring data to the hanging map:
a. For each earthquake, take two beads of the same color. Use one 
bead to represent the epicenter of each quake and the other bead to 
represent its focus.
b. Locate the latitude and longitude of the first quake on the hanging 
map. Mark its epicenter and punch a hole all the way through the 
cardboard with the nail. Thread dental floss through the small bead 
and tie a knot to hold the bead at the correct location. Calculate the 
distance below the map at which the large ball will be hung (the depth 
of the focus) by letting 1 cm stand for 5 km. The bead representing 
earthquake #1 will hang 2 cm below its epicenter. Tie knots to hold 
the beads in place.
c. Repeat this procedure until all the quakes have been plotted on the 
map. When students have finished, invite them to view this 3-D plot 
from many directions.

4. Ask:

 What pattern do you see? Where do the earthquakes concentrate? 
(on the lower right)

 What do you think is happening to the Earths crust in this area? 
(Old crust is being broken off and pushed under the edges of the 
plate, in the process geologists call subduction.)

C. Conclusion
Call students attention to the atlas or wall map of Japan. Ask them if 
they view the map differently now that they can see what it represents 
in three dimensions. What kind of information would clarify their 
view further?

ACTIVITY THREE
WHERE IN NORTH AMERICA?

RATIONALE
By plotting earthquake epicenters on a map, students will learn where 
earthquakes occur on the North American continent and that they can 
occur almost anywhere.

FOCUS QUESTIONS
Where in North America do earthquakes occur?
How often do earthquakes occur in specific locations on the North 
American continent?

OBJECTIVES
Students will:
1. Interpret data tables and plot locations on a map.
2. Discover that most areas are prone to earthquakes.

MATERIALS
 Master 3.4f, North American Epicenters, 1990
 Classroom wall map of North America or transparency made from 
Master 3.4g, Map of North America
 Overhead projector
 Transparency markers in red, green, and blue
 Three transparencies made from Master 3.4g, Map of North America

for each small group
 Student copies of Master 3.4g, Map of North America
 One strip of earthquake epicenters cut from Master 3.4f
 Pencils or pens

PROCEDURE
Teacher Preparation
Make a copy of Master 3.4f. Cut it into as many horizontal sections as 
you have groups, dividing the list of epicenters so each group has 
approximately the same number of earthquakes to plot.

TEACHING CLUES AND CUES
In the EPIC Data Base, times are given in 24-hour Universal Time 
(UT) and carried out to eight places210117.90, for 
example, which would be approximately 9:01 pm. In Master 3.4f they 
have been shortened to four places (2101).

A. Introduction
From the other activities in this lesson, students have discovered 
where earthquakes occur worldwide and how seismologists locate 
them. Ask the class where earthquakes occur on the North American 
continent. Most of them will probably name California. Accept this, 
but try to elicit other locations as well. Some may be aware of the 
New Madrid, Missouri, earthquakes in the 19th century, or of other 
earthquakes close to home.

Remind students that earthquakes sometimes occur where volcanoes 
are present. Ask: Where on the North American Continent are 
volcanoes found? Students will probably identify the western United 
States. Tell them that at one time volcanoes erupted in the eastern part 
of the continent. The famous Palisades, a line of steep cliffs along the 
Hudson River in New York and New Jersey, were caused by volcanic 
activity. Tell students that in this activity they will use selected data 
from the U.S. Geological Survey to plot the locations of earthquakes 
of magnitude 4 or larger that occurred during 1990 on the North 
American continent.

B. Lesson Development
1. Divide the class into groups of three or four students each.

2. Distribute copies of Master 3.4g, the blank map, and the epicenter 
strips. Review latitude and longitude if necessary.

3. Have students plot the locations of the epicenters on their maps. 
Give these directions:
a. As you locate each point, mark it with a small dot. Then write the 
depth and magnitude of the earthquake next to it in small numbers.
b. When you finish, transfer your data to one of the three 
transparencies of Master 3.4g, using the colored pens to code for 
magnitude. Green will represent magnitude 4, blue magnitude 5, and 
red magnitude 6 or greater. Mark each earthquake with an X in the 
appropriate color.

4. When all the data have been plotted, stack the transparencies on the 
overhead so you can display them simultaneously. Ask students to 
comment on the pattern they observe, and compare it with their 
findings in Activity One. Do they see a similar pattern? They should 
see once again that earthquakes occur primarily near plate boundaries 
(for the U.S., on the west coast) but are not limited to those areas. Is 
there a pattern to the depth of the earthquakes? (The deepest quakes 
occur at plate margins under continents. This pattern may not be 
evident in this data.)

C. Conclusion
Remind students that these data are for one year only, and only for 
earthquakes of magnitude 4 or greater. Have them discuss what they 
would need to prepare an earthquake risk map for building codes or 
insurance rates. (The obvious answer will be more data, but point out 
to students some of the things they have already learned about
earthquakes, such as how waves travel through the Earth, and tell them 
that in later lessons they will learn about engineering to improve 
structural resistance to earthquakes.)

ADAPTATIONS AND EXTENSIONS
1. Obtain a copy of the EPIC software (free demonstration files are 
available) or the EPIC CD-ROM, and have students research earth- 
quakes of different magnitudes and different locations. See the unit 
resource list.

2. Have students contact the National Earthquake Information Center 
(NEIC) and report back to class on data and services available. See the 
Unit 2 resource list.

3. Have students contact the Incorporated Research Institutions for 
Seismology (IRIS) and report back to class on data and services 
available. See the Unit 2 resource list.

4. The NEIC and IRIS maintain remote bulletin boards. Have students 
find out how to access them and research earthquakes. ?

3.4a Earthquakes of the Day

Table 1.  Earthquakes That Occurred on January 1, 1990 
as listed in Preliminary Determinations of Epicenters, USGS-NEIC

Table 2.  Earthquakes That Occurred on January 2, 1990 
as listed in Preliminary Determinations of Epicenters, USGS-NEIC

Table 3.  Earthquakes That Occurred on January 1, 1991 
as listed in Preliminary Determinations of Epicenters, USGS-NEIC

Table 4.  Earthquakes That Occurred on January 2, 1991 
as listed in Preliminary Determinations of Epicenters, USGS-NEIC

Table 5.  Earthquakes That Occurred on January 1, 1992 
as listed in Preliminary Determinations of Epicenters, USGS-NEIC

Table 6.  Earthquakes That Occurred on January 2, 1992 
as listed in Preliminary Determinations of Epicenters, USGS-NEIC

Table 7.  Earthquakes That Occurred on January 1, 1993 
as listed in Preliminary Determinations of Epicenters, USGS-NEIC

Table 8.  Earthquakes That Occurred on January 2, 1993 
as listed in Preliminary Determinations of Epicenters, USGS-NEIC

3.4b Notable World Earthquakes 1900-1992 *

*From Bolt, 1993, and Catalog of Significant Earthquakes 2000 B.C.-1990, a 
NOAA publication in preparation. 
**Where data are lacking, assume earthquakes were shallow.

3.4c World Map

3.4d Central Japan

3.4e Selected Earthquakes Since 1980, Japan

This is a listing of events of Magnitude 5 which occurred in the polygon bounded 
by 34N 144E, 38N 134E, 39N 136E, and 35N 146E, centered around Tokyo, Japan. 
Data are from 1980 to 1993. Use the reference number in the first column (under 
the heading Evt. for Event) to mark the location of each earthquake on your map.

3.4f North American Epicenters, 1990

To obtain U.S. Department of the Interior/U.S. 
Geological Survey Preliminary Determinations of 
Epicenters, write to the Superintendent of Documents, 
U.S. Government Printing Office, Washington, DC 
20402. Annual subscription, $21.

BOOKS AND REPORTS
Bolt, Bruce A. (1993). Earthquakes. New York: W.H. 
Freeman & Co. Probably the single most useful basic 
text on earthquakes.

Christman, Robert A. (1980). Epicenters of the 1964 
Alaskan Earthquake and Time Travel: Earthquake 
Waves and Horses. In Activities for Earth Science, 
edited by V. Mayor. Columbus, OH: ERIC 
Clearinghouse (1929 Kenny Road, Columbus, OH 
43210-1079; 614-292-7784).

Davison, Charles. (1978). The Founders of 
Seismology. New York: Arno Press.

Herbert-Gustar, A.L., and Mott, P.A. (1980). John 
Milne: Father of Modern Seismology. Tenterden, 
England: Paul Norburg Publishers Ltd.

Penick, J. (1981). The New Madrid Earthquake of 
1811-1812, revised edition. Columbia, MO: 
University of Missouri Press.

Ross, Katherine E., editor. Making Earthquake 
Education Come AliveThe Development and Use of 
Low Cost Models in the Classroom. Buffalo, NY: 
NCEER, State University of New York; 716-636- 
3391. In press.

Simon, Ruth B. (1981). Earthquake Interpretation: A 
Manual for Reading Seismograms. Los Altos, CA: 
William Kaufmann, Inc.

Steinbrugge, K.V. (1982). Earthquakes, Volcanoes, 
and Tsunamis. New York: Scandia America Group.

Stewart, David, and Knox, Ray. (1993). The 
Earthquake That Never Went Away. The Shaking 
Stopped in 1812, but the Impact Goes On. Marble Hill, 
MO: Gutenberg-Richter Publications.

Utah Geological Survey. (October 1992, Revised). 
Places with Hazards. Salt Lake City, UT: Utah 
Department of Natural Resources; 801/467-7970. A 
teachers handbook on natural hazards in Utah for 
secondary earth science classes. Includes a geologic 
hazard slide set. Identifies and defines nine types of 
soil and rock conditions that pose geologic hazards in 
Utah and their locations.

ARTICLES AND PAPERS
Barker, Gary Keith. (1987). Interfacing the Lehmann 
Seismograph with an Apple Computer. Journal of 
Geological Education 4, 35: 126-128. Provides plans 
for interfacing the Lehmann seismograph with an 
Apple computer and printer through an analog/digital 
converter.

Barker, Gary. (September 1983). A Working 
Seismograph for the Classroom. Michigan Earth 
Scientist. Journal of the Michigan Earth Science 
Teachers Association.

The Bigger One. (Nov. 29, 1987). Los Angeles 
Times Magazine. A fictional account of a magnitude 
7.5 earthquake, worst-case scenario, on the Newport-
Inglewood Fault.

Brownlee, Shannon. (July 1986). Waiting for the Big 
One. Discover 7, 5271. Worth looking fora 
highly readable account of the state of earthquake 
prediction, with excellent illustrations.

Christman, Robert A. (1975). Understanding and 
Interpreting the Bellingham Seismograms of the 1964 
Alaskan Earthquake. Bellingham, WA: Western 
Washington State College. Available from Creative 
Dimensions, PO Box 1393, Bellingham, WA 98227 
(206-733-5024). Design your own classroom activities 
for the interpretation and understanding of a 
seismogram. Written explanations and questions are 
included.

Fuller, Myron L. (1990 reprint). The New Madrid 
Earthquake Scientific Factual Field Account. USGS 
Bulletin 494. Washington, DC: Government Printing 
Office, 1912. (Reprinted by the Southwestern 
Missouri University Center on Earthquake Studies)

Gerencher, J.J., and Jackson, R.F. (1991). Classroom 
Utilization of a Multi-Axis Lehman Seismograph 
System. Journal of Geological Education 39: 306
310. Also see Seismological Data Acquisition 
Software below.

Kerr, R.A. (1979). Earthquake Prediction: Mexican 
Quake Shows One Way to look for the Big Ones. 
Science 201: 10011003.

Kroll, Lawrence. (1987). Construction Modifications 
of the Lehmann Seismograph. Journal of Geological 
Education 4, 35: 124125. Modifications and building 
tips for the Lehmann seismograph built from common 
materials.

Inge Lehmann. Current Biography, 1962, pp. 251-
253.

Plude, C. (April 1986). Charles Richter: Earthquake 
Man. Cobblestone, p. 22. Written for readers 814. 
This issue contains other articles of interest as well.

Proujan, C. (Nov. 29, 1985). Build a Model 
TiltmeterAn Earthquake Warning System. Science 
World, pp. 89. For ages 1215.

Raleigh, C.B., et al. (March 1983). Forecasting 
Southern California Earthquakes. California Geology 
36. California Division of Mines and Geology; 
916-323-5336.

Simon, Ruth. A Personal Memoir of Inge Lehmann 
(1888-1993). Eos (November 2, 1993): 510512.

Tsunami Data. National Geophysical Data Center, 
NOAA, Code E/GCI. 325 Broadway, Boulder, CO 
80303; 303-497-633.

Williams, R.L. (1983). Science Tries to Break New 
Ground in Predicting Great Earthquakes. Smithsonian 
14, 4: 41-50.

PERIODICALS
Earthquakes and Volcanoes, a bimonthly magazine 
published by the U.S. Geological Survey, 904 
National Center, Reston, Virginia, 22029; 703/648-
6078. See especially Pacific Tsunami Warning 
System, Volume 18, Number 3, 1986, and 
Devastating Tsunami Inspires Efforts to Reduce 
Future Tsunami Destruction, Volume 19, Number 2, 
1987.

Eos, Transactions, American Geophysical Union. A 
weekly newspaper of geophysics. American 
Geophysical Union, 2000 Florida Avenue NW, 
Washington, DC 20009; 800-966-2481. See especially 
August 17, August 24, and September 14, 1993.

NON-PRINT MEDIA
EPIC Retrieval Software for the Global Hypocenter 
Data Base CD-ROM. United States Geological 
Survey, National Earthquake Information Center. A 
demonstration disk and information packet are 
available free: Phone 303- 273-8406; Fax 
303-273-8450; E-Mail hdf@neis.cr.usgs.gov 
(Internet). Federal Center, Box 25046, Mail Stop 967, 
Denver, CO 80225-0046. Through EPIC, you can 
access enormous amounts of national and international 
data ranging from 2100 BC to last month.

Jones, Alan L. The Dynamic Seismicity Program. 
version 1.00 level 93.03.02. New York: State 
University of New York, at Binghamton, 1993. Three 
computer disks and instruction manual. Also, PC 
shareware available on Internet 
@sunquakes.geol.binghamton.edu.

Hidden Fury: The New Madrid Quake Zone. 27-
minute video available from Bullfrog Films, 
P.O. Box 149, Oley, PA 19547; 1/800-543-FROG.

IRIS Database. United States Geological Survey, 
National Earthquake Information Center, Incorporated 
Research Institutions for Seismology, 1616 North Fort 
Myer Drive, Suite 1050, Arlington, VA 22209-3019.

Seismograph Model. For sale by Nasco, 800/558-
9595. Includes a recording needle, a support with a 
suspended weight, a recording tape, and a teachers 
guide.

Science ToolKit, Module 2: Earthquake Lab. 
Broderbund Software (Dept. 15, PO Box 6125, 
Novato, CA 94948-6125), 1986, for the Apple. 
Grades 412. Requires Science Toolkit Master 
Module.

Seismological Data Acquisition Software. Described 
in the Gerencher and Jackson article above. Apple 
software and 64-page users manual available from 
J. J. Gerencher, Physics and Earth Sciences, Moravian 
College, 1200 Main Street, Bethlehem, PA 18018-
6650.

Note: Inclusion of materials in these resource listings does 
not constitute an endorsement by AGU or FEMA.

Seismic Sleuths

Earthquakes

A Teachers Package for Grades 7-12
 
Unit Four

Can Buildings Be Made Safer?

This unit is designed to allow students to construct an 
understanding of how the shaking of the ground 
during an earthquake causes damage to buildings and 
how buildings can be made better able to withstand 
this shaking. The activities and experiments of this 
unit culminate in an exciting performance assessment. 
Like the activities in Unit 1, these require 
considerable teacher preparation and will be enhanced 
by the widest possible involvement of community 
members outside the classroom.

Lesson 1, Building Fun, is designed as an attention-
grabber, allowing students to discover the physical 
properties of some materials, practice working 
together, and most of all, have fun while establishing 
the need for constraints in building performance 
requirements. Students are given Styrofoam strips and 
a variety of connection devices and asked to build a 
stable structure of any kind.

Lesson 2 provides students with real experience in 
reinforcing or bracing a wall to carry the horizontal 
loads of an earthquake. They learn three engineering 
techniques and experiment with them on a model wall. 
Students develop the ability to make load path 
diagrams to predict and describe how static and 
dynamic forces travel though a wall.

Lesson 3, Building Oscillation Seismic Simulation, or 
BOSS, is an opportunity for students to explore the 
phenomenon of resonance while performing a 
scientific experiment that employs mathematical 
skills. The students are intrigued by a discrepant event 
involving the BOSS Model and are then set to work 
experimenting with the natural frequencies of 
structures. They experience how structures behave 
dynamically during an earthquake.

Lesson 4, Earthquake in a Box, engages students in 
constructing and using an instrument similar to one 
scientists use to model the impact of earthquake 
shaking. The materials and the procedure are both 
uncomplicated. This activity reinforces the major role 
of horizontal (lateral) forces in an earthquake and the 
importance of designing structures to withstand them.

In Lesson 5, The Building Challenge, students apply 
what they have learned in the first four activities. They 
are challenged to build a Styrofoam structure that can 
sustain the maximum horizontal load possible. The 
students performance in this building contest is an 
authentic assessment of the ideas developed in Unit 4.

Take time to do all the activities in this unit with your 
class. They are all important, not only because this 
unit is more closely integrated than the other units, but 
also because it deals with an aspect of earthquake 
safety that is usually not treated elsewhere in high 
school and junior high learning materials. It will 
kindle your students enthusiasm for science, 
architecture, and engineering.

4.1 Building Fun

TEACHING CLUES AND CUES
The lessons in this unit are a set. Plan time to do them all, for maximum 
learning and enjoyment.
 
Give yourself plenty of time for gathering and cutting materials. There 
is potential for some mess, so leave time for the students 
to clean up.
 
If you are not able to obtain visuals to introduce this lesson, do 
a quick demonstration with a deck of cards instead. Build 
card houses and let students take turns knocking them down by 
shaking the surface they rest on, or invite them to build and test the 
structures. The point is only that buildings need more than walls and a
roof to withstand stress.

RATIONALE
Students investigate the physical properties of building materials and 
design while considering how these might affect the way a structure 
withstands forces.

FOCUS QUESTIONS
What kind of structure would you build for fun?
What are the properties of some uncommon building materials?
How do structures stand up to extra forces?

OBJECTIVES
Students will:
1. Build a model structure.
2. Describe what may happen to a structure when a load is applied.
3. Describe the physical properties of some materials.

MATERIALS
for the teacher
 Master 4.1a, Building Engineering: Teacher Background Information
 Photos, books, slides, and/or videos with images of earthquake 
damage (See Unit 1 Resources.)
 Band saw or other saw
 One brick

for each small group
 6 or more sticks of Styrofoam, 2.5 cm x 2.5 cm x 15 cm (l in. x 1 in. x 6 in.)
 3 pieces of string, each 30 cm long (optional)
 10 paper clips (optional)
 About 20 toothpicks
 Masking tape for labels

VOCABULARY
Horizontal load: the sum of horizontal forces (shear forces) acting on the 
elements of a structure.

Lead: the sum of vertical force (gravity) horizontal forces (shear 
forces) acting on the mass of a structure. The overall load is further 
broken down into the loads of the various parts of the building. Different 
parts of a building are designed and constructed to carry different loads.

Vertical load: the effect of vertical force (gravity) acting on the elements 
of a structure.

TEACHING CLUES AND CUES
Cut more Styrofoam than you will need for this lessonabout 35 
strips per groupsince you will also use these strips in 
Lesson 4. If some of the strips are less than uniform, use them now, 
saving the best ones for Lesson 4.

PROCEDURE
Teacher Preparation
1. You may want to invite an architect, engineer, geologist, or 
seismologist to visit your class during Lesson 4 of this unit, when 
students will again design model buildings. The guest expert could 
initiate the building challenge and help students to understand the 
concepts involved.

2. Read the teacher background information on Master 4.1a. 1f 
possible, assemble visuals from among those listed in the Unit 1 
Resources.

3. Draft a few students to cut the Styrofoam into pieces, or ask the 
industrial arts instructor to help. (Styrofoam is easily cut on a band 
saw.) Finally, collect the building materials for this lesson and put 
them into piles on a table in the front of the room.

A. Introduction
Set the stage by asking students to tell what they know about the 
effect of earthquakes on buildings and other structures, both from 
personal experience and from reading, television, movies, or other 
sources. Be protective of their right to say what they remember, even 
if it may sound exaggerated to other students. If you have pictures or 
slides of earthquake damage, show them now.

B. Lesson Development
1. Divide the class into cooperative working groups of three to five 
students each. Explain that throughout this unit the groups will be 
known as seismic engineering teams, or SETs. Encourage each SET to 
choose a name.

2. Ask the groups to collect materials and build the strongest 
structures they can with the materials and the time allotted. Do not 
direct or criticize their efforts. This activity is for fun. When students 
try again in Lesson 4, they will be able to apply what they have 
learned in this unit.

3. After 20 to 30 minutes, call a halt to construction. Have a 
spokesperson for each group bring its structure to the materials table 
in the front of the room and describe the structure to the class. Ask 
students to explain why they built what they did.

4. With all the structures on one table, ask the class what would 
happen if you were to place a brick on top of each structure. Have the 
brick in hand, but do not actually crush any structure. Explain to the 
students that the brick is simulating the static force of gravity (vertical 
load) that every structure must carry. In this case, the Styrofoam is 
quite strong for its weight, so the brick can also represent the weight 
of all the nonstructural elements of a building, such as floors, wall 
coverings, and electrical wiring. Expect the students to protest 
because they were not told their structures had to support a brick. 
Explain that this activity was only an introduction and a chance to 
discover the physical properties of the materials.

5. Now ask the students what would happen if you shook the base of 
each building. Test a few gently while the students observe. What if 
you held the base of each structure and pushed horizontally on the 
top? Test a few, but again, try not to break any structure. Explain that 
buildings experience horizontal loads or dynamic forces during 
earthquakes. One way to simulate these forces is simply to push or 
pull a structure from the side.

C. Conclusion
Tell students that at the end of this unit there will be another building 
activity, but this time it will be a contest to design and build structures 
that can support a horizontal load. What they learn in this unit can be 
applied in the contest. Let them know there will be clearly defined 
parameters and all groups will have an equal opportunity to succeed. 
Label the structures with SET names and put them aside for the 
contest at the end of this unit.

4.1a Teacher Background Reading
Building Engineering

During an earthquake, a marked spot on the Earth might be seen to move 
erratically, tracing out a random path 
resembling that of a wandering insect. Ground motion is a literal description, 
since the ground moves (generally 
for a distance measured only in centimeters) relative to its starting point. The 
ground motion that is important in 
determining the forces on a building is acceleration. As the seismic waves move 
through the ground, the ground 
moves back and forth. Acceleration is the rate at which ground movement changes 
its speed.

Two other unit measures are directly related to acceleration. Velocity, measured 
in centimeters per second, refers 
to the rate of the motion at a given instant. Displacement, measured in 
centimeters, refers to the distance an object 
is moved from its resting position. If you move your hand back and forth rapidly 
in front of your face, it might 
experience a displacement of 20 to 30 centimeters in one second and its 
acceleration and velocity may be quite 
high, but no damage will be done because the mass of your hand is low. In a 
building with a mass in the 
thousands of metric tons, tremendous forces are required to produce the same 
motion. These forces are transmitted throughout the structure, so if the 
movement repeats for some minutes the 
building may shake to pieces.

To overcome the effects of these forces, engineers rely on a small number of 
components that can be combined to 
form a complete load path. In the vertical plane, three kinds of structural 
systems are used to resist lateral forces: 
shear walls, braced frames, and moment-resistant or rigid frames. In the 
horizontal plane, diaphragms (generally 
formed by the floor and roof planes of the building) or horizontal trusses are 
used. Diaphragms are designed to 
receive lateral force between the vertical resistance elements (shear walls or 
frames). Shear walls are solid walls 
designed to carry the force to the vertical resistance system. In a simple 
building with shear walls at each end, 
ground motion enters the building and moves the floor diaphragms. This movement 
is carried by the shear walls 
and transmitted back down through the building to the foundation. Braced frames 
act in the same manner as shear 
walls, but may not carry as much load depending on their design. Bracing 
generally takes the form of steel rolled 
sections (I-beams), circular bar sections (rods), or tubes. Rigid frames rely on 
the capacity of joints to carry loads 
from columns to beams. Because these joints are highly stressed during movement 
the details of their 
construction are important. As a last-resort strategy, rigid frames use the 
energy absorption obtained by 
deformations of the structure before it ultimately fails.

Architecturally, rigid frames offer a certain advantage over shear walls or 
braced frames because they tend to 
provide structures that are much less obstructed internally than shear wall 
structures. This allows more freedom in 
the design of accompanying architectural elements, such as openings, exterior 
walls, partitions, and ceilings, and 
in the placement of building contents, such as furniture and loose equipment. 
Nevertheless, moment-resistant 
frames require special construction and detailing and therefore, are more 
expensive than shear walls or braced 
frames.

Note: Adapted from FEMA 99, October 1990, Non-technical Explanation of the NEHRP 
Recommended Provisions.

4.2 Structural Reinforcement: 
The Better Building

RATIONALE
Students will learn how diagonal braces, shear walls, and rigid 
connections strengthen a structure to carry forces resulting from 
earthquake shaking.

FOCUS QUESTIONS
How may the structure of a building be reinforced to make it better 
able to withstand earthquake shaking?

OBJECTIVES
Students will:
1. Recognize some of the structural elements of a building.
2. Describe how the horizontal and vertical structural elements carry 
the horizontal and vertical loads of a building.
3. Describe how diagonal braces, shear walls, and rigid 
connections provide paths for the horizontal load resulting from an 
earthquake.
4. Observe how added structural elements strengthen a model wall to 
withstand shaking.


MATERIALS
For the teacher: Materials for one model wall
 Master 4.2a, Building a Model Wall
 21 jumbo craft sticks, about 15 cm x 2 cm x 2 mm thick
 Electric drill with 3/16" bit
 Goggles for eye protection
 1 piece of thin wood (about 2 mm thick) 45 cm x 6 cm (about 
18 in. x 2 in.)
 1 piece of sturdy wood (2 x 6) for a base, about 45 cm (18 in.) long
 16 machine bolts, 10 x 24, about 2 cm long (.75 in.)
 16 machine screw nuts, 10 x 24
 32 washers, #8
 7 small wood screws

reinforcing elements for one wall
 2 pieces of string, each approximately 25 cm (10 in.) long
 1 piece of thin wood (about as thick as the craft sticks) 20 cm x 2 
cm (about 8 in. x 1 in.)
 1 piece of lightweight cardboard, about 15 cm x 15 cm (a little less 
than 6 in. square)
 8 small paper clamps to fasten wood and cardboard

for each small group
 One set of the above supplies if they are each building a model wall
 One copy of Master 4.2b, Load Paths Worksheet
 Pens and pencils

TEACHING CLUES AND CUES
Jumbo craft sticks are available at craft and hobby stores. They are 
larger than ice cream sticks, about the size of tongue depressors.

You may want to build this model and the one in Lesson 4.3 at the 
same time, and introduce them both in the same class period. This 
would allow two groups to be actively engaged with the models of the 
same time.

VOCABULARY
Braces or Bracing: structural elements built into a wall to add 
strength. These may be made of various materials and 
connected to the building and each other in various ways. Their ability to 
withstand stress depends on the characteristics of the materials and 
how they are connected.

Lead: the sum of vertical forces (gravity) and horizontal forces (shear 
forces) acting on the mass of a structure. The overall load is further 
broken down into the loads of the various parts of the building. Different 
parts of a building are designed and constructed to carry different loads.

