Designing

for

Tsunamis

March 2001

National Tsunami Hazard Mitigation ProgramNOAA, USGS, FEMA, NSF, Alaska, California, Hawaii, Oregon, and Washington

Seven Principles for Planning and Designing for Tsunami Hazards
Seven Principles for Planning and Designing

for Tsunami HazardsMarch 2001A multi-state mitigation project of the National Tsunami Hazard Mitigation Program (NTHMP)

National Oceanic and Atmospheric Administration (NOAA)U.S. Geological Survey (USGS)Federal Emergency Management Agency (FEMA)National Science Foundation (NSF)State of AlaskaState of CaliforniaState of HawaiiState of OregonState of Washington

Funding for this project was provided by the U.S. Department of Commerce and the National Oceanicand Atmospheric Administration (NOAA).The opinions and recommendations contained in this report do not necessarily represent those of themember agencies of the National Tsunami Hazard Mitigation Program Steering Committee.

Designing for Tsunamis

Designing for Tsunamis
age ii
Page iii

 Tsunami Hazard

mittee

ncy Services

tes

ernments

Designing for Tsunamis

REPORT CREDITS

National Tsunami Hazard MitigationProgram (NTHMP) Steering CommitteeChairpersonEddie BernardNOAA/PMELNOAAFrank GonzalezPMELRichard HagemeyerNWS Pacific RegionRichard PrzywartyNWS Alaska RegionCharles McCreeryPacific Tsunami Warning CenterTom SokolowskiWest Coast and Alaska Tsunami Warning Center(continued)

GraphicsDaniel JansensonDaniel Jansenson ArchitectExpert Advisors PanelJames E. RussellBuilding Code ConsultantRobert L. WiegelDepartment of Civil and Environmental EngineeringUniversity of California-BerkeleyMark R. LeggLegg GeophysicalCostas E. SynolakisDepartment of Civil Engineering,Tsunami Research GroupUniversity of Southern California
age iv

NSFClifford AstillCivil and Mechanical Systems DivisionAlaskaGary R. BrownAlaska Division of Emergency ServicesRoger HansenGeophysical Institute, University of AlaskaR. Scott SimmonsAlaska Division of Emergency ServicesCaliforniaLori DenglerDepartment of Geology, Humboldt State UniversityRichard EisnerGovernor’s Office of Emergency Services

rd Mitigation

ring Committee

on X

ds Reduction Program

HawaiiLaura KongHawaii Division, USDOT, FHWABrian YanagiState of Hawaii Civil Defense DivisionOregonMark DarienzoOregon Emergency ManagementGeorge PriestOregon Department of Geology and Mineral IndustriesWashingtonGeorge CrawfordWashington State Military Department,Emergency Management DivisionTimothy WalshDivision of Geology and Earth Resources

Report Credits
Page v

Report Credits

ntributions and

ollowing individuals:

elopment Director

nician

Planning Technician

elopment Department

CaliforniaTina Christiansen, DirectorWerner Landry, Senior Engineering GeologistPlanning and Development Review DepartmentCity of San DiegoDon Olson, DirectorBarbara Shelton, Environmental AnalystCommunity Development DepartmentCity of Santa BarbaraErnest Perry, Community Development DirectorDel Norte CountyHawaiiDee Crowell, DirectorKeith Nitta, PlannerPlanning DepartmentCounty of KauaiVirginia Goldstein, DirectorRodney Nakano, Planning Program ManagerPlanning DepartmentCounty of Hawaii

OregonRainmar Bartl, City PlannerCity of Cannon BeachWashingtonKen Kimura, Director, Planning DivisionDepartment of Public ServicesGrays Harbor CountyConnie J. Manson, Senior Library Information SpecialistLee Walkling, Library Information SpecialistWashington Department of Natural ResourcesDivision of Geology and Earth ResourcesOtherAlan L. Yelvington, Project OfficerU.S. Coast Guard
age vi
Page vii

namis to Coastal Communities

nization of the Guidelines

ontext

namis

ss of Tsunamis

mis

e Risk to Your Community

ing Local Tsunami Hazard Information

ying Hazard Information to Reducing Future Losses

ng Scenario for Humboldt and Del Norte Counties

ciple 1: Know your community’s tsunami risk: hazard,

vulnerability, and exposure

ntroduction

Designing for Tsunamis

TABLE OF CONTENTS

1

23

5

7

8

8

9

11

14
age viii

Planning in Reducing Tsunami Risks

ing Land Use Planning Strategies

ning Strategies to Reduce Tsunami Risk

ng in Reducing Tsunami Risk

ing Site Planning Strategies

Strategies to Reduce Tsunami Risk

y Type of Development

town Development Plan

on Design in Reducing Tsunami Risk

ing Construction Design Strategies

nstruction Strategies to Reduce Tsunami Risk

ple 3: Locate and configure new development that occurs

in tsunami run-up areas to minimize future tsunami losses

Table of Contents

ple 2: Avoid new development in tsunami run-up areas to minimize future tsunami losses

ple 4: Design and construct new buildings to minimize tsunami damage

15

15

18

21

21

23

24

2729

30

32
Page ix

wal in Reducing Tsunami Risk

ng Vulnerability Through Renewal Efforts

trategies to Reduce Tsunami Risk

ructure and Critical Facility Location and Design in Reducing Tsunami Risk

menting Infrastructure and Critical Facility Location and Design Strategies

ure and Critical Facility Location and Design Strategies to Reduce Tsunami Risk

al Evacuation in Reducing Tsunami Losses

menting a Vertical Evacuation Strategy

acuation Plan Strategies to Reduce Tsunami Exposure for People

mi Warning Programs

Table of Contents

ciple 5: Protect existing development from tsunami losses through

 redevelopment, retrofit, and land reuse plans and projects

ciple 6: Take special precautions in locating and designing infrastructure

 and critical facilities to minimize tsunami damage

ciple 7: Plan for evacuation

37

37

39

41

41

4447

47

49

51
age x

rnment Officials and the Public

Table of Contents P•1

APHY

Y

CES

53

55

57
Page 1

seven significant tsunamis in the last century, andCrescent City, California, experienced two damagingtsunamis in four years (1960 and 1964), many communities at risk in the Pacific region have no recentexperience with tsunami damage and, hence, mayhave a false sense of security regarding the hazard.An estimated 489 cities within the Pacific states ofAlaska, California, Hawaii, Oregon, and Washingtonare susceptible to tsunamis; as many as 900,000residents of these cities would be inundated by a50-foot tsunami.Beyond preparing for evacuation and emergencyresponse, communities can reduce their tsunami riskby modifying their land use planning and development approval practices. Although planning fortsunamis will not be a top priority for most coastalcommunities, relatively small efforts to plan for thishazard can significantly increase community safety.

The Threat of Tsunamis to CoastalCommunitiesTsunami waves generated by earthquakes, volcanic eruptions, or underwater landslides

can reach 50 feet or more in height and devastatecoastal communities. In recorded history, tsunamisworldwide have killed hundreds of thousands ofpeople. Since 1946 six tsunamis have killed nearly500 people and damaged hundreds of millions ofdollars of property in Alaska, Hawaii, and along theWest Coast of the United States.Tsunamis are infrequent events but can be extremely destructive. While Hilo, Hawaii, suffered

Designing for Tsunamis

INTRO

Introduction

along the

he 1964

nchorage

900,000 people in Alaska, California, Hawaii,Oregon, and Washington live in areas in dangerof being inundated by a 50-foot tsunami.

“Seward was...attacked by the main tsunamiwaves...as the wave traveled along the shore, it spreadburning oil...the resulting fires engulfed thedowntown...surge forces destroyed homes, docks,canneries, and the small boat harbor...virtually theentire downtown...was destroyed by fire.”Account of the effects of the 1964 Alaska earthquakeand resultant tsunami in Seward, Alaska, in Planning forRisk: Comprehensive Planning in Tsunami Hazard Areas.
age 2

Introduction

nization of the

delines is to help coastal

Pacific states—Alaska,

n, and Washington—

i hazards, exposure, and

gate the resulting risk

g, site planning, and

ncy response and evacua

sively in other publications

 these guidelines as they

and building design and

he references at the end of

g emergency response and

sunamis).

nded for use by local

dministrative officials

ing, building regulation,

ent, and related land use

ons in coastal communities.

o be helpful to state

sponsibilities.

These guidelines are organized according to sevenbasic principles:Principle 1: Know your community’s tsunami risk:

hazard, vulnerability, and exposurePrinciple 2: Avoid new development in tsunami run-upareas to minimize future tsunami lossesPrinciple 3: Locate and configure new developmentthat occurs in tsunami run-up areas to minimize futuretsunami lossesPrinciple 4: Design and construct new buildings tominimize tsunami damagePrinciple 5: Protect existing development fromtsunami losses through redevelopment, retrofit, andland reuse plans and projectsPrinciple 6: Take special precautions in locating anddesigning infrastructure and critical facilities tominimize tsunami damagePrinciple 7: Plan for evacuationFor each principle, the discussion includes background information on the topic, recommendedprocess steps for implementing the principle, andspecific how-to strategies. Several case studies in theguidelines illustrate how communities in the Pacific

Damage from the 1964 tsunami in Kodiak, Alaska.Credit: NOAA
Page 3

Introduction

region are addressing tsunami hazards. The guidelines also contain references and contacts forobtaining further information about planning fortsunami hazards. More detailed information on eachof the topics discussed in the guidelines is containedin a companion set of background papers that werecompiled during the preparation of these guidelines.The Regulatory ContextAll development in coastal areas is subject to federal,state, and local policies and regulations. Understanding the regulatory context is critical to the successfulimplementation of a tsunami mitigation program.State and Local Development RegulationsEvery coastal community in the five Pacific states hasa land use planning and regulation process thatresponds to state mandates or guidelines, which varyamong the states:

• All five Pacific states require local land use

planning, and all except Alaska have statewideplanning guidelines. Alaska has statewideplanning guidelines for coastal resource districts.

• Oregon and Washington require local plans to be

consistent with statewide planning goals.California and Hawaii have statewide planningguidelines that are advisory only. Alaska requiresa consistency review of coastal resource districtplans with statewide standards and with otherdistricts’ plans.

• California, Oregon, and Washington require

hazard mitigation as part of their general landuse planning process. Alaska requires it forcoastal resource district plans only. Hawaii onlysuggests that this topic be addressed.

• California, Oregon, and Washington require

conformance with a state model building codebased on the Uniform Building Code (UBC).Alaska only mandates adoption of a fire code,and Hawaii does not have a state-mandatedbuilding code. All of the counties in Hawaii andthe larger cities in Alaska have adopted a versionof the UBC.

