Earthquakes in Arkansas and Vicinity 1699–2010

U.S. DEPARTMENT OF THE INTERIOR

U.S. GEOLOGICAL SURVEY

Base from U.S. Geological Survey National Elevation Dataset

(http://nationalmap.gov/viewers.html).

National Hydrologic Database, and Digital Chart of the World (ESRI, 1993) 

Albers equal-area conic projection, standard parallels 30°30’00”

and 35°00 ́00 ́ ́, central meridian 81°00 ́00 ́ ́, latitude of origin 00°00’00”

Regional Seismic Hazard

SCALE 1:4 000 000

Geographic Projection NAD83

MEMPHIS

LITTLE ROCK

MONROE

MISSISSIPPI

LOUISIANA

ARKANSAS

MISSOURI

TEXAS

OKLAHOMA

SHREVEPORT

TENNESSEE

JACKSON

PINE BLUFF

SPRINGFIELD

FORT SMITH

KANSAS

WEST GULF COASTAL PLAIN

MISSISSIPPI ALLUVIAL PLAIN

SPRINGFIELD-SALEM PLATEAUS

EAST GULF COASTAL PLAIN

OSAGE PLAINS

OUACHITA MOUNTAINS

ARKANSAS VALLEY

TILL PLAINS

BOSTON "MOUNTAINS"

