The NMSZ is the most seismically

 active area of the United States

 east of the Rocky Mountains, 

 according to information from

 the last 40 years of instrumental

 recordings. It experiences an 

 average of 200 earthquakes

 (greater than M1.5) every year—

 most, however, are too small to

 be felt.

Most seismically active area 

east of the Rockies

20

Commemorating the Bicentennial of the New Madrid Earthquake Sequence

December 1811–February 1812 

U.S. Department of the Interior

U.S. Geological Survey

about the

New Madrid Seismic Zone

20 Cool Facts

General Information Product 134

 The first in a series of major earthquakes occurred 

on December 16, 1811, at about 2:15 a.m. near 

present-day Blytheville, Arkansas. Estimated at 

magnitude (M) 7.7,1

 this event awakened people 

across much of what is now the eastern United States, 

up to about 900 miles away, including President James 

Madison in Washington, D.C. There were several large 

aftershocks that day, including the largest “Dawn” 

aftershock at about 7:15 a.m., estimated at M6.8–7.0.

 The maiden voyage of the first steamboat on the 

Mississippi River, the New Orleans, began in 

September 1811 on the Ohio River at Pittsburgh, 

Pennsylvania. It reached the Mississippi River the 

week before the December 16 earthquake. One morning

the passengers woke to find that the island they had 

moored to the night before had disappeared because 

of liquefaction due to frequent earthquake shaking.2

 According to reports of boat captains and others 

on the Mississippi River in December 1811, the 

earthquakes caused the river to fill with debris as the 

tree-covered river banks caved into the river. Other 

reports said the river flooded large tracks of land, 

created temporary waterfalls, and even ran backwards

in some places. Today, similar bank failure, flooding, 

and river debris would affect bridge abutments, farm 

land and industries along the river, and barge traffic.

 The second of the three major earthquakes, 

estimated at M7.5, occurred on January 23, 1812, 

at about 9:15 a.m. Similar to the December 1811 

earthquake, this event was also widely felt 

throughout the region. Damage occurred in an 

area of about 232,000 square miles.

 In 1811, the population of what is now the central 

United States was very sparse. Still considered to be 

the western frontier, there were only about 5,700 

people in the St. Louis area at the time. Most historical 

reports (journals, letters, and newspapers) describing 

the earthquake shaking and its effects were written by 

people who were located east of the Mississippi River. 

Today, about 11–12 million people live in the St. 

Louis–Memphis region.

 The New Madrid earthquakes caused extensive

landsliding along about 125 miles of the bluffs on 

the east side of the Mississippi River north of 

Memphis. A repeat of these earthquake-triggered 

landslides today would affect eastern access to 

the Mississippi River, pipelines, and transmission 

towers located in this area.

 The third and probably the most widely felt of 

the three major New Madrid earthquakes occurred 

on February 7, 1812, at about 3:00 a.m. There were 

several destructive shocks that day, the last and 

largest estimated at M7.7. As a result, the town of 

New Madrid, Missouri, was severely damaged.

 Dr. Daniel Drake, a physician in Cincinnati, 

Ohio, kept a detailed account of the New Madrid 

earthquake sequence and cataloged thousands of 

earthquakes. He reportedly used a pendulum-type 

seismograph that “marked the direction of undulation

from south-southwest to north-northeast.”3

 Research indicates that the 1811–1812 New 

Madrid earthquake sequence was preceded by at 

least two similar earthquake sequences in about 

1450 AD and 900 AD, and that over the past 5,000 

years or so, other large earthquakes have also 

occurred in the region surrounding the main area 

of the currently active New Madrid seismic zone.

 Important surface-deformation features caused 

by the 1811–1812 earthquakes are the Reelfoot 

fault scarp (an uplift of the land surface above the 

fault); Reelfoot Lake in western Tennessee; a large 

sand-blow liquefaction field in Arkansas, Missouri, 

and Tennessee; and the Big Lake and St. Francis 

sunken lands in northeastern Arkansas. The New 

Madrid earthquakes covered the region with sand 

blows, thousands of which remain today and can 

be seen as large, light-colored sandy patches in 

agricultural fields.

 Geologists and archaeologists use Native 

American artifacts buried in the upper Mississippi 

River Valley near earthquake deformation features, 

such as liquefaction sand blows, to help determine 

when large prehistoric earthquakes occurred.

 By March 15, 1812, an estimated 2,000 aftershocks had been felt, but it is likely that tens of 

thousands more were not felt or otherwise noted. 

At the time, many people were afraid to enter their 

homes for fear they would collapse. Damage from 

the largest of these shocks was reported from as 

far as about 300 miles away. Today, a robust aftershock sequence like this would impede rescue and 

rebuilding efforts throughout the region.

 As a result of land subsidence and uplift from 

the February 7, 1812, earthquake, water from the 

Mississippi River flooded the area and formed 

Reelfoot Lake. This event added to reports of the 

Mississippi River flowing backwards.

 The strongest earthquakes to occur in the NMSZ4

since the 1811–1812 sequence happened on January 4, 

1843, and October 31, 1895. The 1843 earthquake,

estimated at M6.0 and located near Marked Tree, 

Arkansas, caused damage in Memphis. The 1895 

earthquake, located near Charleston, Missouri, 

estimated at M6.3−6.6, caused extensive damage to 

chimneys, walls, and windows in homes, churches, 

and schools in the area; and caused damage to almost 

all the commercial buildings in downtown Charleston.