A community’s comprehensive plan is at the top ofthe local land use planning/regulatory processhierarchy. The comprehensive plan is implementedday-to-day through project review and permitting.
age 4

ally require formal approv

 establishment of certain

es”), and the physical

ent.

nd Programs

ment has supported state and

merous programs over the

requirements for statewide

There are, however, two

particularly important for

al areas.

nagement Act (CZMA)

rtnership among the federal

s, and local governments to

ograms for managing coastal

onent consists of federally

ment Programs (CMPs) in 32

es, including the five Pacific

CZMA is to promote the

protection of the country’s

The National Flood Insurance Program (NFIP), established in 1968, is part of a comprehensive approach toreduce flood damage and to cope with the disastrouseffect of floods. The NFIP is administered by the FederalInsurance Administration (FIA), a component of theFederal Emergency Management Agency (FEMA). TheNFIP makes federally-backed flood insurance availablein communities that adopt and enforce floodplainmanagement ordinances to reduce future flood losses.NFIP requires projects to be located above the 100-yearflood or inundation areas.

Introduction
Page 5

P 

• 1 P 

• 2 P 

• 3 P 

• 4 P 

• 5 P 

• 6 P 

• 7

Understanding your community’s tsunami hazard, vulnerability, and exposure to damage

is the foundation for land use and building strategiesthat can mitigate tsunami risk. While much remains tobe learned about tsunamis, sufficient knowledge,technical information, and expertise already exist toassess the tsunami hazard and risk in all coastalcommunities.

The Nature of TsunamisA tsunami is a series of long waves generated by asudden displacement of a large volume of water.Tsunamis are triggered by submarine earthquakes,submarine volcanic eruptions, underwater landslidesor slumps of large volumes of earth, meteor impacts,and even onshore slope failures that fall into theocean or a bay.Most tsunamis originate in the Pacific “Ring of Fire,”which is the most active seismic feature on earth.Tsunamis are typically classified as either local ordistant. Locally-generated tsunamis have minimalwarning times and may be accompanied by damage

resulting from the triggering earthquake such asgroundshaking, surface faulting, liquefaction, orlandslides. Distant tsunamis may travel for hoursbefore striking a coastline.In the open ocean, a tsunami may be only a few feethigh but can travel up to 500 miles per hour. As atsunami enters the shoaling waters near a coastline,its speed diminishes, its wavelength decreases, and itsheight increases greatly. However, the first waveusually is not the largest. Several larger and moredestructive waves often follow the first one. Whiletsunami waves slow upon reaching the coastline,they still travel faster than Olympic long-distancerunners can run—faster than 15 miles per hour.

The configuration of the coastline, the shape of theocean floor, and the characteristics of advancingwaves play important roles in the destructiveness ofthe waves. A wave may be small at one point on acoast and much larger at other points. Bays, sounds,inlets, rivers, streams, offshore canyons, islands, andflood control channels may cause various effectsthat result in greater damage than many people

Designing for Tsunamis

P•1 Principle 1: Know your community’s tsunami risk: hazard, vulnerability, and exposure

es generated

rge volume of

P

•

1
age 6

n estimated, for example,

ering a southern California

uld reach a mile or more

ers at high tide. Offshore

mi wave energy and islands

 orientation of the coast

 the waves strike head-on

er parts of the coastline.

ng that can be damaging

ds of square miles is not

ct long, low-lying stretches

ly extending inland for

. Upon striking a coast, the

, and then can return to the

aves.

n of an approaching

n of water (drawdown)

ceding the advancing, large

d drawdown can create

 inlets and channels that

stal structures due to

rs and pilings. As the

ers can be damaged by

boats or ships straining ator breaking their mooringlines. The vessels canoverturn or sink due tostrong currents, collisionswith other objects, orimpact with the harborbottom.Conversely, a rise in waterlevel may be the firstindication of a tsunami. Theadvancing tsunami mayinitially resemble a strongsurge increasing the sealevel like the rising tide, butthe tsunami surge rises faster and does not stop at theshoreline. Even if the wave height appears to be small,three to six feet for example, the strength of theaccompanying surge can be deadly. Waist-high surgescan cause strong currents that float cars, smallstructures, and other debris. Boats and debris areoften carried inland by the surge and left strandedwhen the water recedes.

The Pacific “Ring of Fire” is the most activeseismic feature on earth. Tsunami wavestriggered by seismic activity can travel acrossthe Pacific Ocean at up to 500 miles per hour,striking distant coastal areas in a matter ofhours. The figure shows the estimated number ofhours for tsunami-generated waves to travelacross the Pacific Ocean from Alaska and Chile,respectively.

5

Principle 1: Know your community’s tsunami risk: hazard,

 vulnerability, and exposure
Page 7

P • 1 P • 2 P • 3 P • 4 P • 5 P • 6 P • 7 Outflow following inundation also creates strong currents, which rip at structures and pound them with debris, and erode beaches and coastal structures. As tsunamis reach the shoreline, they may take the form of a fast-rising tide, a cresting wave, or a bore. The bore phenomenon resembles a step-like change in the water level that advances rapidly (from 10 to 60 miles per hour). Normal tidal bores at the Bay of Fundy, Canada, or the Yellow River, China, provide examples of this phenomenon. The force and destructive effects of tsunamis should not be underestimated. At some locations, the advanc- ing turbulent wave front will be the most destructive part of the wave. In other situations, the greatest damage will be caused by the outflow of water back to the sea between crests, sweeping all before it and undermining roads, buildings, bulkheads, and other structures. This outflow action can carry enormous amounts of highly damaging debris with it, resulting in further destruction. Ships and boats, unless moved away from shore, may be dashed against breakwaters, wharves, and other craft, or be washed ashore and left grounded after the withdrawal of the seawater. The Destructiveness of Tsunamis Though rare, tsunamis are devastating events for humankind. In recorded history, hundreds of thousands of people all over the world have died as a result of tsunamis. Some scholars believe that a tsunami resulting from the eruption of the volcano Thera destroyed the Minoan culture in the Mediter- ranean in 1628 B.C. Since 1946, six destructive tsunamis have caused nearly 500 deaths and damaged hundreds of millions of dollars of property in Alaska, Hawaii, and along the U.S. West Coast. The destructive potential of tsunamis was most dramatically illustrated by the 1960 Chile earth- quake and the 1964 Alaska earthquake, two of the largest earthquakes ever measured. The 1960 earthquake off coastal Chile devastated parts of Chile and almost instantly raised a Califor- nia-sized piece of land on the ocean floor about 30 feet. Its companion series of tsunami waves resulted in further losses in many other Pacific Rim and island locations, including Hilo, Hawaii, and Japan. 

lows down 

.

Principle 1: Know your community’s tsunami risk: hazard,

 vulnerability, and exposure

P•1
age 8

t, including 61 in Hawaii

rthquake-generated

d on tide gauges for more

Pacific Rim.

by the 1964 Alaska

destruction around the

ne, waves and the effects of

marine landslides destroyed

astal communities. Whittier

oil facilities, and rail

up noted at an elevation of

age. Kodiak suffered

oundshaking, followed by

hat inundated the low

roying virtually all docking

ts and other debris ashore.

marine landslides triggering

destroying much of the

ed 30- to 40-foot tsunamis

dslides, causing extensive

reas and fires in petroleum

Exposure to TsunamisCoastlines have always been a favored location forhuman settlements. Because of the attractiveness ofcoastal locations and the long gaps between devastating tsunami events, coastal communities havecontinued to develop in recent times with newhousing, maritime facilities, and resort developments. As a result, more people and facilities arethreatened by the destructive force of tsunamis.According to one recent estimate, 489 cities inAlaska, California, Hawaii, Oregon, and Washingtonare susceptible to tsunami inundation, with anestimated 900,000 people living or working withinareas that could be inundated by a 50-foot tsunami.Understanding the Risk toYour CommunityUnderstanding the tsunami threat is the first step inreducing potential losses. These guidelines repeatedlystress the importance of compiling and applying goodlocal tsunami hazard information.

Principle 1: Know your community’s tsunami risk: hazard, vulnerability, and exposure

Potential destructiveness of tsunamis inthe five Pacific states
Page 9

P • 1 P • 2 P • 3 P • 4 P • 5 P • 6 P • 7 Tsunami risk is a function of three factors: 1) the nature and extent of the tsunami hazard; 2) the vulnerability of facilities and people to damage; and 3) the amount of development or number of people exposed to the hazard. There is no substitute for having a local evaluation of a community’s hazard, vulnerability, and exposure. The information will help communities understand the causes and consequences of a tsunami in order to design specific loss-prevention measures and programs. Process for Obtaining Local Tsunami Hazard Information 1) Prepare Tsunami Inundation Studies The first step in understanding your risk is to estimate the extent and pattern of your community’s potential tsunami inundation, tsunami frequency (recurrence interval), and the reliability of the estimate. In all five Pacific states, state agencies are conducting ongoing tsunami mapping programs. The methodologies used and the geographic coverage of efforts vary from state to state. Generally, the mapping programs involve some combination of computer modeling, historical research, and field confirmation. The current round of tsunami inundation mapping is designed primarily to support evacuation plan- ning, but provides a good starting point for land use planning as well. Because of the often simplistic assumptions that are made in a statewide study, local land use managers should conduct their own more refined assessments of tsunami inundation potential. Each level in the land use planning, site planning, and building design hierarchy requires a different level of refinement in the information concerning potential inundation and destructive effects. In many cases, it will only be possible to gather adequate information about the potential effects of local tsunamis because distant tsunamis are more difficult to model.

Principle 1: Know your community’s tsunami risk: hazard,

 vulnerability, and exposure

ia, from the

eople in the five

n zone for a

 Historical

P•1
age 10

nclude:

ords and describing

tant tsunami sources

or ground failures and other

waves, their heights,

ndation depths

cities and debris loads

es of occurrence and levels

ll ordinarily require the

ecialists. Local governments

n advisory committee

m nearby colleges and

gencies, consulting organiza

ional organizations.

oss Scenario Studies

pattern of inundation

ssess the potential damage

o to existing development

ario studies based on

assumed conditions provide a graphic illustrationof what can happen to a community, both duringand after a destructive tsunami. These studiesshould also address other hazards, such as localearthquakes, that may cause concurrent damage.Local tsunamis pose unique problems for emergency planners since the facilities and infrastructure needed for evacuation may be damaged bythe earthquake that triggers the tsunami.Such scenarios typically assess potential losses toimportant buildings and structures, transportationsystems, and utility systems. The resulting tsunamiloss scenario study will provide the foundation forreducing potential losses. The most importantprinciple is that the study be accepted as the bestthat could have been done within the constraintsof funding, time, and knowledge. Because of theinherent limitations associated with loss studies, itwill be important for all involved to reach consensus on the results. This will help ensure communityand political acceptance–a key ingredient forestablishing effective loss-reduction measures.