HIGHLAND RIM

90°

90°

92°

92°

94°

94°

38° 38°

36° 36°

34°

32°

34°

32 32°

1911

1919

1971

1938

1843

1976

1976

1878

1811

1970

2003

1939

1969

1982

1982

Oklahoma

Arkansas

Tennessee

Missouri

Mississippi

Louisiana

1972

1898

1974

1974

1977

2010 1879

1924

2001

1918

1918

1937 1966

1952

1976

1865

1883

Texas

2005

1933 1971

18651955

1883

1918

1982

1947

1982

1927

2005

1923

1923

Memphis

Jackson

Monroe

Little Rock

Shreveport

Fort Smith

Joplin

Pine Bluff

Texarkana

Longview

North Little Rock

Marshall

Greenville

Hot Springs

Bastrop

Bartlett

Springfield

El Dorado

Ruston

Fayetteville

Jonesboro

Camden

Springdale

Miami

Mena

Kilgore

Hope

Searcy

Kennett

White Oak

Warren

Canton

Linden

Minden

Poplar Bluff

Tallulah

Carthage

Sylvan Hills

Ripley

Greenwood

Paragould

Clarksdale

Blytheville

Jacksonville

Crossett

Vicksburg

Bossier City

Vinita

Cairo

Barling

West Memphis

Conway

Benton

Hayti

Magnolia

Grenada

Harrison

Van Buren

Monett

Paris

Idabel

Webb City

Sikeston

Ava

Neosho

Rogers

Malvern

Leland

Fordyce

Homer

Dyersburg

Stuttgart

Jefferson

Collierville

West Plains

Cleveland

Wynne

Wister

Clinton

Helena

Batesville

Forest

Monticello

Yazoo City

Osceola

Eudora

Hamburg

Dumas

Sardis

Brinkley

Batesville

Pocahontas

Newport

Millington

Russellville

Mount

Pleasant

Heavener

Aurora

Rector

Indianola

Ava

Picher

Marianna

Atlanta

Dermott

Morrilton

Dexter

Tchula

Walnut Ridge

Galena

Earle

Malden

Kosciusko

Pearl

Pittsburg

Gilmer

McAlmont

Foreman

Poteau

Springhill

Prescott

Mountain Home

Cullen

North

Shreveport

Brownsville

Morton

Thayer

Itta Bena

Oxford

Steele

De Witt

Halls

McGehee

Charleston

Forrest City

Piggott

Vivian

Durant

Arkadelphia

Chetopa

Columbus

Clarksville

Shelby

Atkins

Advance

Augusta

Marks

Drew

Parkin

Lexington

Clarendon

De Queen

Hooks

Obion

Tahlequah

Belzoni

De Kalb

Bentonville

Lonoke

Nashville

Daingerfield

West Helena

Covington

Arcadia

Afton

Rayville

Judsonia

Lake

Village

Calion

Holly

Springs

Leola

Vian

Caruthersville

Delhi

Strong

Granby

Shaw

Heber Springs

East Prairie

Hickman

Doniphan

Sallisaw

Marvell

Clarksville

Stamps

Mansfield

Corning

Webb

Tunica

Capleville

Huttig

Rison

Grove

Sheridan

Mammoth Spring

Mound City

Oak

Grove

Kensett

Marionville

Como

Berryville

Alton

Gladewater

Ashdown

Senatobia

Hazen

Dierks

Charleston

Baxter Springs

England

Oswego

Moorhead

Trumann

Waskom

Bernice

Charleston

Haynesville

Stigler

Star City

Gould

Benton

Ruleville

Oran

Hartford

Somerville

Bruce

Monette

New Boston

Imboden

Hollandale

Salem

Arbyrd

Hampton

New Madrid

McCurtain

Republic

Keota

Booneville

Gillett

Cabot

Tuckerman

Bearden

Campbell

Water Valley

Carlisle

Stilwell

Danville

Mount Vernon

Luxora

Coldwater

Pierce City

Ozark

Piedmont

Rosedale

Bernie

Lepanto

Panama

Hernando

Fowlkes

Cotton Plant

Commerce

Edwards

Mountain Grove

Billings

Ridgely

Bradford

Caraway

Wilson

De Valls Bluff

Pangburn

Avinger

Lake Providence

Tiptonville

Bono

Quitman

Lambert

Farmerville

Crenshaw

Altheimer

Delight

Portageville

Siloam Springs

Bokoshe

Bloomfield

Clinton

Lincoln

Smackover

Hughes Springs

Waltersville

Plain

Dealing

Arkansas City

Morehouse

Broken Bow

Queen City

Mer Rouge

Rosemark

Lockesburg

Mountain View

Wright City Carthage

Gurdon

Kingsland

Pelahatchie

Gravette

Bald Knob

North Highlands

Lewisville

Mound Bayou

Junction City

Leachville

Lone Star

Sterlington

Westville

Yellville

Maury City

Olive Branch

Marked Tree

Gosnell

Calhoun City

Grady

Mansfield

Dardanelle

Saint Charles Friars Point

Gibsland

Gunnison

Oak

Ridge

Harrisburg

Mountain

View

Crowder

YELL

CASS

LEE

LE FLORE

POLK

POPE

WHITE

UNION

MCCURTAIN

BOWIE

PIKE

DREW

UNION

CLARK

SCOTT

YAZOO

ASHLEY

CLAY

DESHA

BARRY HOWELL

OZARK

CADDO

SHELBY

SALINE

BENTON

BOLIVAR

BOSSIER

LOGAN

PULASKI

DYER

TANEY

ARKANSAS

LONOKE

RIPLEY

IZARD

LEAKE

CROSS

BUTLER

SHARP

NEWTON

HOLMES ATTALA

ADAIR

OREGON

STONE

MILLER

PERRY

PRAIRIE

GRANT

HARRISON

SEVIER

CHICOT

PHILLIPS

MADISON

SEARCY

DALLAS

JEFFERSON

PANOLA

BOONE

MISSISSIPPI

DOUGLAS

TATE

POINSETT

MARION

FAYETTE

MADISON

BAXTER

FULTON

STONE

SCOTT

GREENE

GARLAND

NEVADA

WAYNE

DELAWARE

BRADLEY

STODDARD

COLUMBIA

LEFLORE

TITUS

JOHNSON

NEWTON

JACKSON

MONROE

CARROLL

WEBSTER

WASHINGTON

OUACHITA

CARROLL

CLAIBORNE

CHEROKEE

UPSHUR

MARSHALL