Lead path: the path a load or force takes through the structural elements 
of a building.

Rigid connections: connections that do not permit any motion of the 
structural elements relative to each other.

Shear force: force that acts horizontally (laterally) on a wall. 
These forces can be caused by earthquakes and by wind, among 
other things. Different parts of a wall experience different shear forces.

Shear walls: walls added to a structure to carry horizontal (shear) 
forces. These are usually solid elements, and are not necessarily 
designed to carry the structures vertical load.

Structural elements or structural features: a general term for all the 
essential, non-decorative parts of a building that contribute structural 
strength. These include the walls, vertical column supports, horizontal 
beams, connectors, and braces.

PROCEDURE
Teacher Preparation
Assemble the model wall, following the diagram on Master 4.2a, 
Building a Model Wall, and try it out before class. Be sure the bolts 
are just tight enough to hold the structure upright when no force is 
applied.

A. Introduction
Tell students that this lesson is designed to demonstrate how the 
structural elements of a wall carry forces. The activity deals with three 
structural elements that carry the lateral shear forces caused by ground 
shaking during an earthquake: diagonal bracing, shear walls, and rigid 
connections. It is designed around an apparatus called the model wall. 
Remind the students that this is a model, designed to demonstrate only 
certain characteristics of real walls.

B. Lesson Development
1. Show students the model and tell them that it represents part of the 
frame of a building. Describe the components of the wall, and ask 
them, What holds this wall up? The answer is in the interaction of 
the vertical and horizontal elements, but try to keep the students 
focused on discovery, since in this activity they will see the 
architectural principles demonstrated. Explain to students that what 
they refer to as weight will be called the force of gravity in this 
lesson.

2. Now ask students to predict what would happen if you quickly 
pushed the base of the wall, simulating an earthquake. Remind them 
that an earthquake may cause ground shaking in many directions, but 
for now we are modeling shaking in one direction only.

3. Divide the class into the same seismic engineering teams (SETs) as 
for Lesson 1 and give each group one copy of Master 4.2b, Load 
Paths Worksheet. Invite students to take turns investigating the 
models response in their small groups.
a. Instruct one student in each group to push at the bottom of the 
model from the lower right or left side. (When pushed just fast 
enough, the model should collapse at the first floor only.) Ask 
students why the other floors didnt collapse. (The first floor 
collapsed because it was too weak to transfer enough horizontal force 
to move the upper stories. It could not transfer the shaking to the 
upper stories.)
b. Direct students attention to the load path diagrams on Master 4.2b 
and explain that pushing the base of the building is equivalent to 
applying force horizontally to the upper stories. A force applied 
horizontally to any floor of a building is called the shear force on that 
floor. Shear forces can be caused by the ground shaking of an 
earthquake as well as by high winds. Invite students to carefully apply 
horizontal forces at different points on the model to simulate 
earthquake shaking. (Earthquakes affect buildings at ground level.)

TEACHING CLUES AND CUES
This activity is designed as a demonstration or as a group activity. If you 
decide to have each group build a model wall you will need more materials.
 
Encourage students to choose roles within their SETs and later report 
their results by role, with the technician reporting the data, the 
engineer describing the calculations, the scientist explaining the 
relationships, and the coordinator facilitating.
 
Students may try both pushing the structure directly and moving the 
table. Shaking the table on which the structure rests would 
simulate the transfer of energy from the ground to the building.

4. Ask students how they could add structural elements to create a 
path for the load to follow to the ground when strong forces act upon 
the structure. Help the students discover the effect of adding a shear 
wall, diagonal bracing, and rigid connections, using string, cardboard, 
extra wood, and clamps, as in the diagrams on the master. On each of 
the three diagrams provided, have students draw a force arrow (a 
vector) and trace the path the force takes to the ground.

5. Challenge students to design and build three different arrangements 
of the six structural elements depicted on the worksheet. Each time 
they modify the design they must modify the diagram to show the new 
load path. Check each structure and diagram until you are sure that 
students understand the concepts. When a structure is well reinforced, 
you should be able to push on the upper story and slide the whole 
structure without any of the walls failing.

6. Either have the groups discuss the questions on the master, with 
one student recording each groups response, or ask individual 
students to write responses to specific questions. After all the groups 
finish the questions, have a reporter for each SET present its response 
to one of the questions. Allow the class to come to some consensus on 
their responses to that question, then proceed to another group until 
all the questions have been discussed.

C. Conclusion
As a closing activity, challenge a volunteer to remove an element (a 
craft stick) that, according to the load path diagram, is not carrying 
any load. Have the student unbolt one end of that element and push 
the reinforced structure to see if it holds. It will, if the load path is 
correct.

Finally, help the students connect the behavior of their model walls to 
their mental images of real buildings during an earthquake. Emphasize 
that the back and forth, horizontal component (or shearing) of ground 
shaking is the force most damaging to buildings. Buildings are 
primarily designed to carry the downward pull of
gravity, but to withstand earthquake shaking they need to be able to 
withstand sideways, or horizontal, pushes and pulls.

ADAPTATIONS AND EXTENSIONS
1. Challenge students to find the minimum number of diagonal braces, 
shear walls, or rigid connections that will ensure horizontal stability in 
their models.

2. Invite students to design, construct, and test other structural 
elements that could make buildings earthquake-resistant, such as 
square rigid connections. Some might try putting wheels or sleds on 
the bottom of their buildings.

3. If you have some very interested students, you may give them 
access to all your building supplies and challenge them to design and 
construct larger structures. Ask students to consider how they could 
design a building so that the ground shaking does not transfer to the 
building. There are new technologies that allow the ground to move, 
but not the building. One of these is called base isolation. Have 
students research this topic in periodicals. (See Unit Resources.)

4.2a Building a Model Wall

1. Stack 21 craft sticks one on top of the other. Wrap a rubber band around the 
center to hold them together. 
Using a 3/16 in. bit, carefully drill a hole through all the sticks at once, 1 
cm from the end of the stack. Drill 
slowly to avoid cracking the wood.

2. Select the thinner of the two large pieces of wood (45 cm x 6 cm). Drill a 
3/16 in. hole 1 cm from one end and 
1 cm from the edge. Measure the distance between the holes drilled in the craft 
sticks and space three more 3/16 
in. holes at that distance 1 cm from the edge so that a total of four holes are 
drilled (see illustration).

3. Use the small wood screws to mount this piece of wood on the base (the 2 x 
6), fastening at the bottom and in 
the center. Leave the pre-drilled holes sticking up far enough above the top to 
accept the drilled craft sticks.
 
4. Using the bolts, washers, and nuts, assemble the craft sticks to build a 
model wall.

5. Experiment with tightening bolts and washers until they are just tight enough 
for the wall to stand on its own.

4.2b Load Paths Worksheet 
 
Name
Date

A. Failing Wall
Observe and explain how the wall fails when its base is shaken rapidly back and 
forth, simulating the motion of a 
building hit by S waves during an earthquake. Tighten all the nuts just enough 
to allow the joints to move. 
Sharply push the base a few centimeters horizontally (right or left).

1. What part of the wall fails first?

2. Imagine how the horizontal force you applied to the base travels to the upper 
parts of the wall. What caused the 
first structural failure?

B. Load Paths with Additional Structural Elements

1. Pick up the two rigid connections, one shear wall (cardboard), one solid 
diagonal brace, and two pieces of 
string. Add structural elements to your wall to provide paths for the horizontal 
forces, or loads, to travel through 
the wall. Study the diagrams below to see how these structural elements provide 
load paths.
 
Use arrows to show the load path on each diagram.

2. Put additional structural elements on your wall and 
push the third level. If the elements you added provided 
a load path to the base, the base of the wall should move. 
If they do not, the wall will fail somewhere. When you 
discover a setup that works, diagram it and sketch the 
load paths with arrows. Have your instructor look it over 
before you continue.
 
3. Design and build another set of additional structural 
elements. Sketch the load path here and have your 
instructor check it. Be sure each member of the team 
designs a set. The base of the model wall should move 
when lateral force is applied to the top elements.
 
4. Design and build a third set of additional structural 
elements. Use as few additional elements as possible. 
Sketch the load path and have your instructor check it. 
Be sure each member of the team designs a set. Test 
your load paths by removing elements not in the path to 
see if the building will stand up to a force.

C. Summary

1. What is a load path? 

2. Why must additional structural elements be added to a wall before it can 
carry horizontal forces?

3. How many additional elements did you need to add?

4. Why doesnt the force take some path other than the one you diagrammed?

4.2b Load Paths Worksheet (key)

A. Failing Wall
Observe and explain how the wall fails when its base is shaken rapidly back and 
forth, simulating the motion of a 
building hit by S waves during an earthquake. Tighten all the nuts just enough 
to allow the joints to move. 
Sharply push the base a few centimeters horizontally (right or left).

1. What part of the wall fails first?     The first floor

2. Imagine how the horizontal force you applied to the base travels to the upper 
parts of the wall. What caused the 
first structural failure?     The first floor has to carry all the load to the 
upper stories. It transfers forces to move 
the upper stories.

B. Load Paths with Additional Structural Elements

1. Pick up the two rigid connections, one shear wall (cardboard), one solid 
diagonal brace, and two pieces of 
string. Add structural elements to your wall to provide paths for the horizontal 
forces, or loads, to travel through 
the wall. Study the diagrams below to see how these structural elements provide 
load paths.
 
Use arrows to show the load path on each diagram.

2. Put additional structural elements on your wall and 
push the third level. If the elements you added provided 
a load path to the base, the base of the wall should move. 
If they do not, the wall will fail somewhere. When you 
discover a setup that works, diagram it and sketch the 
load paths with arrows. Have your instructor look it over 
before you continue.
 
3. Design and build another set of additional structural 
elements. Sketch the load path here and have your 
instructor check it. Be sure each member of the team 
designs a set. The base of the model wall should move 
when lateral force is applied to the top elements.
 
4. Design and build a third set of additional structural 
elements. Use as few additional elements as possible. 
Sketch the load path and have your instructor check it. 
Be sure each member of the team designs a set. Test 
your load paths by removing elements not in the path to 
see if the building will stand up to a force.
 
C. Summary

1. What is a load path? 
The path that the load (or force) follows through the structural elements of a 
building.

2. Why must additional structural elements be added to a wall before it can 
carry horizontal forces?
Normally, buildings only have to support vertical force (gravity). When 
horizontal forces are applied, as in an 
earthquake, additional elements are needed to carry them.

3. How many additional elements did you need to add?
Each joint needs only one additional structural element. Only one joint on each 
floor needs to carry the 
horizontal force, in this model.

4. Why doesnt the force take some path other than the one you diagrammed?
The diagram shows the places that are strong enough to carry the load. If there 
were more than one place, the 
load (or force) would travel through both.

4.3 The BOSS Model:
Building Oscillation Seismic Simulation

TEACHING CLUES AND CUES
As noted in lesson 4.2, you may want to have one group of students 
working with this model while another is working with the model wall.

RATIONALE
During an earthquake, buildings oscillate. If the frequency of this 
oscillation is close to the natural frequency of the building, resonance 
may cause severe damage. The BOSS model allows students to 
observe the phenomenon of resonance.

FOCUS QUESTIONS
Why do buildings of different heights respond differently in an 
earthquake?

OBJECTIVES
Students will:
1. Predict how a structure will react to vibrations (oscillations) of 
different frequencies.
2. Perform an experiment to establish the relationship between the 
height of a structure and its natural frequency.
3. Describe the phenomenon of resonance.

MATERIALS
for one BOSS Model
 Master 4.3a, BOSS Model Assembly
 4 pieces of wood, 1 x 4, each 15 cm (6 in.) long
 1 piece of wood, 2 x 4, for a base, about 45 cm (18 in.) long
 2 threaded rods, 10 x 24, each 96 cm (36 in.) long
 2 threaded rods, 10 x 24, each 61 cm (2 ft.) long
 Goggles for eye protection
 Hacksaw or power saw with metal-cutting blade
 Electric drill or hand drill with -in. and -in. wood bore bits
 Hammer
 8 wing nuts, 10 x 24
 8 tee nuts, 10 x 24
 8 washers, #8
 A wide permanent marker in any color that will contrast with the 
wood
 Poster paints: red, green, blue, black, and white, and 5 brushes 
(optional)

for each small group
 One copy of Master 4.3b, BOSS Worksheet
 Pencils or pens
 Stopwatch
 Meter stick

TEACHING CLUES AND CUES
Since the rods can break with rough handling, you may want to buy one or 
two extra.

VOCABULARY
Amplitude: a measurement of the energy of a wave. Amplitude is the 
displacement of the medium from zero or the height of a 
wave crest or trough from a zero point. (In this activity its how far to 
the side the block moves.)

Frequency: the rate at which a 
motion repeats, or oscillates. The frequency of a motion is directly 
related to the energy of oscillation. In this context, frequency is the number 
of oscillations in an earthquake wave that occur each second. In 
earthquake engineering, frequency is the rate at which the top of a building 
sways.

Hertz (Hz): the unit of measurement for frequency, as recorded in cycles 
per second. When these rates are very large, the prefixes kilo or mega 
are used. A kilohertz (kHz) is a frequency of 1,000 cycles per second 
and a megahertz (MHz) is a frequency of 1,000,000 cycles per 
second.

Oscillation or vibration: the repeating motion of a wave or a 
materialone back and forth movement. Earthquakes cause 
seismic waves that produce oscillations, or vibrations, in materials 
with many different frequencies. Every object has a natural rate of 
vibration that scientists call its natural frequency. The natural frequency of 
a building depends on its physical characteristics, including the design 
and the building materials.

Resonance: an increase in the amplitude (in this case, the distance 
the top of a building moves from its rest position) of a physical system 
(such as a building) that occurs when the frequency of the applied 
oscillatory force (such as earthquake shaking) is close to the natural 
frequency of the system.

PROCEDURE
Teacher Preparation
Build the BOSS model by following the directions on Master 4.3a. 
Practice with your model until youve got a feel for each frequency 
and you can get any of the rod assemblies to resonate. One technique 
is to use a firm push first, then watch the number you want and wiggle 
the base very lightly at its natural frequency to get resonance.

A. Introduction
Find out what students already know about the concepts of amplitude, 
frequency, and resonance. If they are not familiar with these terms, 
introduce them by building on what students already know from other 
areas. They may know, for example, that resonance and frequency are 
used in describing the tone of musical instruments and the quality of 
sound produced by different recording techniques and players. The 
phenomenon of resonance also accounts for laser light and for the 
color of the sky.

B. Lesson Development
1. Direct students attention to the BOSS model, and explain its name. 
Ask the students to predict which numbered rod assembly will 
oscillate the most when you wiggle the base. Have them hold up 1, 2, 
3, or 4 fingers to indicate their prediction. (They will probably say 
number 1 because it is the tallest.)

2. Oscillate the BOSS model so that some rod assembly resonates 
other than the one most students predicted. This will baffle the 
students, so let them predict again. Again make the rod resonate for an 
assembly they did not predict. Finish this demonstration after several 
tries by making the rod resonate for the assembly most of the students 
did predict, so that they get it right. Invite discussion.

3. Relate the blocks and rods to buildings of various heights in an 
earthquake. Ask students if they think buildings would oscillate like 
this in an earthquake. (They always do, and in some earthquakes the 
effect is especially pronounced. In the 1985 Mexico City earthquake, 
the ground shaking resonated with the natural frequencies of 8-to-10-
story buildings. The effect was severe damage to medium-height 
buildings that had the same frequency as the ground shaking and 
resonated with it. Higher and lower buildings were hardly damaged.) 
Use the BOSS model as a visual aid when describing this event. You 
may also want to draw attention to the photos or books you used in 
Lesson 1 of this unit.

4. Divide students into seismic engineering teams (SETs) and 
distribute one copy of Master 4.3b, BOSS Worksheet, to each group. 
Tell students that they will take turns performing an experiment with 
the model, recording their data, and providing the answers asked for 
on the data sheet. Give these directions:
a. Hold the base stationary, pull the wooden number 1 out several 
centimeters to the side, and release it. As the rod oscillates, use a 
stopwatch to measure the time for 10 oscillations. Record this 
number.
b. Practice until you can get almost the same swing each time, then 
repeat the measurement four times. Calculate the average of these four 
times. Now calculate the natural frequency of the number by dividing 
10 cycles by the average time. Record it. Repeat this procedure for the 
other three numbers.
c. Measure the height of each assembly from the base to the top, and 
record it.
d. Plot height versus natural frequency on the graph provided. 
(Students should come up with a hyperbola, a curve representing an 
inverse relationship in which, as the height of the structure increases, 
its natural frequency decreases.)
e. Ask the class: From what you have learned, do the earthquakes with 
the highest numbers on the Richter Scale always do the most damage? 
(Students should already know that the amount of damage has to do 
with population density and other factors, but now they will be aware 
of something new. To illustrate the relationship of frequency and 
resonance, use the example of someone pushing a child in a swing. 
The person pushes a little at a time, over time, and soon the swing 
goes very high without a big push. Each small push is at the right 
frequency. Similarly, a building may vibrate with a great amplitude 
without big earthquake vibrations because the smaller vibrations came 
at that structures natural frequency.)

TEACHING CLUES AND CUES
You may choose to have students build models in class. In that case, you 
will need to make student copies of Master 4.3a, and assembly will become step 1 
under 
Lesson Development. You will also need more materials.

Instruct students to start the stopwatch as a numbered block reaches 
its maximum swing and start counting with zero. Often 
students will start counting with one when they start the stopwatch and 
end up with only nine swings.

5. Ask the SETs to share and discuss their results. Again point out the 
connection between the experimental results and the way real 
buildings resonate. Other things being equal, taller buildings have 
lower natural frequencies than short buildings.

C. Conclusion
Review the terms and concepts introduced in this lesson. Explain that 
seismic waves caused by earthquakes produce oscillations, or 
vibrations, in materials with many different frequencies. Every object 
has a natural rate of vibration that scientists call its natural frequency. 
The natural frequency of a building depends on its physical 
characteristics, including the design and the building materials. 
Resonance is a buildup of amplitude in a physical system that occurs 
when the frequency of an applied oscillatory force is close to the 
natural frequency of the system. In the case of an earthquake, the 
ground shaking may be at the same frequency as the natural frequency 
of a building. Each vibration in the ground may come at or 
dangerously close to the natural frequency of the structure.

Ask the class to hypothesize what would happen when buildings of 
two different heights, standing next to each other, resonate from an 
earthquake. Wiggle the BOSS model so that assemblies 2 and 3 
vibrate greatly, and let students see how buildings hammer together 
during powerful earthquakes. If you have some images of this effect 
from actual earthquakes, show them now.

Entice students to further investigation by leaving them with the 
question: How could you add structural elements to reduce resonance 
in a building?

ADAPTATIONS AND EXTENSIONS
1. Tell students that one way to protect a building from resonating 
with an earthquake is to isolate its foundation, or base, from the 
ground with devices much like wheels. This technique is called base 
isolation. Structural engineers are now developing the technology to 
place buildings on devices that absorb energy, so that ground shaking 
is not directly transferred to the building.

Invite students to add standard small wheels from a 
hardware store to their models as an illustration of one of 
the many base isolation technologies, or add wheels to 
your own BOSS model, then shake the table. Better yet, 
place the model in a low box or tray and shake it. Then 
take out the model, fill the box with marbles or BBs, and 
replace the model on this base. Now shake the box. 
Challenge students to come up with other base isolation 
techniques.
 
2. If any of your students have studied harmonic motion in 
a physical science or physics class, challenge them to 
explain how the BOSS model is an example of an inverted 
pendulum.

3. To help students connect the numbered rod assemblies 
to actual buildings, make paper sleeves and decorate them 
to resemble buildings in your area. At some point in the 
lesson, slide the sleeves over the rod assemblies to show 
how buildings can collide, or hammer against each other, 
during an earthquake.

4.3a BOSS Model Assembly

1. Cut one of the meter-long threaded rods down 
to 75 cm, leaving the other full length.

2. Cut one of the 61-cm threaded rods down to 45 
cm, leaving the other full length.
3. Drill a .63-cm (1/4 in.) hole through the center 
of one of the short sides in each of the 15-cm 
pieces of wood. (See assembly diagram.)

4. Hammer a tee nut into the hole on one end of 
each 15-cm piece.

5. Countersink four 3/4-in. holes about 1/8 in. 
deep into the 45-cm 2 x 4 at 12-cm intervals, as 
marked on the diagram. (This will allow you to 
countersink the nuts so they dont scratch the 
surface where the model rests.)

6. Drill four 1/4-in. holes in the 45-cm 2 x 4 in the 
countersunk holes.

7. Hammer a tee nut into each countersunk hole. 
Turn the board over so the tee nuts are on the 
bottom.

8. Assemble the rods and the base as shown on 
the diagram.

9. Use the permanent marker to label the 15-cm 1 
x 4 blocks in order, 1, 2, 3, and 4.
Optional: Paint the four 15-cm pieces of wood 
in four different colors. When they are dry, 
number them, with the white paint.
 
4.3b BOSS Worksheet
 
Name
Date
Cooperative Group

Scientist
Coordinator

Technician
Engineer

Record oscillation times in the data table below in the appropriate place for 
each rod assembly. These times are 
measured in seconds per 10 cycles. Repeat the measurement four times to minimize 
human error, then record.
Caution: Start the stopwatch as a numbered block reaches its maximum swing and 
start counting with zero, otherwise you 
will end timing only nine swings. Practice this until your times for 10 
oscillations are fairly close to each other.

Calculate the average time for each oscillation by adding four measurements and 
dividing by four. Record.

Calculate the natural frequency. Divide 10 cycles by the average time (do not 
simply move the decimal point). 
Frequency is measured in hertz, or cycles per second. Record.

A. Data Table: Oscillation Times

1. How much variation do you notice among the four trials?
2. What relationship do you notice, if any, between the height of the rods and 
their natural frequencies?

B. Heights of the Rod Assemblies

1. Measure the height of each rod assembly from the base to the top of the block 
and record it.

2. What is the approximate difference in height between #1 and #2, #2 and #3, 
and so on?

3. Plot the height versus the natural frequency of each 
rod assembly on the graph provided. You should have 
four data points. Connect the points with the best fitting 
straight or curved line you can.

4. What kind of line did you get from your data?

5. As the height of the rod assemblies gets larger, what 
happens to their natural frequency?

C. Summary
1. What variable is manipulated in this experiment? (How do the four rod 
assemblies differ from each other?)

2. What is the responding variable in this experiment? (What did you measure?)

3. What does oscillate, or vibrate, mean?

4. Define frequency.

5. Why does only one rod assembly oscillate greatly (or resonate) when you 
wiggle the base?

6. What is resonance?

7. How are the rod assemblies like buildings?

8. (extra credit) How can a building be protected from resonating with seismic 
vibrations?

Record oscillation times in the data table below in the appropriate place for 
each rod assembly. These times are 
measured in seconds per 10 cycles. Repeat the measurement four times to minimize 
human error, then record.
Caution; Start the stopwatch as a numbered block reaches its maximum swing and 
start counting with zero, otherwise you 
will end timing only nine swings. Practice this until your times for 10 
oscillations are fairly close to each other.

Calculate the average time for each oscillation by adding four measurements and 
dividing by four. Record.

Calculate the natural frequency. Divide 10 cycles by the average time (do not 
simply move the decimal point). 
Frequency is measured in hertz, or cycles per second. Record.

A. Data Table: Oscillation Times
1. How much variation do you notice among the four trials?  Oscillation times 
vary by less than 10 percent.	
2. What relationship do you notice, if any, between the height of the rods and 
their natural frequencies?
The shorter the rod, the higher the natural frequency. The taller the rod, the 
lower the natural frequency.	 
	

B. Heights of the Rod Assemblies
1. Measure the height of each rod assembly from the base to the top of the block 
and record it.

2. What is the approximate difference in height between #1 and #2, #2 and #3, 
and so on?
Approximately 15 cm, the height of the wooden rectangle at the top of each rod 
assembly.	

Note: Data will vary with specific BOSS model and student. Values in the tables 
are to assist the teacher and are not to be used in 
evaluating students.

3. Plot the height versus the natural frequency of each rod 
assembly on the graph provided. You should have four data 
points. Connect the points with the best fitting straight or 
curved line you can.

4. What kind of line did you get from your data?
 A symmetrical curve, or hyperbolic curve.	

5. As the height of the rod assemblies gets larger, what 
happens to their natural frequency?
 As the height increases, the natural frequency decreases.	 

C. Summary
1. What variable is manipulated in this experiment? (How do the four rod 
assemblies differ from each other?)
  The height of the rods varies.	
2. What is the responding variable in this experiment? (What did you measure?)
  The natural frequency of each rod assembly.	
3. What does oscillate, or vibrate, mean?
  Wiggle back and forth, or move repetitively.	
4. Define frequency.
  In this case, the frequency is the number of oscillations per second.	
5. Why does only one rod assembly oscillate greatly (or resonate) when you 
wiggle the base?
  The vibration only adds up in one rod, or only one rod will resonate at each 
shaking.	 
  You have found the rods natural frequency.	
6. What is resonance?
  When a structure is vibrated at its natural frequency, the vibrations add up. 
This is called resonance.	
7. How are the rod assemblies like buildings?
  They have mass that is attached to the base by a structure.	
  OrThey have fixed bases attached to freely oscillating tops by tall, stiff 
structures.	
8. (extra credit) How can a building be protected from resonating with seismic 
vibrations?
  Dampen the buildings vibration with something like the shock absorbers on a 
car.	 
  Isolate the base of the building from the ground. (Accept other reasonable 
suggestions.)	


4.4 Earthquake in a Box

VOCABULARY
Retrofitting: making changes to a completed structure to meet needs 
that were not considered at the time it was built; in this case, to 
make it better able to withstand an earthquake.

Variable: in a scientific experiment, the one element that is altered to test 
the effect on the rest of the system.

RATIONALE
In cooperative SETs (seismic engineering teams), students win 
construct an inexpensive shake table for testing structures they have 
built.

FOCUS QUESTIONS
How do earthquake engineers use shake tables to model the effects of 
an earthquake on buildings, bridges, and other structures?

OBJECTIVES
Students will:
1. Construct a model of a shake table.
2. Design structures of various types and use the shake table to test 
their seismic survivability.
3. Analyze the failures of their design models and suggest ways to 
reduce damage.

MATERIALS
for each small group
 One copy of Master 4.4a, Shake Table Directions
 One piece of cardboard approx. 28 cm by 38 cm (11 in. x 15 in.)
 Wide packaging tape
 Hole-punching tool
 Metric ruler
 One cardboard box with flaps removed, approx. 30 cm by 40 cm by 
 20 cm (12 in. x 16 in. by 8 in. deep)
 Dark blue or black marker
 Phillips screwdriver
 3 strands of packaging string, one about 30 cm long (12 in.) and 
two about 60 cm long (24 in.)
 4 heavy-duty rubber bands
 Paper clips
 Two craft or ice cream sticks
 VCR and videotape (optional; see adaptations)
 A variety of materials for building structures, such as sugar cubes, 
ice cream sticks, small interlocking blocks, peanut butter (for 
mortar), dry spaghetti, straws, pipe cleaners, paper clips, cardboard, 
string, aluminum foil, and Styrofoam

TEACHING CLUES AND CUES
Use corrugated cardboard for greatest strength.
 
The size of the box may vary, as long as the size of the cardboard varies 
with it.

TEACHING CLUES AND CUES
A gallon plastic jug with the top cut off makes an excellent storage 
container for the dry materials.