However, consensus may be hard to reach in these

Principle 1: Know your community’s tsunami risk: hazard, vulnerability, and exposure

Wave generated by the 1946 tsunami in theKeaukaha area of Hilo, Hawaii. Credit: PacificTsunami Museum
Page 11

P • 1 P • 2 P • 3 P • 4 P • 5 P • 6 P • 7 studies, and differing interpretations or conclu- sions need to be identified and discussed. The case study on page 14 describes an earthquake and tsunami scenario for the north coast of California, including damage probability and assessments for a variety of facilities, infrastruc- tures, and services. The Federal Emergency Management Agency (FEMA) has developed a geographic information system (GIS)-based natural hazard loss estimation methodology, called HAZUS, that can be adapted to address tsunami hazards in scenario studies. Release of any loss scenario study should be accompanied by briefings of key community groups and leaders, the media, elected and appointed officials, and others important to adopting and applying loss reduction measures. Strategies for Applying Hazard Information to Reducing Future Losses Strategy 1: Incorporate Hazard Information into Short- and Long-Term Planning Processes One of the best ways to prevent future losses from natural hazards is to ensure the subject is ad- dressed along with all other issues in short- and long-term comprehensive planning programs and project reviews. Some jurisdictions require that public safety considerations or specific hazards be addressed. The resulting information becomes part of the evaluation and decision-making processes. The scope of the hazard information will vary with the breadth or narrowness of the project, such as amending a growth management plan, reviewing a specific development proposal, or modifying a zoning ordinance. The information should be used to evaluate major development proposals so that risk mitigation is factored into decisions, approvals, and permits.

Principle 1: Know your community’s tsunami risk: hazard, vulnerability, and exposure

P•1
age 12

Principle 1: Know your community’s tsunami risk: hazard,

 vulnerability, and exposure

uch information will be

lopers should be required to

ata and mitigation measures

Communities should have

d review procedures to

f this process.

rd Information to Build

upport for Mitigation

 estimates, and planning

ools to create understand

mitigation. They should be

ulace with their exposure

wer them to take precau

political consensus about

g policies and programs,

ncy preparedness and

mation, or procedures for

tion, should be included in

cesses affecting current

. This will ensure that risk

management becomes a regular part of thedecision-making processes leading to sustainableand more disaster-resistant communities.

Strategy 3: Estimate Reduced FutureLosses by Evaluating the Effectiveness ofLoss-Prevention MeasuresOne of the biggest challenges in preventing lossesfrom natural hazards, especially for rare eventssuch as tsunamis, is to show that mitigationmeasures would be effective. At the communitylevel, the value of mitigation investments can beestimated by using scenarios and maps to evaluateactions taken to reduce vulnerability and exposureto tsunami hazards. Informed judgments can be madeby quantifying the losses that likely would haveoccurred if such precautions had not been taken.Strategy 4: Periodically Re-evaluate CommunityVulnerability and ExposureThe tsunami hazard is unlikely to change over time,but communities are changing constantly. Thisdynamic process leads to changes in vulnerabilityand exposure. Effective long-term tsunami
Page 13

P • 1 P • 2 P • 3 P • 4 P • 5 P • 6 P • 7 mitigation means that loss studies should be reviewed and revised periodically

—at least every five

years

—to reflect changes in development patterns

and demographics. Regular review and revision willensure that the most current information is applied,and it could help to demonstrate the effectiveness ofloss prevention.Community vulnerability certainly should bere-evaluated following a disaster or other severeevent, perhaps including comparable events in otherlocations around the world.

n the Waiakea

rs were bent

ves. Credit:

Principle 1: Know your community’s tsunami risk: hazard, vulnerability, and exposure

P•1
age 14

Principle 1: Case Study

ing Scenario for Humboldt and Del

Division of Mines and Geology published Special 

ed Planning Scenario in Humboldt and Del Norte

Great Earthquake on the Cascadia Subduction Zone.

scription with supporting maps of the potential

he cities of Eureka (Humboldt County) and Crescent

This report is an example of local hazard and risk

used to support mitigation efforts.

 is assumed to generate a local tsunami that would

earthquake. The maps depict potential structure and

nd show locations likely to be flooded by a tsunami

at earthquake (magnitude 8.4) occurring offshore on

e Cascadia Subduction Zone.

cludes damage probability and assessments for a

tructure, and services including: schools and

ways, airports, marine facilities, railroads, and

er, natural gas, petroleum products, water supply,

ssessments are intended to assist localities in

response efforts and pre-disaster retrofitting and

rts. Excerpt from Scenario Map for Humboldt and Del Norte Counties
Page 15

P 

• 2 P 

• 3 P 

• 4 P 

• 5 P 

• 6 P 

• 7 P •T

 1

sunami risk can be mitigated most effectively

by avoiding or minimizing the exposure of

people and property through land use planning.Development should be prevented in high-hazardareas wherever possible. Where developmentcannot be prevented, land use intensity, buildingvalue, and occupancy should be kept to a minimum.Where these strategies are not available anddevelopment will occur in possible tsunami inundation areas, planners and designers must look tomitigation through site planning techniques asdiscussed under Principle 3 or building constructiontechniques as discussed under Principle 4.

The Role of Land Use Planning inReducing Tsunami RisksLand use planning in communities guides thelocation, type, and intensity of development andcan, therefore, be used to reduce the community’sexposure to tsunami hazards. Principle 2 focuses onlarge-scale land use planning issues, such as thosethat are dealt with in comprehensive plans, zoning

ordinances, and subdivision regulations. It focuses onthe types, patterns, and densities of uses that couldand should be allowed within potential tsunamiinundation areas based on consideration of the risk.It is important to remember that the more locationalmitigation (Principle 2) is used, the less designmitigation (Principles 3 and 4) is required.

Process for Implementing Land UsePlanning StrategiesThe following outlines the steps that can be takenwhen formulating a community land use strategy fortsunami risk mitigation.1) Understand Locational ContextOpportunities for reducing tsunami risk differdepending on local circumstances, so a one-sizefits-all approach cannot be used. The presence orabsence of development within tsunami hazardareas will determine the type of planning approach that is feasible. For example, vacant landconversion, such as expansion of an existing

Designing for Tsunamis

P•2 Principle 2: Avoid new development in tsunami run-up areas to minimize future tsunami losses

uake damage

tent of

m the 1964

-dependent

ety goals.

erior

P

•

2
age 16

ment of a new community, 

gation strategies than will 

ent such as infill, redevelop- 

n occupancy (see Principle 5). 

Offs 

aking trade-offs between or 

when dealing with land use 

mi hazards. For example, the 

Coastal Zone Management 

r locating visitor-serving 

astline; yet this access can be 

safety goals for minimizing 

ami inundation areas. 

opment such as ports and 

ure, have to be situated on 

t with safety goals. Other 

ompact/dense downtowns 

ed risk. 

be recognized in the 

vision process for a compre- 

me to weigh alternatives and 

als. 3) Review and Update Existing Safety Element The existing safety or natural hazards element of the comprehensive plan should be reviewed to deter- mine if it adequately recognizes tsunami hazards and how the risk is managed when decisions are made. The following information should be inventoried and updated, as necessary (see Principle 1): • technical information such as inundation zones • loss scenario information • goals and policies In addition, it should be recognized that tsunami hazards often overlap other hazards and that mitigation for other hazardous conditions can assist in mitigating tsunami risk. Such hazards might include riverine flooding, hurricanes/typhoons, landslides, coastal erosion, and earthquakes. 4) Review and Update Existing Land Use Element and Other Plans The existing land use element, other comprehensive plan elements, and special plans should be reviewed to determine what changes are needed to address

Principle 2: Avoid new development in tsunami run-up areas to minimize future tsunami losses

Erosion along the Oregon coast. Mitigation for otherhazardous conditions such as erosion, flooding,hurricanes, and seismic hazards can assist inmitigating tsunami risk. Credit: Oregon Departmentof Land Conservation and Development
Page 17

P 

• 2 P 

• 3 P 

• 4 P 

• 5 P 

• 6 P 

• 7 P • 1 the tsunami hazard, and be updated as necessary. Land use policies and programs should address tsunami hazards as part of a comprehensive tsunami mitigation program. Such an update should focus on the location and vulnerability to damage of existing and planned land uses in the community, including the following: • residential • commercial/visitor-serving • industrial (general) • industrial (hazardous materials) • public facilities (transportation and water systems) • critical facilities and systems (communication, emergency response, electrical power, water supply, and natural gas systems) 5) Review and Update Existing Zoning, Subdivision, and Other Regulations Existing zoning, subdivision, and other regulations should be reviewed and updated with an eye toward mitigating future tsunami losses. Requirements for consistency between the comprehensive plan and zoning and subdivision regulations vary among the states. In California, for example, the zoning code is considered part of the local coastal program (LCP) for coastal communities and is required to be consistent with the general plan. 6) Planning for Post-Tsunami Reconstruction Disasters create the opportunity to eliminate nonconforming uses and reshape existing patterns of development to minimize future losses. On the other hand, they can also create enormous pressure to rebuild the community quickly and exactly as it was before the disaster. These rebuild- ing issues should be addressed through the land use planning process before a disaster strikes so that a community is prepared to deal with rebuild- ing issues in the event of a disaster.