HOWARD

CARTER

LINCOLN

SEQUOYAH

FAULKNER

MOREHOUSE

RED RIVER CALHOUN

VAN BUREN

CONWAY

FRANKLIN

TUNICA

HEMPSTEAD

DUNKLIN

CRAIG

CRAIGHEAD

TIPTON

LAFAYETTE

HINDS

RANDOLPH

SUNFLOWER

CLEBURNE

SHANNON

DE SOTO

ST FRANCIS

LAWRENCE

WASHINGTON

OTTAWA

COAHOMA

MONTGOMERY

OUACHITA

LINCOLN

NEW MADRID

CRAWFORD

CHRISTIAN

SCOTT

WOODRUFF

CLEVELAND

MARION

PEMISCOT

HOT SPRING

SEBASTIAN

INDEPENDENCE

TEXAS

CRITTENDEN

LAFAYETTE

SHARKEY

BIENVILLE

GRENADA

WARREN

MADISON

MCDONALD

RANKIN

LITTLE RIVER

JASPER

TALLAHATCHIE

LAWRENCE

RICHLAND

QUITMAN

CALHOUN

YALOBUSHA

OBION

MAYES

GREGG

ISSAQUENA

LAUDERDALE

MISSISSIPPI

HAYWOOD

MORRIS

CAMP

CHEROKEE

GREENE WRIGHT

JACKSON

LATIMER

WEBSTER

RUSK

WEBSTER

REYNOLDS BOLLINGER

HASKELL

LAKE

HUMPHREYS

EAST

CARROLL

WEST

CARROLL

PUSHMATAHA

BENTON

SMITH

CHOCTAW

FULTON

PANOLA FRANKLIN

ALEXANDER

TIPTON

FULTON

HICKMAN

WINSTON

DE SOTO

NESHOBA

GIBSON LCAR

HHAR

WHAR

WLAR

CCAR

90°

90°

91°

91°

92°

92°

93°

93°

94°

94°

95°

95°

37°

37°

36°

36°

35°

35°

34°

34°

33°

33°

SCALE 1:1 150 000

Albers Conic Equal-Area Projection

0 12.5 25 50 75 100 125

MILES

0 25 50 75 100 125

KILOMETERS

0 25 50 75 100 125

MILES

EXPLANATION

%g (2%/50yrs)

160–200

120–159

80–119

60–79

50–59

40–49

30–39

20–29

18–19

16–17

14–15

12–13

10–11

8–9

6–7

4–5

2–3

0–1

Physiographic

Province

Urbanized Area

0 12.5 25 50 75 100 125

KILOMETERS

NEW MADRID

SEISMIC ZONE

EXPLANATION

Magnitude

<3.0

3.0–3.9

4.0–4.9

5.0–5.9

6.0–6.9

>6.9 

Seismic network station

CCAR—Station name

Deformation area

Sunken land

Depressed area

Submerged area

LEE County Name

Urbanized Area

Prepared in cooperation with

the Arkansas Geological Survey

Enola Earthquake Swarm Area

Earthquake Locations

COLUMBIA

ABBREVIATED MODIFIED MERCALLI

INTENSITY SCALE 

Expressed as Roman numerals, earthquake intensities are not 

instrumentally derived; they are assigned values based on descriptive 

reports of felt shaking and damage. The different intensity levels 

are defined as folllows:

 I. Not felt. 

 II. Felt by a few persons at rest, especially on upper floors, or in 

 favorable locations. 

 III. Felt indoors, especially on upper floors. Hanging objects swing. 

 Many may not recognize it as an earthquake. Standing automobiles 

 may rock slightly. Vibrations felt. Duration estimated.

 IV. Felt outdoors by many. Some sleepers awaken. Dishes, glasses, 

 windows, doors clink and rattle. Walls make creaking sounds. 

 Heavy vibrations and jolting sensations felt. Standing automobiles 

 rock noticeably.

 V. Felt outdoors. Felt by nearly everyone; many sleepers awaken. 

 Unstable objects are displaced. Liquids are disturbed. Pendulum 

 clocks may stop. Doors swing. Pictures move.

 VI. Felt by all, many frightened, some panic. Walking unsteady. 

 Windows break, pictures fall. Objects fall off shelves. Furniture 

 moves and is overturned. Some plaster cracking and falling. Damage 

 to buildings is slight. Trees and bushes shake.

 VII. Difficulty standing. Noticeable to drivers. Hanging objects move. 

 Furniture breaks. Some damage to buildings. Some wall cracking 

 and plaster falling. Some chimneys break. Small landslides form. 

 Waves and water turbidity noticed. 

VIII. Damage to structures variable (slight to considerable) depending on 

 Construction style. Chimneys, factory stacks, columns, 

 monuments, and towers may twist and fall. Heavy furniture is overturned. 

 Masonry and stucco is damaged. Tree limbs break. Flow and temperature 

 changes occur in wells and springs. Some ground cracking. Steering 

 impaired.

 IX. General panic. Damage great in substantial buildings with partial 

 collapse. Buildings shifted off foundations. Serious damage to reservoirs 

 and underground pipelines. Ground cracks and liquefaction features form 

 in alluvial areas.

 X. Some well-built wooden structures are destroyed; most masonry and 

 frame structures are destroyed. Rails are bent. Heavy 

 damage to dams and embankments occurs. Large landslides form.

 XI. Few, if any (masonry) structures remain standing. Bridges are destroyed. 

 Rails are bent greatly. Underground pipelines are disabled.

XII. Damage nearly total. Large rock masses are displaced. Lines of sight and 

 level are distorted. Objects are thrown into the air.

Seismic hazard is expressed as 

peak ground acceleration (PGA) 

on firm rock, in percent g, expected 

to be exceeded in a 50-year period 

with a probability of 2 percent.