PROCEDURE
Teacher Preparation
1. Several days before you plan to do this activity, ask students to 
bring cardboard boxes and building materials from home. Suggest the 
items at the end of the materials list; students may think of others on 
their own. Gather the remaining materials, including extra odds and 
ends for students who forget, and arrange them in a convenient place.

2. Following the directions on Master 4.4a, build one shake table to 
use as a demonstration model.

A. Introduction
Tell the class that earthquake engineers use devices called shake 
tables to model the effects of an earthquake on buildings, bridges, and 
other structures. In this lesson, students will build simple shake tables 
and use them to test their own model structures.

B. Lesson Development
1. Direct students to gather into SETs as for the other lessons in this 
unit.

2. Distribute one copy of Master 4.4a, Shake Table Directions, to 
each team. Invite students to assemble their materials and build the 
shake tables. Offer assistance only as needed.

3. When all the groups have completed their tables, list these 10 
variables on the chalkboard or poster paper:
 shape of structure
 height of structure
 construction materials
 shape of structural elements (triangle or rectangle)
 nonstructural exterior features (overhanging moldings, heavy 
decorative panels)
 foundation strength
 siting (type of soil structure is built on)
 duration (how long the earthquake lasts)
 intensity (how intense earth shaking is at the buildings site)
 frequency

TEACHING CLUES AND CUES
Give students plenty of time to complete this step.
 
Use a paper clip to anchor one end of the rubber band, and a 
second paper clip as a needle to thread the rubber bands 
through the holes.

Ask each SET to select three variables from the list and design one 
model to test their impact, singly or in combination, when the 
structures are placed on the shake table. Remind students to include 
lifelines like bridges and electrical wires with their supports, as well 
as houses and other buildings.

4. Have students in each SET take turns operating the model, while 
the other members of the team record their observations.

5. Assign each SET to write a brief report, based on the notes from 
testing, that includes
 a summary of the teams observations
 reasons why their design suffered and/or resisted damage
 suggestions for making each design more quake resistant
 suggestions for retrofitting structures, where applicable
 diagrams illustrating all of the above

TEACHING CLUES AND CUES
Work with the class to standardize the operating procedure as 
much as possible. Have them practice putting the string in 
one short jerk, and be sure that everyone uses approximately the 
some kind of pull. This will allow you to compare the work of various 
groups, and make students results reproducible.

C. Conclusion
Invite one representative from each SET to share the highlights of the 
teams report. When all the reports have been given and discussed, 
conduct open discussion around one or more of these topics:

 How do municipalities develop building codes for earthquake-
prone areas?

 Should schools, senior citizen homes, hospitals, fire stations, police 
stations, and other essential facilities be forced to follow tougher 
earthquake codes? Why? Why might governments encounter 
resistance to these standards? (because of the expense involved, 
among other factors)

 Is it possible to develop a classification system for types of 
structures and their reaction to an earthquake? What factors would 
such a system include?


ADAPTATIONS AND EXTENSIONS
1. If a VCR is available, have each team record its experiments and 
play them back in slow motion for detailed observation. Try to 
determine the frequency of each structure.

2. Challenge students to develop improved shake table designs, based 
on this model and their own ideas. Some students may choose to 
develop a shake table and test their best model structures as a science 
fair project.

3. Interested students might design a lifelines model that effectively 
illustrates the impact of a damaging earthquake upon buried pipe, 
sewer, gas, oil, water, and electrical lines.

4. As a research project, students might assess, in dollars and cents, 
the, loss of property that has occurred in specific earthquakes because 
of structural and nonstructural failures, then research the cost and 
availability of earthquake insurance in:
 your respective area
 New Madrid, Missouri
 San Francisco, California
 Boston, Massachusetts
 Anchorage, Alaska
 Kona, Hawaii
 Charleston, South Carolina
 Syracuse, New York
 other geographic areas of interest

Do the insurance policies have the same premiums and regulations in 
all of the above geographic areas? Explain. Is all earthquake damage 
covered by insurance? Why or why not? ?

Note: This activity was inspired by one developed by Katharyn E. K. Ross, 
(1993), 
Using Shake Tables in The Pre-College Classroom: Making The Impact of 
Earthquakes Come Alive, Proceedings: 1993 National Earthquake Conference, 
Central United States Earthquake Consortium, Memphis, TN, Vol. 1, pp. 423-429.

4.4 Shake Table Directions

A. The Shake Platform
1. Reinforce the cardboard by covering all four edges with packaging tape or 
doubling the thickness.

2. Center a hole in each corner of the piece of cardboard 2.5 cm (1 in.) from 
both edges.
 
3. Locate the center of the long side of the cardboard by measuring halfway 
between the two holes you made at 
the comers in step 2. Punch a hole at that center point, one inch from the 
outside edge on one side. Repeat for the 
two short sides. Punch a hole in the exact center of the cardboard. You now have 
a total of eight holes in the 
platform.

B. The Shoe Box
1. On one of the two ends of the box that is 30 cm across 
(one of the shorter sides), measure 6 cm (about 2.5 in.) 
down from the top and mark this point. Draw a straight 
line through the point all the way across this end of the 
box. Measure 4 cm (about 1.5 in.) in from the right edge 
along the line and mark this point. Punch a hole there 
with the Phillips screwdriver. Punch another hole in the 
center of the box bottom.
 
Note: Size of platform should be 5-8 cm 
less than box dimensions to allow room 
for shaking. Dimensions will vary with 
box size.

2. Measure 4 cm from the left edge on the same line and punch another hole, as 
illustrated. Punch two more holes 
4 cm beneath the top two. Then, measure to find the point at the center of a 
four holes on this side. Mark that 
point and punch one small hole.

3. Follow the same procedure on the opposite end of the box.

C. Putting It Together
1. Tie the 30-cm length of string securely to the center of a craft or ice cream 
stick. Pull the free end of the string 
down through the center hole on the top of the shaking platform. The stick will 
keep the string from pulling 
through the hole. Leave enough string to pull through to the outside of the box.
 
2. Tie the two longer pieces to the center of a craft or ice cream stick. Pull 
them 
down through the center hole on the long side of the platform, then out through 
the 
center hole on the short sides of the platform. Reinforce the stick with tape if 
desired. 
When the table is fully assembled, you will pull on these strings to shake the 
platform.

3. While one student holds the platform in place inside the box, parallel to the 
floor, 
another student will thread a rubber band through the right upper hole in the A 
end of 
the box and the right outer hole of the shake platform, then out the lower hole 
in the 
box.

Use a paper clip to hold the rubber band in place. Do the same thing with the 
opposite holes on End A. Then, turn 
the box and repeat with End B. Pull the loose ends of both strings out through 
the center holes.
 
4.5 The Building Challenge

VOCABULARY
Braces, or Bracing: structural elements built into a wall to add strength. These 
may be 
made of various materials and connected to the building and each 
other in various ways. Their ability to withstand stress depends on the 
characteristics of the materials and how they are connected.

Diagonal braces: structural elements that connect diagonal joints. These braces 
may be made of 
solid materials or flexible materials. How they function depends on what 
they are made of and how they are connected.

Load: the sum of vertical forces (gravity) and horizontal forces (shear 
forces) acting on the mass of a structure. The overall load is further 
broken down into the loads of the various parts of the building. Different 
parts of a building are designed and constructed to carry different loads.

Rigid connections: connections that do not permit any motion of the 
structural elements relative to each other.

Shaking: in this lesson, rapid horizontal vibration of the base of the 
model, simulating an earthquake. In an actual earthquake, of course, 
shaking occurs in many directions.

RATIONALE
A model structure can demonstrate the effects of diagonal bracing, 
shear walls, and rigid connections on a buildings ability to carry 
loads similar to those created by an earthquake.

FOCUS QUESTIONS
How can you design and build a model structure to carry vertical and 
horizontal loads?

OBJECTIVES
Students will:
1. Use diagonal bracing, shear walls, and rigid connections to provide 
load paths in a structure.
2. Design and build a structure that will carry both vertical and 
horizontal loads caused by ground shaking.
3. Measure the magnitude of the shear force or horizontal load a 
structure can carry.

MATERIALS
for each small group (SET)
 Structures from Lesson 4.1
 20 Styrofoam sticks, 2.5 cm x 2.5 cm x 15 cm, precut in preparation 
for lesson 4.1
 3 pieces of string, each 30 cm long
 10 paper clips
 20 toothpicks
 Any materials from Lesson 4.4 that students want to use
 1 square of tag board, 17.5 cm x 17.5 cm (about 7 in. square), to act 
as a shear wall
 2 right triangles of tag board, cut from a 6-cm square, to act as rigid 
connections
 1 square of cardboard, 30 cm x 30 cm or larger (about 1 ft square) 
to serve as the base
 One copy of Master 4.5a, Building Challenge Design and Analysis 
Sheet

for the teacher
 Hot glue and glue gun (to be used by one group at a time, under 
direct supervision)
 Shaking table from Lesson 4.4
 A dog leash or other nylon strap about 2.5 cm wide and at least 60 
cm long
 Several meters of string
 A small pulley
 Weights, either a kilogram mass set or a small basket and pennies
 Master 4.5b, Certificate of Achievement
 Slides or videos from the unit resource lists (optional)

VOCABULARY
Shear force: force that acts horizontally (laterally) on a wall. 
These forces can be caused by earthquakes and by wind, 
among other things. Different parts of a wall experience different shear 
forces.

Shear walls: walls added to a structure to carry horizontal shear 
forces. These are usually solid elements, and are not necessarily 
designed to carry the structures vertical load.

Structural elements or Structural features: a general term for all the 
essential, non-decorative parts of a building that contribute structural 
strength. These include the walls, vertical column supports, horizontal 
beams, connects, and braces.

PROCEDURE
Teacher Preparation
1. If you want to make the testing of student models a special event, 
make plans now. See Adaptation 1. If you have arranged to involve 
guest experts, remind them of the date.

2. Prepare the testing setup. Collect all the materials and have them 
ready to distribute.

A. Introduction
Briefly review with students what they have experienced so far in this 
series of activities. Especially promote discussion of the ideas 
developed in Lesson 4.2. Be careful to leave the applications of those 
ideas very open, to avoid giving students the impression that there is 
only one right way to design a structure.

B. Lesson Development
1. Direct students to gather in the seismic engineering teams (SETs) 
they formed in Lesson 1 of this unit. You may want to have students 
choose roles within the teams, like coordinator, engineer, and 
technician, to organize the effort and to assign accountability for 
timing, design, construction, and describing the performance of the 
structure.

2. Return to each team the structure members built in Lesson 1. 
Challenge the teams to design and build a new structure that will be 
tested in a controlled environment. Hand out the worksheets and give 
students time to design their structures before they receive their 
materials. Circulate among the groups and approve step 1 and step 2 
of the designs as they are completed.

3. Demonstrate the procedure you will use to test the structures.

4. Hand out all the materials except the glue guns, being certain every 
team receives the same set of materials. Allow some time for 
experimentation with the materials before students finalize their load 
path diagrams. Be sure students in each group have drawn force 
arrows on their design (step 3) to predict how they think earthquake 
shear forces will travel through (or load) their structure.

5. Establish how much time the SETs will have to build their 
structures, either by setting a uniform time for all or by inviting each 
SET to commit to a time limit and appoint one member of the team to 
keep track of time. (This could simulate the process of bidding on 
contracts, and add an extra element of competition.) Then give the 
signal to begin.

6. When building is finished, use one of the models from Lesson 1 to 
demonstrate fastening the structures to the center of the cardboard 
bases with hot glue. Have groups bring their models to the materials 
table to use the glue gun so you can supervise the process.

TEACHING CLUES AND CUES
This design may take a full class period.

Trace the structures outline with a pencil or pen, put glue on the 
cardboard along the outline, and press the structure down 
firmly. The hot glue may melt the Styrofoam if applied directly. Warn 
students not to drip the glue on their hands.

This activity will generate considerable excitement. 
Let students enjoy it, but maintain order to be sure 
all students have fun and are treated equally.

C. Conclusion
As the teams in turn bring their models to the front of the room for 
testing, test every model two wayswith the shaking table and by 
applying weight. Tell students they are not allowed to touch their 
structures during testing.

Ask two students from each team to hold the cardboard base down 
while you test their model with weights. Use the strap to add horizontal stress 
in any increment the group specifies. Call out the weights 
and keep a record on the board of the greatest weight each structure 
held. Award the certificate of achievement to the teams whose 
structures withstand the shaking table and hold the greatest stress 
before breaking. (This may be one team or two.)

Ask one member of each team to describe how their structure behaved 
in testing. Where did it fail? Why?

Close by connecting the images students have of earthquake damage to 
buildings with how their structures were damaged by the artificial 
earthquakes of this event. Slides or videos would help to make this real.

ADAPTATIONS AND EXTENSIONS
1. After you have done this with one class and feel comfortable with 
it, you may want to make the testing of student models a special event. 
Create some award for the structure that carries the greatest shear 
force. Invite your local newspaper reporters and school board 
members, arrange to use the auditorium, tape appropriate music, and 
plan refreshments. Take videos of the structure tests. Ask the principal 
to apply the weights and judge the event, and invite local emergency 
services officials to attend.

2. The experiences and materials the students developed in this unit 
make a fine portfolio. Invite students to include drawings of their 
designs and evaluate their learning by describing how they would build 
a structure next time or how they would retrofit their structure. ?

4.5a Building Challenge Design and Analysis Sheet

Name
Date
Cooperative Group		

Scientist		
Coordinator 		

Technician		
Engineer		

1. Sketch a design for your structure in the space provided below.

2. Use this space to show what it will look like from the front.

3. Use this space to show what it will look like from the side.

4. Do a load path diagram for your structure on the back of this page.

In all your drawings, show clearly how the joints will be made.
Get your instructors approval for all four drawings before actually building 
your structure.

Books
Arnold, Christopher, and Reitherman, Robert. (1982). 
Building Configuration and Seismic Design. New 
York: John Wiley and Sons.

Federal Construction Council Consulting Committee 
on Civil and Structural Engineering. (1992). Base 
Isolation for Seismic Safety: Summary of a 
Symposium. Washington, DC: National Academy 
Press. Summaries of nine papers describing the theory 
and practice of base isolation.

Federal Emergency Management Agency. (October 
1990). Non-Technical Explanations of the NEHRP 
Recommended Provisions. FEMA 99. Washington, 
DC: Building Seismic Safety Council. Explains the 
necessity of a building code and how earthquakes 
affect buildings.

Lagorio, Henry J. (1990) EarthquakesAn Architects 
Guide to Nonstructural Seismic Hazards. New York: 
John Wiley and Sons.

Moore, Gwendolyn B., and Yin, Robert K. (1984). 
Innovations in Earthquake and Natural Hazards 
Research: Synthetic Accelerograms. Washington DC: 
Cosmos Corporation (202-728-3939). Discusses the 
use of computer-derived earthquake simulations to 
predict how buildings will respond to earthquake 
shaking.

Plafker, G., and Galloway, J.P., eds. (1990). Lessons 
Learned from the Loma Prieta, California, 
Earthquake of October 17, 1989. U.S. Geological 
Survey Circular 1045. Washington, DC: U.S. 
Geological Survey.

Salvadori, M. (1990). The Art of Construction. 
Chicago, IL: Chicago Review Press. Simple and 
readable, expressly written for young readers.

Periodical Articles
Bedway, B. (Feb. 23, 1990). Building for a 
Landscape on the Loose. Science World, pp. 9+. For 
ages 1215.

Boraiko, AA. (1986). Earthquake in Mexico. 
National Geographic 169: 655675.

Brady, Gerry. Desk Top Model Structure for 
Dynamic Earthquake Demonstrations. U.S. 
Geological Survey. Applies simple models to predict 
natural frequency. Plans provided for constructing 
models of strong column/weak beam and weak 
column/strong beam buildings, plus descriptions of 
buildings reactions to earthquakes and explanations 
for the results.

Robison, Rita. (November 1989). Isolated 
Examples. Civil Engineering: 6467. Describes base 
isolation in practice.

Rosenstock, L. (March 17, 1989.) Can Buildings Be 
Made to Survive Earthquakes? Current Science, pp. 
67. For ages 1016.

Taries, Alex. (April 1993). First U.S. Application of 
Seismic Base Isolation. Phenomenal News: Natural 
Phenomena Hazards Newsletter: 1-4.

Non-Print Media
The Great Quake of 89. Videodisc and Macintosh 
software. Includes segments taken from ABC news 
coverage showing actual damage to the Bay Bridge, 
Highway 880, the San Francisco Marina, and the 
downtown. The Voyager Company, Santa Monica, 
CA; 310-451-1383.

Note: Inclusion of materials in these resource listings does 
not constitute an endorsement by AGU or FEMA.

Seismic Sleuths

Earthquakes

A Teachers Package for Grades 7-12

Unit Five

What Should People Do Before, 
During, and After an Earthquake?

Following the pattern established in earlier units, this set of lessons returns 
students from model structures to the actual structures in their own community. 
Some of the activities will require outside help. The relationships with experts 
in the community that you and your students established in Unit 1 and have 
developed in subsequent units will stand you in good stead.

In Lesson 1, students explore the tantalizing possibilities of earthquake 
prediction. The first activity is based on an actual series of events stemming 
from one rather ambivalent recent prediction of an earthquake on the New Madrid 
Fault, the site of the most widely felt earthquake in U.S. history in 1811-1812. 
Students read accounts of the prediction and its aftermath, discuss the 
reactions of different groups, and learn how to evaluate such a prediction. In 
the second activity they consider levels of probability and categorize various 
scientific and nonscientific approaches to predicting earthquakes. When they 
have finished these activities, they will realize they cannot place their faith 
in any warning system currently available. Their best bet, wherever they live, 
is to be prepared for earthquakes and other natural disasters.

Lesson 2 begins where the students are, in school and at home. The first 
activity is an earthquake and evacuation drill, followed by a classroom hazard 
assessment. The earthquake and evacuation drill is absolutely basic for your 
students safety; do not omit this lesson. Even if your students do not live in 
an earthquake-prone area now, they may someday.

Students develop a checklist for home hazard assessment in the second activity 
of Lesson 2. In Lesson 3, they learn the elements in the construction of a 
typical wood frame house by visiting a house to inspect its foundation and other 
structural elements. They complete a checklist and take home detailed 
instructions for reinforcement projects they can do with the assistance of a 
parent or other adult.

Moving out into the community, in Lesson 4 students evaluate the potential 
earthquake damage to various structures in their community. They will conduct a 
sidewalk survey to estimate vulnerability of buildings to earthquake damage. 
Engineers and other experts you contacted earlier will provide valuable 
assistance in this project. They can not only help students to generate data, 
but also advise them on how to interpret it.

Lesson 5 builds directly on work students did in Unit 1 to assess their own 
communitys vulnerability. In this activity they will see the relationships of 
various secondary disasters to the earthquake that initiates them and describe 
how local emergency services would work together to alleviate their effects. The 
community map begun in Unit 1 and elaborated in Unit 2 will be further developed 
in this activity.

5.1 Predicting Earthquakes

ACTIVITY ONE
I READ IT IN THE NEWSPAPER

VOCABULARY
Prediction: a statement that something is likely to happen based on past 
experience. A prediction is usually only as reliable as its source.

Probability: in mathematics, the ratio of the number of times something will 
probably occur to the total number of possible occurrences. In common usage, an 
event is probable, rather than merely possible, if there is evidence or reason 
to believe that it will occur.

Retrofitting: making changes to a completed structure to meet needs that were 
not considered at the time it was built; in this case, to make it better able to 
withstand an earthquake.

RATIONALE
By reading newspaper accounts of an earthquake prediction or forecast that 
proved to be false, students will learn to be critical consumers of media 
reports. They will analyze the content of articles spanning more than a year and 
compare the varying reactions of different people and groups.

FOCUS QUESTIONS
What would you do if an earthquake was predicted for your town?

OBJECTIVES
Students will:
1. Read media accounts analytically.
2. Visualize the effect of an earthquake prediction on a community.
3. Know how to obtain reliable earthquake information from the 
appropriate government agencies.

MATERIALS
 Student copies of Master 5.la, Newspaper Accounts (6 pages)
 Paper and pencils or pens


PROCEDURE
Teacher Preparation
Read the articles before you distribute them to students. Outline the 
highlights of each article, especially noting the effects of the forecast 
upon the community, how the forecast is reported slightly different in each 
story, and the response of governmental agencies.

TEACHING CLUES AND CUES
According to the Federal Emergency Management Agency (FEMA), an earthquake 
prediction must include time, place, magnitude, and probability. An earthquake 
forecast is much less precise.

A. Introduction
Tell the class that in the fall of 1989, climatologist Iben Browning reportedly 
predicted that an earthquake of magnitude 6.0 or greater would occur on December 
3, 1990, plus or minus 48 hours. However, his forecast also said that the 
earthquake would occur between the 30 N and 60 N lines of latitude, an area 
that encircles the Earth. According to scientists, the probability that a 
seismic event of magnitude 6.0 or greater will happen in such a broad zone of 
the Earths surface is actually very high.

However, the media reported that Browning had specifically predicted a 
catastrophic earthquake in the highly seismic area of New Madrid, Missouri, 
which in 1811-12 was the epicenter of the most powerful earthquakes ever 
recorded in the continental United States. People in the New Madrid area reacted 
to the continual flow of media coverage about the impending quake by stocking up 
on food and water, purchasing expensive earthquake insurance, making plans to 
travel to distant places, developing emergency community preparedness plans, 
and retrofitting buildings. School systems even scheduled earthquake breaks. 
On the day of the predicted seismic event, the little midwestern town of New 
Madrid was overrun by the television and newspaper media.

TEACHING CLUES AND CUES
The second activity in this lesson, Faulty Reasoning, reviews the federal 
governments official protocol for assessing earthquake predictions.

B. Lesson Development
1. Divide the class into groups of four or five students each and distribute at 
least two newspaper articles on Master 5.la to each group. Instruct students to 
read the articles and take notes individually, then discuss what they have read. 
Student notes should answer the following questions:

 How did government agencies react to the prediction?

 How did the scientific community react?

 How did some entrepreneurs react (people who saw an opportunity to make 
money)?

 How did many laypeople react?

2. Now ask students in each group to pool their notes and write a brief 
team report that covers the following points:

 How did Iben Browning arrive at his prediction?

 How did the people of the New Madrid seismic zone and surrounding, areas react 
to the media coverage?

 How did the scientific community react?

 How did the news media react?

 In your opinion, which governmental agencies should citizens consult to obtain 
information about the accuracy of earthquake forecasting?

 How would personally react to headlines and newspaper accounts of a 
devastating earthquake that was forecast for your home town?

3. Invite teams to orally present their reports to the class. When all groups 
have reported, discuss and analyze the teams conclusions in light of new 
information from other teams. Encourage students to point out discrepancies 
among the various reports. (Iben Brownings doctoral degree, for example, is 
variously reported as being in physiology, in climatology, in zoology, in 
biology, and in genetics and bacteriology.) Point out, however, that the pages 
were originally arranged in chronological order, so it takes the full set to 
tell the full story. No one group will have as much information as the class as 
a whole.

C. Conclusion
Invite discussion of the nature of Brownings earlier successful predictions. 
Could they have been of the same open-ended nature as this one? How difficult is 
it to successfully predict an earthquake after it has happened? Be sure students 
know where to obtain accurate earthquake information: from the U.S. Geological 
Survey, the Federal Emergency Management Agency, their state office of emergency 
services, and the state geological surveys. (The latter have various names, such 
as the California Governors Office of Emergency Services, the Missouri 
Emergency Management Agency, the Vermont Division of Emergency Management, and 
the Utah Division of Comprehensive Emergency Management.) Check the resource 
list in Unit 1 and your local telephone books for these listings.

ADAPTATIONS AND EXTENSIONS
1. According to the articles, Browning specified a time period that 
would coincide with the Moons maximum gravitational attraction 
upon the Earth. Ask students how they would set up a test to 
demonstrate that the Moon affects earthquake or volcano activity.
2. Distribute copies of the August 1991 article, the last in the set, to 
every student, or read it aloud with the class. Discuss the conclusion 
that the scientific community was partly to blame.

ACTIVITY TWO
FAULTY REASONING

VOCABULARY
Generalization: a statement made after observing occurrences 
that seem to repeat and to be related.

RATIONALE
Because of the randomness of seismic events and the fact that scientific 
understanding about earthquake-generating mechanisms is still evolving, 
earthquake prediction today is imprecise, indeed even speculative.

FOCUS QUESTION
Why is predicting earthquakes not an exact science?

OBJECTIVES
Students will:
1. Explain the purpose of predicting earthquakes.
2. Identify several types of seismic predictions.
3. Explain why earthquake prediction is complex and based largely on 
probability.

MATERIALS
 Chalkboard or overhead projector, chalk or markers
 Student copies of Master 5.1b, Approaches to Predicting Earthquakes
 Student copies of Master 5.1c, Levels of Generalization:
Classification Chart
 Back of Master 5.1c, Answer Key

TEACHING CLUES AND CUES
Point out that the degree of probability is an essential element in pre-
diction. You can predict with a probability of 99.9% that an 
earthquake of magnitude 2 will occur in southern California tomorrow. For 
larger quakes, the degree of probability drops sharply.

PROCEDURE
A. Introduction
Tell students that with increasing numbers of the worlds people 
living in active earthquake zones, earthquake prediction or forecasting 
has been receiving more and more attention in recent years. Begin by 
asking students to name some advantages of being able to predict 
earthquakes. Record responses on the overhead or chalkboard. (Likely 
answers will include saving lives and reducing property loss and 
damage, providing guidelines for development and human settlement, 
providing valuable data for the scientific community, helping people 
to prepare for earthquakes on both a short-term and a long-term basis, 
and allowing communities to return to normal more quickly after an 
earthquake.)

Ask: Would there he any disadvantages to being able to predict or 
forecast earthquakes? (Answers might include financial losses to 
businesses forced to close and the anxiety people would feel if they 
knew an earthquake was imminent.

Lesson Development
1. Ask: Are we, in fact, able to predict or forecast earthquakes with 
any certainty? Students may have heard of some theories and attempts 
at prediction, but they will also know that earthquakes have claimed 
lives and property in recent years. If earthquake prediction was an 
exact science, these losses would have been greatly reduced.

Remind students that while significant efforts at developing systems 
of accurate prediction are underway in earthquake-prone countries 
like Japan, the United States, and the Peoples Republic of China, 
seismologists are still a long way from accurate prediction. Point out 
that of the several types of phenomena that may predict an earthquake, 
many may be due to other causes and yield false alarms.

2. Organize the class into groups of three of four students each. Have 
all the students in each group list these terms at the top of a blank 
sheet of notebook paper: time, magnitude, place, and probability. Ask 
each group to write briefly how they think these terms relate to 
seismic prediction and why they are important. Also discuss the idea 
of coincidence, versus that of causality. For example, a sunrise occurs 
within 24 hours of every earthquake, but sunrises cannot be said to 
cause earthquakes.

3. After several minutes, ask one student in each of the groups to 
summarize the groups findings. While answers may vary, the pattern 
of response should consistently indicate how helpful such precise 
information would be to surviving an earthquake with minimum loss 
of life and property damage.

4. Write this statement on the overhead or chalk board: Earthquake 
prediction or forecasting takes place at several levels of generalization 
and involves various approaches. Stress the term generalization, so 
students will recognize that prediction is broadly based and in many 
instances, largely theoretical.

5. Distribute copies of Master 5.lb and instruct students to classify 
each of the approaches to predicting earthquakes listed into one of the 
three categories on the table that follows. Their challenge is to 
organize the data about earthquake predictions into a chart classifying 
different kinds of information.

6. When the students have developed the charts, allow time for 
sharing and comparing answers. The important element in this part of 
the activity is not that students make the right classification, but that 
they can defend their reasoning.