Principle 2: Avoid new development in tsunami run-up areas to minimize future tsunami losses

P

•

2
age 18

 Planning Strategies 

i Risk 

 recommended land use 

 community can use to 

e Tsunami Hazard Areas 

ing of tsunami hazard areas 

 as agriculture, parks and 

zard areas is recommended 

ning strategy to consider. 

to keep development at a 

s. It is particularly effective 

t experienced development 

more difficult in areas that 

eloped or that have strong 

sunami Hazard Areas 

quire tsunami hazard areas 

n-space acquisition has 

strictly regulatory 

approaches such as zoning. Acquisition ensures that the land will be controlled by a public agency or nonprofit entity, and it removes any question about a regulatory taking. The primary disadvantage to acquisition is cost. There are multiple approaches to acquisition. Since land ownership is in effect a bundle of rights, including the rights to sell, lease, and develop the property, some of these rights, such as the right to develop, can be sold separately from the rest of the property. For example, a purchase of development rights (PDR) program is based on purchasing the right to develop land from the bundle of rights associated with the land. A PDR program involves the purchase of the development rights to a property, generally through the granting of a conservation, open-space, or scenic easement that restricts the uses to which the property owner may put the land. A PDR program can also be constructed to purchase a fee- simple interest in a property and then to resell the property with an easement restricting future

Principle 2: Avoid new development in tsunami run-up areas to minimize future tsunami losses

Park on the Hilo, Hawaii, waterfront. Open spaceuses such as parks can keep development at aminimum in hazard areas. Credit: County of Hawaii
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• 7 P • 1 development. A similar result can be obtained through purchasing a fee-simple interest and then leasing the property with restrictions on use. PDR programs are more effective in preserving land from development where development pressure has not yet driven up land prices. Strategy 3: Restrict Development through Land Use Regulations In areas where it is not feasible to restrict land to open-space uses, other land use planning measures can be used. These include strategically controlling the type of development and uses allowed in hazard areas, and avoiding high-value and high-occupancy uses to the greatest degree possible. For example, plan designations and zoning districts can use density restrictions or large-lot zoning (e.g., 10-acre minimum) to ensure that only very low- density residential uses are allowed in hazard areas. Another technique is to require clustering of develop- ment on site areas where risks are the lowest. Strategy 4: Support Land Use Planning through Capital Improvement Planning and Budgeting The capital improvement planning and budgeting process can be used to reinforce land use planning policies. A major factor in determining future development patterns is where a local jurisdiction chooses to extend sewer and water lines, roads, and other public facilities and services. Decisions can either discourage or encourage development in tsunami and other hazard areas. Natural hazard risk mitigation should be integrated into infrastructure policy. Infrastructure policies by themselves will not preclude development in certain areas, but they can reinforce land use plans, and they can shape market forces to encourage development in less hazardous areas by not subsidizing infrastruc- ture that serves a higher-risk hazardous area.

Principle 2: Avoid new development in tsunami run-up areas to

 minimize future tsunami losses

 site areas

nly very low

d in hazard

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her Programs and 

omprehensive plan and the 

other programs designed to 

ensive plan may contain 

cable to tsunami risk 

mi hazards are not men- 

f these programs and 

ed relatively easily to 

. For example, existing 

llside and landslide controls, 

ic, recreational, and wildlife- 

can help address tsunami 

odified for that purpose.

Principle 2: Avoid new development in tsunami run-up areas to minimize future tsunami losses
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When development is to be sited within a tsunami hazard area, the physical configuration of structures and uses on a site can reduce

potential loss of life and property damage. Thisincludes the strategic location of structures andopen space areas, interaction of uses and landforms,design of landscaping, and the erection of barriers.

The Role of Site Planning in ReducingTsunami RiskWithin the broader framework of a comprehensiveplan, site planning determines the location, configuration, and density of development on particularsites and is, therefore, an important tool in reducingtsunami risk.At the site planning level in the planning/regulatoryhierarchy, the focus typically is on a single parcel orcollection of parcels of land 2 to 200 acres in size,under the control of a single owner. This scale ofplanning provides limited opportunities for avoidingthe tsunami hazard entirely, but can provide a broadrange of opportunities to design a project tominimize tsunami damage.

Process for Implementing SitePlanning StrategiesThe following outlines the steps that can be takenwhen formulating a site planning strategy fortsunami hazard mitigation.1) Create a Project Review Process that isCooperative, Comprehensive, and IntegratedThe most effective site planning in coastal areasincludes a project review process that reflects thearea’s vulnerability and exposure to tsunamihazards, considers the broader policy and regulatory context, and is part of a larger mitigationstrategy. An interactive and informed site planningand review process can save time for projectsponsors and provide better mitigation solutions.Communities interact with project proponents atvarious levels in the preparation and review of siteplans. The level of review relates to the scale andcontext of a project. Some projects require site andconcept review, while others require a review offully developed designs. Community-level project

Designing for Tsunamis

P•3 Principle 3: Locate and configure new development that occurs in tsunami run-up areas to minimize future tsunami losses

ity, California,

dit: USGS

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el to the design process in

ternatively, project site

tive based on predeter

 adopted comprehensive

 waterfront areas to ensure

of a review process that

gation plan, economic

ty design concepts. Without

community-wide mitigation

oked in a site plan review

erent disciplines and

d decision-making bodies.

Site Conditions

nd project sponsors must

gies that reflect the

immediate context. This

how tsunamis impact

ography, land uses and

opment patterns. The depth

peed of currents, presence of

onditions, debris load, and

reatly from site to site.

The site analysis phase can be used to establish siteplan parameters for tsunami mitigation. Manycommunities have mapped hazard areas. Within theseareas, communities may also have more detailedplans that include site analysis. The analysis typicallyincludes geographic conditions, critical infrastructure(see Principle 6), area access and egress (see Principle7), and existing and future development patterns. Theanalysis may also include economic feasibility and

community design objectives.Regional hazard maps can identify many of these at-risk

areas, but typically they do not reflect the catastrophicpotential of a tsunami that is accompanied by otherdisasters. Besides inundation, near-source earthquakes can cause damage and possibly lower theelevation of the entire region, causing flooding. Fires,broken infrastructure, liquefaction, mudslides, erosion,and other hazardous conditions can create scenariosthat make communities even more vulnerable totsunami waves. Therefore, each site assessmentshould identify other hazardous conditions besideselevation and shoreline configuration.

Principle 3: Locate and configure new development that occurs in tsunami run-up areas to minimize future tsunami losses
Page 23

P • 1 P • 2 P • 3 P • 4 P • 5 P • 6 P • 7 3) Choose a Mitigation Strategy for the Site Many communities work with project sponsors to select a mitigation approach during the site plan- ning process. Generally, this includes siting solutions that avoid, slow, steer, or block inundation. These can be blended with building design and engineer- ing that provides hardened or passive ways of handling the force of a tsunami (see Principle 4). Specific Site Planning Strategies to Reduce Tsunami Risk There are four basic site planning techniques that can be applied to projects to reduce tsunami risk: 1) Avoid inundation areas 2) Slow water currents 3) Steer water forces 4) Block water forces These basic strategies can be used separately or be combined into a broader strategy. The methods can be used in passive ways to allow tsunamis to pass through an area without causing major damage, or they can be used to harden structures and sites to withstand the force of a tsunami. The efficacy of these techniques depends on the intensity of the tsunami event. If the tsunami hazard is underesti- mated, development in the area may still be vulner- able to a larger event. Strategy 1: Avoiding Avoiding a tsunami hazard area is, of course, the most effective mitigation method. At the site planning level, this can include siting buildings and infrastructure on the high side of a lot or raising structures above tsunami inundation levels on piers or hardened podiums. Strategy 2: Slowing Slowing techniques involve creating friction that reduces the destructive power of waves. Specially designed forests, ditches, slopes, and berms can slow and strain debris from waves. To work effectively, these techniques are dependent on correctly estimating the inundation that could occur.

Principle 3: Locate and configure new development that occurs in tsunami run-up areas to minimize future tsunami losses

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e the force of tsunamis

ructures and people by

ctures, using angled walls

aved surfaces that create a

er to follow.

h as walls, compacted

ing structures, and other

ock the force of waves.

result in amplifying wave

redirecting wave energy to

ies by Type of

various types of new

e exposed to tsunami

ossible mitigation strategies

of development.

1) Infill HousingIn small communities, individual homes and infillhousing are the most common forms of development. Often, there is great political pressure to allowdevelopment of smaller sites that do not permitlocating development out of the hazard area.Communities can require that these smaller projectsbe raised above inundation levels and that engineering features be added to their design. However,they can still be vulnerable to damage from debrisand other structures that may break free and collidewith them. In some cases, new infill buildings can besited on the high side of a lot to avoid being hit byanother structure.2) New Neighborhoods and SubdivisionsTo reduce tsunami damage, the layout of newsubdivisions in shoreline areas can include:

• providing maximum spacing between buildings• elevating buildings above inundation levels• placing houses behind a tsunami control forest or

larger hardened buildings

Principle 3: Locate and configure new development that occurs in tsunami run-up areas to minimize future tsunami losses

Steering

 Blocking
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structures above estimated inundation levels, andbuffering smaller buildings with larger hotels andwaterfront structures.5) Community CommercialThe downtowns of most coastal communities arelocated adjacent to piers and beach areas. The primaryaccess roads typically follow the coastline and are linedwith commercial enterprises. Both of these development patterns are susceptible to damage by tsunamis.Strengthening and expanding harbor structures canhelp protect adjacent commercial areas. Depending onthe tsunami, however, breakwaters can be swampedby the rising tide and be ineffective. New buildings canbe elevated above inundation levels or hardened anddesigned to withstand tsunami forces.6) IndustrialDry docks, refineries, power plants, and othershoreline industrial facilities are of special concern.Destruction or flooding of industrial facilities can addanother environmental dimension to a tsunamidisaster with burning oil, toxic chemicals, and otherhazardous materials. Floating buildings, debris, and

• siting primary access roads outside inundation

areas and secondary access roads perpendicularto the shore

3) High-Rise HotelsNew hotels in coastal areas are typically multilevel concrete frame structures. The lower levelsof these buildings can be designed for public areassuch as lobbies and support uses (such as parking)for upper level rooms. In Hawaii, for example,lower levels of hotels have been designed to allowwaves to pass through the ground floor parking,lobby, and service spaces, leaving upper levelrooms and meeting spaces undamaged. Thesebuildings must be designed to withstand bothtsunami and earthquake forces.4) ResortsResorts can include a broad range of facilities andservices, such as small-scale cottages, large hotels,tennis facilities, swimming pools, golf, and beachrelated recreation. Resort planning can draw on avariety of mitigation methods, including openspace and tsunami forests, elevating or locating

Principle 3: Locate and configure new development that occurs in tsunami run-up areas to minimize future tsunami losses

i. Lower level is

through. Credit:

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d tanks. Protecting

walls and stronger anchor

ocating these types of uses

ones is the most effective

cal Facilities

stations, hospitals, sewage

 other critical infrastruc

ot be located in inundation

se types of facilities out of

 be an integral part of any

. Where essential service

tions or permanent

be located in tsunami

ld be designed or retrofit

amage. This topic is

 under Principle 6.