Data from Petersen and others, 2008

Base from National Hydrologic Database, 

and Digital Chart of the World (ESRI, 1993)

ISOSEISMAL MAPS

The isoseismal maps (below) show interpolated and contoured intensity values for the January 5, 1843, intensity VII; and the December 16, 1811, intensity XI

northeast Arkansas earthquakes. The locations of intensity observations and their assigned values are shown as solid colored circles. The December 16, 1811,

earthquake at 2:15 a.m. local time (08:15 UTC), was the first event in the New Madrid sequence. Intensity data for this event came from Hough and others

(2000), Hough and Martin (2002), Bakun and others (2002), Street (1982), and Nuttli (1973). Intensity data for the 1843 event came from Bakun and others

(2002). The data were interpolated using an inverse distance weighted algorithm. The extent of interpolation was defined by the locations of the intensity

observations.

REFERENCES

Ausbrooks, S.M. and Doerr, J.W., 2007, Enola Swarm Area —Faulkner County, Arkansas: Arkansas Geological Survey,

GH–EQ–ENOLA–002 map.

Bakun, W.H., Johnston, A.C., and Hopper, M.G., 2002, Modified Mercalli Intensities (MMI) for large earthquakes near

New Madrid, Missouri, in 1811–1812 and near Charleston, South Carolina, in 1886: U.S. Geological Survey Open-File

Report 02–184, 31 p.

Bolt, B.A., 1978, Earthquakes — Primer: San Francisco, W.H. Freeman and Company, 241 p.

Cox, R.T., and Van Arsdale, R.B., 1997, Investigation of surface faulting in the southern Mississippi embayment: Technical

report to U.S. Geological Survey, Contract 1434–HQ–97–GR–03014, 30 p.

Crone, A.J., compiler, 1998, Fault number 1026, Saline River fault zone, in Quaternary fault and fold database of the

United States: U.S. Geological Survey accessed on March 10, 2010 at http://earthquakes.usgs.gov/regional/qfaults.

Crone, A.J., and Schweig, E.S., compilers, 1994, Fault number 1023, Reelfoot scarp and New Madrid seismic zone, in

Quaternary fault and fold database of the United States: U.S. Geological Survey, accessed on March 10, 2010

at http://earthquakes.usgs.gov/regional/qfaults .

Dart, R.L., and Hansen, M.C., 2008, Earthquakes in Ohio and vicinity 1776–2007: U.S. Geological Survey Open-File

Report 2008–1221. [Available at http://pubs.usgs.gov/of/2008/1221/].

Dart, R.L., Talwani, Pradeep, and Stevenson, Donald, 2010, Earthquakes in South Carolina and Vicinity 1898–2010: U.S.

Geological Survey Open-File Report 2010–1059. [Available at http://pubs.usgs.gov/of/2010/1059/].

Ervin, C.P ,

., and McGinnis, L.D., 1975, Reelfoot rift—Reactivated precursor to the Mississippi embayment: Geological

Society of America Bulletin, v. 86, p. 1287–1295.

ESRI, 1993, Digital Chart of the World for use with ARC/INFO, data dictionary: ESRI, Redlands, California

at http://www.esri.com/ .

Fenneman, N.M., and Johnson, D.W., 1946, Physical divisions of the United States: U.S. Geological Survey, 1 sheet, scale

1:7,000,000.

Guccione, M.J., and VanArsdale, R.B., 1995, Origin and age of the St. Francis Sunklands using dranage patterns and

 sedimentology: Final report submitted to the U.S. Geological Survey, Award no. 1435–93–G–2354, Washington, D.C.

Guccione, M.J., VanArsdale, R.B., and Hehr, L.H., 2000, Origin and age of the Manila high and associated Big Lake

"Sunklands" in the New Madrid seismic zone, northeastern Arkansas: Geological Society of America Bulletin 112, p.

579–590.

Hildenbrand, T.G., Kane, M.F., and Hendricks, J.D., 1982, Magnetic basement in the upper Mississippi embayment

region—A preliminary report, in McKeown, F.A., and Pakiser, L.C., eds., Investigations of the New Madrid, Missouri,

earthquake region: U.S. Geological Survey Professional Paper 1236, p. 39–53.

[Available at http://pubs.er.usgs.gov/usgspubs/pp/pp1236/ ].

Hildenbrand, T.G., 1985, Rift structure of the northern Mississippi embayment from the analysis of gravity and magnetic

data: Journal of Geophysical Research, v. 90, no. B14, p. 12607–12622.

Hough, S. E., Armbruster, J. G., Seeber, L., and Hough, J. F., 2000, On the modified Mercalli intensities and magnitudes of

the 1811–1812 New Madrid, central United States earthquakes: Journal of Geophysical Research, v. 105, p.

23839–23864.

Hough, S. E. and S. Martin, 2002, Magnitude estimates of two large aftershocks of the 16 December 1811 New Madrid

earthquake: Bulletin of the Seismological Society of America 92, p. 3259–3268.

Jibson R.W. and Keefer, D.K., 1988, Landslides Triggered by Earthquakes in the central Mississippi valley, Tennessee and

Kentucky: U.S. Geological Survey Professional Paper 1335–C, 24 p.