TEACHING CLUES AND CUES
According to Bruce Bolt (Earthquakes, 1993 edition, p. 185), the 
methods of prediction that currently show the most promise 
require elaborate equipment and many workers, so that their cost is 
likely to be prohibitive.

C. Conclusion
Explain to the class the federal governments official protocol for 
evaluating earthquake predictions.
The National Earthquake Prediction Evaluation Council (NEPEC) 
convenes to hear evidence for the prediction of an earthquake above 
magnitude 5.5. If the NEPEC validates the prediction, the following 
will occur:

Issuance of Earthquake Predictions. The Director of the 
United States Geological Survey (USGS) is hereby given the 
authority, after notification of the Director of the Federal 
Emergency Management Agency (FEMA), to issue an 
earthquake prediction or other earthquake advisory as he 
[sic] deems necessary. ... The Director of FEMA shall have 
responsibility to provide state and local officials and residents 
of an area for which a prediction has been made with 
recommendations of action to be taken.
Public Law 95-124, Earthquake Hazards Reduction Act, 
as amended [P.L. 96-472]

Add that the USGS also issues earthquake advisories. The state of 
California has its own earthquake prediction evaluation council and its 
own notification protocol.

Ask students to review the notes they have taken and the chart data 
they have organized, then select the theory or approach that seems 
most plausible to them. As homework or in class, each may write a 
personal prediction of how this approach will be developed and 
refined in the coming years. Students may want to defend their 
predictions in a class discussion.

ADAPTATIONS AND EXTENSIONS
1. It may be useful to illustrate the concept of mathematical 
probability with dice or the toss of a coin. The probability of heads in 
a coin toss is 50-50.

2. Invite interested students to learn more about some of the scientific 
prediction methods, such as creep meters and radon monitoring, and 
report back to the class. Consult the unit resources and your local 
libraries.

5.1a Newspaper Accounts
 
Volume 1
News of Geologic Importance
Issue 1

From the Arkansas Democrat, 
November 29, 1989

New Madrid tremors due, forecast says

MEMPHIS, TNA climatologist who predicted the San Francisco earthquake Oct. 17 
says the New Madrid Fault region could be in 
for serious tremors next year.
   Iben Browning is a Tijeras, NM, scientist 
who develops long-range weather forecasts 
for businesses. He bases his quake predictions 
on the theory that tidal forces of the Sun and 
Moon produce stress in the Earth.
   Browning, an inventor with a doctorate in 
physiology, has studied weather for 30 years, 
but does not publish his findings in scientific 
journals. He is better known in business circles, and publishes a monthly 
newsletter. His 
New Madrid forecast is based on a 179-year 
cycle of tidal forces last felt in 1811. 
Browning said the conditions will be ripe for 
tremors Dec. 3, 1990.
   The configuration will be the same as it 
was the year the original earthquake went 
off, Browning said Monday.
   That isnt to say tidal forces would cause 
a major earthquake next year south of St. 
Louis to a point north of Memphis, he said.
   Experts have predicted a major 
earthquake in the New Madrid zone could 
cause major damage to match that of the 
recent California quake.
   Dr. Arch Johnston, director of the Center 
for Earthquake Research and Information at 
Memphis State University, said the tidal force 
theory is backed by some scientific data, but 
isnt conclusive by any means.

 From the Dallas Morning News, July 22, 1990
Prediction prompts residents 
to wonder, worry

THE NORTHEAST ARKANSAS TOWN 
OF 25,000a county seat with Air Force 
base and several small industriesis 
perched directly over the site of [Iben 
Brownings earthquake] prediction. 
Knowing what lies beneath the flat delta 
farmland clearly makes some uneasy.
   Our fire chief told our firemen they 
cant take a vacation. Some already asked, 
said Mr. Edwards, a Fire Department lieu- 
tenant. He said we could ship our families 
out, but were staying. It was said kind of in 
a jest, but I think that everyone is actually 
pretty serious about this.
   One geophysicist studying Dr. Brownings methods says the projection cant be 
ignored because he had predicted other 
earthquakesincluding last Octobers California temblor.
   But most experts dismiss the warning. 
They acknowledge that there is a 50-50 
chance that a destructive quake will hit the 
fault by decades end, but they say the projection lacks scientific validity.
   It seems like people are becoming worried about it for no reason at all, 
said Dr. 
Brian Mitchell, chairman of the Department 
of Earth and Atmospheric Sciences at St. 
Louis University.
   At the center of the furor is an ailing 72- 
year-old inventor from Tijeras, NM, who 
has spent much of the last 20 years offering 
clients advice on the esoteric topic of future 
world climates.
   Dr. Browning declined to be inter-
viewed. But his daughter, Evelyn Browning 
Garriss, said her father began forming his 
wide-ranging theories while working at 
Sandia Laboratories in Albuquerque, NM. 
Dr. Browning has a doctorate in biology 
from the University of Texas, and Ms. 
Garriss said his interests range across many 
fields. She said he has been a test pilot and 
developed weaponry and TV technology.
   Ms. Garriss said the ideas that spawned 
her fathers latest projection arose from 
research for the U.S. government on peaceful uses for atomic bombs. While 
studying 
how explosions affect the atmosphere, she 
said, he became fascinated with volcanoes. 
He found that volcanoes are triggered by the 
same gravitational pulls that cause ocean 
tides, and he discovered that the same forces 
that trigger volcanoes also trigger 
earthquakes, she said.
   That theory produced his projection of an 
earthquake on the New Madrid Fault. Al-
though rejected by most scientists, Dr. 
Brownings new warning has gained attention 
from many in a region already worried about 
the New Madrid Faults potential for 
destruction.
   Some earthquake-preparedness efforts 
have been underway for six years because 
seismologists warned in the early 1980s that a 
temblor measuring 6.0 on the Richter scale 
had a 50-50 chance of occurring before 2000. 
Indiana, Kentucky, Missouri, and the cities of 
Carbondale, IL, Memphis, TN, and St. Louis 
have approved seismic building codes in the 
past two years.
   Since 1984, seven states and the Federal 
Emergency Management Agency have developed a regional emergency response sys-
tem through the Central U.S. Earthquake 
Consortium in Memphis.
   Most state officials place little stock in the 
prediction, but they hesitate to reject it for 
fear of encouraging complacency about real 
threats posed by the fault. Mississippi 
officials are accelerating preparedness planning. And in Illinois, officials are 
forming a 
plan to address panic that might result if any 
detectable tremors hit the region near the 
predicted date, said Tom Zimmerman, the 
states emergency planning director.
   To further soothe regional concerns, state 
emergency officials want scientific experts to 
formally evaluate the prediction. Several state 
officials said they have asked the National 
Earthquake Prediction Evaluation Council, 
based in California, to address the issue.
   The council of pre-eminent earth scientists has turned down the request.
   They dont want to glorify the 
prediction, Dr. Mitchell said.

San Francisco Chronicle, July 25, 1990
What If Hes Right?
by Jerry Carroll

ALBUQUERQUE, NMThe scariest man in 
America walked through the door with his 
daughter, looking with his bald head and spectacles like everybodys idea of a 
nice grandpa. 
Given what we were going to talk about, I half 
expected to see Iben Browning in long robes and 
a tall wizards list.
   He told audiences before last Octobers 
earthquake that the earth was going to move  
in the Bay Area, and now he says there is a  
50-50 chance therell be a major earthquake 
December 3 on the New Madrid Fault in 
Missouri, on the Haywood Fault in East Bay,  
or in Tokyo.
   Browning bases his forecastswhich he 
calls mathematical calculations about the pressures the Sun and Moon exert on 
the Earths 
surfaceon forces he says have a profound if 
little known effect on the course of civilization.
   While his projections fascinate the media, 
they leave the science community with a  
healthy dose of skepticism.
   No evidence, say some.
   Scientists who have studied tidal influences 
of the Sun and the Moon have come up with  
no evidence that they trigger earthquakes, said 
James Dorman, associate director of the Center 
for Earthquake Research and Information at 
Memphis State University. In 1972, Dorman 
studied 30,000 earthquakes looking for a correlation, but failed to find one. 
Browning has 
not convinced anyone he knows what hes 
doing, he said.
   But Browning has his believers.
   The New Madrid Fault was responsible in 
1812 for the mightiest earthquake in American 
history. Estimated at more than 8.5 on the 
Richter Scale, it toppled chimneys in  
Cincinnati, made church bells ring in Boston, 
and awakened James Madison in the White 
House and Thomas Jefferson in Monticello. A 
similar quake today could claim hundreds of 
thousands of lives and cause more than $50 
billion in damages.
   The South Mississippi County School 
District No. 57 in Arkansas, for one, thought 
enough of Brownings warning to cancel classes December 3 and 4. The Missouri 
and 
Arkansas National Guards are planning earth-
quake exercises those days.
   In a memorandum last month to midwestern 
earthquake experts and the Missouri Emergency 
Management Agency, David Stewart of the 
Center for Earthquake Studies  
at Southeast Missouri State University in Cape 
Girardeau, MO, wrote: That he was correct in the Loma Prieta event is a 
verifiable  
fact.
   Furthermore, Stewart continued, He was 
also apparently correct within a few days of 
predicting the eruption of Mount St. Helens on 
May 18, 1980. In this latter instance he was 
speaking before a group of several hundred in 
Portland, OR, on May 15, 1980 when he told 
them it would go in about a week. The volcano, dormant for 123 years, had been 
threatening to blow since March 27.
   Stewart said: His calculations had also 
picked the dates of Sept. 19, 1985, and Nov.  
13, 1985, upon which the Mexico City earth-
quake and the Nevado del Ruiz volcano eruption in Columbia, respectively, 
occurred.
   The memo, which was leaked, got Stewart in 
hot water. He swallowed Brownings story 
hook, line, and sinker, Dorman said. Stewart 
did not boost his own stock in the scientific 
community.
A Visionary?
So who is this man and how can he appear to do 
with a sharp pencil what seismologists  
cant, for all their high-tech laser beams, strain 
gauges, and tilt and creep meters? Is he a seer,  
a visionary who screws his eyes shut and holds a 
finger to his temple?
   Do we lump him in the same category as Jim 
Berkland, the Santa Clara County geologist who says he predicts earthquakes 
using  
a theory based in part on how many pets run 
away from home?
   He has an intellect like a giant, said 
Dwaine W. Rogge, president and founder of the 
Commerce Financial Group in Lincoln, NE.  
He must have an IQ of 200-plus, said agricultural specialist Roger Spencer, a 
first vice-
president of Paine-Webber of Chicago.
   The two of them, like the majority of 
Brownings clients and the subscribers to his 
monthly newsletter, rely on him for help in 
investments and business decisions based on 
Brownings analysis of climatic trends. Before 
diabetes limited his mobility, Browning shared 
top billing at business and economic conferences with the likes of Milton 
Friedman and 
Henry Kissinger. He spoke 40 to 50 times a  
year, getting $2,500 for his talks. Earthquake 
projections, Browning told me, are purely a 
sideline, one that has really become a nuisance.
   He said that he made only seven projections about earthquakes or volcanoes 
erupting 
and has been right each time. It doesnt bother him that his fellow scientists 
ignore him. 
Given his lack of formal credentials in the field, 
its to be expected, he said. Anyway, Im not 
talking to them. Im talking to my clients.
Scientist, Master Consultant
Browning is primarily an inventor. He has 67 
patents, the most recent for a high-definition 
television system licensed to the Japanese. He 
has been a consultant for business in the 
fields of bio-engineering, computers, electronics, environmental systems, 
information theory, microbics, microminiaturization, optics, 
and space navigation.
    I was a test pilot in Victorville [CA], flying two-engine and four-engine 
airplanes. 
While fellow pilots drank beer after work, 
Browning, who has total recall, stuffed his  
mind with the Encyclopedia Brittanica. I read 
articles at random, integrating them into what  
I already knew. By wars end, he had read  
more than a thousand.
   After the war, he got a masters degree from 
the University of Texas in physics and bacteriology and a doctorate there in 
genetics and 
bacteriology.
Military Consultant
When he wasnt inventing, Browning worked  
as a consultant for defense industries. But  
while studying the effects of atomic bombs for 
the Sandia National Laboratories in 1957, he 
realized they were puny compared to the  
power unleashed by volcanic eruptions.
   Thats when he began his study of climate, 
immersing himself in several scientific disciplines in a manner not often done 
in an age  
of narrow specialization. The data he consult- 
ed ranged from magnetic field intensities during ancient Egyptian dynasties to 
records of  
lynx pelts bought from trappers by Hudson Bay 
Co. in the 17th century.
   He became convinced that earthquakes  
and volcanic eruptions were triggered by  
sunspot activity and the pull of the Sun and 
Moon on the Earths brittle crustthe tidal 
effect.
   Seismologist William Ellsworth of the U.S. 
Geological Survey in Menlo Park, a major  
leader in quake research, says, If there is a  
tidal effect, it clearly is not something either 
universal or of any practical importance.
   At least two other scientists agree.
   Brian Mitchell of the Department of Earth 
and Atmospheric Sciences at St. Louis  
University and Arch Johnson of the Center for 
Earthquake Research in Memphis wrote disaster officials in the New Madrid Fault 
area pointing out that of five earthquakes Browning 
said were triggered by tidal forces, only one 
occurred during a high-tide period.
   I don't think the prediction is anything we 
should pay attention to, Mitchell said.
Not Over Yet
Browning says that even if December 3 (when 
tidal forces hit a 27-year high) arrives and it  
turns out that seismic pressures here, in  
Missouri, and Japan havent yet built to the  
point where earthquakes are triggered, that 
doesnt mean were out of the woods. January  
19, 1992, will bring on the highest highs in  
more that 1,600 years.
   Youre a pessimist, I said. No Im not, 
Browning replied with equanimity. Man will 
survive. He always has.

The Dallas Morning News, July 26, 1990
Experts to evaluate earthquake warning
by Lee Hancock
The U.S. Geological Survey will officially 
evaluate a New Mexico mans warning that  
an earthquake may rock the central United  
States on Dec. 3, 1990, an agency official  
said Wednesday.
   Walter Hays, an official with the  
Geological Survey in Washington, said the 
agency would convene a panel of geologists  
and seismologists from throughout the central United States to study the 
prediction.
   Were not at all impressed with this 
forecast, he said. On the surface we would  
not expect there is any basis for concern. But  
we do want to set people at ease and be satisfied in our own minds that we 
havent 
overlooked something.
   The location of the predicted earthquake  
is along the New Madrid Fault, which runs 
between Marked Tree, AR, and Cairo, IL,  
and has branches in West Tennessee and  
the Missouri boot heel.
   Scientists say it is impossible to predict 
exactly when an earthquake will occur. However, 
they say they are trying to estimate the probability of an earthquake along 
several highly active faults in the United  
States.
   The decision to evaluate the prediction 
follows a plea for help by the regions seven-state 
earthquake response coalition, an  
agency that has been struggling for more  
than a month to address growing regional  
fears about the prediction by Iben Browning,  
a self-styled climatologist from Tijeras, NM.
   Dr. Hays said U.S. Geological Survey scientists have considered about 300 
predictions since 1977 that ranged from the scientific to the ridiculous. But he 
said that the 
widespread public concern makes Dr. 
Brownings prediction unique and that it  
was the primary reason for the evaluation.
   Dr. Hays said the study probably would  
be completed by the end of September.
   The National Earthquake Prediction 

   
Council, an advisory board of earth science 
experts set up by the U.S. Geological Survey, last 
month refused to evaluate Dr.  
Brownings prediction. They didnt want to 
glorify it, one mid-south seismologist said.
   Dr. Hays said the 13-member council  
would evaluate the findings of the region- 
al scientists group at the request of the federal geological agency.
   On the surface we dont expect to see  
any basis for this to be a credible prediction, he said. But you have to go 
through  
a process.
   The council has officially endorsed 13 
predictions since its creation in 1980, said  
Dr. Hays, deputy chief for research applications in the Geological Surveys 
office of 
earthquakes, volcanoes, and engineering.  
The endorsed predictions, which project  
activity along faults in Alaska and California over 
periods ranging from four to 30 years,  
are still pending, Dr. Hays said.

The New York Times, August 20, 1990 
Midwest Quake Is Predicted 
by William Robbins
   
NEW MADRID, MO., AUG. 15Life on the 
fault line is always interesting, as people in this 
trembly old Mississippi River town often say, but 
a prediction by a man named Iben  
Browning is making life hereabouts down- 
right exciting.
   Dr. Browning, a climatological consultant 
from New Mexico, has calculated that on Dec.  
3, give or take 48 hours, this area could once 
again be the center of a destructive earthquake. 
People in Missouri and neighboring states are 
taking his prediction seriously enough to plan 
events like National Guard drills and informational town meetings, to store 
food, and to 
consider closing schools on the appointed day.
   There is considerable skepticism among 
experts and residents of this area about Dr. 
Brownings prediction, which involves calculations of tidal forces resulting 
from the gravitational effects of the Earth, the Moon, and  
the Sun. But New Madrid is conditioned by its 
history to take a sober view of warnings.
   This town is near the epicenter of one of  
the most devastating earthquakes ever record- 
ed in North America. A series of quakes, beginning with a colossal shock, struck 
at 2 a.m. on 
Dec. 16, 1811, while settlers and Indians in the 
Mississippi River frontier slept. Tremors shook 
the earth almost continuously for months, and 
two even greater shocks struck on Jan. 23 and 
Feb. 7, 1812.
Debate on Predictability
Seismologists say it is impossible to predict when 
another big earthquake might strike. But based 
on what they know of geologic conditions, they 
calculate that there is a 50 percent chance for a 
6.3-magnitude quake by the end of the decade 
and a 90 percent chance for such a  
quake by 2040.
   Most scientists doubt the ability to pinpoint 
the date of an earthquake. But at least one,  
David Stewart, director of the Earthquake 
Information Center at Southeast Missouri  
State University in nearby Cape Girardeau,  
says he has looked into Dr. Brownings previous 
predictions and accords him respect.
   Dr. Brownings previous warnings have 
been widely reported in another quake-skittish 
locale, San Francisco. He is known to have predicted the 1989 San Francisco 
earthquake a week 
in advance in an appearance before  
about 500 business executives and their wives  
at a convention. He is also said to have predicted the eruption of Mount Saint 
Helens in 
1980.
   Like the experts, the people with the  
biggest stake in the debate, those who live here, 
are also divided on Dr. Brownings prediction.
   Don Lloyd, the city administrator, typified 
the most optimistic stance. We know its coming sometime, but its just as 
likely to happen 
tomorrow as next Dec. 3, he said the other day.
   Most people are like the police chief, Jimmy 
Helines, or officials of the National Guards of 
Missouri and Arkansas. While they are not 
panicking, they see nothing wrong with taking precautions, either.
   Missouris Army National Guard is planning earthquake exercises Oct. 13 to 
14, and the 
Arkansas National Guard is planning a  
similar drill Dec. 1 to 5. We were planning  
an exercise anyway, said Maj. Cissy  
Lashbrock, the Arkansas Guards public information officer. But Browning has 
attracted so 
much attention, this looked like a good time  
to let people know we do have a plan.
   Mr. Helmes has planned to store food and 
water supplies in a warehouse and to station 
school buses nearby for emergency transportation. Mayor Dick Phillips and Mr. 
Lloyd are 
planning a town meeting at which Dr. Stewart 
will discuss precautions.
   In addition, officials of a few schools in near-
by towns are considering closing them for the 
day. Gerald Murphy, a high school coach,  
wants his wife, Beth, to take their baby and  
got out of town, and James and Gloria Taylor  
of nearby Lilboum are planning to take their 
daughter and son-in-law on a trip on the first 
weekend in December.
   The talk has naturally focused attention  
on the man who made the prediction.
   Dr. Brownings academic background is in 
mathematics, physics, and microbiology, and  
his doctorate, in biology, is from the University 
of Texas. He is also a self-taught climatologist 
and serves as a consultant on the subject to  
many businesses and executives.
No Public Pronouncements
I make no public pronouncements, the 72-
year-old scientist said in a telephone interview 
from his home in Sandia Park, NM. What I  
say is for my clients. He said predictions that 
have surfaced publicly have been recounted by 
members of private audiences.
   It was at a convention of the Equipment 
Manufacturers Institute in San Francisco that  
he said his calculations indicated an earth 
quake there about Oct. 16, the day before it 
occurred, and one on Dec. 3 in the New Madrid 
area.
   Emmett Barker, president of the institute, was present and heard the 
predictions.
   Regarding Dr. Brownings method, Brian 
Mitchell, chairman of the Department of Earth 
and Atmospheric Sciences at St. Louis 
University, said, Recent studies with the best 
available data show no correlation between  
tidal forces and earthquakes.
   And Pat Jorgenson, a spokeswoman for the 
United States Geological Survey in Menlo  
Park, CA, said scientists there are not at this 
time doing any research into earth tides and  
any possible relation to seismic activity, 
although they are aware that this is a much-
discussed proposition. She said that the agencys scientists had conducted 
studies on the 
claims but that these proved inconclusive.
   Still, Dr. Stewart, of Southeast Missouri 
State, said he thinks Dr. Brownings method 
should not be summarily rejected. Heres a  
man who has hit several home runs, he said. 
Will he hit another on Dec. 3? We dont know, 
but thats no excuse for not being prepared. 
   
The Wall Street Journal, September 18, 1990
Will the Earth Move on Dec. 3?
Midwest Is Rattled By a Scientists Prediction of a Major Earthquake
by Michael J. McCarthy
   
MEMPHIS, TENN.Friday nights used to be 
slow at The Fault Line, a nightclub here on  
busy Poplar Avenue. But after word spread  
that a major earthquake was forecast for Dec.  
3 in the Midwest, The Fault Line began throwing 
earthquake parties.
   On Friday nights now, hundreds of patrons 
pour into the club to swig Earthquake  
Shooters and sign up to win December 
Earthquake Escape Packages to the Bahamas  
or Hot Springs, AR.
   But even as Memphians whoop it up, the 
prediction that the Big One may come this 
December is triggering tremors up and down  
the Mississippi River Valley. Shaken, thou- 
sands of people are crowding into earthquake 
survival classes. In Arnold, MO, 3,000 people 
showed up for one course.
   In Missouri and Arkansas, some schools  
and businesses have announced plans to close  
in early December. Entrepreneurs are hawking quake survival insurance, survival 
kits, and 
gas-line safety gadgets.
   Some people are planning to flee. You cant 
run from everything, says Tammy  
McCormick, a nurse in Bytheville, AR, who will 
take her two youngsters and spend several days with the relatives in North 
Carolina. 
But it seems stupid to stay on a fault line  
with a prediction like this one.
   Iben Browning, a 72-year-old scientist, 
predicted October's Bay Area quake a week 
before it happened, say people who heard him 
speak to the Equipment Manufacturers  
Institute. And he predicted geological disaster on Sept. 19, 1985, along a 
band of latitude 
that included Mexico Citywhere a massive 
quake struck on that day.
   Mr. Browning, who has a Ph.D. in physiology, genetics, and bacteriology, 
writes a climate newsletter out of New Mexico. He has 
clients, such as Paine-Webber, Inc., who have 
long paid for his wisdom on how the weather 
will affect their agricultural investments.
   Since 1971, Mr. Browning says, he has 
picked the correct dates of four large earth-
quakes, two volcanoesand one day with both  
a volcano and an earthquake.
   He bases his forecasts on tidal forces caused 
by the positions of the Sun and the Moon 
an old theory, critics say, that doesnt wash.  
On Dec. 3, those forces are expected to be at  
a 27-year high. Mr. Browning says that will  
exert pressure that could trigger faults already 
ripe to fail.
A Skeptical Majority
Skepticism abounds. No responsible scientist 
can predict an exact day for an earthquake,  
says Brian Mitchell, a quake expert at St. Louis 
University, echoing the majority opinion.
   But Mr. Browning shouldnt be written off 
so quickly, says Southeast Missouri States Mr. 
Stewart, who recently spent four days with Mr. 
Browning. He has a methodology that can 
determine, plus or minus a window of a day  
or two, an enhanced probability of a volcano  
or an earthquake in certain latitudes, says Mr. 
Stewart. No one else is able to replicate it, but 
that doesnt mean its wrong.
   Mr. Browning says its not easy being on 
record with predictions that few other scientists will support. I feel like a 
lonely little petunia in a cabbage patch, he says. But asked if  
he enjoys being right, he says, Its the only 
damn thing that matters. If one is a business 
consultant, they dont pay you for being wrong.
   Mr. Browning says he is tentatively booked 
to give a talk in Minneapolis on Dec. 3, and  
he doesnt plan to go there via St. Louis. But  
he adds: I highly recommend against panic. 
That will kill more people than earthquakes. 

The New York Times, October 19, 1990
Panel of Scientists Finds No Basis 
For Prediction of Missouri Quake

ST. LOUIS, OCT. 18 (AP)Projections of a 
major earthquake in the Midwest in early 
December are without scientific basis, a group  
of scientists said today.
   The 11 scientists reporting to the United 
States Geological Survey said there was a long-
term possibility of a major earthquake along  
the New Madrid Fault, but said there was no 
credibility in the widely circulated projection 
made by Iben Browning, a climatologist and 
business consultant based in Sandia Park, NM, of 
a 50-50 chance it will happen Dec. 3.
   Public anxiety over Mr. Brownings New 
Madrid projection has been widely reported, 
coupled with reports that Dr. Browning had  
also warned of last years Northern California 
earthquake a week in advance in an appearance before about 500 business 
executives and 
their wives at a convention in San Francisco.
   The scientific group said today that it had 
found no evidence that Mr. Browning had 
predicted last years earthquake. Mr. Browning 
has said the reports of his predictions are based 
on accounts from members of the private audiences that he addresses.
      A woman who answered the telephone 
Thursday at Mr. Brownings home and identified 
herself as his wife said he was unavailable for comment.
   The scientists said a transcript of his Oct.  
10, 1989, speech showed that his statement  
was there will probably be several earth- 
quakes around the world, Richter 6 plus, and 
there may be a volcano or two. No mention is 
made of an earthquake occurring in the San 
Francisco area or even California.
   The scientific group issued its finding at a 
news conference in St. Louis. The scientists  
who contributed to the report were brought 
together from universities and governmental 
agencies to evaluate the scientific validity of  
Mr. Brownings projection.
   Such a projection, especially at the 
predicted 50-50 chance level, implies a level  
of detailed knowledge that simply does not  
exist for the New Madrid or any other fault  
zone in the world, the group said in its reports 
for the National Earthquake Prediction 
Evaluation Council.
   Mr. Browning bases his projections on the 
forces of tides and gravity. He has said that  
for 48 hours before and after Dec. 3, these  
forces will be particularly strong.
   Brownings correlation of earthquake activity with danger periods at times 
of highs in  
tidal forces does no better at predicting earth-
quakes of magnitudes greater than 6.5 than  
does random guessing, the scientists report  
said.
   The New Madrid Fault runs from Marker 
Tree, AR, across southeastern Missouri to 
southern Illinois, and produces hundreds of  
small quakes every year, most hardly felt. It  
is named for the Missouri town of New Madrid, 
about 140 miles south of St. Louis.
   In 1811-1812, a series of quakes estimated at up to 8 on the Richter scale of 
ground 
motion struck the New Madrid region, causing the Mississippi River to appear to 
flow 
backward and ringing church bells in 
Washington, DC.