Principle 3: Locate and configure new development that occurs in

 tsunami run-up areas to minimize future tsunami losses

Damage to port facilities in Seward, Alaska, fromthe 1964 tsunami. Locating industrial facilitiesoutside of inundation zones is the most effectivemitigation technique. Credit: U.S. Army Corps ofEngineers
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lo Downtown Development Plan

own Development Plan was adopted in 1974 to guide 

alize the downtown core of Hilo, Hawaii. The Plan

District based on the 1946 and 1960 tsunami

redevelopment in the Safety District was subject to

ilding design standards. Any structure below the 20-

ur line was required to be designed to withstand the

ami. A Parking District was also designated in the

Principle 3: Case Study

Plan to provide parking for downtown businesses and to use parkingstructures as a protective barrier from a tsunami for inland structures.Parking facilities have been constructed in accordance with the Plan.In 1985, the Hilo Downtown Development Plan was superceded by theDowntown Hilo Redevelopment Plan under the authority of Chapter 27,Flood Control, of the Hawaii County Code.

wer downtown area from the Hilo Downtown Development Plan. Credit: County of Hawaii

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Where buildings are to be constructed in a tsunami hazard area, the design and

construction of the buildings–including constructionmaterials, building configuration, and tsunamispecific design features–can reduce loss of life andproperty damage.

The Role of Construction Design inReducing Tsunami RiskAs discussed under Principles 2 and 3, in areassubject to tsunamis and damaging run-up, the mosteffective mitigation technique is to locate newbuildings away from potential inundation areas.Where this is not possible, building design andconstruction will play a critical role in the performance of structures in the event of a tsunami.Performance ObjectivesA performance objective for a building dependsupon several considerations:

• location of the building and its configuration

(size, shape, elevations, and orientation)

• intensity and frequency of the tsunami hazard

selected for design

• structural and non-structural design standards• choice of structural and finish materials• reliability of utilities• professional abilities of designers• quality of construction• level of confidence in these factors

Hospitals, fire stations, and schools would beassigned higher performance objectives than thoseassigned to tourist accommodations.Potential tsunami damage to buildings can beminimized during the early project design stagewhere performance objectives are decided, governing standards are reviewed, and the configuration ofthe building is chosen. These decisions govern thebuilding’s final design and its actual construction.However, while special engineering techniques andmaterials can be used to resist tsunami forces andinundation, in the case of an intense tsunami, theywill reduce losses but not prevent severe damage.

Principle 4: Design and construct new buildings to minimize

 tsunami damage

Designing for Tsunamis

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, from the 1960

eering techniques

 resist tsunami

 intense tsunamis,

event severe

Museum
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he United States is governed

ng codes. Building codes

table requirements for

 property damage, and

th, safety, and welfare in the

g codes are applied to new

existing buildings

n, repair, rehabilitation, or

ture of the use is changed to

reases the risk or exceeds the

 building.

menting

gn Strategies

 Appropriate Building

andards

used in the Pacific states are

ding Code (UBC) prepared

erence of Building Officials

on, and Washington, the

ate code adoption and

vel. Alaska only mandates

adoption of a fire code, and Hawaii does not mandatethe use of a model code, leaving the option to countygovernments. All the counties in Hawaii and the largercities in Alaska have adopted a version of the UBC. Thestates mandating the use of the UBC allow local government amendments that are more stringent than the

mandated code provisions.The UBC includes design requirements and standardsfor fire, wind, floods, and earthquakes, but it does notcontain requirements for tsunami-resistant design.While a few communities have adopted tsunamiresistant building design standards, the vast majorityof coastal communities have not. The City and Countyof Honolulu has adopted special requirements forfloods and tsunamis as part of its Revised Ordinances.With appropriate modifications to reflect localconditions, these could serve as a general model forother states and municipalities. Guidance for architectsand engineers in the design for tsunami forces isincluded in FEMA’s Coastal Construction Manual, also

known as FEMA 55. The manual deals with tsunamisin a manner similar to the Honolulu ordinance butuses more current information.

Principle 4: Design and construct new buildings to minimize

 tsunami damage

 Forces on structures created by tsunamis
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2) Ensure That Codes and StandardsAddress the Full Range of Potential HazardsWhile these guidelines emphasize tsunami lossprevention, other hazards such as earthquakegroundshaking should, of course, also be addressedin the design of new buildings. Landslides, liquefaction, and other ground failures are potentialproblems in many coastal areas, as are seasonalfloods where rivers and streams enter the ocean.Loss-prevention measures have already beenadopted for most of these hazards, and it is important to recognize them in the effort to minimizedirect tsunami losses.3) Apply Locally Valid Tsunami HazardInformationWhere a tsunami hazard study has been prepared toinform local design decisions, the information canbe used to decide whether to permit construction ata given site. If construction is to be permitted, thebuilding design must address tsunami-relatedforces, including water pressure, buoyancy, currentsand waves, debris impact, scour, and fire. The

analyses will vary depending on location, buildingsize, and type of construction, such as reinforcedconcrete, wood, light metal, and others.

4) Select the Intensity of Design EventsIt is essential in the local hazard study to estimate tsunamiintensity for various return intervals. Small tsunamis areless damaging, but they may be more frequent thanoccasional greater events. Smaller tsunamis might serveas the basis for designing most buildings. However, therarer large events with higher water levels andstronger forces should be the basis for designing criticalfacilities, such as hospitals, fire stations, and refineries.5) Define the Building’s Performance LevelPerformance levels describe expectations of owners,occupants, and regulators relative to the amount ofdamage a building could sustain from a tsunami andthe building’s ability following a tsunami event tosupport the uses for which it was intended. The designof a building to achieve a particular performance levelinvolves a set of decisions that begins with determiningthe importance of the building and understanding theconsequences of damage to the building.

Principle 4: Design and construct new buildings to minimize tsunami damage

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age 32

nce levels that can be

minimum, safety,

onal levels.

ed, and constructed to the

hstand water forces without

ndations or sites, but they

 debris, flooding, ground

perform at a safety level

orces, debris and wave-break

king, ground failure, and fire

ural damage. People in taller

o evacuate vertically above

esulting from a locally

a reoccupancy level should

erformance, but additional

ken so they can be reoccu

 weeks after cleanup, minor

on of utilities. This level

ce of the building location

stant materials.

Finally, the most demanding requirements are used todesign buildings to meet the operational level ofperformance. These buildings should be capable ofresisting all expected forces and hazards. They mustalso have backup emergency systems and utilities sothey can be used immediately following a tsunami.

Specific Design and ConstructionStrategies to Reduce Tsunami RiskStrategy 1: Choose Appropriate DesignSolutions Based on Expected TsunamiEffectsDesign and construction of new buildings shouldaddress forces associated with water pressure,buoyancy, currents and waves, debris impact, scour,and fire.Substantially constructed buildings of concrete,masonry, and heavy steel frames are likely to performfairly well in a tsunami unless compromised byearthquake shaking. Wood-frame buildings,

Principle 4: Design and construct new buildings to minimize

 tsunami damage

Damage to buildings in Hilo, Hawaii, from the1946 tsunami. Credit: Pacific Tsunami Museum
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Page 33

manufactured housing, and light steel-frame structures at lower elevations close to the shoreline arelikely to fare poorly in a tsunami. Not every areaaffected by tsunami run-up, however, will experiencedamaging forces. Buildings in less hazardous areasaffected by shallow run-up water depths shouldsurvive with repairable damage if they are designedand constructed well. The force of currents andbreaking waves, fast-moving waterborne debris, andscouring currents may exceed the resisting capabilitiesof most buildings unless the buildings are constructedwith specific design elements and materials.The table on page 35 lists the possible effects oftsunamis on structures (such as flooding, waterpressures and forces, buoyancy, debris impacts,foundation scouring) and suggests possibledesign solutions for each of the potential effects(such as elevating and anchoring buildings;designing for water forces, pressures, and impactloads; and using deep piles or piers). As notedabove, it is important that the design measures bebased on the local hazard study so that expectedforces determine the design solutions.

Strategy 2: Require Qualified Architects andEngineers to Design Large BuildingsBuilding design is governed by engineering principles and practices and by building codes thatestablish minimum standards relating to publichealth and safety; however, codes are no substitutefor competent engineering, design, construction, andquality assurance.Specialized expertise is often needed when designing and constructing large, complex, or unusuallyshaped buildings. Communities should identifyproposed projects that require specially qualified andlicensed professionals, see that the owning/developing organizations secure such assistance early in theproject planning phase, and help locate sources ofqualified assistance. Professional associations canhelp local officials find needed experts such asarchitects and geotechnical, coastal, and structuralengineers who are familiar with coastal design andconstruction issues.Some jurisdictions require that such professionals beinvolved in building design and be identified on the

Principle 4: Design and construct new buildings to minimize tsunami damage

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ifications. The use of such

ortant when codes and

nadequate, or when the

nded to exceed the mini

s contained in commonly

s.

onstruction to Assure

t

 important to ensure that

according to the appropriate

nspections can be provided in

alified permitting agency

nt technical experts retained

on; or 3) requiring the owner

e reports would be provided

on for review and accep

sed construction inspectors

provide these services.

Principle 4: Design and construct new buildings to minimize tsunami damage
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Principle 4: Design and construct new buildings to minimize tsunami damage

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The challenges in protecting existing develop ment from tsunami losses are many and

complex. For coastal communities that are nearlybuilt out, protecting existing development may bethe only real mitigation option available. However,land uses, buildings, and infrastructure change overtime, creating opportunities to incorporate tsunami(and other hazard) loss-prevention measures to helpmake communities less vulnerable in the future.

The Role of Renewal in ReducingTsunami RiskEfforts to renew communities can take many forms,including redefining permitted land uses, changingzoning standards, changing building uses andoccupancies, retrofitting and rehabilitating buildings,and redeveloping districts to improve their economicvitality. There may also be special considerations intsunami-vulnerable areas such as protecting landmarks and historic structures, creating scenic vistas,providing improved access to coastal amenities,improving services, and accommodating neededhousing and commercial activities.

While many tsunami mitigation techniques used innew development can be applied to existing development, their application will be limited by site constraints and building conditions.The reconstruction process following a disasterprovides an opportunity to create or modify land uses,implement redevelopment plans, rehabilitate buildings, and vacate high-hazard lands subject to repetitivelosses–all with the intent of reducing future losses.

Process for Reducing VulnerabilityThrough Renewal Efforts1) Inventory At-Risk Areas and PropertiesIf not already available, an inventory should becompleted of buildings, critical facilities, andinfrastructure elements in the potential tsunamiinundation area (see Principle 1 for a more detaileddiscussion of this topic). More than a simple tally, thisinventory should take into account the type ofstructure, its age, size and configuration, constructionmaterial, and use.