McFarland, J.D., 2001, Faulkner County earthquakes: Arkansas Geolgical Commission Open-File Report.

Nuttli, O.W., 1973, The Mississippi Valley earthquakes of 1811 and 1812: Intensities, ground motion, and magnitudes:

Bulletin of the Seismological Society of America, v. 63, p. 227-248.

Obermeier, S.F., Weems, R.E., and Jacobson, R.B. 1987, Earthquake-induced liquefaction features in the coastal South

Carolina region: U.S. Geological Survey Open-File Report 87–504.

Obermeier, S.F., 1988, Liquefaction potential in the central Mississippi Valley: U.S. Geological Survey Bulletin 1832, p. 21.

[Available at http://pubs.er.usgs.gov/usgspubs/b/b1832/ ].

Petersen, M.D., Frankel, A.D., Harmsen, S.C., Mueller, C.S., Haller, K.M., Wheeler, R.L., Wesson, R.L., Zeng, Yuehua,

Boyd, O.S., Perkins, D.M., Luco, Nicolas, Field, E.H., Wills, C.J., and Rukstales, K.S., 2008, Documentation for the

2008 update of the United States national seismic hazard maps: U.S. Geological Survey Open-File Report

2008–1128, 61 p. [Available at http://pubs.usgs.gov/of/2008/1128/ ].

Rabak, Ivan, Langston, Charles, Bodin, Paul, Horton, Steve, Withers, Mitch, and Powell, Christine 2010, The Enola,

Arkansas, Intraplate swarm of 2010: Seismological Research Letters, v. 81, no. 3, p. 549–559.

Stover, C.W., and Coffman, J.L., 1993, Seismicity of the United States Earthquakes, 1568–1989 (revised): U.S. Geological

Survey Professional Paper 1527, p. 327–331. [Available at http://pubs.er.usgs.gov/usgspubs/pp/pp1527/ ].

Street, R. W., 1982, A contribution to the documentation of the 1811–1812 Mississippi Valley earthquake sequence:

Earthquake Notes, 53, p. 39–52.

Tarr, A.C., and Wheeler, R.L., 2006, Earthquakes in Virginia and vicinity 1774–2004: U.S. Geological Survey Open-File

Report 2006–1017. [Available at http://pubs.usgs.gov/of/2006/1017/ ].

Wheeler, R.L., 2003, Tectonic summaries for web-served earthquake responses, southeastern North America: U.S.

Geological Survey Open-File Report 03–343, 27 p. [Available at http://pubs.usgs.gov/of/2003/ofr-03-343 ].

Wheeler, R.L., Omdahl, E.M., Dart, R.L., Wilkenson, G.D., and Bradford, R.H., 2003, Earthquakes in the Central United

States 1699–2002: U.S. Geological Survey Geologic Investigation Series I–2812.

This map summarizes approximately 300 years of Arkansas earthquake history. It is one in a series

of similar State earthquake-history maps. Work on the Arkansas map was done in collaboration with

the Arkansas Geological Survey. The three previously released maps for Virginia (Tarr and Wheeler,

2006), Ohio (Dart and Hansen, 2008), and South Carolina (Dart and others, 2010) are accessible at

http://pubs.usgs.gov/of/2006/1017/, http://pubs.usgs.gov/of/2008/1221/, and http://pubs.usgs.

gov/of/2010/1059/.

As with the three previous maps, the history of Arkansas earthquakes was derived from letters,

journals, diaries, newspaper accounts, academic journal articles, and beginning in the early 20th

century, instrumental recordings (seismograms). All historical (pre-instrumental) earthquakes that

were large enough to be felt have been located based on felt reports. Some of these events caused

damage to buildings and their contents. The more recent widespread use of seismograph recordings

has allowed many smaller magnitude earthquakes, previously undetected, to be located. The

earthquake location map (center right) shows historically located and instrumentally recorded

earthquakes in and near Arkansas. Most of these are instrumentally recorded events.

EARTHQUAKES

Earthquakes occur as a result of slip on faults, typically many kilometers underground, and most

earthquakes occur along the boundaries of moving crustal plates. Arkansas is within the North

American plate. The nearest plate boundary is approximately 1,700 kilometers south of Arkansas

near the coast of Honduras, where the North American and Caribbean plates join, and is not related

to the earthquakes in this region. Usually, it is not possible to determine exactly which faults cause

earthquakes. Accordingly, the most direct indicators of earthquake hazards are the earthquakes

themselves, not the faults on which they occur or the motions of crustal plates. No known

seismogenic faults have been mapped at the ground surface within Arkansas.