 The first seismograph in the region (called a 

Wiechert) was installed at Saint Louis University 

in 1909. This instrument recorded its first earthquake on October 9 of that year.

 In the 1930s, a seismograph was installed in Cape

Girardeau, Missouri. It is the oldest continuously 

recording seismic station specifically installed to 

study the NMSZ. In 1974, installation began on a 

dense network of 50 seismic stations in and around 

the NMSZ. Today there are about 270 seismograph 

stations in the New Madrid cooperative network in 

the area between St. Louis and Memphis.

 There is a 7–10% chance or probability that a 

quake of magnitude 7.0 or greater will occur in 

the New Madrid region within the next 50 years. 

The probability of a quake of magnitude 6.0 or 

greater occurring during the same time period is 

somewhere between 28 and 46%.

 A M5.0 earthquake occurred in Poinsett County, 

Arkansas, at the southern end of the NMSZ, on 

March 24, 1976. It was felt over 174,000 square 

miles and caused power outages, downed telephone 

lines, broken windows, and roof damage.

1

An earthquake’s magnitude (M) represents the size of the earthquake determined from

 seismographic observations.

2

From J.H.B. Latrobe’s First Steamboat Voyage on the Western Waters (1871). Hosted

 online by the Making of America digital library (University of Michigan) at

 http://quod.lib.umich.edu.

3

From Daniel Drake’s Natural and Statistical View, or A Picture of Cincinnati and the Miami

 Country, Illustrated by Maps (1815). Published in Cincinnati, Ohio, by Looker and Wallace. 4

New Madrid Seismic Zone.

First Mainshock Earthquake

Second Mainshock Earthquake

Third Mainshock Earthquake

First steamboat voyage interrupted

Riverbanks caved, widespread flooding

Only 5,700 people lived in St. Louis in 1811

Landslides

Widespread ground failure and

sand blows

Reelfoot Lake forms

Thousands of aftershocks

It had happened before 1811

More quakes—M6.0 in 1843, M6.6 in 1895

1909—Seismograph installed at 

Saint Louis University

Growth of seismograph network

Another quake—M5.0 in 1976

Archaeological age constraints on Will a damaging earthquake occur again earthquake timing

 In 1814, Missouri Territorial Governor William 

Clark (of the Lewis & Clark Expedition) asked for 

Federal relief for the “inhabitants of New Madrid 

County.” In response, Congress allocated $50,000 

for recovery in 1815. This was the first disaster 

relief act in the United States. Today, a repeat of 

the New Madrid earthquake sequence would cause 

billions of dollars in damage, especially to older 

unreinforced brick buildings.

First Disaster Relief Act

Homemade seismograph records quakes

in Cincinnati

For more information concerning this publication, contact:

Center Director, USGS Geologic Hazards Science Center

Box 25046, Mail Stop 966 

Denver, CO 80225

Phone: (303) 273-8579 

Web site: http://geohazards.cr.usgs.gov/

Publishing support: 

Edited by Melanie Parker, Denver Publishing Service Center

Design and layout by Carol Quesenberry, Denver Publishing Service Center

IOWA

MISSOURI

ARKANSAS TENNESSEE

MISSISSIPPI

KENTUCKY

ILLINOIS

INDIANA

MICHIGAN

IOWA

MISSOURI

ARKANSAS TENNESSEE

MISSISSIPPI

ALABAMA

KENTUCKY

ILLINOIS

INDIANA

MICHIGAN

ALABAMA

Chicago

Saint Louis

Memphis

Jonesboro

Jackson

Clarksville

Paducah

Moline

Joliet

Huntsville

Florence

Peoria

Rockford

Davenport

South Bend

Evansville

Cedar Rapids

Waterloo

Alton

Pine Bluff

Terre Haute

Belleville

Bloomington

Kankakee

Chicago Heights

Waukegan

Decatur

Decatur

Champaign-Urbana

Bloomington

Lafayette

Columbia

Kokomo

Owensboro

Iowa City

Ottumwa

Saint Charles

Dubuque

Cape Girardeau

Poplar Bluff

Jefferson 

City

Little Rock

Springfield

Nashville

Indianapolis

Miss ouri River

Mississippi River

Ark ansas River

M ississippi River

Tennessee River

Lake Michigan

Ohio River

1843

1811

1812 1812 1865

1895

1917

1968

1857

1838

1891

2008

1987

1909

Earthquake Magnitude

3.0–3.9

4.0–4.9

5.0–6.9

1811–1812 Event

1

2

3

4

5

6

7

8

9 12

1

4

7

13

14

11

10

15

16

17

19

18

ILLINOIS

MISSOURI

ARKANSAS

MISSISSIPPI ALABAMA

TENNESSEE

KENTUCKY

INDIANA

New Madrid, MO

New Madrid

Seismic Zone

EXPLANATION

INDEX MAP

Selected historical earthquakes (since 1811) 

and earthquakes recorded by instrument 

from 1974 to early 2010

New Madrid

Bicentennial

Information 

http://newmadrid2011.org

USGS

Earthquake

Program

http://earthquake.usgs.gov

USGS

Earthquake

Handbook

http://pubs.usgs.gov/gip/119

New Madrid

20 Cool Facts

Poster

http://pubs.usgs.gov/gip/134