Designing for Tsunamis

Principle 5: Protect existing development from tsunami losses through P•5 redevelopment, retrofit, and land reuse plans and projects

the Columbia

itigation

ment can be

but their

constraints and

Corps of

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Principle 5: Protect existing development from tsunami losses through redevelopment, retrofit, and land reuse plans and projects

Anchor bolts. Measures to resist earthquakeshaking, such as anchoring and bracingbuildings, can also help to reduce tsunamidamages. Credit: Northridge Collection,Earthquake Engineering Research Center,University of California, Berkeley

oses, it is important to

uildings and their construc

ficant deterioration may

t retrofit and rehabilitation

her cases.

plex, having been modified

t is rare that adequate

gs are available. This

gineering study is needed

haracteristics of the

pecific rehabilitation or

e.

e Plans and

ss Redevelopment,

sues

es perform an in-depth

heir land use, comprehen

ement plans. The periodic

broad context within

nd renewal policies and

Building codes primarily address new construction;generally, they do not address renovations andretrofitting comprehensively or in detail. Localbuilding codes should be amended to fully addressrisk mitigation in the context of building renovation.As a starting point, there are several examples ofcode amendments concerning retrofitting buildingsfor earthquake hazards that can be adapted fortsunami hazards. The Federal Emergency Management Agency (FEMA) sponsored the preparation of amultiple-volume guide on rehabilitating buildings toresist earthquake forces. Several states and communities have also adopted laws and ordinancesgoverning the retrofitting and rehabilitation ofexisting buildings to reduce future losses fromearthquakes.
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Principle 5: Protect existing development from tsunami losses through

 redevelopment, retrofit, and land reuse plans and projects

Specific Renewal Strategies toReduce Tsunami RiskStrategy 1: Adopt Special Programs andDevelopment RegulationsThere is a variety of specific development regulationsand programs that local communities can implementto minimize tsunami risk, including:

• redesignating and rezoning land in tsunami hazard

areas for uses more consistent with the risk as nonconforming uses are phased out

• limiting additions to existing buildings in tsunami

hazard areas

• buying specific properties in tsunami hazard areas

and removing or relocating buildings

Strategy 2: Use Redevelopment Strategies toReduce Tsunami RiskRedevelopment land acquisition and financingpowers can be used on a district-wide scale toreconfigure uses or infrastructure, retrofit specificbuildings, or remove buildings altogether intsunami hazard areas.

Strategy 3: Use Incentives and Other FinancialMeasures to Support Loss PreventionOne key to the success of redevelopment and otherrenewal measures is helping building owners bear thecost of the proposed changes. There are manycommonly used incentives that help spur renewal,such as reduced property taxes, waiving of permit andinspection fees, and low interest loans. Local officialsshould ensure that whatever incentives are usedinclude risk mitigation as an eligible purpose.Strategy 4: Adopt and Enforce Special Provisions for the Retrofit of Existing BuildingsRetrofit of existing buildings should be encouragedwhen the effort will improve tsunami resistance toa level capable of meeting identified performanceobjectives, or to minimize floating debris that candamage nearby buildings. Retrofitting may berequired for all buildings within a hazard zone, ormay be mandated only when substantial modifications are made to existing structures or when thereare changes in building occupancy.

dation map in

Plan. Credit:

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Principle 5: Protect existing development from tsunami losses through redevelopment, retrofit, and land reuse plans and projects

ed with strengthening

quire the development,

ation of special codes,

s. Moreover, special purpose

uch as codes governing the

uildings, that may or may

protecting against hazards.

 to ensure that effective

 be applied to such proper

upting their original

ng buildings involve the

ng new buildings; however,

ected performance objec

mplement after initial

. Dealing with the vulner

s is difficult because of the

tives and cost of remedial

and hydrodynamic and

esistance to tsunamis in

more frequently occurring

hazards are more likely to be feasible. These includeelevating buildings above the base flood elevation,improving foundations to resist scour and erosion,and anchoring and bracing the buildings to resistearthquake shaking. Although these measures canreduce tsunami damage, especially in the statisticallymore-frequent small tsunamis, they will not ensurethat a building is able to withstand the intense forcesassociated with larger events.

Strategy 5: Require Qualified Architects andEngineers to Design Effective Measures toProtect Existing DevelopmentAs discussed under Principle 4, specialized expertiseshould be used to help design measures to reducefuture losses. Such expertise is important whenconsidering measures to strengthen existingdevelopment because of the complexities associatedwith such projects and the greater reliance placed onexperience and judgment. Design professionals andengineers who specialize in rehabilitation andretrofit practices can be located through professionalassociations and contacts with local practitioners.
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Certain facilities in a community deserve special attention in the planning and design process

to minimize damage to them. Infrastructure such astransportation systems for people and goods, andutility systems such as communications, natural gas,water supply, power generation, and transmission/distribution systems are essential to the continuedoperation of a community and need to befunctional—or easily and rapidly repairable—following a disaster.Other facilities in the community are consideredcritical because of their occupants or the functionsthey contain. These include: 1) essential servicefacilities such as fire stations; 2) hazardous facilitiessuch as chemical plants or fuel storage tanks; and 3)special occupancy structures with uses such asgovernment functions important to sustaining acommunity, buildings with large numbers of occupants, or buildings such as convalescent homes withoccupants who cannot evacuate the premises readily.

The Role of Infrastructure and CriticalFacility Location and Design inReducing Tsunami RiskInfrastructure and critical facilities are often locatedon the coast within tsunami hazard areas. In somecases, such as fire stations, the facilities may need tobe located in tsunami hazard areas; in other cases,they could just as easily be located outside thetsunami hazard area.Because of the services these facilities provide—orthe harm they could cause—to the community, theirperformance during natural hazard events is acommunity-wide concern that needs to be considered as part of a tsunami risk management effort.Process for ImplementingInfrastructure and Critical FacilityLocation and Design Strategies1) Understand Tsunami MitigationResponsibilitiesManaging the tsunami risk is a responsibility sharedby the government and private sectors. Depending

Designing for Tsunamis

P•6 Principle 6: Take special precautions in locating and designing infrastructure and critical facilities to minimize tsunami damage

ad bridge at the

g the 1946

Museum

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structure systems and 

owned and managed by 

pecial districts, private 

ganizations, federal depart- 

t powers authorities, or 

ams need to involve all 

ing process. 

escribe the Nature and 

i Hazards for Infrastruc- 

lities 

kground information on local 

hazard scenarios. In such 

 include information about 

l facilities and to identify 

eir location, design, con- 

 maintenance. This work 

zard (see Principle 1) and 

y (expected effects) and 

ence. 

data about infrastructure 

facilities in the potential damage area and describe why their functions make tsunami resistance an important issue for the community and what makes each facility vulnerable to damage from tsunami forces. • Identify the responsible organizations and include their representatives in the mitigation process. 3) Adopt Comprehensive Risk Management Policies Communities should adopt policies to manage the tsunami risk and integrate them into coastal management programs, land use plans, floodplain zoning, capital outlay plans, building regulation programs, and other procedures used to control the use and safety of facilities near the shoreline. Essential service facilities should be operational following a hazard event. This concept already is contained in the Uniform Building Code (UBC) and could be adapted for tsunami hazards. The UBC requires the use of enhanced seismic and wind forces for design, and enhanced structural inspection during construction of essential service facilities. To ensure stronger structures, the UBC uses

Principle 6: Take special precautions in locating and designing infrastructure and critical facilities to minimize tsunami damage

A boat washed up over 400 feet onshore fromthe wharf by the 1946 tsunami in Hilo, Hawaii.Credit: Pacific Tsunami Museum
Page 43

P • 1 P • 2 P • 3 P • 4 P • 5 P • 6 P • 7 an “importance factor” to increase the force levels by 15 to 50 percent over those calculated for other occupancy categories. 4) Adopt a Comprehensive Infrastructure and Critical Facility Plan Communities should revise or adopt measures that deal with existing and new infrastructure, critical facilities, and waterfront-dependent uses in relation to tsunami hazards. These comprehensive infra- structure and critical facility plans should define performance objectives for the various types of existing and planned facilities in the community. Strategies should include relocating or, if possible, strengthening existing infrastructure and critical facilities against tsunami forces. They should also include providing redundant facilities and emer- gency response measures to lessen the impact of losing infrastructure and critical facilities that remain at risk. Proposals for new critical facilities and infrastruc- ture located in tsunami hazard areas should be considered carefully to determine whether the performance expected is acceptable once feasible design measures are implemented. Proposals for new infrastructure should be evaluated in terms of the increased risk because of induced growth. For example, construction of new buildings and facilities may be facilitated by the provision of new water or wastewater collection services in the hazard area. Existing infrastructure and critical facilities are particularly problematic. It is difficult and expen- sive to improve the tsunami performance of existing facilities and infrastructure, and relocation is usually impractical, especially in the short term. However, understanding the risk to these existing facilities and anticipating the consequences of tsunami events can lead to long-term risk-reduc- ing strategies (see Principle 5 for a more detailed discussion of issues related to existing buildings). Because of the varied nature and differing impor- tance of infrastructure systems and critical facilities, an effort must be made to rank their relative importance to the community and to establish

Principle 6: Take special precautions in locating and designing infrastructure and critical facilities to minimize tsunami damage

cture and

(cont.)

king lots and

systems

 and rail and

 passengers

am, and motor

nce facilities,

s, control

d tubes

raffic control

ading/unloading

luding tank farms),

rs, seawalls, and

sion, substations,

ssing, storage,

bution systems

ms: switching

lines

P•6
age 44

o help guide mitigation 

es the following:

 performance levels

e condition for a given

probability). See Principle 4

ormance levels.

xisting system and facility has

d earthquake mitigation plus

ards, such as potential

es.

tive importance to help focus

 preventing losses of the

 may be more important

 of the wastewater system).

ntervals for each element

ospital must be minimally

hour of the event, but a major

ed for two weeks).

and critical facilities, deter

ormance levels and whether

on a waterfront location.

ure and critical facilities,

gation options or combina

uce the risk and whether

uld be acceptable.

Specific Infrastructure and CriticalFacility Location and Design Strategies to Reduce Tsunami RiskStrategy 1: Locate New Infrastructure andCritical Facilities Outside the Tsunami HazardArea or Design to Resist Tsunami Forces

• Examine plans for infrastructure and critical

facilities to see if other, equally efficient alternative locations, alignments, and routes can beused. Most critical facilities need not be located ina tsunami hazard area to serve their intendedpurpose. Some essential facilities may need to belocated in a tsunami hazard area becausealternative locations will not serve the day-today needs of the community.