Before earthquakes were instrumentally recorded, their locations at the ground surface (epicenters)

were estimated, typically within a few tens of kilometers of their actual locations. Even with modern

instrumentation, earthquake locations within the earth (hypocenters) are only approximations,

usually within several kilometers of their actual subsurface locations. However, in areas where

seismic networks of closely spaced recording instruments exist, earthquakes are more accurately

located. The earthquake location symbols used on the map (center right) represent the best estimates

of location and magnitude for both pre-instrumental and instrumental earthquakes. These data came

from several earthquake sources (see list, below).

Intensity and Magnitude

An earthquake's magnitude (M) and intensity are measurements of its size and the severity of ground

shaking, respectively. Although earthquake magnitude is characterized by a single

number, intensity is expressed as a range of values based on varying levels of ground shaking over

the affected (felt) area.

Typically, ground shaking will decrease from a maximum near the earthquake's epicenter to its

lowest levels near the edge of the felt area. Intensity values are determined from the Modified

Mercalli Intensity Scale (MMI, lower right), based on written accounts (letters, journals, and

diaries), and published records (newspapers and official reports) of the ground shaking effects that

people, buildings, and landscape have undergone within the affected region. The Modified Mercalli

Intensity Scale consists of a range of values from Roman numeral I, barely felt or not felt, to XII,

near total destruction. Isoseismal maps show the estimated level of ground shaking in terms of the

distribution of intensities and the general pattern of decreasing shaking away from an earthquake’s

epicenter. Isoseismal maps also illustrate how different ground conditions can affect ground shaking,

resulting in intensity patterns that may be more irregular than expected.

An earthquake's size reflects the total energy released and is measured in logarithmic units of

magnitude. This means that the amount of energy released during an earthquake will be 30 times

greater for a magnitude 5 earthquake than for a magnitude 4 earthquake (Bolt, 1978). There are

several methods of calculating magnitude, all are based on seismic wave variables as recorded on

earthquake seismograms. The different measuring methods can give slightly different magnitude

values for the same earthquake. As a result, differences of several tenths of a magnitude may be

reported. A more complete discussion of magnitude and the U.S. Geological Survey policy on

reporting magnitude can be found at http://earthquake.usgs.gov/aboutus/docs/

020204mag_policy.php. For pre-instrumental earthquakes, magnitudes are estimated from intensity

values that were recorded at the time of the earthquake or shortly after.

EASTERN U.S. EARTHQUAKES

Earthquakes are less common east of the Rocky Mountains than in Pacific coast states, such as

California. However, because of differences in geologic properties, an earthquake in the central

United States (U.S.) of the same magnitude as a West Coast earthquake can affect a much larger

area, by about ten times. A magnitude 4 central U.S. earthquake typically can be felt 100 km (60 mi)

from where it occurred. By comparison, a magnitude 5.5 central U.S. earthquake usually can be felt at a

distance of 500 km (300 mi) (Tarr and Wheeler, 2006).

EARTHQUAKES IN ARKANSAS AND VICINITY

In terms of tectonic setting, Arkansas is part of a much larger province known as the Stable

Continental Region (Wheeler, 2003), which includes all of eastern North America. Exclusive of

several selected areas, like the New Madrid Seismic Zone, the Stable Continental Region undergoes

infrequent earthquakes. When earthquakes do occur, they can happen almost anywhere and at

irregular intervals. Although there are many known faults within the Stable Continental Region of

North America, few of the earthquakes that occur here are associated with known faults.

Various institutions and agencies compile earthquake data. The earthquake data plotted on the map

(right) are from several sources. Below are these sources and the time periods of their data listings.

• AGS (Arkansas Geological Survey), 1699–2010

,

• MDEQ (M.B.E. Bograd, Mississippi Department of Environmental Quality, personal commun., 2010),

1853–2002

,

• NMSN/CERI (New Madrid Seismic Network/Center for Earthquake Research and Information),

1974–2010

• NCEER (National Center for Earthquake Engineering Research), 1627–1985

• PDE (Preliminary Determination of Epicenters), 1973–2010

The earthquake location symbols shown on the map are sized and colored according to magnitude

(see map explanation, right). The map is intended as a general information tool only, and not for

hazard assessment or engineering design purposes.

New Madrid Seismic Zone

Northeastern Arkansas is located within the New Madrid seismic zone, the most seismically active

area in central and eastern North America. In the winter of 1811–1812, at least three major

earthquakes occurred in the New Madrid seismic zone. They were among the largest historical

earthquakes to occur in North America. The modern seismicity in the New Madrid seismic zone is

associated with the Reelfoot rift (Ervin and McGinnis, 1975), a northeasterly-trending, 70-km-wide,

deeply buried graben (Hildenbrand and others, 1982; Hildenbrand, 1985). The seismicity and current

deformation in the region are controlled by a regional stress field in which the maximum compressive

stress is oriented approximately east-northeast-west-southwest. Within this stress field, ancient

faults, most of which originally formed as extensional features during rifting, have been reactivated

mainly as strike-slip faults. The modern seismicity is concentrated into three major trends that form a

northeasterly-trending, zigzag pattern.