Southeast Missourian, Cape Girardeau, MO, Dec. 3, 1990 
Circus comes to New Madrid: 
Projection puts town in spotlight  
by David Hente, Staff Writer

NEW MADRIDFor the past several months, 
tiny New Madrid has been the focus of growing national and international 
attention. On 
Sunday, the media circus came to town.
   The attention was touched off by the projection of climatologist Iben 
Browning that a 
major earthquake could occur along the geo- 
logical fault named after the town.
   Residents of New Madrid and others who 
live along the fault will learn today if Dr. 
Brownings projection comes to pass.
   New Madrid, population 3,204, is located  
at the head of a large bend in the Mississippi 
River, in the Missouri boot heel.
   Until recently, few people outside of this area 
had heard very much about New Madrid, and 
even fewer knew how to pronounce the name of 
the town correctly (New MAD-rid).
   But Brownings projection caught the attention of the news media, and New 
Madrid is  
now on the minds of people throughout the 
nation and the world.
   Over the weekend, tourists, visitors, and  
the news media have flocked into the town.
      Ive seen more tourists in the past two 
weeks than I had seen in the past six months, 
said Jean Hanner, manager of Ricks Texaco, 
located on Main Street a few blocks from the 
river.
   As Dec. 3 approached, the media continued to swarm into town. By midday 
Sunday, 
more than 20 satellite transmission trucks and 
vans were parked along the New Madrid levee 
and in other parts of town. A network technician 
said that was more than were at the Super Bowl 
game last year.
   The four major networks, CBS, ABC, NBC, 
and Cable News Network, along with television stations from Atlanta, GA, 
Chattanooga, 
TN, Louisville, KY, Dallas-Fort Worth, TX, 
Nashville, TN, Kansas City, and St. Louis were 
preparing to transmit live coverage Sunday  
and Monday via satellite. Numerous other  
radio stations and print media reporters were  
also on hand.
   
Research News, August 1991 
The Lessons of Dr. Browning 
by Richard A. Kerr

When a self-taught climatologist predicted a major quake for the 
Midwest, seismologists ignored him, but leaving the field to 
pseudoscience proved a big mistake.
BOULDER, COLORADOJill Stevens wanted 
to alert millions of Midwesterners to the 
earthquake threat beneath their feet. As head  
of the information side of the Center for 
Earthquake Research and Information at 
Memphis State University, she had been warning, with limited success, that much 
remained 
undone to protect the citizenry from rare but 
lethal quakes. But to the average  
Midwesterner, earthquake country stopped at  
the California border, so why worryuntil  
the winter of 1989, when one Dr. Iben  
Browning came along.
   A self-taught climatologist, Browning did 
Stevens job for herand more. He predicted 
that a catastrophic earthquake would strike the 
Mississippi Valley during the first week of 
December 1990. The media leaped on the pre- 
diction and suddenly the populace became all too 
aware of the threat. That might have been to the 
good, says Stevens, except that the pre- 
diction was scientifically groundlessand so 
specific and apocalyptic as to provoke near-hysteria. Stevens recalls a 6-year-
old girl whose 
earthquake fears could not be soothed on the 
phone, and elderly callers to her center who 
worried how they would get back in their 
wheelchairs after the big one struck. Schools  
and factories closed on the target day, 3 
December, and groups such as the Red Cross 
wasted precious funds in their efforts to calm  
the public.
   Although ultimate responsibility for the 
misleading quake prediction has to rest with 
Browning (who died 3 weeks ago), Stevens and 
others who gathered here last month for the  
16th Annual Hazards Research and  
Applications Workshop lay a healthy share of 
blame at the feet of a group that wanted no  
part of Browning or his prognostications: the 
scientific community. If I have any criticism, 
said Lacy Suiter, director of the Tennessee 
Emergency Management Agency, its why the 
scientific community that had the ultimate 
responsibility didnt call Browning a quack  
early on. And it was this concern that led participants of the meeting to hope 
that the next time 
a bogus earthquake prediction surfaces 
and there are sure to be morescientists will 
recognize its potential for touching off a frenzy
and promptly do their part to squelch it. 

5.1b Approaches to Pending Earthquakes

Attempts to predict or forecast earthquakes have been based on these approaches, 
among others:
1. Recognizing that seismic activity concentrates in zones of plate tectonic 
activity
2. Observing and recording the abnormal behavior of animals
3. Monitoring seismic activity at plate boundaries
4. Observing and recording persistent changes in the elevation of given 
topographic survey points
5. Locating and monitoring faults in places other than plate boundaries
6. Compiling data on the seismic history of a given area and measuring the 
intervals between 
previous quakes
7. Monitoring the changes in emission of radon (radioactive gas) from rocks by 
electronic monitoring of deep wells
8. Monitoring the level of the water in wells
9. Measuring variations in the magnetic field of large rock formations
10. Trenching across a fault to uncover evidence of past earthquake movement
11. Detecting strain in the rocks of the Earths crust by geodetic surveys
12. Using creep meters (wire strands extending across a fault) to indicate 
stress and movement 
l3. Recording variations in the speed of waves in the swarms of tremors that 
frequently precede 
earthquakes
14. Talking to earthquake survivors and recording their descriptions of past 
quakes
15. Observing foreshocks and measuring variations in P waves
16. Placing a network of seismograph stations on the ocean floor across the 
continental shelf and 
an ocean trench
17. Monitoring selected sites in an area that has no history of major seismic 
activity to detect 
micro-earthquakes
18. Monitoring changes in the occurrence of micro-earthquakes.

5.1c Levels of Generalization Classification Chart

Name
Date

Directions: Place the number of each item on the preceding list in the category 
you think is most appropriate.

Subjective Observation
Seismic Zone Analysis
Instrumentation and Measurement

5.1c Levels of Generalization Classification Chart (key)

Suggest answers 
(Note that some items may belong in either of the last two categories.)

Subjective Observation 2, 14
Seismic Zone Analysis 1, 3, 6, 10, 12, 16
Instrumentation and Measurement 4, 5, 6, 7, 8, 9, 11, 12, 13, 15, 16, 17, 18

5.2 Starting Here, Starting Now

ACTIVITY ONE
LEARNING THE DRILL

VOCABULARY
Aftershock: an earth-
quake that follows a 
larger earthquake, or 
main shock, usually 
originating in the same fault zone as 
the main shock.

Foreshock: an earthquake that 
precedes a larger earthquake, or 
main shock, usually originating in the 
same fault zone as the main shock.

RATIONALE
Students who have rehearsed what to do in the event of an earthquake 
are more likely to stay calm and proceed rationally than students who 
have not.

FOCUS QUESTIONS
If an earthquake happened here, right now, what would you do?

OBJECTIVES
Students will:
1. Describe and recognize the early signs of an earthquake.
2. Drop, cover, and hold until a quake is over.
3. Evacuate the school or other building in an orderly fashion.
4. Describe procedures for coping with various earthquake hazards.

MATERIALS
 Materials to produce sound effects (optional)
 Standard first-aid manual

PROCEDURE
Teacher Preparation
1. Choose an open area outside the school where your class would be 
safe in the aftermath of an earthquake. You may also want to let 
teachers in neighboring classrooms know that your class will be 
holding an earthquake and evacuation drill.

2. Review basic emergency procedures in a standard first-aid manual, 
such as how to apply pressure for bleeding and how to handle injured 
people.

TEACHING CLUES AND CUES
Most moderate-to-large earthquakes are followed, within the 
ensuing hours, days, and months, by numerous smaller 
earthquakes (aftershocks) in the same vicinity.

A. Introduction
Tell students that instead of a fire drill, they are going to have an 
earthquake drill. Impress them with the seriousness of this exercise; 
like a fire drill, it could literally save their lives. Explain that when 
they hear the signal Drop, cover, and hold, every student is to follow 
this procedure:
 Get under the table or desk.
 Turn away from the windows.
 Cover the back of your neck with one hand.
 Tuck your head down.
 Hold onto a leg of the table or desk, and move with it if it moves.

Reinforce the list of actions by writing one word for each action on 
the board and asking students to repeat the three words Drop, Cover, 
and Hold. Remind them that earthquake shaking typically lasts less 
than a minute, so they will not be uncomfortable for long.

B. Lesson Development
1. Have several students demonstrate the drop, cover, and hold drill 
for the class, then have students practice it all together.

2. Ask for a volunteer to describe the beginning of the earthquake, 
complete with sound effects, if the student chooses, and then to signal 
drop, cover, and hold. (Students will be familiar with earthquake 
sights and sounds by this time, so most of them should be prepared for 
this task.) Instruct the volunteer to begin talking at your signal, and to 
call out Drop, cover, and hold after just a moment or two of 
description.

3. When the student signals, take cover, begin counting, and count 
slowly up to 60. (Remember, most earthquakes last less than a 
minute.) Then tell students that the earthquake is over, but they must 
be prepare for aftershocks. Ask them to evaluate their performance.

4. If either you or the students believe the class could have done 
better, tell them an aftershock is beginning and repeat the procedure 
with a different volunteer. Emphasize the need for a quick response.

5. When you are satisfied with the students response, tell them that 
the shaking has stopped and it is time to evacuate the building. Follow 
your normal fire drill route (or a safer route) to the outside of the 
building and lead the class to the spot you have chosen.

6. When everyone is gathered outside, explain to the class that they 
will stay there for the rest of the period. It would not be safe to go 
back into the building until it has been inspected. Ask students to 
name some hazards they might have encountered along the way if an 
earthquake had occurred (fallen lockers or trophy cases, fires, smoke, 
fumes from laboratory chemicals or broken equipment, live electrical 
wires). Discuss procedures for dealing with these hazards. Then 
brainstorm responses to some other contingencies that might develop,
indoors or out. Ask students what they would do if.

 their normal evacuation route is blocked by wreckage? (Take time 
now to plan an alternate route with the class and be sure that 
everyone understands it.)

 an aftershock occurs while they are outside or en route? (drop and 
cover)

 a student or teacher is injured and cant walk? (Dont try to move 
the person unless there is immediate danger of fire or flooding. 
Instead, cover him or her with a sturdy table or whatever is 
available and send someone for medical help after the earthquake 
shaking stops.)

 someone is cut by shattered glass and is bleeding severely? (Apply 
pressure to stop the bleeding.)

 someone is hit by a falling lamp or brick? (If the person is 
conscious and able to walk, take him or her to a first-aid station as 
soon as possible. Even if the person appears to be unhurt, assign 
someone to stay close and watch for signs of dizziness or nausea.)

TEACHING CLUES AND CUES
This simulation may arouse feelings of fear or anxiety for some 
students. Encourage students to express their feelings 
freely and to be supportive of each others feelings. Emphasize that 
these reactions are normal and healthy, but that learning how to 
avoid injury will increase their chances of survival and those of 
everyone around them. Be aware that inappropriate optimism (It cant 
happen to me) is just as unrealistic as extreme fear and anxiety.

Do not excuse students with special needs from participating in earthquake
drills. It may not be possible for students with impaired mobility to get under 
a desk 
or table. They can, however, learn to react quickly and turn away from 
windows, move away from light fixtures and unsecured bookcases, 
and use their arms or whatever is handy to protect their heads. 
Encourage other students to plan procedures to assist them with 
immediate protection and evacuation.

7. If any time remains in the class period, use it to review first-aid 
procedures and listen to the students feelings about the possibility of 
an earthquake or other natural disaster. Better yet, arrange for the 
school nurse or a Red Cross trainer to present this information.

C. Conclusion
The next day, back in the classroom, ask students to name some of the 
other places they might be when an earthquake occurs, and suggest 
safety procedures for each situation. Answers might include:

 Outdoors (Find an open place away from trees, buildings, power 
lines, and other structures. Kneel or sit until the shaking passes.)

 In a car (Stop as soon as possible, ideally in a level place away 
from buildings, power lines, bridges, and highway overpasses and 
underpasses. Passengers should stay in the car and hold on to doors 
and seats. The vehicles shock absorbers may cushion some of the 
shaking.)

 On the bus or subway (Stay calm and follow instructions from the 
driver or conductor.)

 In an open mall, a gymnasium, or other, indoor place with no 
shelter (Move to an inside wall. Kneel next to the wall, facing away 
from windows. Bend head close to knees, cover sides of head with 
elbows, and clasp hands behind the neck. If you are carrying a coat, 
a notebook, a package, or even a towel, hold it over your head for 
protection from debris or flying glass.)

Conclude with time for questions and discussion.

ADAPTATIONS AND EXTENSIONS
1. Some students may enjoy making an audiotape to use in step 2 of 
Lesson Development, above.

2. Encourage students to take classes in first aid and cardiopulmonary 
resuscitation (CPR) from the Red Cross or other community 
organization, and to update training they already have. If a number of 
students are interested, arrange for a trainer to visit your class or 
provide presentations for the entire school. Students will gain 
confidence as well as competence.

3. Invite the schools health instructor or a representative from the 
Red Cross or other emergency agency to participate in the earthquake 
drill.

4. Invite the class to join you in setting up a schoolwide earthquake 
drill. Invite the school administration and local emergency services 
officials with whom you established contact in Unit 1.

5. If you repeat this drill in Unit 6 as part of the community 
earthquake simulation, vary it by putting up signs at one point along 
the evacuation route to indicate that the route is blocked. Lead the 
class out by the alternate route you planned in step 6, above.

ACTIVITY TWO

RVS AT YOUR ADDRESS: RAPID VISUAL SCREENING OF SCHOOL 
AND HOME FOR EARTHQUAKE HAZARDS

VOCABULARY
Hazard: an object or situation that holds the possibility of injury or 
damage.

Nonstructural feature: an element of a building that is not essential to its 
structural design and does not contribute structural strength. 
Examples are windows, cornices, and parapets.

Rapid visual screening (RVS): a method of assessing risk that relies 
on external observation. An observer who is trained in RVS can derive 
enough information from a quick visual assessment to know if closer 
examination is necessary.

Retrofitting: making changes to a completed structure to meet needs 
that were not considered at the time it was build; in this case, to make it 
better able to withstand an earthquake.

RATIONALE
Every teacher wants the classroom to be a safe environment for 
students. In this activity, you and your students will assess the safety 
of your classroom and make plans to remedy any earthquake hazards. 
Students will also assess their own homes.

FOCUS QUESTIONS
Can you imagine what your classroom would be like during an 
earthquake?
How could you make your classroom and your school a safer place to 
be?
How could you make your home safer?

OBJECTIVES
Students will:
1. Distinguish between structural and nonstructural features of a 
building.
2. Recognize nonstructural earthquake hazards in the classroom.
3. Develop a rapid visual screening format to use in their homes.
4. Devise methods to reduce earthquake hazards in school and at home.

MATERIALS
 Paper and pencils or pens
 Chalkboard and chalk or overhead projector and markers
 Student copies of Master 5.2a, RVS Checklist for the Classroom, 
one for each small group
 Student copies of master 5.2b, RVS Checklist for the Home

PROCEDURE
Teacher Preparation
Write a brief letter telling parents that you are teaching a unit on 
earthquakes and encouraging their participation in a rapid visual 
screening of their home.

Using the checklist on Master 5.2a, look around your classroom and 
note any items that could harm you and your students if an earthquake 
suddenly started to shake the room. Do not make any changes at this 
time unless you see a situation that needs immediate correction.

A. Introduction
1. Place several books on a desk. Have a student come up to the front 
of the room and shake the desk. Ask students to describe what they 
observed.

TEACHING CLUES AND CUES
If students made a shaking table in Unit 4, have volunteers demonstrate on the 
shaking table instead.

2. Remind students that in earlier lessons they have demonstrated the 
importance of structural features in increasing building safety. Ask 
them to name some structural features. (girders, beams, floors, load-
bearing walls, columns, foundations)

3. Ask: Are these the only features of buildings that are affected by an 
earthquake? Explain that nonstructural featuresoutside brick walls 
that dont bear weight, decorative overhangs, and panels added after 
construction; and inside cabinets, bookshelves, desktop computers, 
laboratory equipment, hanging light fixtures, wall decorations, 
aquariums, potted plants, and windowscan also injure people and 
damage property if they are not properly fastened to survive a strong 
earthquake.

B. Lesson Development
1. Ask students to quickly scan the classroom and each write down the 
name of at least one object or nonstructural feature that could be a 
hazard during earthquake shaking. Tell them they have just completed 
a rapid visual screening, or RVS.

2. On the chalkboard or overhead projector, compile a list of the items 
students noted. Build a class discussion around the observations, 
asking students to specify why they considered particular items 
hazardous.

3. Divide students into small groups and distribute copies of Master 
5.2a, RVS Checklist for the Classroom. Give students about 10 
minutes to complete the checklist. When they have finished, ask: Did
the list suggest any items we overlooked in our own assessment? If so, 
add these items to the class list.

4. Ask students to share the methods they proposed to make the 
classroom safer during an earthquake. Many will be as simple as 
relocating or removing furnishings. Others may require tie downs, 
anchors, or fasteners to hold them in place during the shaking.
Help the class reach consensus on a short list of changes to improve 
their own classroom for earthquake safety.

5. Give students class time to develop an RVS checklist for their 
homes, based on their own screening of the classroom and Master 
5.2b. Assign students to screen their homes, with the cooperation of 
their families, and write brief reports of their findings, including 
suggestions for what they could do to make their homes safer during 
an earthquake.

C. Conclusion
Let colleagues know that your students are available to do hazard 
screenings of other classrooms. Assign teams of students to screen the 
classrooms of any interested teachers and develop plans to retrofit 
those classrooms for earthquake safety.

ADAPTATIONS AND EXTENSIONS
1. Encourage your students to present their data, analysis, and suggestions for 
retrofitting to the schools principal, staff, or parent 
teacher organization and to their families. Both in school and at home, 
students may volunteer to do all or some of the work.

2. Invite interested students to develop a one-minute radio or television 
spot to inform their community about rapid visual screening. ?

5.2a RVS List for the Classroom
 
Name
Date

Instructions
1. Check yes or no for each of the following items. Skip any items that are not 
applicable to your classroom. 

2. Go back and circle all the nos. These are the items that you have identified 
as potentially dangerous to you and 
your classmates.

3. For each no, suggest a way to remove the danger. (Use the comments space.)

4. For each yes, explain why your team thinks the feature is earthquake 
resistant.

Are desks and tables located where they cannot slide and block exits? 
comments:

Are large, heavy office machines secured to the wall or floor and located where 
they cannot slide, 
fall, or, block exits? 
comments:

Are the tops of tall (4- or 5-drawer) file cabinets securely attached to the 
wall? 
comments:

Do file cabinet doors have latches? 
comments:

Are desktop computers securely fastened to work spaces? 
comments:

Are bookshelves, cabinets, and coat closets secured to the wall and/or attached 
to each other? 
comments:

Are display cases or aquariums protected against overturning or sliding off 
tables? 
comments:

Is floor-supported, freestanding shop equipment secured against overturning or 
sliding? 
comments:

Is freestanding equipment on wheels protected against rolling? 
comments:

Are all wall-mounted objects that weigh more than five pounds firmly anchored to 
the buildings 
structural framing?
comments:

Are all heavy, sharp, or breakable wall decorations securely mounted, with 
closed-eye hooks, for 
example?
comments:

Do books or materials stored on shelves have adequate restraints to keep them 
from flying off the 
shelves?
comments:

Are laboratory chemicals on shelves restrained? Are potentially hazardous 
chemicals stored 
securely? Are chemical storage areas vented, and located away from exits and 
corridors? Is there 
an up-to-date inventory of all chemicals stored?
comments:

Are the fluorescent light fixtures merely resting on the hung ceiling grid, or 
do they have other 
supports?
comments:

Are decorative ceiling panels or latticework securely attached? 
comments:

Will hanging light fixtures swing freely without hitting each other if allowed 
to swing a minimum 
of 45 degrees?
comments:

Are fire extinguishers securely mounted? 
comments:

If there are potted plants and other heavy items on top of file cabinets or in 
other overhead 
locations, are they restrained?
comments:

Do you see other hazards not included on this list? Specify. 
comments:

5.2b RVS List for the Home

Name
Date

1. Place beds so that they are not next to large windows.

2. Place beds so that they are not below hanging lights.

3. Place beds so that they are not below heavy mirrors.

4. Place beds so that they are not below framed pictures.

5. Place beds so that they are not below shelves with objects that can fall.

6. Replace heavy lamps on bed tables with light, nonbreakable lamps.

7. Change hanging plants from heavy pots into lighter pots.
?
8.
Use closed hooks on hanging plants, lamps, etc.

9. Make sure hooks for hanging plants, lamps, etc. are attached to studs.

10. Remove all heavy objects from high shelves.

11. Remove all breakable things from high shelves.

12. Replace latches, such as magnetic touch latches on cabinets, with latches 
that will hold during an 
earthquake.

13. Take glass bottles out of medicine cabinets and put on lower shelves. 
(PARENT NOTE: If there are small children around, make sure you use childproof 
latches when 
you move things to lower shelves.)

14. Remove glass containers that are around the bathtub.

15. Move materials that can easily catch fire so they are not close to heat 
sources.

16. Strap water heater to the studs of the nearest wall.*

17. Move heavy objects away from exit routes in your house.

18.Block wheeled objects so they cannot roll.

19. Attach tall heavy furniture, such as bookshelves, to studs in walls.

20. Use flexible connectors where gas lines meet appliances such as stoves, 
water heaters, and dryers. 

21. Attach heavy appliances such as refrigerators to studs in walls.

22. Nail plywood to ceiling joists to protect people from chimney bricks that 
could fall through the 
ceiling.

23. Make sure heavy mirrors are well fastened to walls.

24. Make sure heavy pictures are well fastened to walls.

25. Make sure air conditioners are well braced.

26. Make sure all roof tiles are secure.

27. Brace outside chimney.

28. Bolt house to the foundation.*

29. Remove dead or diseased tree limbs that could fall on the house.

30. Install plywood reinforcements.*

* See Master 5.3c, Strengthening Your Wood Frame House, for materials and 
instructions.

Seismic Sleuths

Earthquakes

A Teachers Package for Grades 7-12

Unit Five (continued)

5.3 Find and Fix the Hazards 
(Wood Frame Homes)

TEACHING CLUES AND CUES
If possible, prepare your students for this activity and the others in this 
lesson, then conduct one field trip that combines several of the 
activities.
 
This activity emphasizes wood frame houses because they are 
common single-family dwellings in many parts of the 
country. If you are not teaching all the lessons in this unit, be sure 
students understand that other types of structures also pose serious 
hazards.

RATIONALE
Relatively simple modifications can greatly increase the safety of a 
wood frame house. Even students who do not currently live in such 
houses may at some future time.

FOCUS QUESTIONS
What are some structural earthquake hazards in a typical wood frame 
home?
What can be done to reduce structural hazards in these homes?

OBJECTIVES
Students will:
1. Assess risk factors in an existing wood frame house.
2. Name several ways to strengthen an existing wood frame
construction.

MATERIALS
 Classroom map of the local area, from Unit 1
 Master 2.5b, Soil and Geologic Maps and Map Sources (optional)
 Student copies of Master 5.3a, Structural Checklist
 Student copies of Master 5.b, Wood Stud Frame Construction
 Flashlights
 Goggles or other eye protection
 Head protection (helmet or hard hat)
 Clip board, paper, and pencil for notes
 Knee pads (optional)
 Student copies of Master 5.3c, Strengthening Your Wood Frame House

PROCEDURE
Teacher Preparation
Contact a local realtor to find a nearby wood frame house that stu-
dents can visit to conduct their assessment, or arrange with a con-
tractor to visit a building site. If no vacant home is available, plan to 
use your own home or that of a friend or colleague. Arrange for 
transportation and permissions as necessary.

A. Introduction
Survey the class, asking: How many students live in wood frame 
houses? How many have friends or relatives who live in wood frame 
houses? How many have lived in such houses at some point in their 
lives? (Be sure students understand that the frame of the house may be 
wood even if the outside sheathing is stucco, decorative brick, brick 
veneer, stone, or some other material.) Record a count of student 
answers on the board.

Tell the class that many homes in regions across the country are 
constructed of wood frame systems. These wooden structures are 
lightweight and flexible, and properly nailed joints are excellent for 
releasing earthquake energy and resisting ground shaking. 
Nevertheless, frame houses are sometimes damaged by an earthquake, 
causing a great deal of unnecessary trouble and expense for 
homeowners. This damage is unnecessary because most often it could 
have been prevented by some very basic alterations. It pays to find out 
if your home needs rehabilitation or strengthening and what can be 
done to lessen the earthquake hazard.

B. Lesson Development
1. Tell students that they are going to play the role of potential home 
buyers. Each of them has just landed a new job at a higher salary, and 
has decided to buy a new wood frame house. First, however, they 
must conduct a visual inspection of each home they consider buying to 
identify potential earthquake hazards. In this lesson they will learn 
what to look for in the foundation and other structural components.

2. Ask: What seismic hazard designation has been applied to the area 
where we live? (In Unit 3, Lesson 3, you noted this information on the 
classroom local map. It is also available on Master 1.3b, U.S. 
Earthquake Hazard Map.) Explain that the degree of earthquake risk 
in any structure depends on where it is located as well as how it is 
built. If your school is located in a region identified on Master 1.3b as 
one of low seismic hazard, however, remind students that this map 
depicts what has happened; it does not predict what may happen. 
Earthquakes can occur anywhere in the world. Moreover, most 
Americans move several times in the course of their lives.

3. If you did Lesson 2.5, students will also know the soil characteristics of 
their own region. If this information is not on your class-
room map, refer students to local maps of soil characteristics, and
ask them to characterize the soil of the site they will be visiting. (See 
Master 2.5b, Soil and Geologic Maps and Map Sources.) Emphasize 
again that the site and the mode of construction interact.

4. Distribute copies of Master 5.3a, Structural Checklist, and Master 
5.3b, Wood Stud Frame Construction. Point out the numbered areas 
on the drawing, and tell students that these are among the things they 
will be inspecting on their field trip.

5. Travel with your class to the site you have chosen. Direct pairs or 
small groups of students to conduct inspections. When one group has 
finished, those students can complete their worksheets while the 
others proceed.

TEACHING CLUES AND CUES
Engineers and architects are the people best qualified to assess the 
strength of structures and their resistance to earthquakes. 
If your students have serious concerns, encourage them to discuss 
with their parents the possibility of bringing in a professional. Even the 
first modification on Master 5.3c is best undertaken after structural 
analysis, especially an analysis of foundation soils.

C. Conclusion
If you are in a moderate- or high-risk area, and your students find that 
their own homes could be reinforced to better withstand an 
earthquake, distribute copies of Master 5.3c, Strengthening Your 
Wood Frame House. Assign students to take home these simple 
directions for four inexpensive projects. High school students and 
their parents can follow the steps on these pages to reinforce their 
wood frame homes.

ADAPTATIONS AND EXTENSIONS
If a majority of your students live in wood frame houses, you may 
assign this activity as an out-of-class exercise. Cover the information 
in the introduction with the whole class, then hand out copies of 
Master 5.3a, Structural Checklist. Ask students to assess the stability 
of their own homes and complete a report to share with their families 
and/or their classmates. Have students check on local building laws or 
talk to the city building inspector. Invite the building inspector to visit 
your class and talk about local building codes.

Note: Master 5.3c, Strengthening Your Wood Frame House, is adapted from 
An Ounce of Prevention: Strengthening Your Wood Frame House for 
Earthquake Safety, with permission from the Bay Area Regional Earthquake 
Preparedness Project, 101 8th Street, Room 152, Oakland, CA 94607.

5.3a Structural List

Name
Date

Instructions. Rate each component listed on a scale 
from 1 (good) to 5 (poor).