• Reserve sites for infrastructure and critical

facilities either outside the tsunami hazard areaor in areas where the risk can be reducedthrough feasible measures.

• Prohibit new critical facilities in tsunami hazard

areas unless: 1) they are waterfront dependentand the design can mitigate the vulnerability tosuch an extent that the resulting facility willperform as needed; 2) risk is reduced through

Principle 6: Take special precautions in locating and designing infrastructure and critical facilities to minimize tsunami damage

• Cellular systems, switching stations,

antenna, and towers

• Cable systems for television, radio, and data• Satellite systems for television and data• Potable water systems: wells, water supply

sources, storage, pumps, and treatmentand distribution systems

• Sewerage collection, mains, pumps,

treatment facilities, and outfalls

• Pipelines that transport oil, fuels, and other

petroleum products

• Storm water runoff facilities, drainage, and

pipelines

CRITICAL FACILITIESEssential Services• Police stations• Firehouses• Hospitals with surgery, acute care, or

emergency rooms

• Emergency operations and communications

facilities and equipment

• Garages and shelters for emergency

vehicles and aircraft

Examples of infrastructure and criticalfacilities (cont.)

(cont.)
Page 45

P • 1 P • 2 P • 3 P • 4 P • 5 P • 6 P • 7 mitigation and emergency planning measures; or 3) the need for the facility outweighs the consequences of its loss during a tsunami (e.g., a small hospital in a remote, tsunami-prone area may be justified because it needs to be close to the population for routine emergencies).

• Prohibit infrastructure improvements that will

encourage construction of other facilities thatcannot withstand the tsunami hazard.

• Consider the impact of new infrastructure on

hazard intensity and distribution. For example,does it change drainage patterns, increaseexposure to inundation, or channel currents in away that will increase the hazard?

• Provide redundant facilities and infrastructure

outside tsunami hazard areas where elementsand facilities must serve high-hazard areas.

• Employ design professionals qualified in coastal,

structural, and geotechnical engineering oninfrastructure and critical facility projects inhigh-hazard areas. Communities should identifyproposed projects that should involve speciallyqualified and licensed professionals, see that theowning organizations secure the specializedassistance as early as possible in the project

planning, and locate both local and distantsources of qualified assistance that can becontacted when needed.

• Where it is impractical to locate infrastructure and

critical facilities outside tsunami hazard areas,ensure that adequate mechanisms exist to isolatethe damaged area, such as shutoff valves, detours,and others.

Strategy 2: Protect or Relocate ExistingInfrastructure and Critical Facilities

• Do not allow expansion or renovation of existing

facilities in tsunami hazard areas without requiring measures to reduce the risk.

• Construct barriers (reinforced walls and columns)

to protect against impact forces and scour.

• Elevate existing facilities above the inundation

elevation.

• Relocate portions of at-risk facilities.• Take advantage of the eventual obsolescence of

existing infrastructure and critical facilities as anopportunity to phase out the facility, relocate thefacility, or incorporate design standards that will allowfor acceptable performance following a tsunami.

Principle 6: Take special precautions in locating and designing infrastructure and critical facilities to minimize tsunami damage

ipment for

aining water

rial or

 essential,

ncy facilities

s

and nursing

 other utility

s operations

chemicals

cks, and

 and critical

P•6
age 46

mergencies and Recovery 

ans to cope with the 

and expedite recovery. 

endent infrastructure and 

ot be newly designed or 

nd tsunami forces, they 

 expendable and planning 

n for evacuation, emergency 

nd replacement facilities. It 

mber that in a tsunami an 

may turn into debris that 

d non-expendable structures.

Principle 6: Take special precautions in locating and designing infrastructure and critical facilities to minimize tsunami damage

Petroleum tank on fire due to damage from the1964 tsunami on Highway 101 near CrescentCity, California. Credit: Del Norte Historical Society
Page 47

P 

• 1 P 

• 2 P 

• 3 P 

• 4 P 

• 5 P 

• 6 P 

• 7

The primary strategy for saving lives immedi- ately before tsunami waves arrive is to evacuate people from the hazard zone. Two methods are

generally available:

• horizontal evacuation—moving people to more

distant locations or higher ground

• vertical evacuation—moving people to higher

floors in buildings

Horizontal evacuation and other emergencyresponse measures are outside the scope of theseguidelines and have been addressed in otherpublications (see Resources and Bibliography at theend of the guidelines). Vertical evacuation, however,is addressed in these guidelines since it is linked toissues of land use, siting, and building design andconstruction.

The Role of Vertical Evacuation inReducing Tsunami LossesEvacuating people can save lives and reduceinjuries, but it will have little, if any, effect onreducing property and economic losses. In coastal

areas where building and population densities arehigh, where roads, bridges, and other horizontalevacuation methods are limited, or where warningtime may be insufficient, vertical evacuation maybe needed as an alternative or supplement tohorizontal evacuation. Land use planning, siteplanning, and building design discussed in theprevious principles play an important role in acommunity’s ability to rely, at least partially, onvertical evacuation to protect people.Process for Implementing a VerticalEvacuation Strategy1) Inventory Existing BuildingsThe building stock for vertical evacuation variesgreatly across communities. Thus, it is critical that acommunity inventory and assess buildings that couldserve as vertical evacuation shelters. This may bedifficult because important information aboutexisting buildings, such as drawings and calculations,may not be available. Professional engineers play akey role in evaluating the capacity of structures to

Designing for Tsunamis

P•7 Principle 7: Plan for evacuation

P

•

7
age 48

nd their reports often lead to 

t work designed to 

 This topic is discussed in 

ple 5. 

Standards Apply to 

gnated as vertical evacua- 

ufficient structural integrity 

mi forces and earthquake 

mis originating locally. 

 applicable standards should 

earthquake resistance of 

ndards should go beyond 

requirement of most locally- 

ng owners should also secure 

d professionals in the fields 

and structural engineering. 

ut building siting and design 

ciples 3, 4, 5, and 6. 3) Designate Emergency Services Personnel to Lead the Program Vertical evacuation, while dependent on structures for its success, is primarily an emergency preparedness and response measure. It is important, therefore, that those community officials responsible for planning and managing emergency programs and operations take lead responsibility for vertical evacuation planning. In addition, it is extremely important to involve building owners and tenants in the process of establishing a vertical evacuation program. 4) Resolve Related Issues There are several other issues that are important to vertical evacuation. These vary among communities and states, but include emergency preparedness requirements, standards of care for evacuees, access to designated shelters, and liability of public agencies and building owners.

Principle 7: Plan for evacuation
Page 49

P 

• 1 P 

• 2 P 

• 3 P 

• 4 P 

• 5 P 

• 6 P 

• 7

Specific Vertical Evacuation PlanStrategies to Reduce TsunamiExposure for PeopleStrategy 1: Identify Specific Buildings toServe as Vertical SheltersSome existing buildings can serve as vertical sheltersand newer ones can be located, designed, andconstructed with that use in mind. Local buildingofficials and consulting engineers can help inventorythe community’s stock of candidate buildings,evaluate the buildings’ tsunami- and earthquakeresistant capabilities, and establish criteria andstandards for rehabilitation or new construction thatmeet the expected hazard forces so the buildings willbe able to serve as shelters.Factors to be considered in determining a building’ssuitability include size, number of stories, access,contents, and available services. Only those buildingsjudged able to withstand the potential tsunami andearthquake forces and that meet other occupancycriteria should be designated as shelters. For example,if expected tsunami wave heights will not exceed onestory (about 10 feet), then open-floor designs can be

used to allow the waves to pass through with minimalimpact on the building. Further information aboutevaluating the tsunami resistance of existing buildingsis discussed under Principle 5.

Strategy 2: Work Out Agreements andProcedures with Building OwnersTo a large extent, vertical evacuation shelters will bedesignated in privately owned buildings. For aprogram to be effective, therefore, appropriateagreements should be negotiated with the owners,and the owners or their representatives should beinvolved in the creation and maintenance of theprogram. While they will vary among communitiesand states, issues related to notification, standards ofcare, compensation, duration of occupancy, security,and liability will be important to the owners.Strategy 3: Ensure Procedures Exist toReceive and Disseminate WarningsIt is very important that tsunami-vulnerable communities have adequate procedures and systems fornotification by official warnings so appropriateactions can be taken, sometimes many hours in

Principle 7: Plan for evacuation

Crescent City,

P

•

7
age 50

mis. Local tsunamis pose 

 insufficient time might 

s. Some communities are 

r residents and visitors to 

henever earthquake shaking 

ing is issued, people can 

nt Effective Information 

ams 

chures, single-page instruc- 

ystem tests, electronic and 

signs, and emergency 

intain awareness and instill 

or. Some of this information 

pecialized institutions, such 

convalescent-care facilities, 

g community members. 

sm in many coastal commu- 

is designed especially for 

e community’s needs, it is 

on and education efforts be 

and tailored for special 

Strategy 5: Maintain the Program Over the Long Term Tsunamis are rare events, but their impacts on coastal communities can be devastating. It is a challenge to maintain emergency preparedness programs and procedures when the threat is perceived as remote. It is, therefore, important that vertical evacuation measures be integrated into community response plans and that they be reviewed and revised regularly. Since cooperation is essential, these reviews should include building owners and others involved in the program. Periodic simulations are a valuable learning exercise, and regular informational and instructional materials should be provided to those occupying potential tsunami damage areas.

Principle 7: Plan for evacuation

Tsunami evacuation map from the civil defensesection of the Hilo, Hawaii, telephone book
Page 51

P • 1 P • 2 P • 3 P • 4 P • 5 P • 6 P • 7

Principle 7: Case Study

Tsunami hazard zone logo

 Warning Programs

ption of tsunami warning programs. This topic is not directly related to 

t provides helpful background information.

operative effort to save lives and protect property, the National Oceanic and

s (NOAA) National Weather Service operates two tsunami warning centers.

sunami Warning Center (WCATWC) in Palmer, Alaska, serves as the regional

Alaska, British Columbia, Washington, Oregon, and California.

g Center (PTWC) in Ewa Beach, Hawaii, serves as the regional tsunami

nd as a national/international warning center for tsunamis that pose a

rnational warning effort became a formal arrangement in 1965 when PTWC

arning responsibilities of the Pacific Tsunami Warning System (PTWS). The

rnational member states that are organized as the International Coordina

Warning System in the Pacific.

nters coordinate the information being disseminated. The objective of the

o detect, locate, and determine the magnitude of potentially tsunamigenic

ormation is provided by seismic stations. If the location and magnitude of an

 criteria for generation of a tsunami, a tsunami warning is issued to warn of

. The warning includes predicted tsunami arrival times at selected coastal

graphic area defined by the maximum distance the tsunami could travel in a

with additional predicted tsunami arrival times is issued for a geographic

the tsunami could travel in a subsequent time period.

continued on next page

P•7
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Principle 7: Case Study

If a significant tsunami is detected by sea-level monitoring instrumentation, the tsunami warning isextended to the entire Pacific Basin. Sea-level (or tidal) information is provided by NOAA’s National OceanService, PTWC, WCATWC, university monitoring networks, and other participating nations of the PTWS.Tsunami watch, warning, and information bulletins are disseminated to appropriate emergency officialsand the general public by a variety of communication methods:

• Tsunami watch, warning, and information bulletins issued by PTWC and WCATWC are disseminated to

local, state, national, and international users as well as the media. These users, in turn, disseminatethe tsunami information to the public, generally over commercial radio and television channels.