Enola Earthquake Swarm

The Enola swarm began with a magnitude 1.2 earthquake on January 12, 1982, near the town of

Enola in Faulkner County, Arkansas. More than 40,000 seismic events have been recorded since this

date. Most of these earthquakes were small-magnitude events that were not felt. However, as many

as 93 of the swarm's recorded events were felt. The largest of these was a magnitude 4.5 earthquake

that occurred on January 21, 1982. No structural damage was reported (Ausbrooks and Doerr, 2007).

The Enola swarm involved several episodes of activity and does not appear to be associated with a

single fault (Rabak and others, 2010). The swarm is not considered to be associated with the New

Madrid seismic zone (McFarland, 2001). The swarm's seismic activity is ongoing, with periods of

increased activity in 2001 and in October 2010. Magnitude 4.0 and 3.8 swarm earthquakes on

October 11 and 15, 2010, were felt widely across Arkansas.

Notable Arkansas Earthquakes

Arkansas has had a long earthquake history. Information about the earthquake history of Arkansas is

available at http://earthquake.usgs.gov/earthquakes/states/arkansas/history.php and

http://earthquake.usgs.gov/earthquakes/states/historical_state.php. Arkansas's earliest seismic event

was documented by Jesuit missionaries in 1699 traveling down the Mississippi River near present

day Helena, Arkansas, in Phillips County (Wheeler and others, 2003). Other notable earthquakes are

felt events within the past 200 years of magnitude 4.0 and greater. Several of these earthquakes

caused property damage within the State. Arkansas' magnitude 4.0 and greater earthquakes are

identified by date and location on the map (center right).

SEISMIC HAZARD

Seismic hazard maps, like the one shown at right, are tools for determining possible risk. As such,

they are critical in helping to save lives and preserve property by providing information essential to

the creation and updating of the seismic design provisions of local building codes. Additional

applications of the information derived from seismic hazard maps include setting insurance rates,

determining related ground-failure hazards, engaging in disaster response planning, and promoting

earthquake education.

Some level of seismic hazard from earthquake ground shaking exists in every part of the United

States. The severity of the ground shaking, however, can vary greatly from place to place. Regional

seismic hazard maps illustrate this variation. The hazard shown on seismic hazard maps is based on a

variety of factors, such as earthquake rate of occurrence, magnitude, extent of affected area, strength

and pattern of ground shaking, and geologic setting.

Because many buildings and other structures in the central United States are not built to withstand

severe ground shaking, damage could be catastrophic in the event of a powerful earthquake. The

generalized seismic hazard map (right) illustrates this hazard. It is a computer generated contour map

(Petersen and others, 2008) portraying seismic hazard calculated by the USGS as color bands (cooler

for lesser hazard, warmer for greater hazard). Shaking level is expressed as a percentage of the

acceleration of gravity (% g), and seismic hazard values are computed for particular time intervals (here,

50 years) and probability of exceedance (here, 2 percent). For example, the hazard value in Little

Rock, Ark., is between 18–30%g .That means structures built on firm rock have a 1 in 50 chance (2-

percent probability) of undergoing ground shaking of 18–30 percent g or higher in the next 50 years. In

terms of shaking, the acceleration a person or object experiences is proportional to the force applied

by the passing seismic wave. The value 50 is a random amount and has no inherent significance.

Seismic hazard maps are estimates of how the ground in a particular area is likely to respond to local

and regional earthquakes. They differ from isoseismal maps (below) in that they are probability maps,

illustrating likely shaking levels. Sediment and soil properties near the ground surface are important

in hazard map design. During an earthquake, seismic energy radiates in all directions as waves. As the

seismic waves move upward they are amplified or de-amplified as they travel through sediment and

soil layers, thus greatly affecting the level of ground shaking that might occur. The map at right is a

regional depiction of ground response to earthquake shaking; it does not show the amplifying or deamplifying effects of local near-surface soil conditions.

For additional information on seismic hazard mapping, consult these internet web links:

http://earthquake.usgs.gov/regional/ceus//urban_map/index.php

http://earthquake.usgs.gov/hazards/

http://earthquake.usgs.gov/hazards/products/

Author's Note:

The information presented was derived from existing

sources and earlier publications. Specifically, the general

earthquake and seismic hazard discussions were modified

from Tarr and Wheeler, 2006.