1. The foundation must react as one unit for maximum 
earthquake resistance. The best foundations are steel-
reinforced concrete that reach down to bedrock. 
Examine the foundation.
-	Is it wood, brick, or concrete?
-	Is there any sign of steel reinforcement?
-	Are there holes or pits in the foundation?
-	Is the concrete powdery or crumbly?
-	Are there signs of water damage?
-	Are there visible cracks longer than 1 cm?
Rating (Circle one):      1         2         3         4         5

2. The wood plate (also known as a sill plate or a 
mudsill). This is the first structural wooden member 
placed on the foundation. Examine the wood plate.
-	Is it bolted to the foundation?
-	How far apart are the bolts? (The standard 
spacing is about four feet apart.)
-	Is the wood plate fasten or reinforced with metal 
plates?
Rating (Circle one):      1         2         3         4         5

3. Short stud walls (cripple walls)
-	Are they made of wood, brick, or another 
material?
-	Are they braced to resist earthquake-generated 
lateral forces?
-	Are they connected to the wood plates?
-	How is the floor frame fastened to the stud wall?
Rating (Circle one):      1         2         3         4         5

4. Exterior walls (shear walls)
-	What are the exterior walls made of? (brick, 
block, wood siding?)
-	Are they tied together?
-	If the walls are brick, block, or stone, what is the 
condition of the mortar?
-	Are they braced to resist earthquake-generated 
lateral forces?
Rating (Circle one):      1         2         3         4         5

5. Masonry fireplace chimneys. An unreinforced brick 
chimney is the weakest part of a house when 
earthquake shaking begins.
-	Does the house have one or more chimneys?
-	Is each chimneys foundation part of the house?
-	What are the chimneys made of?
-	Are they reinforced and designed to be earthquake 
resistant?
Rating (Circle one):      1         2         3         4         5

6. Utilities and their mountings
-	Is the gas main mounted on flexible pipes?
-	Is the electrical service firmly mounted?
-	Is the main water shutoff accessible?
Rating (Circle one):      1         2         3         4         5

7. Exterior porches
-	Does the house have one or more porches?
-	Is the porch or porches attached to the house? 
How?
-	Is the foundation of the porch attached to the 
foundation of the house?
Rating (Circle one):      1         2         3         4         5

8. Make specific recommendations on how to correct 
any seismic deficiencies identified.

5.3b Wood Stud Frame Construction

Reproduced from Rapid Visual Screening of Buildings for Potential Seismic 
Hazards: A Handbook, FEMA Earthquake 
Hazard Reduction Series 41.

5.3c Strengthening Your Wood Frame House: Four Projects

adapted with permission of the Bay Area 
Regional Earthquake Preparedness Project

Step 1: Steel Plate Bolting
Materials and Tools Needed
 1 cm (1/2 in.) diameter expansion bolts of a style acceptable to the 
local building department. Length of bolt determined by depth of 
hole, thickness of sill plate, and a projection of not less than 2.5 
cm (1 in.) above sill plate

 Masonry drill bit with carbide tip. Size determined by size and 
style of expansion bolt.

 Electric rotary impact drill or heavy-duty drill

 Short-handled sledge hammer or carpenters hammer for setting 
the bolts.

 1 cm (3/8 in.) diameter plastic tubing

 Adjustable crescent wrench

 Chalk or lumber crayon

 Measuring tape

 Eye protection

 Noise protection

 Dust mask

Installation Instructions for Step 1
1. Lay out bolt locations. Bolts should be spaced at not more than 2 
m (6 ft) apart. Begin layout at not less than 10 cm (4 in.) or more 
than 30 cm (12 in.) from the end of any section of sill plate.

2. Drill holes through the sill plate and into the foundation with a carbide 
drill bit of the size recommended for the style of expansion bolt 
used. Drill holes a minimum of 11.5 cm (4.5 in.) into foundation wall.

3. After drilling a hole, clean out the concrete dust by inserting the plastic 
tubing into the hole and blowing out the dust.

4. Place a cut washer over the bolt so it rests on top of the sill plate. Place 
the nut on the bolt and turn until the top of the nut is even with 
the top of the bolt. Insert expansion bolt into the hole until it stops. Using 
the sledge hammer or carpenters hammer, strike the top of the 
hole.

5. Using a crescent wrench, tighten the nut until the sill plate begins to crush 
under the washer.

Step 2: Install Blocking at Sill Plate
Note: This blocking is necessary only when the depth of the studs is different 
from the width of the sill plate, such as 2 x 4 studs attached to a 2 x 6 sill. 
If the stud depth and the sill plate width are the same, skip this step.
Materials and Tools Needed
 Nominal 5 cm (2 in.) thick lumber (actually 4 cm, or 1.5 in. thick) the same 
depth as the studs

 16d (16-penny) common nails

 Electric drill to pre-drill holes for nails, if necessary

 0.2 cm (1/16 in.) diameter drill bits for pre-drilling nail holes and a bit at 
least 0.2 cm (1/16 in.) larger than the diameter (point-to-point 
distance across) of the anchor bolt nut

 Carpenters hammer

 Measuring tape

 Pencil

 Eye protection

 Dust mask

Installation Instructions for Step 2
1. Measure distance between studs.

2. Cut pieces of blocking from 5 cm (2 in.) thick piece of lumber, the same 
depth as the studs, equal to the distance between studs, that the 
blocking fits snugly.

3. In those stud spaces, where a new anchor bolt has been installed, mark the 
bolt location on the bottom of the blocking and drill a hole 
large enough that the blocking fits over the bolt and rests fully on the sill 
plate.

4. Nail the blocking to the sill plate with between 3 and 6 16d nails. If 
blocking begins to split while the nail is driven, remove the nail and 
drill pilot holes for each nail with the 0.2 cm (1/16 in.) diameter drill bit.
 
Step 3: Install Plywood
Materials and Tools Needed
 1 cm (3/8 in.) or 1.2 cm (15/32 in.) thick plywood of Structural 1 
of CDX grade

 Nominal 5 cm (2 in.) thick lumber (actually 4 cm or 1.5 in. thick) 
the same depth as the studs. This will be used for blocking, if 
required.

Note: The size of access to the average crawl space frequently 
doesnt allow large pieces of plywood. You may need to use two or 
more smaller pieces of plywood. When multiple pieces are used to 
cover the height of the wall, blocking must be installed at the joint 
and completely nailed. If a single piece of plywood can be installed 
the full height of the reinforcing wall, blocking will not be necessary.

 8d common nails for use with 1 cm (3/8 in.) plywood

 10d common nails for use with 1.2 cm (15/32 in.) plywood

 16d common nails for use with blocking, if required

 Electric circular saw

 Electric drill

 0.2 cm (1/16 in.) diameter drill bit for pre-drilling nail holes if 
blocking is required

 Nail gun or carpenters hammer

 Measuring tape

 Chalk, lumber crayon or pencil

 4 cm to 5 cm (1.5 in. to 2 in.) diameter hole saw

Installation Instructions for Step 3
1. If access to the crawl space under the house is such that full-width 
sheets, or sheets cut to the height of the cripple studs, will not fit, cut 
plywood sheets lengthwise to a width not less than 46 cm (18 in.).

2. If sheets need to be cut, blocking will be necessary. Cut the 5 cm (2 in.) 
nominal thickness lumber to fit snugly between the studs. Nail 
each block to the studs with 2 16d nails at each end. Nails should be driven 
into the side of the stud. Pre-drilling for the nails will make this 
operation easier. Blocking should be installed at the same height for the full 
length of the plywood sheet.

3. Starting at a comer, measure across the studs to find a stud where the sheets 
of plywood can butt. In order to do this, find the stud closest 
to, but not less than 1.2 m (4' ft.) or closest to, but not more than 2.4 m (8 
ft.) from the corner. Measure the location of all ventilation vents 
and cut out holes in the plywood to match the vents.

4. Mark the location of each stud at the top plate and on the foundation wall 
with chalk or lumber crayon.

5. After cutting the plywood to fit, lay it up against the studs and hammer a 
nail in each comer of the plywood to hold it in place. Using a 
nail gun, or a carpenters hammer, place a nail every 10 cm (4 in.) around the 
perimeter of the plywood sheet. Then place a nail every 15 
cm (6 in.) along each stud. Use the nails appropriate for the thickness of the 
plywood.

6. Once the plywood has been fully nailed, drill a 4 cm to 5 cm (1.5 in. to 2 
in.) diameter hole above and below the blocking.

Step 4: Strap Water Heater
Materials and Tools Needed
 Two 1.8 m (6 ft.) lengths of 4 cm (1.5 in.) 
gauge pre-drilled strap

 One 3.1 m (10 ft.) length of 1 cm (.5 in.) 
EMT tube (conduit)

 Four 1 cm x 7.5 cm (5/16 in. x 3 in.) lag 
screws with washers

 Two 1 cm x 2 cm (5/16 in. x 3/4 in.) hex 
head machine bolts with 1 nut and 2 
washers each

 Two 1 cm x 3 cm (5/16 in. x 1-1/4 in.) 
hex head machine bolts with 1 nut and 2 
washers each

 Electric drill

 Tape measure

 Hammer

 Hacksaw

 Crescent wrench

 Vise or clamp

 Power drill

 1 cm (3/8 in.) drill bit

 Center punch

Installation Instructions for Step 4
1. Mark water heater at 15 cm (6 in.) from 
top and about 46 cm (18 in.) up from 
bottom. Transfer these marks to the wall. 
Locate the studs in the wall on both sides of 
the water heater.

2. Drill a 0.5 cm (3/16 in.) hole 7.5 cm (3 in.) deep through the wall sheathing 
and into the center of the wood studs at the four marks made 
in step 1.

3. Measure around the water heater and add 7.5 cm (3 in.) to the measurement. 
Using a hacksaw, cut the two 4 cm (1.5 in.) 16-gauge metal 
straps to this length for encompassing water heater.

4. Mark 4 cm (1.5 in.) from each end of metal straps, insert them in a vise, and 
bend the ends outward to approximately a right angle. Bend 
the straps into a curve.

5. Measure the distance from a point midway on each side of the water heater to 
the hole drilled in the wan (probably two different 
lengths). Add 4 cm (1.5 in.) to these measurements. Using a hacksaw, cut two 
pieces of tube to each of these two lengths.

6. Using a hammer, flatten approximately 4 cm (1.5 in.) at each end of the four 
pieces of tubing by laying the tube on a flat metal or 
concrete surface and striking with the hammer. Be sure you flatten both ends on 
the same plane.

7. Insert the flattened ends of the tubes, one at a time, into a vise or clamp. 
With the hammer and center punch make a mark 2 cm (3/4") from each end at the 
center of the flattened area of the tube. Drill 1 cm (3/8 in.) holes in each end 
of all four tubes (8 holes). Be sure tubes are clamped down while drilling. Bend 
each end to about 45 degrees.

8. Wrap the straps around the heater and insert a 1 cm x 3 cm (5.16 in. x 1.25 
in.) bolt with washers into the bent ends. Tighten nuts with fingers. Insert 1 
cm x 2 cm (5/16 in. x 3/4 in.) bolts through straps from the inside at the mid-
point on each tube strut and insert on hole in the wall stud. You may need to 
tap the lag screw gently into the hole to start it, then tighten with crescent 
wrench.

9. Adjust the straps to the proper height and tighten nuts snugly. If the nuts 
are too tight, the straps could tilt the heater.
Note: Flexible gas and water supply lines to the water heater will greatly 
reduce the danger of water pipe leaks and fire or explosion from a gas leak 
after an earthquake. If your water heater does not have a flexible gas line, 
contact a licensed plumber to install one. These instructions are for a 30 to 40 
gallon water heater within 30.5 cm (12 in.) of a stud wall.


5.4 Rapid Visual Screening (RVS) in the Community

VOCABULARY
Canopy: a covered area that extends from the wall of a building, 
protecting an entrance.

Cantilever: a beam, girder, or other structural member which projects 
beyond its supporting wall or column. Cladding: an external covering or 
skin applied to a structure for aesthetic or protective purposes.

Cornice: the exterior trim of a structure at the meeting of the roof 
and wall.

Glazing: glass surface.

Masonry veneer: a masonry (stone or brick) facing laid against a wall 
and not structurally bonded to the wall.

Parapet: part of a wall which is entirely above the roof.

Portico: a porch or covered walk consisting of a roof supported by 
columns.

Veneer: an outside wall facing of brick, stone, or other facing materials 
that provides a decorative surface but is not load-bearing.

RATIONALE
Students will perform an informal RVS (rapid visual screening) to 
determine the nonstructural hazards to people and property that could 
be caused by buildings in their community during an earthquake.

FOCUS QUESTIONS
What buildings in my town or city might pose a serious risk of 
casualties, property damage, and/or severe curtailment of public 
services, if a damaging earthquake happened here?

OBJECTIVES
Students will:
1. Conduct a sidewalk survey of nonstructural building hazards in 
their community.
2. Record their observations on data collection forms.

MATERIALS
 Transparency from Master 1.3b, U.S. Earthquake Hazard Map
 Classroom wall map of your own region which includes seismic 
hazard designations. This may have been prepared in Unit 1.
 Overhead projector (optional)
 Transparency made from Master 5.4a, Nonstructural Hazards
 Student copies of Master 5.4a, Nonstructural Hazards
 Student copies of Master 5.4b, RVS Observation Sheet, six for 
each team
 Clipboard for holding observation sheets and drawing paper
 Pens or pencils
 Blank drawing paper
 Straightedge or ruler for drawing sketches
 Camera, preferably instant (optional; if available, replaces sketches)
 Tape or stapler, for affixing photo (optional)
 Red marking pen

PROCEDURE
Teacher Preparation
Select site(s) for the class field assignments, choosing the nearest 
large concentration of buildings. Students may choose buildings to 
survey or they may be assigned.

A. Introduction
Tell students that they are going to assume the role of building 
inspectors in completing an informal sidewalk survey of buildings in 
their community.

B. Lesson Development
1. Ask students whether their region of the country is thought to be at 
low, moderate, or high risk for earthquakes. If you do not have this 
information on your classroom map, project the transparency made 
from Master 1.3b, U.S. Earthquake Hazard Map. If your school is 
located in a region pictured on the map as one low seismic hazard, 
remind students that they may not always live where they live now, 
and other natural disasters may affect the buildings.

2. Tell students that a building may be structurally sound but its 
exterior decorations may create a hazard. These are called 
nonstructural hazards. Project the transparency made from Master 
5.4a, Non-structural Hazards, and elicit student descriptions of 
nonstructural hazards on the outside of buildings in the drawing.

3. Tell students that for the purpose of this exercise, they will assume 
that a major earthquake is likely in their area in the next several years. 
They will take a walk and record their observations of nonstructural 
hazards.

4. Assign each student a partner. Distribute six copies of Master 5.4b, 
RVS Observation Sheet, to each pair, and ask each pair of students to 
complete the following steps for six buildings, noting all the 
information on their observation sheets.
a. Record a description of the building and its address or location.
b. Note materials used in construction.
c. Estimate the year of its construction.
d. Record its size (number of floors, area, shape, and other 
information).
e. Determine the current use (business, apartments or other).
f. List the readily visible nonstructural hazards.
g. Sketch or photograph the building.

5. Back in the classroom, suggest ways for students to fill in any missing 
information. Individuals may volunteer to call their mentors in the 
chamber of commerce, the local building department, or the public 
works department. Students could also call the firm that developed or 
manages a building. Then instruct all the students who filled out forms 
on the same building to compare their data and discuss any 
discrepancies. The goal of this process should be an assessment of 
each building surveyed that represents the students best consensus.

C. Conclusion
On the classroom local map you started in Unit 1, use a red marker to 
circle any block or group of blocks where concentrated nonstructural 
damage could be expected in the event of an earthquake. Open a class 
discussion of what students have learned. If students have not already 
expressed an opinion, ask if the sidewalks they traveled would be safe 
places to be during an earthquake. Generally, the most dangerous 
place to be is at building exits and directly adjacent to buildings (on 
the sidewalks, for example).

ADAPTATIONS AND EXTENSIONS
1. If a structural engineer is present or structural information is 
available from the building manager, students may also informally 
judge which buildings could be expected to withstand heavy earth- 
quake shaking.

2. If structural information is available from the building manager, 
students may also list the type of building construction used (wood, 
steel, masonry, cement, or other building materials.) ?

5.4a Nonstructural Hazards

Name
Date
 
5.4a Nonstructural Hazards (key)

Date:
 
5.4b RVS Observation Sheet

Name
Date

1. Building name

2. Street address

3. Materials used in construction

4. Year of construction

5. Size (number of floors), area, and shape

6. Current use

7. List of nonstructural hazards (see Master 5.4a and vocabulary for 
illustrations and definitions)
a.
b.
c.
d.
e.
f.
g.
h.
i.
j.
k.
l.
m.

Sketch building or attach photo.

(Continue on back if necessary)

5.5 Are the Lifelines Open? 
Critical Emergency Facilities and Lifeline 
Utility Systems

VOCABULARY
Lifeline: a service that is vital to the life of a community. Major life-
lines include transportation systems, communication 
systems, water supply lines, electric power lines, and petroleum or natural 
gas pipelines.

RATIONALE
How well a community recovers from a damaging earthquake depends 
on the survival of critical emergency facilities and major utility 
systems (lifelines). In this lesson, students resume their focus on 
community preparedness.

FOCUS QUESTIONS
Where are the critical emergency facilities and major lifelines in my 
community, and how vulnerable are they?
How would my community survive a damaging earthquake?

OBJECTIVES
Students will:
1. Name and locate the critical emergency facilities and lifelines in 
their community, and evaluate their sites for geological hazards.
2. Contact civic leaders, heads of emergency facilities, and public 
utility officials to learn about their emergency plans, or renew existing 
contacts.
3. Report to the class and the community on what they have learned.

MATERIALS
 Brainstorming list of survival necessities from Unit 1, Lesson 2
 Master 5.5a, Lifelines and Critical Emergency Facilities
 Back of Master 5.5a, Problem Areas
 Master 5.5b, A Chain of Disasters
 Local map(s) showing locations of major emergency facilities and 
lifeline systems
 Classroom local map developed in Lesson 1.3, with notes on soil 
conditions from Lesson 2.5
 Red marking pen
 Local telephone directories

TEACHING CLUES AND CUES 
If your students have not developed a map of your own area that contains 
information on fault and soil types, use the maps on Master 2.5c to 
show them how this kind of information is presented visually.

PROCEDURE
Teacher Preparation
Read Master 5.5a, Lifelines and Critical Emergency Facilities. Decide 
how you will group students for this activity. If necessary, combine 
categories, such as natural gas and petroleum fuels, so that together 
the groups cover all the areas. For each group, make one copy of the 
local map(s) with locations of major emergency facilities and lifeline 
systems. Also make one copy of a local map showing geological hazards, if your 
classroom map does not already have this information.

TEACHING CLUES AND CUES
If your community is in one of the parts of the country where
earthquakes have not been recorded, students can learn about 
preparations for other kinds of natural hazards, such as floods, 
hurricanes, and tornadoes. In many cases the same systems would be 
affected and the some kinds of preparations will have been made. 
Fire departments will be an excellent source of emergency information.

A. Introduction
Display the list of necessities for survival that students developed in 
Unit 1, Lesson 1. Review the list with the class and ask if they have 
anything to add, or if anything they included at that time now seems 
less than essential. When the class has reached consensus, display 
Master 5.5a or distribute copies. Does the list include anything 
students have omitted? To reinforce the connections among the many 
kinds of damage earthquakes can cause, display Master 5.5b, A Chain 
of Disasters. Have students revise their list of necessities again to 
incorporate anything they may have missed. Emphasize the 
importance of emergency facilitiessuch as hospitals, fire stations, 
and police departmentsand of public utilitiessuch as telephone 
lines, electric power systems, water supply systems, and 
transportation into and out of the affected area.

B. Lesson Development
1. Divide the class into small groups and assign one or more of the 10 
systems listed on Master 5.5a to each group. Individual students 
responsibilities will reflect their mentors areas.

2. Distribute one set of maps to each group. Instruct students to 
compare the lifeline maps to the classroom local map and note any 
geological features in their service area that might constitute a hazard. 
Invite them to develop their own system for indicating relative 
degrees of risk on the lifeline maps: coding by color, by number, or by 
different kinds of symbols, for example. When they have worked out a 
system that satisfies everyone, students can transfer this information 
to the classroom map.

3. Instruct students in each group to plan reports on the communitys 
plans for surviving the first 72 hours after an earthquake. They may 
need to renew their contacts with key people in their assigned service 
areas and schedule phone interviews. Give students class time to 
prepare lists of questions for their interviews. Then ask each group to 
exchange its list with another group and critique the questions.

TEACHING CLUES AND CUES
Emphasize that every student is to make at least one phone call. 
Calling several people in each system will increase the 
amount and quality of information students receive. Students are also 
likely to find what they learn reassuringfor example, that local 
hospitals have emergency backup generators.

4. When every groups questions have been reviewed and students are 
satisfied that they will elicit the necessary information, ask students to 
make the phone calls outside of class and take notes on what they 
learn.

5. The next time the class meets, allow 10 minutes for students in each 
group to pool their information. Then invite a representative
from each group to report to the class on how the system that group 
studied would operate during an emergency.

C. Conclusion
On the classroom local map, use red ink to indicate any lifelines or 
critical facilities that may be at high risk in the event of an earth- 
quake or other natural disaster.
Discuss students reactions to what they have learned. If they are 
pleased with the communitys level of preparedness, overall or in any 
of the separate systems, encourage them to write letters of congratulation to 
the appropriate officials or to the newspaper. If they are 
concerned that preparation seems inadequate, or if they have concerns 
about siting and geological hazards, they may write letters expressing 
their concern and recommending improvements.
Direct students to put their notes from this activity away in a safe 
place. They will need this information again in the Unit 6 role-playing 
activity.

ADAPTATIONS AND EXTENSIONS
1. If you know that your area is one of low seismicity, try to locate 
flooding maps, erosion maps, or maps of other types that are 
particularly relevant to your area. Have students learn about 100-year 
floods, the effect of windstorms over time, or other hazards that are 
specific to your community.

2. Provide maps of the state or the region surrounding your local area. 
Challenge students to identify alternate emergency facility locations 
and alternate transportation routes and map them out for classroom 
display. ?

5.5a Lifelines and Critical Emergency Facilities

A. Critical Emergency Facilities
1. Medical facilities: hospitals, blood banks
2. Emergency response facilities: police stations, fire departments
3. Local office: emergency operations center

B. Lifeline Utility Systems
1. Transportation systems: highways, freeways, bridges, airports, railroads, 
docks and marinas
2. Communication systems: telephones, radio, television, newspapers
3. Water supply: dams and reservoirs, aqueducts, distribution lines
4. Waste water: treatment plants, holding tanks, collection lines, effluent 
lines
5. Electric power: transmission towers and lines, switching stations, power 
generating plants, local distribution 
lines
6. Natural gas: holding tanks, pipeline distribution lines
7. Petroleum fuels: refineries, tank farms, pipelines

5.5a Problem Areas

Name
Date:

1. If electricity is cut off, electric appliances will not function. Without 
refrigeration, large amounts of food and 
medicine will be liable to spoil. Gasoline pumps and auto service stations win 
be unable to pump gasoline. 
Without power, airport control towers will have to rely on backup systems. 
Airports may function at limited 
capacity or not at all.

2.
If water distribution systems fail, the community will have no clean drinking 
water. Water may be limited or 
unavailable for fighting fires.

3. If hospitals are damaged, they will not be able to provide care and treatment 
for injuries and casualties. Even if 
a buildings structure survives, its services may be limited by lack of water 
and electricity and lack of 
transportation. Modern hospitals rely heavily on technology.

4. Rupture of petroleum fuel or natural gas pipelines may cause serious fires in 
the community and outlying areas, 
as well as shortages of heat and power.

5. If sewer systems fail, lack of sanitation may cause epidemics, such as 
cholera.

Books
American Red Cross, Los Angeles Chapter. (1985). 
The Emergency Survival Handbook. In English and 
Spanish. A simple, practical, and easy-to-use guide; 
includes disaster planning, first aid, and survival 
skills.

Bay Area Regional Earthquake Preparedness Project 
(BAREPP). (1990). An Ounce of Prevention: 
Strengthening Your Wood Frame House for 
Earthquake Safety. Oakland, CA: CA-OES, 
415-540-2713.

Federal Emergency Management Agency (FEMA). 
(September 1986). Family Earthquake SafetyHome 
Hazard Hunt and Earthquake Drill. FEMA 113. 
Tips on safe places and danger zones in the house, 
earthquake drills, and what should be done before and 
after.

Federal Emergency Management Agency (FEMA). 
(1990). Guidebook for Developing a School 
Earthquake Safety Program. FEMA 88. Washington 
DC: FEMA Publications, 500 C St., SW, Washington, 
DC 20472. This 50-page guide covers earthquake 
hazard identification; drills; response, communication, 
& shelter planning.

Federal Emergency Management Agency. (1993). 
Identification & Reduction of Nonstructural Hazards 
in Schools. FEMA 241.

Federal Emergency Management Agency. (October 
1990). Non-Technical Explanation of the NEHRP 
Recommended Provisions. FEMA 99. Washington, 
DC: Intended to help individuals assess how earth- 
quakes affect buildings & how enforcement of 
building codes helps to minimize loss.

Federal Emergency Management Agency. (July 1988). 
Rapid Visual Screening of Buildings for Potential 
Seismic Hazards: A Handbook. FEMA 154. 
Washington, DC: FEMA Describes the technique of 
rapid visual screening of buildings for potential 
seismic hazard.

Federal Emergency Management Agency. (1989). 
Seismic Considerations: Elementary and Secondary 
Schools. FEMA 149. Washington, DC: Building 
Seismic Safety Council. Covers the costs & benefits of 
applying seismic design in the construction of new 
school facilities. Explains how damage occurs to 
nonstructural components & building contents.

Helfant, David Benaroya. (1989). Earthquake Safe: A 
Hazard Reduction Manual for Homes. Berkeley, CA: 
Builders Booksource. A little book with reasonable 
explanations, detailed procedures, and plentiful 
illustrations.

Lagorio, Henry J. (1990). Earthquakes. New York: 
John Wiley and Sons, Inc. An architects guide to 
nonstructural seismic hazards. Focuses on site 
planning, building design, urban planning and design, 
rehabilitation of existing buildings, and disaster 
recovery and reconstruction.

Matthys, Levy, and Salvadori, Mario. (1992). Why 
Buildings Fall Down. New York and London: W.W. 
Norton and Company.

Wesson, R.L., and Wallace, R.E. (1985). Predicting 
the Next Great Earthquake in California. Scientific 
American 252, 2: 35-43.


Nonprint Media
Microstation, V. 5. A computer-assisted drafting 
program for student use. Order from Intergraph 
Corporation, Huntsville, AL, 1-800-345-4856. 
$150 with educational discount.

Reducing Nonstructural Earthquake DamageA 
Practical Guide for Schools. Video (13:00 min). 
Schools & EarthquakesBuilding Schools to 
Withstand Earthquakes. Video (14:27 min). Both 
available from FEMA.

Note: Inclusion of materials in these resource listings does 
not constitute an endorsement by AGU or FEMA.

Seismic Sleuths

Earthquakes

A Teachers Package for Grades 7-12

Unit Six
 
Now You Know It, Can You Show It?
The concluding unit of this curriculum offers a 
variety of summing-up and assessment activities. 
Students will feel pride in their accomplishments 
after a pair of high-pressure simulations, a fast-
paced quiz game, and finally, a reprise of the 
writing activity in Unit 1. The appendix to this 
unit provides materials from an intensive, 
communitywide simulation developed by Vermont 
teacher Sean Cox and adapted with his permission. 
You can use these materials to enrich your 
students experience of Lesson 6.2.