• The NOAA Weather Radio System, based on a large number of VHF transmitter sites, provides direct

broadcast of tsunami information to the public.

• The U.S. Coast Guard also broadcasts urgent marine warnings and related tsunami information to

coastal users equipped with medium frequency (MF) and very-high-frequency (VHF) marine radios.

• Local authorities and emergency managers are responsible for formulating and executing evacuation

plans for areas under a tsunami warning. The public should stay tuned to the local media for evacuation orders should a tsunami warning be issued. And, the public should not return to low-lying areasuntil the tsunami threat has passed and the local authorities announce the “all clear.”

Case Study: Tsunami Warning Programs, cont.
Page 53

drop below the ambient water level as read on a

pt vertical front or wall of water. Under certain

of a tsunami wave may form a bore as it

e. A bore may also be formed when a tsunami

and may travel upstream penetrating to a

the general inundation.

 interference of waves from the edge of a harbor

nce can cause amplification of the wave heights

wave activity from a tsunami.

nce:

wave penetrates onto the shore. Measured

sea level position of the water's edge, it is usually

distance for a particular segment of the coast.

d reference level, to which a particular location is

water.

measured horizontally from the edge of the coast,

in 1000 km of the area of interest. Local or near

t travel time (30 minutes or less), mid-field or

e times on the order of 30 minutes to 2 hours.

times used to refer to a tsunami of landslide

Designing for Tsunamis

Period:The length of time between two successive peaks or troughs. May vary due tocomplex interference of waves. Tsunami periods generally range from 5 to 60minutes.Run-up:Maximum height of the water onshore observed above a reference sea level.Usually measured at the horizontal inundation limit.Seiche:An oscillating wave in a partially or fully enclosed body of water. May beinitiated by long period seismic waves, wind and water waves, or a tsunami.Tidal Wave:Common term for tsunami used in older literature, historical descriptions, andpopular accounts. Tides, caused by the gravitational attractions of the sun andmoon, may increase or decrease the impact of a tsunami, but have nothing todo with their generation or propagation. However, most tsunamis (initially)give the appearance of a fast-rising or fast-ebbing tide as they approachshore, and only rarely appear as a near-vertical wall of water.Travel Time:Time (usually measured in hours and tenths of hours) that it took the tsunamito travel from the source to a particular location.Tsunami:A Japanese term derived from the characters “tsu” meaning harbor and

“nami” meaning wave. Now generally accepted by the international scientificcommunity to describe a series of traveling waves in water produced by thedisplacement of the sea floor associated with submarine earthquakes,volcanic eruptions, or landslides.

LOSSARY
age 54
Page 55

CAL GOVERNMENT OFFICIALS AND

rary Information Specialist, Washington

rces, Division of Geology and Earth Resources

ional Geologists, 1993. The Citizens' Guide to

Understanding Geologic Hazards, Including

ls, Earthquakes, Volcanoes, Landslides, Subsidence,

Arvada, CO: American Institute of Professional

nd easy-to-understand explanations)

eat Waves. New York: McGraw-Hill Book Com

ers by Design—A Reassessment of Natural

Washington, D.C.: John Henry Press. (Prepared

sternas; Joanne Bourgeois; Walter C. Dudley;

H. Stauffer, compilers, 1999. Surviving a Tsunami—

nd Japan. U.S. Geological Survey Circular 1187.

agement Agency, 1998. The Project Impact

 for Northwest Communities—Alaska, Idaho,

gton, D.C.: U.S. Federal Emergency Management

nal resources and websites and books in the

Designing for Tsunamis

RES

U.S. Federal Emergency Management Agency, 1993. Are You Ready? YourGuide to Disaster Preparedness. Washington, D.C.: U.S. Federal EmergencyManagement Agency.U.S. Federal Emergency Management Agency, 1998. Property AcquisitionHandbook for Local Communities. 3 vol. poster (FEMA 317). Washington, D.C.:U.S. Federal Emergency Management Agency. (For more information: http://www.fema.gov/mit/handbook/)U.S. Federal Emergency Management Agency, 2000. Coastal ConstructionManual—Principles and Practices of Planning, Siting, Designing, Constructing,and Maintaining Residential Buildings in Coastal Areas. 3rd. ed., 3 vol. (FEMA55) Washington, D.C.: U.S. Federal Emergency Management Agency. (For moreinformation: http://www.fema.gov/MIT/bpat/bpn0600e.htm)PERIODICALSNatural Hazards Observer (print and online versions) (http://www.colorado.edu/IBS/hazards/o/o.html)The bi-monthly newsletter of the Natural Hazards Center. It covers currentdisaster issues; new international, national, and local disaster management,mitigation, and education programs; hazards research; political and policydevelopments; new information sources; upcoming conferences; and recentpublications.TsuInfo Alert NewsletterThe bi-monthly newsletter of the National Tsunami Hazards MitigationProgram is distributed to approximately 250 emergency managers of the fivePacific coastal states. Back issues are online: http://www.wa.gov/dnr/htdocs/ger/tsuinfo/index.html

ESOURCES
age 56

RESOURCES

shington.edu/tsunami/intro.html

n Geophysics Program - many links to other

rary/tsunamif.htm

and links.

ov/tsunami/

ith links to inundation mapping, modeling, events,

nal Tsunami Hazards Mitigation Program sites.

ov/tsunami-hazard/links.html

tsunami sites.

/disaster/safety/guide/tsunami.html

with overview, discussion of warning systems, and good

n.

m/CapeCanaveral/Lab/1029/

George P.C. (Pararas-Carayannis)

u'd need to know about tsunamis!

it/handbook

dbook for Local Communities (FEMA 317).

VIDEOSForum: Earthquakes and Tsunamis (2 hrs.)CVTV-23, Vancouver, WA (January 24, 2000)Two lectures: Brian Atwater describes the detective work and sources ofinformation about the January 1700 Cascadia earthquake and tsunami;Walter C. Dudley talks about Hawaiian tsunamis and the development ofwarning systems.Tsunami: Killer Wave, Born of Fire (10 min.)NOAA/PMEL.Features tsunami destruction and fires on Okushiri Island, Japan; goodgraphics, explanations, and safety information. Narrated by Dr. EddieBernard (with Japanese subtitles).Waves of Destruction (60 min.)WNET Video DistributionAn episode of the "Savage Earth" series. Tsunamis around the Pacific Rim.Disasters Are Preventable (22 min.)USAIDWays to reduce losses from various kinds of disasters through preparednessand prevention.Tsunami: Surviving the Killer Waves (13 min.)DOGAMITwo versions, one with breaks inserted for discussion time.Raging Planet; Tidal Wave (50 min.)Produced for the Discovery Channel in 1997, this video shows a Japanesecity that builds walls against tsunamis, talks with scientists about tsunamiprediction, and has incredible survival stories.
Page 57

Designing for Tsunamis

ving the Farm: A Handbook for Conserving

sco: American Farmland Trust, January 1990.

gineers, Task Committee on Seismic Evaluation

 Facilities of the Petrochemical Committee of the

delines for Seismic Evaluation and Design of

York: ASCE, 1997.

ertical Shelter Policy: The Experience of Two

17, (3) (1989): 193-217.

., “On Mitigating Rapid Onset Natural Disasters:

actions, American Geophysical Union (June 14,

s to Reduce Impact of Tsunamis on Pacific States,”

Geophysical Union Vol. 79 (June 2, 1998):

rd Mitigation: The Alaskan Experience Since

Department of Geography, University of

mi Engineering,” United States Army Corps of

iment Station, Vicksburg, MS, Special Report

al Estate. A Real Estate Guide. Sacramento, 1997.

ainable Development

.gov)

m, Municipal and Regional Assistance Division,

nd Economic Development, State of Alaska

/mra/Mradplan.htm)

Department of Community, Trade, and Economic Development, State ofWashington (http://www.cted.wa.gov)Department of Land Conservation and Development (DLCD), State of Oregon(http://www.lcd.state.or.us)Dudley, Walt. Tsunamis in Hawaii. Hilo, HI: Pacific Tsunami Museum, 1999.

Dudley, Walter C. and Min Lee. Tsunami! Honolulu: University of Hawai’i Press,1998.Earthquake Engineering Research Institute, “Reconnaissance Report on the

Papua New Guinea Tsunami of July 17, 1998,” EERI Special Earthquake Report(January 1998).Federal Emergency Management Agency (FEMA) (http://www.fema.gov/)Federal Emergency Management Agency. Coastal Construction Manual—Principles and Practices of Planning, Siting, Designing, Constructing, andMaintaining Residential Buildings in Coastal Areas. 3rd ed., 3 vol. (FEMA 55)Washington, D.C.: FEMA, 2000.Federal Emergency Management Agency. Multi-Hazard Identification and RiskAssessment: A Cornerstone of the National Mitigation Strategy. Washington, DC:FEMA, 1997.Foster, Harold D. Disaster Planning: The Preservation of Life and Property.

New York: Springer-Verlag New York, Inc., 1980.Governor’s Office of Planning and Research, State of California. General Plan

Guidelines, 1998 ed. Sacramento, 1998.Hawaii Coastal Zone Management Program, Office of Planning, Departmentof Business, Economic Development and Tourism, State of Hawaii (http://www.state.hi.us/dbedt/czm/index.html)

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Open Space. People for Open Space, San Francisco, September 1985.Petak, William J. and Arthur A. Atkisson. Natural Hazard Risk Assessment andPublic Policy: Anticipating the Unexpected. New York: Springer-Verlag NewYork Inc., 1982.Ruch, Carlton E., H. Crane Miller, Mark Haflich, Nelson M. Farber, Philip R.Berke, and Norris Stubbs. The Feasibility of Vertical Evacuation. Monograph

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