Students who have developed relationships with 
people responsible for emergency preparedness 
will particularly enjoy the opportunity to role-play 
in the first two lessons. In the first they will enact 
a meeting of a crisis team charged with developing 
a comprehensive local earthquake preparedness 
plan. In the second, Earthquake Simulation, they 
will put that plan into practice.

How much your students and your community 
benefit from Lesson 2, in particular, depends on 
how much you and they have invested in the 
curriculum up to this point. With the full 
involvement of community disaster officials and at a 
locale outside the school, this activity can be 
incredibly realistic and dramatic, as the experience of 
Sean Cox and his community makes clear.

After the excitement of Lesson 2, students will 
welcome the purely intellectual stimulation of 
Lesson 3, Test Your E.Q. I.Q. The questions are 
designed to test attitudes as well as information, and 
to reinforce knowledge by repetition.
Both you and your students will be pleased to see 
how much information they can add to their Unit 1 
compositions in the final postassessment activity. 
This process reinforces essential writing and thinking 
skills.

Now that students have completed this series of 
lessons, encourage them to continue to read and write 
about earthquakes and disaster preparedness. Some 
of the topics that have been introduced in these units 
may lead to science projects, college majors in 
related topics, and future careers. The information 
students have gained may even save their lives.

6.1 Preparing for the Worst: 
A Simulation

RATIONALE
When natural disasters occur, many communities are totally unprepared because 
they lack a comprehensive emergency management 
program. Coordinated planning is essential if the stricken community 
is to return to a normal state of affairs.

FOCUS QUESTIONS
What kind of plans need to be in place to serve a community in the 
event of a natural disaster?

OBJECTIVES
Students will:
1. Recognize the importance of advance planning for a communitys 
emergency response.
2. Simulate the development of a community emergency plan for 
preparing for, responding to, and recovering from a natural disaster.

MATERIALS
 Transparency made from Master 6.1a, Edenton Map and Profile
 Transparency made from back of Master 6.1a, Edenton Map and 
Profile
 Overhead projector
 Student copies of Master 6.1a, Edenton Map and Profile (2 sides)
 Master 1.3a, Preparedness People (from Unit 1)
 Master 6.lb, Planning Roles (optional, for reference only)
 Self-adhesive name tags, one for each student
 Transparency made from Master 6.1c, Phases of an Effective 
 Management Plan
 Transparency markers in four colors

PROCEDURE

TEACHING CLUES AND CUES
In most parts of the country, there has not been any significant 
effort to coordinate community resources to respond to a 
major civic emergency like an earthquake. This planning scenario 
is intended to address an emergency resulting from an earthquake, but the 
process will yield procedures for dealing with other kinds of disasters 
as well.

A. Introduction
Begin by asking students what they would do if an earthquake struck 
the area where their school is located. Help them to recognize that the 
most important immediate response is not to panic and to seek cover 
as quickly as possible. The most available cover in the classroom is 
the protection offered by the desks and tables the students are using, 
so drop, cover, and hold is the first response. If you have not done 
so recently, conduct a drop-and-cover drill now, using the instructions 
in Unit 5, Lesson 2.
Now expand the discussion to determine what students think would 
happen in their community if the earthquake was powerful enough to 
cause both loss of life and major property damage.

 How would the community respond?

 Who would be in charge of managing the rescue operation?

 Who would be in charge of long-term recovery?

 What plans are already in place to assure that the emergency would 
be responsibly managed?

B. Lesson Development
1. Explain the purpose of the simulation and tell students that they 
will be playing the roles of community leaders charged with 
developing an outline for emergency management in the event of a 
disaster resulting from a natural or human-made hazard. They are 
meeting to develop a system to manage the effects of an emergency, 
preserve life and minimize damage, provide necessary assistance, and 
establish a recovery system in order to return the city to its normal 
state of affairs as quickly as possible. Their plan must define clearly 
who does what, when, where, and in what order to deal with the 
community crisis.

Each student will adopt the role that she or he began learning about in 
Lesson 3 of Unit 1. For this activity, however, they are citizens of 
Edenton, a mid-size city located in an area of moderate risk for 
earthquake activity. In the late summer and fall, brush and forest fires 
also pose a threat to the community. Other disaster situations could 
develop from terrorism, civil disorder, a major transportation accident 
like a bus or train wreck, or an accident involving the release of 
hazardous materials. When the emergency exceeds the local 
governments capability to respond, city officials may also call on 
state and federal governments for assistance.

2. Project the back of Master 6.1a, Edenton Map and Profile, and go 
over the information with the class. Then project the map. Distribute 
copies of both sides for students reference.

3. Direct students attention to the map of Edenton on Master 6.la. On 
the basis of the information provided, and other knowledge of the 
community they have gained from the profile, ask students to identify
all of the following. (The student who is playing the role of city 
manager will mark the transparency as indicated, using a different 
color for each type of information.)
a. at least one area where you could expect landslides, liquefaction 
failures, and/or fault ruptures. (These areas should be outlined and 
numbered.)
b. at least two groups of blocks where you could expect concentrated 
building damage. Include at least one commercial and one residential 
block group. (These areas should also be outlined and numbered, and 
may be referred to as Concentrated Damage Area 1,2,3, and so forth.)
c. major facilities, such as hospitals, schools, government buildings, 
and high rise buildings that might be rendered at least temporarily 
unusable by an earthquake or other natural disaster.
d. highway overpasses, roads, and other transportation facilities that 
might collapse or be left impassable by an earthquake.

TEACHING CLUES AND CUES
Be sure students understand that the lines they draw around these areas 
are only rough indications. In reality, each would be 
surrounded by a zone of influence, in which repercussions would also be 
felt.
 
Students may choose whether to work in committees for part of 
the planning period or to remain in one group.

4. As a review, and to focus students on the roles they have been 
learning about, ask each to prepare a brief job description. Have 
students exchange their job descriptions with each other and ask and 
answer questions until they are clear about the functions and 
responsibilities of each. Master 6.lb contains some sample job 
descriptions for your reference.

5. Once roles have been reviewed and job descriptions written, project 
Master 6.1c, Phases of an Effective Management Plan. Have the city 
manager convene the Edenton Emergency Management Planning 
Committee and call the meeting to order.

6. Students will work together to develop a plan. The city manager, 
referring to the Phases transparency, will remind the group that every 
plan must have three parts:
a. Before: preparations to be made before an emergency strikes, such 
as purchasing safety equipment, upgrading building codes, and 
educating the public.
b. During: strategies for emergency response during an earthquake or 
other crisis. Lines of communication will be particularly critical in 
this phase.
c. After: recovery plans for returning the community to conditions as 
normal as possible.

7. When the group has completed its emergency management plan, 
provide time for students to report the details of their plan. Help them 
to evaluate their plan by asking these questions:

 Is the plan realistic and timely?

 Is it comprehensive?

 Is it cost-effective?

Do we have the resources to implement it? If not, how might we 
obtain additional resources?

C. Conclusion
Ask each student to augment her or his written job description with 
any particular responsibilities that will develop during a community 
crisis. Tell students that in the next activity they will have a chance to 
implement their plan. If questions arose in the planning process about 
how their city would function in an emergency, encourage students to 
contact their mentors before the next class meeting.

6.1a Edenton Map 

6.1a Edenton Profile

Edenton, the county seat of Belle County, has a population of 150,000. The 
county itself has 300,000 citizens. As 
Belle Countys only city, Edenton is the focal point of almost all services and 
activities. Its economy depends on a 
railroad repair facility operated by Amtrak and a large pharmaceutical 
manufacturing plant. These two operations 
are the citys largest employers. Because of its pleasant climate year round, 
its easy accessibility by interstate 
highways from all parts of the state, and a landscape that invites hunting, 
fishing, hiking, cycling, and camping, 
tourism in recent years has become an increasingly important part of the local 
economy.

Vital Statistics
Population150,000
Schools
    8 elementary schools
    4 middle schools
    2 high schools
    1 community college
Communications
    3 AM stations
    1 FM station
    1 television station
    1 daily newspaper (The Lark)
Hospitals2 (Mercy Hospital is a trauma center)
Police Department150 officers/20 civilian 
employees
Fire Department50 firefighters/10 civilian 
employees
Recreational System
    8 city parks
    3 swimming pools
    4 fieldhouses
    1 golf course
Houses of Worship24
Airport1 (within city limits; single runway; 
provides jet service)
Railroadsservice by Amtrak
Highways2 interstates converge five miles north 
of the city
Hotels2 in center city, Motels20, most in the 
areas served by the interstates
LibrariesMain library with 8 neighborhood 
branches (all single-story buildings)
Day Care Centers10 licensed facilities
Nursing Homes4
Retirement Communities2
Mobile Home Parks3
Shopping Malls2
Power Plants1 (oil/gas)
Water SupplyAqueducts, pipelines, 2 pumping 
stations, 2 water treatment plants

6.1b Planning Roles

Chief of Police
The police chief is responsible for protecting lives and 
property in the area he serves. Specific responsibilities 
include preserving the peace, preventing criminal acts, 
enforcing the law, and arresting violators. The chief is 
under oath to uphold the law 24 hours a day. He or she 
makes many of the final decisions dealing with budgets 
and services provided by the police force.

Fire Chief
This official is responsible for protecting lives and 
property from the hazards of fire. Responsibilities include 
fighting fires, rescuing trapped individuals, conducting 
safety inspections, and conducting fire drills and fire 
safety education. The fire chief also assists in other types 
of emergencies and disasters in community life. He or she 
makes many of the final decisions dealing with budgets 
and services provided by the fire department. The fire 
chief usually comes through the ranks, starting as a 
firefighter.

Director of Public Works
This official is responsible for the maintenance of systems 
built at public expense for the common good, such as 
highways and dams. In some communities these 
responsibilities may be dealt with separately by officials 
responsible for highway safety and community 
transportation services, water and sewage, and other areas; 
in some, they may be combined in one office.

Director of Public Health
This official, usually a physician, is responsible for 
controlling the spread of communicable disease in the 
community and for mitigating any threats to the public 
safety, such as the contamination of public water supplies. 
He or she also engages in proactive education and 
advocacy to encourage positive behaviors, such as proper 
nutrition, and discourage negative ones, such as smoking 
and the abuse of alcohol and other drugs.

Coordinator of Community Transportation Services
This official is responsible for the safety of public 
transportation and both public and private vehicles. He or 
she arranges for registration, licensing, and state 
inspections. The coordinator inspects public vehicles and 
coordinates operation and maintenance of equipment, 
storage facilities, and repair facilities. She or he directs 
the recording of expenses and controls, purchasing and 
repair spending. This official also helps plan and direct 
transportation safety activities.

Public Information Officer
This official supervises a staff of public relations workers, 
directs publicity programs designed to inform the public, 
and directs information to appropriate groups. He or she 
clarifies the local governments points of view on 
important issues to community or public interest groups 
and responds to requests for information from news 
media, special interest groups, and the general public. In 
an emergency, this function assumes added importance.

Superintendent of Schools
This official is responsible for managing the affairs of an 
entire public school district. He or she oversees and 
coordinates the activities of all the schools in the district 
in accordance with standards set by the board of 
education. Responsibilities include selecting and hiring 
staff, negotiating contracts with union employees, and 
settling labor disputes. He or she creates and implements 
plans and policies for educational programs, and, when 
necessary, interprets the school systems programs and 
policies. The superintendent is also responsible for the 
development and administration of a budget, the 
maintenance of school buildings, and the purchase and 
distribution of school supplies and equipment, and 
oversees the schools transportation system and health 
services.

City Manager or Mayor
This professional in public administration has general 
responsibility for the overall operation of the city. All 
department heads answer to this official, who serves as the 
citys chief executive officer. A city manager is hired by 
the city council and serves at its discretion. A mayor is 
elected by the voters, but holds many of the same 
responsibilities.

Members of the City Council (as needed)
Each member determines the needs of the ward or district 
he or she represents by seeking out interviews, responding 
to constituents phone calls and letters, and referring 
persons to specific agencies for services. The member 
speaks before neighborhood groups to establish 
communication and rapport between the members of the 
community and the service agencies available. The 
members of the council also have the responsibility to 
help resolve problems facing the community at large, in 
such areas as housing, urban renewal, education, welfare, 
unemployment, disaster response, and crime prevention.

6.1c Phases of an Effective Management Plan

6.2  Simulation: 
Putting Plans Into Action

RATIONALE
Most emergency preparedness plans are never put into effect. In this 
activity students will have a chance to test the plans they have made, 
while also testing their own localitys state of emergency 
preparedness. By the end of this session, students should have a good 
geographic sense of their community and some understanding of how 
the rest of the community will react to emergencies.

FOCUS QUESTIONS
How current, comprehensive, and effective are your communitys 
emergency preparedness plans?

OBJECTIVES
Students will:
1. Understand how a community government works and how it 
responds to emergencies.
2. Evaluate their localitys earthquake emergency preparedness plans.
3. Suggest changes in the existing emergency preparedness plan to 
reflect what has been learned.
4. Develop a personal earthquake emergency response.

MATERIALS
 Master 6.2a, Disaster Script
 Classroom community map (from Unit 1)

PROCEDURE
Teacher Preparation
Secure the cooperation of at least some of the mentors who have been 
working with your students throughout this curriculum. If possible, 
arrange for a place outside of school, such as a city government 
building, where students can conduct this simulation. Work with the 
mentors to develop a disaster script, using Master 6.2a as a
beginning. Arrange to have at least one emergency preparedness 
official in attendance for this exercise and the debriefing that follows.
If your class has developed the community map they began in Unit 1, they 
will have a strong sense of their own communitys physical and social 
arrangements. If not, you may want to work with the class to prepare a 
community profile similar to the Edenton Profile in Lesson 1 of this unit.

TEACHING CLUES AND CUES
This activity can be as elaborate as you choose to make it. You may 
want to set aside a half day, or even a full day.
 
The appendix that follows this unit is a report of an actual teacher-
planned community earthquake preparedness drill. This 
is incorporated as a framework to use in constructing such an activity 
for your community.

A. Introduction
Tell students that in this last unit of the Seismic Sleuths curriculum 
they will have a chance to draw on all that they have learned. Agree 
on a place to serve as the emergency command center. This may be a 
room at city hall, if you have made previous arrangements; your 
school auditorium, or a circle of chairs in the front of your own 
classroom. The community map will be the focal point of this area.

B. Lesson Development
1. Have the student who is playing the role of mayor or city manager 
convene a meeting of the preparedness council established in the last 
lesson. The purpose of this meeting is to discuss the budget of each 
department and clarify each administrators role in an emergency. 
Focus on the lines of communication and each persons response to 
specific emergency situations (major fire, tornado, flood, earthquake, 
chemical plant disaster, etc.focus on those most likely in your 
community). Whoever conducts the meeting will use the large 
community map to plot where each persons main area of interest lies 
and what geographic areas are essential to maintaining the continuity 
of essential services, such as water treatment, sewage treatment, and 
electrical power.

2. After 10 minutes or more, when the main points have been 
reviewed, but without warning, tell the students that an earthquake is 
occurring. Conduct a drop, cover, and hold drill, following the 
instructions in Unit 5, Lesson 2. Immediately after the drill, begin 
reading the script. Explain the time frame of the exercise. Students 
should then begin to take control of the situation and implement their 
emergency plans.

C. Conclusion
At the next class meeting, set aside some time for a debriefing and 
evaluation. Give students class time to write thank-you letters to their 
mentors and other members of the community who participated in this 
exercise and/or in earlier lessons. Mail the letters from school.

ADAPTATIONS AND EXTENSIONS
1. Encourage students who have shown particular interest to maintain 
contact with their mentors, perhaps through volunteer work, a part-
time job, or a request for career information. This association may 
inspire some students choice of a career.

2. Write your own letters of appreciation to any community helpers 
who have not worked directly with individual students. With 
encouragement, some of these individuals may maintain an interest in 
the school and become valuable resources for students and faculty.

6.2a Disaster Script

At 10:05 a.m. today, Tuesday, September 26, 1995, a magnitude 7.0 earthquake 
struck the community. At noon, 
the following damage had been reported:
The downtown area was hardest hit. People have reported that most shelves, 
bookcases and display stands were 
knocked over. Masonry structures have sustained major damage, brick facades are 
collapsing, chimneys are 
falling, and some buildings have serious structural cracks. No fatalities have 
yet been reported.

The hospital reports that its three-story gerontology unit has pancaked, 
causing the second and third floors to 
collapse on the first floor. At the time of collapse, 34 persons29 patients and 
5 staff memberswere in that 
part of the building. Other parts of the hospital suffered nonstructural damage, 
some disruption to power, and an 
end to all but lifesaving procedures. The latest information indicates that the 
hospital will be at 50% operational 
capacity by 2:30 this afternoon.

Of the three fire stations, two have stayed operational. The downtown station 
has been destroyed. Fire department 
personnel were able to move only one pumper wagon before the building collapsed 
on the ladder truck, 
ambulance, and emergency generator truck.

This can be changed, embellished, tailored, and expanded for your community and 
your students. Additional 
effects that may be included:
 Large fire has broken out in downtown area
 Water mains are cut
 20% of the population has sustained injuries
 Utility lines are down
 Animals in the zoo have escaped from their cages
 Looters are rampaging through downtown
 Sewers have backed up, endangering public health

6.3 Whats Your E.Q. I.Q.?

TEACHING CLUES AND CUES
Students may enjoy competing in the teams they established for the 
unit 4 activities (SETs).

RATIONALE
Students will review and solidify what they have learned in the 
preceding units by answering questions in cooperative teams.

FOCUS QUESTIONS
How well can students recall and apply what they have learned?

OBJECTIVES
Students will:
1. Ask and answer questions about earthquakes and earthquake 
preparedness.
2. Keep score.
3. Learn from incorrect responses as well as correct ones.

MATERIALS
 Master 6.3a, Earthquake Review Questions
 Back of Master 6.3a, Answer Key
 Minute timer
 Chalkboard and chalk for recording the score
 Tag board and laminating materials (optional)

PROCEDURE
Teacher Preparation
Copy Master 6.3a and cut the pages apart into cards. You may want to 
back them on tag board and/or laminate them for durability.

A. Introduction
Divide the class into teams of four or five students each and give each 
team a number or a name.
Give groups about 15 minutes to review the earthquake materials in 
their notebooks and ask each other questions as a warm-up.

B. Lesson Development
1. Call two teams at a time to the front of the room. Instruct students 
to arrange chairs in two rows facing each other. Hand the deck of 
question cards to one team. For the first round, this team will ask and 
the other team will answer.

2. Asking and answering both begin with the student on the left. The 
first asker reads a question out loud and starts the timer. The first 
student on the opposing team tries to answer it. If that student cannot 
answer the question, play passes to the second student on the same 
team, then to the third, if necessary, and so on until one minute is up. 
The questioning team keeps score, tallying one point for each correct 
answer.

3. When any member of the team that is up answers incorrectly, play 
passes to the other team and the roles are reversed. When a member of 
the second team answers incorrectly, call two new teams to the front 
of the room.

TEACHING CLUES AND CUES
When all the cards have been used once, shuffle them and begin again. 
Repetition reinforces learning.

C. Conclusion
When all the teams have had a chance to play, the team with the 
highest score may challenge any other team to a new round. If another 
team exceeds their score, they become the new challengers. The team 
with the highest score at the end of the period wins.

ADAPTATIONS AND EXTENSIONS
Invite students, to write questions and answers of their own to add to 
the deck. Be sure that all members of a group agree on the answer and 
the phrasing of the question before the card is put into play.

6.3a Earthquake Review Questions
 
1. According to geologic studies, approximately how 
old is the Earth?

[a]	2 thousand years
[b]	7 thousand years
[c]	2 million years
[d]	4.54 billion years
 
2. All of the following people made major 
contributions to our knowledge of the Earths physical 
history and structure except:

[a]	Alfred Wegener
[b]	Inge Lehmann
[c]	Anna Maria Alberghetti
[d]	Andrija Mohoroviic

3. Earthquakes are caused by:

[a]	strain energy that builds up and is suddenly 
released
[b]	tides
[c]	bad vibrations
[d]	the Richter scale

4. Approximately how many earthquakes large enough 
to be rated significant by the U.S. Geological Survey 
occur worldwide during a calendar year?

[a]	More than 20
[b]	More than 100
[c]	More than 1000
[d]	More than 15,000

5. Although earthquakes occur almost everywhere, 
strong, damaging quakes are especially common in 
the:

[a]	Eastern United States
[b]	Pacific Ring of Fire
[c]	Mediterranean Region
[d]	Great African Rift
 
6. Which of these statements best describes the 
relationship between earthquakes and volcanoes?

[a]	Earthquakes cause volcanoes.
[b]	Volcanoes cause earthquakes.
[c]	Volcanoes and earthquakes both occur along the 
margins of Earths tectonic plates.
[d]	Volcanoes only occur in hot countries.
 
7. Scientists can accurately predict earthquakes in the 
short range by studying:

[a]	the behavior of animals
[b]	changes in radon emissions
[c]	Rayleigh waves
[d]	none of the above
 
8. The Richter scale measures an earthquakes:

[a]	magnitude
[b]	amplitude
[c]	pulchritude
[d]	intensity

Answer Key

 
1 b
 
2 c
 
3 d
 
4 a
 
5 d
 
6 c
 
7 a
 
8 d

9. How much greater is the amount of energy released 
by a magnitude 7 earthquake than the amount released 
by a magnitude 6 quake?

[a]	twice as great
[b]	10 times as great
[c]	about 30 times as great
[d]	100 times as great
 
10. The method architects and structural engineers use 
to quickly assess a buildings earthquake resistance is 
called:

[a]	eyeballing
[b]	sedimentation
[c]	rapid visual screening
[d]	estimating

11. The earthquake waves that are the first to arrive at 
the epicenter are called:

[a]	P waves
[b]	A waves
[c]	First waves
[d]	Love waves

12. About how long does the violent shaking last in a 
typical earthquake?

[a]	20 seconds
[b]	one minute
[c]	five minutes
[d]	30 minutes

13. In which one of these states are strong and 
potentially damaging earthquakes relatively frequent?

[a]	Texas
[b]	Florida
[c]	Wisconsin
[d]	Alaska
 
14. If a strong earthquake struck while you were 
inside a building, what would you do to protect 
yourself?

[a]	run outside
[b]	dial 911
[c]	drop, cover, and hold
[d]	freeze
 
15. How much damage a building suffers in an 
earthquake depends upon:

[a]	how close it is to the fault
[b]	what it is build of and how it is built
[c]	what kind of soil it is built on
[d]	all three
 
16. To make a room safer in an earthquake, you 
would:

[a]	fasten all unsecured heavy objects
[b]	remove all pets
[c]	turn on the radio
[d]	lock the doors and windows

Answer Key
 
9 d
 
10 c
 
11 d
 
12 a
 
13 c
 
14 c
 
15 a
 
16 a

17. A break in the Earths crust along which 
earthquake movement has occurred is called:

[a]	a gap
[b]	a fault
[c]	an epicenter
[d]	an isoseismal
 
18. A gigantic ocean wave caused by an earthquake is 
called:

[a]	a samurai
[b]	a sand boil
[c]	a tsunami
[d]	a surface wave

19. All of the following are structural elements 
except:

[a]	windows
[b]	bearing walls
[c]	braces
[d]	horizontal beams

20. All of the following are good sources of 
earthquake information except:

[a]	United States Geological Survey
[b]	The National Enquirer
[c]	Federal Emergency Management Agency
[d]	National Earthquake Prediction Evaluation 
Council
 
21. Resonance is buildup of amplitude in a physical 
system that occurs when the frequency of an applied 
oscillatory force is close to the natural frequency of 
the system.

[a]	true
[b]	false
[c]	sometimes
[d]	dont know
 
Answer Key
 
17 b
 
18 a
 
19 b
 
20 c
 
21 a
 
6.4 Hey, Look at Me Now!
 
RATIONALE
This activity is designed to serve students and teachers as a gauge of 
what they have learned from this curriculum.

FOCUS QUESTIONS
What have you learned about earthquakes and earthquake 
preparedness?
What will you do differently as a result of these lessons?

OBJECTIVES
Students will correct, elaborate, and refine their earlier writings by 
applying information they have gained from this curriculum.

MATERIALS
 Writing paper and pens or computers and printers

PROCEDURE
A. Introduction
Explain that in this postassessment activity each student is to 
complete the same task he or she did in the preassessment activity. In 
rewriting each of the three passages, however, students are urged to 
draw upon what they have learned from the unit. Remind the students 
to focus on how their new knowledge has changed their way of 
thinking about earthquakes and earthquake preparedness.

B. Lesson Development
As they did in Unit 1, students will invent a specific quake. Each of 
their three accounts will describe the same earthquake, but the styles 
of the three will vary.
New Reportera short, concise article describing the who, what, 
where, why, and when of the earthquake.
Scientista scientific account stating what is objectively known 
about the earthquake: its causes, its Modified Mercalli and Richter 
ratings, and the possibility of aftershocks or more large earthquakes.
Eyewitnessa personal letter to a friend telling about being in an 
earthquake. This will describe what happened during the earthquake 
to the student, the building in which the student was, family members 
and pets, and the family home. Describe what you had done before the 
earthquake to be prepared, how effective your preparations were, and 
what you would do differently in preparation for the next earthquake. 
Also describe what life was like in the two weeks following the 
earthquake.

C. Conclusion
After collecting the papers, pair each students postassessment 
writings with the same students preassessment writings, and hand 
them out to a different student. Assign students the task of reading 
both sets and commenting on what the writer has learned from the 
unit. Follow with a class discussion of these comparisons, either the 
same day or the next.

Books
Davis, James F.; Bennett, John H.; Borchardt, 
Glenn A.; Kahle, James E.; Rice, Salem J.; and Silva, 
Michael A. (1982). Earthquake Planning Scenario for 
a Magnitude 8.3 Earthquake on the San Andreas 
Fault in the San Francisco Bay Area. San Francisco: 
California Department of Conservation, Division of 
Mines and Geology. Although the maps and much of 
the discussion are specific to California, the sections 
on transportation, communications, water and waste, 
electrical power, natural gas, and petroleum fuels 
would be helpful for planning in other areas.

Federal Emergency Management Agency. Central 
City: A Model Community. Integrated Emergency 
Management Course. Emmitsburg, MD: Federal 
Emergency Management Agency, 1988. (SM 171.1)

Plafker, G., and Galloway, J.P., eds. (1990). Lessons 
Learned from the Loma Prieta, California, 
Earthquake of October 17, 1989. (U.S. Geological 
Survey Circular 1045). Reston, VA: U.S. Geological 
Survey, 703-648-6891.

Steinbrugge, Karl V.; Bennett, John H.; Lagorio, 
Henry J.; Davis, James F.; Borchardt, Glenn A.;
and Topozada, Tousson R. (1987). Earthquake 
Planning Scenario for a Magnitude 7.5 Earthquake on 
the Hayward Fault in the San Francisco Bay Area. 
San Francisco: California Department of 
Conservation, Division of Mines and Geology. 
Although the maps and much of the discussion are 
specific to California, the sections on hospitals, 
schools, transportation, communications, water and 
waste, electrical power, natural gas, and petroleum 
fuels would be helpful for planning in other areas.

Watson, R.W.; Poda, J.H.; Miller, C.T.; Rice, E.S.; 
and West, G. (1990) Containing Crisis: A Guide to 
Managing School Emergencies. Bloomington, IN: 
National Educational Service.

Non-Print Media
Silent Quake: Preparedness for the Hearing-Impaired. 
A videotape using American sign language, 
captioning, and voice-overs. Developed by the 
American Red Cross, Los Angeles, CA, available on 
loan from BAREPP, Oakland, CA; 415327-6017.

Note: Inclusion of materials in these resource listings does 
not constitute an endorsement by AGU or FEMA.

Seismic Sleuths

Earthquakes

A Teachers Package for Grades 7-12

Appendix

Earthquake Drill: 
A Critical Skills Exercise

by Sean P. Cox, Teacher 
Salem High School, Salem, New Hampshire

Abstract
Earth science students at Salem High School have participated in an environment 
of critical skills. Events are student 
centered, learning stresses both process and curriculum content, and the 
foundation for activity is problem-solving projects. 
This particular project had students designing and rehearsing part of an 
emergency management plan in response to a 
hypothetical earthquake affecting Salem, NH. Students assumed the roles of town 
officials in a three-hour drill held in 
Salems Emergency Operations Center (EOC). The drill was sponsored by the town 
of Salem and the New Hampshire Office 
of Emergency Management. Project origin, planning, performance, and follow-up 
are detailed in this paper.

Introduction
For seven months students in this class spent more than 100 hours not only 
learning about specific topics in Earth science but 
also learning specific strategies for learning and working together. In March, 
as our plate tectonics unit progressed, the time to 
apply our learning had arrived. A project was designed in cooperation with our 
towns emergency management director and 
the New Hampshire Office of Emergency Management.
In this project students were to design, document, and use a hazard plan to be 
added to Salems Emergency Management Plan 
for earthquake response. Students did extensive research and documentation, 
preparing a plan and also preparing themselves 
to play roles as decision makers in a disaster. The teacher, the emergency 
management director, and Office of Emergency 
Management staff members met and communicated many times to finalize the 
details.

The actual drill, held in Salems Emergency Operations Center (EOC), greatly 
surpassed all expectations. Students handled 
crisis after crisis as part of a three-hour drill that included mass 
destruction, dam failure, utility outages, looting, hospital 
closings, and multiple evacuations. Groups of students rotated through three 
one-hour shifts filling various roles in turn, 
including those of the school superintendent, reporters, and selectmen. There 
was confusion and near hysteria as a myriad of 
details crowded the EOC. Students struggled at times to prioritize and solve 
problems. All the participants and observers 
came away with a new respect for each other and a new appreciation of the need 
to be prepared for the worst.

How It All Began
Teaching in this class proceeds from the philosophy that learning is a very 
complex behavior. Learning is different for each 
individual, and schools need to recognize these differences. Schools also need 
to teach not only the what but also the how 
of learning. With this in mind, these 96 people were provided a student-centered 
environment that made them ultimately 
responsible for their learning both as individuals and as a group. Students 
spent many class periods doing activities that 
provided experience with various learning styles. Projects were used to create 
concrete and abstract opportunities for learners, 
including reading, writing, coordinating, prioritizing, and communicating.

Emphasis is placed on the belief that there are often many viable solutions to a 
problem. For this reason, creativity is strongly 
fostered, as students are urged to produce quality work from their own base of 
knowledge and experience. The teacher is not 
the fountain of knowledge. Students must find their own answers that they can 
support fiercely and intimately. Guidance 
and direction are given in the form of specific teacher questions. As students 
gain experience and comfort completing 
curriculum-based projects in this student-centered class, they begin to take 
more control of their education, needing less 
teacher input. With greater student responsibility, the teachers goal is to 
balance content and process so that each remains 
equally valued in learning.

Earthquake in Salem, NH
So why dabble with earthquakes, not to mention the towns Emergency Management 
Plan? Because high school students are 
interested in earthquakes. Earthquakes are unpredictable, damaging, and loud
characteristics admired and even shared by 
many teenagers. Moreover, the teachers saw a need for earthquake education, 
preparedness, and response within the 
community.

In preparation for this major project, classes throughout the year dealt with 
process strategies and critical skills. Skills 
including decision making, problem solving, communication, cooperation, and 
documentation were addressed, rehearsed, 
refined, and incorporated into our classes. Additionally, students carried out 
many short-term projects in the field of plate 
tectonics and seismology. Specifically, students researched, modeled, and 
demonstrated types of seismic waves, seismic 
forecasting, hazard assessment, and New Englands seismic history.

The next step in the project involved a contact with the person in Salem 
responsible for emergency management. The teacher 
had to determine if the anticipated needs existed and whether or not direct 
community involvement was possible. Salems fire 
chief, who also serves as its emergency management director, acknowledged a void 
in the towns disaster response and was 
completely open to student input and community cooperation. As the teacher and 
the director discussed their needs, the 
project evolved into what they hoped would be a truly meaningful experience. 
Ninety-six of Salems teenagers might 
permanently and positively affect their community.

The teacher expressed the following goals:
A. Students will develop and implement a solution with an educational component 
to a real problem in our community. They 
will:
	1. do community-based research
	2. incorporate many information-gathering techniques
	3. use a maximum number of resources
	4. use preexisting models and/or plans where appropriate

B. Students will select, implement, and refine certain process skills, such as 
decision making, problem solving, 
communication, cooperation, and documentation.

C. Students will be able to describe all major theories on plate tectonics as 
well as how those theories relate to earthquakes.

D. Students will be able to describe New Englands earthquake history and its 
susceptibility to future seismic activity.

E. The adults will empower students to come up with their own plan in an open 
environment with a minimum of restrictions.

Planning, Planning, and More Planning
The director suggested a drill that would test the students solutions as a way 
of summing up and evaluating the project. This 
drill would not only satisfy the teachers desire to test students, but also 
provide a rehearsal of the towns Emergency 
Management Plan. The teacher and the director outlined the towns need for a 
hazard plan and discussed the specific ways in 
which students might meet that need. A time and date for the drill were set, and 
a letter to the students was drafted, 
recognizing their recent experiences in these areas and requesting their aid.

The next task was kicking off this 15-day extravaganza by arranging for expert 
speakers to come into the school. Issues 
discussed included seismology, engineering, hazard assessment, emergency 
response planning, and plan implementation. All 
of our guest experts graciously supplied printed materials to supplement their 
presentations.

On kick-off day, the educators and the experts decided students needed 
additional guidelines to properly design a hazard plan. 
The design of the plan was separated into five areascommunication, evacuation, 
hazard assessment, private resources, and 
public resources. As the first few days passed, students struggled to prioritize 
the components of the problem and divide up 
responsibilities. The teacher carefully guided students by questioning them and 
challenging them to use skills and knowledge 
they had already developed.

Meanwhile, the director scripted the drill, provided the teacher with the roles 
and titles students would assume during the drill 
(see list below), and secured access to a wide variety of resources. The 
resources included a college text, Federal Emergency 
Management Agency (FEMA) pamphlets, and a blank hazard plan illustrating plan 
design. Also made available were the 
telephone numbers of the towns department heads and of state and regional 
emergency management personnel, and lastly, the 
most precious resource of all, personal attention and dedication. The New 
Hampshire Office of Emergency Management and 
its natural hazards program specialist also provided generous amounts of both 
time and materials.

EOC Town Officials and Staff Roles

TOWN OFFICIALS
Chairman, Board of Selectmen
Members, Board of Selectmen (4)
Town Manager
Emergency Management Director
Fire Chief
Police Chief
Public Works Director
Health Officer
Chief Building Inspector
Director of Human Resources (Welfare)
American Red Cross Director
Superintendent of Schools

EOC STAFF
Message Loggers (2)
Message Runners (2)
Updater, Status Board (1)
Radio Communications (2)
EOC Security (2)
EOC Logistics (2)
Public Information Officer
Reporters (3)

As the project continued, the teacher noticed an ever-increasing level of 
student anxiety and misdirection. Therefore, the 
teacher and the director arranged for a debriefing of the projects progress. 
The students presented their ideas and findings to 
a panel consisting of the director, educators, and the New Hampshire natural 
hazards specialist. The panel was able to give 
students valuable feedback on their plans strengths and weaknesses. This day-
long debriefing also allowed students a chance 
to look at the project from a critical point of view, breathing new life into 
their design and implementation efforts.

At the beginning of the second week, the teacher finalized student sign-up for 
the roles they were to assume in a three-shift 
rotation. Each student selected (1) a decision making role, where he or she 
would play an active part in the Emergency 
Operations Center (EOC), and (2) an EOC staff role or a role with rescue 
equipment and media presentations. Each student 
also had to identify one shift during which to start a journal, recording not 
only observations of the drills varied actions and 
reactions, but also an introspective analysis of the projects progression from 
start to finish.

The director coordinated the attendance of the towns department heads, the 
school superintendent, the American Red Cross 
representative, a utility company representative, and the media, as well as 
state and regional emergency management officials. 
The director and the teacher finalized details and made arrangements for 
physically disabled and motivationally disabled 
students, school and community rules implementation, lunch, and debriefing.

Its D-Day!
At 8:30 a.m. on D-Day (Drill Day), students anxiously gathered materials and 
boarded the bus to Salems EOC, not knowing 
quite what to expect. Upon arrival at the Main Street fire station housing the 
EOC, students heard building rules and 
consequences, dropped off their coats, and positioned themselves for the first 
shift of the drill. With Salems youth in place as 
fire and police chiefs, building inspector, school superintendent, radio 
operator, message runners, EOC security, and 
newspaper reporters, the EOC opened and the drill began.

The script for the day explained that the EOC had been opened in response to an 
earthquake at 7:50 a.m., measuring 7.5 on 
the Richter scale and centered in nearby Hudson, NH. With Salems adult 
department heads as advisors, students enacted 
their plan, prioritizing needs, communicating with counterparts, and solving 
problems, all while using the towns minimal 
remaining resources as judiciously as possible.

An excerpt from the drill script details the crisis students were reacting to.

SHIFT CHANGESTATUS REPORT
It is now 8:00 am (the second morning).

During the night, the public works department began repairs on the known broken 
water mains. The water towers are back up 
to capacity, but water service is provided to only a small portion of the town 
(Main St./Depot area and Lawrence Rd./Cluff 
Rd. area).

The sewer system is completely out of service and sewerage is beginning to leak 
into some streams and onto roads. All power 
in town went out for most of the night and is beginning to come on in sections. 
Cable TV is still out. The cracks in the dam at 
Arlington Pond appear to be worsening.

The evacuation center has housed approximately 200 people who are in need of 
food.

The Police Department spent a long night dispersing looters and making arrests. 
Approximately 20 people are in custody.

The Fire Department responded to several building collapses, two house fires, 
numerous downed power lines, and 15 
ambulance calls. Most of the patients were taken to a temporary first aid 
station.

Two relatively minor aftershocks were felt during the night.

Decisions are made, aid is rendered, and nerves are wracked as each shift 
struggles with a seemingly endless onslaught of 
high-priority problems. At times, the EOC becomes a jumble of noise and 
confusion. Internal communication deteriorates and 
priorities temporarily blur. Selectmen try to solicit information from the 
building inspector, only to find him tied up with both 
the public works director and the health official. Finally, the emergency 
management director shouts for order, quieting the 
din and returning the EOC to a semblance of organization. After 180 minutes, 
simulating 24 hours of emergency responses 
highlighted by a telephone call from the Director of FEMA, Mr. Stickney, the 
drill concludes with a press conference.

As we await the arrival of lunch, all participants are relieved, excited, 
exhausted, and slightly saddened to know the project 
has reached its end. Students share the disasters and the responses of each 
shift. Some write feverishly in their journals, not 
wanting to forget a single moment. As the 30 pizzas arrive, students and staff 
alike enjoy a carefree lunch and conversation.

With lunch cleared away, the group assembles for the anticipated critique and 
debriefing. Town and state emergency 
management officials have many kind words for the students, followed by praise 
from Salems emergency management 
director and the teacher. In spite of the positive input, students decide that 
their hazard plan can be improved, and request 
permission to keep the document for that purpose.

At 1:15 p.m., the students, document in hand, say their good-byes and their 
thanks as the teachers and directors shake hands. 
After a short ride, the once and future emergency managers are back in school, 
heading off to their last-period class. These 96 
young teens have had the experience of a lifetime, gaining a priceless 
perspective on their community and themselves.

Project Strengths and Weaknesses
The success of the project far exceeded all expectations. Students were able to 
not only synthesize a plan for dealing with a 
natural disaster, but also put their plan into action. There were some areas of 
concern, however.

Even though the plan allotted 15 decision-making roles, representing town 
officials, and another 15 staff roles in the EOC, 
there were, several students who had to double up in order to participate in the 
EOCs operation. The EOC was always 
overcrowded with students, adult advisors, state and regional observers, and 
media.

The strengths were numerous. This activity was truly student centered. Students 
took the initiative in researching and 
preparing the plan, several times even meeting after school and on weekends. 
Additionally, students had to make dozens of 
community contacts to gather materials and information. There was a rush of 
positive public relations for both the school and 
the town of Salem. Print media from Lawrence, MA, and Salem, NH, as well as TV 
news from Manchester, NH, covered the 
drill. Most satisfying to the teacher, the students ended the experience still 
wanting to do more, as they communicated through 
their lengthy and detailed journals.

Earthquake Glossary

Aftershockan earthquake that follows a larger 
earthquake, or main shock, usually originating along 
the same fault as the main shock.

Amplitudea measurement of the energy of a wave. 
Amplitude is the displacement of the medium from 
zero or the height of a wave crest or trough from a 
zero point.

Body waveswaves that move through the body 
(rather than the surface) of the Earth. P waves and S 
waves are body waves.

Braces or Bracingstructural elements built into a 
wall to add strength. These may be made of various 
materials and connected to the building and each other 
in various ways. Their ability to withstand stress 
depends on the characteristics of the materials and 
how they are connected.

Canopya covered area that extends from the wall of 
a building, protecting an entrance.

Cantilevera beam, girder, or other structural 
member which projects beyond its supporting wall or 
column.

Cartographera map maker.

Claddingan external covering or skin applied to a 
structure for aesthetic or protective purposes.

Cornicethe exterior trim of a structure at the 
meeting of the roof and wall.

Compressionsqueezing, being made to occupy less 
space. P waves are called compressional waves 
because they consist of alternating compressions and 
dilations, or expansions.

Consolidatedtightly packed, composed of particles 
that are not easily separated.

Continental driftthe theory, first advanced by 
Alfred Wegener, that Earths continents were 
originally one land mass, pieces of which split off and 
gradually migrated to form the continents we know.

Diagonal bracesstructural elements that connect 
diagonal joints. These braces may be made of solid 
materials or flexible materials. How they function 
depends on what they are made of and how they are 
connected.

Durationthe length of time that ground motion at a 
given site shows certain characteristics. Most 
earthquakes have a duration of less than one minute, in 
terms of human perceptions, but waves from a large 
earthquake can travel around the world for hours.

Earthquakea sudden shaking of the ground caused 
by the passage of seismic waves. These waves are 
caused by the release of energy stored in the Earths 
crust.

Earthquake hazardany geological or structural 
response to an earthquake that poses a threat to human 
beings and their environments.

Elevationin architecture, a flat scale drawing of one 
side of a building.

Epicenterthe point on Earths surface directly 
above the location (focus) of the earthquake below the 
surface.

Epitaphan inscription on a tombstone, often 
intended to sum up the achievements of a persons life.

Faulta break or fracture in Earths crust along 
which movement has taken place.

Focus (pl. foci)the point within the Earth that is the 
origin of an earthquake, where stored energy is first 
released as wave energy.

Forcethe cause or agent that puts an object at rest 
into motion or affects the motion of a moving object. 
On Earth, gravity is a vertical force; earthquake 
shaking includes both horizontal and vertical forces.

Foreshockan earthquake that precedes a larger 
earthquake, or main shock, usually originating along 
the same fault as the main shock.

Frictionmechanical resistance to the motion of 
objects or bodies that touch.

Frequencythe rate at which a motion repeats, or 
oscillates. The frequency of a motion is directly 
related to the energy of oscillation. In this context, 
frequency is the number of oscillations in an 
earthquake wave that occur each second. In 
earthquake engineering, frequency is the rate at which 
the top of a building sways.

Generalizationa statement made after observing 
occurrences that seem to repeat and to be related.

Glazingglass surface.

Gravitythe force of attraction between any two 
objects with mass. Gravity is especially noticeable 
when an object of great mass, such as Earth, attracts 
an object of lesser mass.

Ground watersubsurface or underground water.

Hazardan object or situation that holds the 
possibility of injury or damage.

Hertz (Hz)the unit of measurement for frequency, 
as recorded in cycles per second. When these rates are 
very large, the prefixes kilo or mega are used. A 
kilohertz (kHz) is a frequency of 1,000 cycles per 
second and a megahertz (MHz) is a frequency of 
1,000,000 cycles per second.

Horizontal loadthe sum of horizontal forces (shear 
forces) acting on the elements of a structure.

Index fossila fossil that, because its approximate 
date is known, allows scientists to determine the age 
of the rock in which it is imbedded.

Infilla construction method that starts with a 
structural steel or reinforced concrete frame and fills 
the empty spaces between structural elements with 
brick or hollow concrete block.

Intensitya subjective measure of the amount of 
ground shaking an earthquake produces at a particular 
site, based on human observations of the effect on 
human structures and geologic features. The Modified 
Mercalli Intensity scale uses Roman numerals from I 
to XII.

Isoseismal linea line on a map that encloses areas 
of equal earthquake intensity.

Jointa break or fracture in the Earths crust along 
which movement has not taken place.

Joiststhe parallel planks or beams that hold up the 
planks of a floor or the laths of a ceiling.

Lag timethe difference between the arrival time of 
P waves (Tp) and S waves (Ts).

Landfilla site where soil has been deposited by 
artificial meansoften, where garbage or rubbish has 
been disposed of, then covered with dirt and 
compacted.

Landslidean abrupt movement of soil and bedrock 
downhill in response to gravity. Landslides can be 
triggered by an earthquake or other natural causes.

Latitudethe location of a point north or south of the 
equator, expressed in degrees and minutes. Latitude is 
shown on a map or globe as east-west lines parallel to 
the equator.

Lifelinea service that is vital to the life of a 
community. Major lifelines include transportation 
systems, communication systems, water supply lines, 
electric power lines, and petroleum or natural gas 
pipelines.

Liquefactionthe process in which a solid (soil) 
takes on the characteristics of a liquid as a result of an 
increase in pore pressure and a reduction in stress.

Loadthe sum of vertical force (gravity) and 
horizontal forces (shear forces) acting on the mass of a 
structure. The overall load is further broken down into 
the loads of the various parts of the building. Different 
parts of a building are designed and constructed to 
carry different loads.

Load paththe path a load or force takes through the 
structural elements of a building.

Loessan unstratified, windblown mixture of clay, 
sand, and organic matter, usually crumbly and buff or 
yellow-brown in color.

Longitudethe location of a point east or west of the 
prime meridian, expressed in degrees and minutes. 
Longitude is shown on a map or globe as north-south 
lines left and right of the prime meridian, which 
passes through Greenwich, England.

Longitudinal wavesp-waves. This term is used to 
emphasize that p-waves move particles back and forth 
in the same line as the direction of the wave.

Love wavessurface waves that move in a back and 
forth horizontal motion.

Magnitudea number that characterizes the size of 
an earthquake by recording ground shaking on a 
seismograph and correcting for the distance to the 
epicenter of the earthquake. Magnitude is expressed in 
Arabic numbers.

Masonrystone, brick, or concrete building 
materials.

Masonry veneera masonry (stone or brick) facing 
laid against a wall and not structurally bonded to the 
wall.

Mass movementthe movement of surface material 
caused by gravity.

Meteorologythe study of Earths atmosphere.

Modified Mercalli scale of 1931a qualitative scale 
of earthquake effects that assigns an intensity number 
to the ground shaking for any specific location on the 
basis of observed effects. Mercalli intensity is 
expressed in Roman numerals.

Natural hazardany of the range of natural Earth 
processes that can cause injury or loss of life to human 
beings and damage or destroy human-made structures.

Nonstructural featurean element of a building that 
is not essential to its structural design and does not 
contribute structural strength. Examples are windows, 
cornices, and parapets.

Oscillation or vibrationthe repeating motion of a 
wave or a materialone back and forth movement. 
Earthquakes cause seismic waves that produce 
oscillations, or vibrations, in materials with many 
different frequencies. Every object has a natural rate 
of vibration that scientists call its natural frequency. 
The natural frequency of a building depends on its 
physical characteristics, including the design and the 
building materials.

P wavesprimary waves, so called because they 
travel faster than S waves, or secondary waves and 
arrive at the station first. These waves carry energy 
through the Earth as longitudinal waves, moving 
particles in the same line as the direction of the wave.

Paleomagnetismthe natural magnetic traces that 
reveal the intensity and direction of Earths magnetic 
field in the geologic past.
Paleoseismologythe study of ancient earthquakes.

Parapetpart of a wall which is entirely above the 
roof.

Path, or Load paththe direction in which energy is 
distributed throughout a structure. In most structures, 
it should be directed toward the ground.

Peata deposit of semicarbonized plant remains in a 
water-saturated environment. Peat is an early stage in 
the development of coal.

Periodthe time between two successive wave crests.

Pioneera person who moves into new and 
uncharted territory.

Plate tectonicsthe theory that Earths crust and 
upper mantle (the lithosphere) are broken into a 
number of more or less rigid, but constantly moving, 
segments, or plates.

Porticoa porch or covered walk consisting of a roof 
supported by columns

Predictiona statement that something is likely to 
happen based on past experience. A prediction is 
usually only as reliable as its source.

Principle of crosscutting relationshipsthe 
principle stating that a rock is always younger than 
any other rock across which it cuts. Earthquake 
faulting illustrates this principle: Faults are always 
younger than the rocks they cut.

Principle of superpositionthe principle upon 
which all geologic chronology is based stating that in 
any sequence of sedimentary layers that has not been 
overturned or faulted, each layer is younger than the 
one beneath, but older than the one above it.

Principle of uniformitarianismthe fundamental 
principle stating that geologic processes have operated 
in essentially the same way throughout geological 
time.

Probabilityin mathematics, the ratio of the number 
of times something will probably occur to the total 
number of possible occurrences. In common usage, an 
event is probable, rather than merely possible, if there 
is evidence or reason to believe that it will occur.

Qualitativehaving to do with perceived qualities; 
subjective. Examples: large, cold.

Quantitativehaving to do with measurable 
quantities; objective. Examples: 10 m long, 5 C.

Radiometric datingthe process of using natural 
radioactivity to determine the age of rocks.

Rapid visual screening (RVS)a method of 
assessing risk that relies on external observation. An 
observer who is trained in RVS can derive enough 
information from a quick visual assessment to know if 
closer examination is necessary.

Rayleigh wavessurface waves that carry energy 
along Earths surface by elliptical particle motion, 
which appears on the surface as a ripple effect.

Recurrence intervalthe actual or estimated length 
of time between two earthquakes in the same location.

Resonancean increase in the amplitude (a 
measurement of wave size) in a physical system (such 
as a building) that occurs when the frequency of an 
applied oscillatory form (such as earthquake shaking) 
is close to the natural frequency of the system.

Retrofittingmaking changes to a completed 
structure to meet needs that were not considered at the 
time it was built; in this case, to make it better able to 
withstand an earthquake.

Richter magnitudethe number that expresses the 
amount of energy released during an earthquake, as 
measured on a seismograph or a network of 
seismographs, using the scale developed by Charles 
Richter in 1935.

Rigid connectionsconnections that do not permit 
any motion of the structural elements relative to each 
other.

Rotationturning from side to side.

Run-up elevation or heightthe highest altitude 
above the tide line, in meters, that the water reaches as 
it is forced up on land by a tsunami.

S wavessecondary waves; waves that carry energy 
through the Earth in very complex patterns of 
transverse (crosswise) waves. These waves move more 
slowly than P waves (in which the ground moves 
parallel to the direction of the wave). In an earthquake 
S waves are usually bigger Ps.

Sag ponda small body of water occupying an 
enclosed depression formed by fault movement.

Sand boila forcible ejection of sand and water from 
saturated soil, caused by strike-slip an earthquake or 
heavy flooding.

Saturatedhaving absorbed water to the point that 
all the spaces between the particles are filled, and no 
more water can enter.

Sedimentmaterial that has been transported by 
wind, water, or ice and come to rest in a new location.
Sedimentary depositsaccumulations of small solid 
particles that originated from the weathering of rocks 
and that have been transported or deposited by wind, 
water, or ice.

Seismicityearthquake activity.

Seismicof or having to do with earthquakes.

Seismic sea wavea tsunami generated by an 
undersea earthquake.

Seismic zonea region in which earthquakes are 
known to occur.

Seismogramthe record of earthquake ground 
motion recorded by a seismograph. 

Seismographan instrument that records vibrations 
of the Earth, especially earthquakes.

Seismograph stationa site at which an array of 
seismographs is set up and routinely monitored.

Seismologythe scientific study of earthquakes.

Shakingrapid horizontal vibration of the base of the 
model, simulating an earthquake. In an actual 
earthquake, of course, shaking occurs in many 
directions.

Shear forceforce that acts horizontally (laterally) 
on a wall. These forces can be caused by earthquakes 
and by wind, among other things. Different parts of a 
wall experience different shear forces.

Shear wallswalls added to a structure to carry 
horizontal (shear) forces. These are usually solid 
elements, and are not necessarily designed to carry the 
structures vertical load.

Sill platethe structural member at the base of a 
wood frame building that joins the building to its 
reinforced concrete foundation.

Slumpa type of landslide in which a block of rock 
or soil moves along a curved surface and rotates.

Soft storiesstories in a building, usually lower 
stories with many openings, that are poorly supported 
or braced, and hence vulnerable to collapse.

Stick-slip movementa jerky, sliding movement 
along a surface. It occurs when friction between the 
two sides of a fault keeps them from sliding smoothly, 
so that stress is built up over time and then suddenly 
released.

Strata (s. stratum)layers of rock or other materials 
formed at different periods in geologic time.

Strike-slip faultingfault movement in which the 
fault is horizontal.

Structural elements or structural featuresa 
general term for all the essential, non-decorative parts 
of a building that contribute structural strength. These 
include the walls, vertical column supports, horizontal 
beams, connectors, and braces.

Studsupright pieces in the outer or inner walls of a 
building to which panels, siding, laths, etc. are nailed 
or bolted.

Subductionthe process in which one lithospheric 
plate is forced down under another plate and drawn 
back into the Earths mantle.

Surface waveswaves that move over the Earth at its 
surface. Rayleigh waves and Love waves are surface 
waves.

Topography (adj. topographic)the shape of the 
land; the contours and the arrangement of surface 
features that characterize a region.

Torsiontwisting or turning. A building must be 
resistant to extreme torsion to resist earthquake 
damage.

Transverse waveswaves that vibrate particles in a 
direction perpendicular to the waves direction of 
motion (S waves).

Triangulationusing data from three or more known 
points to locate an unknown point, in this case, the 
epicenter of an earthquake.

Tsunamia potentially destructive ocean wave 
created by an earthquake or other large-scale 
disturbance of the ocean floor; a seismic sea wave. 
This Japanese word has the same form in both the 
singular and the plural.

Unconsolidatedloosely arranged, not cemented 
together, so particles separate easily.

Unreinforced masonrybrick, stone, or adobe walls 
without any steel reinforcing rods or other type of 
reinforcement. Buildings of this type were probably 
built before 1940.

Variablein a scientific experiment, the one element 
that is altered to test the effect on the rest of the 
system.

Veneeran outside wall facing of brick, stone, or 
other facing materials that provides a decorative 
surface but is not load-bearing.

Vertical loadthe effect of vertical force (gravity) 
acting on the elements of a structure.

Wave heightthe vertical distance from a waves 
crest to its trough. (This measurement will be twice 
the amplitude measured for the same wave.)

Wave crestthe highest point a wave reaches. The 
lowest point is called its trough.

Wavelengththe horizontal distance between two 
successive crests, often measured in meters.