INTERNET EARTHQUAKE INFORMATION RESOURCES

Advanced National Seismic System (ANSS): http://www.ncedc.org/anss/catalog-search.html. Last accessed on April 27, 2010. Information on U.S. earthquakes.

Arkansas Center for Earthquake Education and Technology Transfer (ACEETT): http://quake.ualr.edu/. Last accessed on June 7, 2010. Information on Arkansas earthquakes.

Center for Earthquake Research and Information (CERI): http://www.ceri.memphis.edu/seismic/catalogs/cat_nm.html. Last accessed on March 17, 2011. The New Madrid

earthquake catalog and information on Central U.S. earthquakes.

Earthquake Engineering Research Institute (EERI): http://www.eeri.org/site/. Last accessed on March 11, 2010. Technical information on earthquakes.

National Center for Earthquake Engineering Research (NCEER): http://folkworm.ceri.memphis.edu/catalogs/html/cat_nceer.html. Last accessed on March 17, 2011.

Information on Central U.S. earthquakes before 1986.

National Earthquake Hazards Reduction Program (NEHRP): http://www.nehrp.gov/ and the National Seismic Hazards Maps Program

(NSHM): http://earthquake.usgs.gov/hazards/products/conterminous/2008/catalogs/. Last accessed on Mary 15, 2010. Information on hazards risk reduction in the United

States and information on U.S. probabilistic maps and data.

National Geophysical Data Center (NGDC/DNAG/NOAA): http://www.ngdc.noaa.gov/hazard/earthqk.shtml. Last accessed on March 11, 2010. Information on geophysical

data products and services.

U.S. Geological Survey National Earthquake Information Center (NEIC), Preliminary Determination of Epicenters (PDE), Significant U.S. Earthquakes (Stover and Coffman,

1993), Significant Earthquakes in the U.S. catalog (USHIS), and Eastern, Central and Mountain States of U.S.

(SRA): http://earthquake.usgs.gov/earthquakes/eqarchives/epic/; and Earthquake Hazard Program: http://earthquake.usgs.gov/, call toll-free 1–888–ASK–USGS. Last

accessed on May 15, 2010. Information on global earthquakes.

Physiographic regions are divisions 

of the land surface based on terrain 

te

° xture, rock type, and geologic 

structure and history as defined by 

Fenneman and Johnson (1946). 

Differences in near-surface geologic 

conditions affect how seismic energy 

propagates through the ground and 

how it is amplified at the ground 

surface.

1U.S Geological Survey, Box 25046, MS 966, Denver, CO 80225 USA

2 Arkansas Geological Survey, 3815 West Roosevelt Rd., Little Rock, AR 72204, USA

Any use of trade, product or firm names is for descriptive purposes only and 

does not imply endorsement by the U.S. Government.

Although this information product, for the most part, is in the public domain, it 

also contains copyrighted materials as noted in the text. Permission to 

reproduce copyrighted items for other than personal use must be secured 

from the copyright owner.

Although these data have been processed successfully on a computer system 

at the U.S. Geological Survey, no warranty expressed or implied is made 

regarding the display or utility of the data on any other system, or for general 

or scientific purposes, nor shall the act of distribution constitute any such 

warranty. The U.S. Geological Survey shall not be held liable for improper or 

incorrect use of the data described and/or contained herein.

The suggestions and illustrations included in this document are intended to 

improve earthquake awareness and preparedness; however, they do not 

guarantee the safety of an individual or structure. The contributors and 

sponsors of this publication do not assume any liability for any injury, death, 

property damage, or other effects of an earthquake.

This and other USGS information products are available at

http://store.usgs.gov/. 

U.S. Geological Survey

Box 25286, Denver Federal Center

Denver, CO 80225

To learn about the USGS and its information products visit

http://www.usgs.gov/. 

1-888-ASK-USGS

This report is available at:

http://pubs.usgs.gov/of/2011/1118

Publishing support provided by: 

Denver Science Publishing Network

Manuscript approved for publication on May 3, 2011.

For more information concerning this publication, contact:

Center Director, USGS Geologic Hazards Science Center

Box 25046, Mail Stop 966

Denver, CO 80225

(303) 273–8679

Or visit the Geologic Hazards Science Center Website at:

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

Suggested citation:

Dart, R.L, and Ausbrooks, S.M., 2011, Earthquakes in

Arkansas and vicinity 1699–2010: U.S. Geological Survey

Open-File Report 2011–1118, 1 sheet.

KANSAS

MISSOURI

OKLAHOMA

ARKANSAS

TEXAS

LOUISIANA

MISSISSIPPI

TENNESSEE

EXTENT OF DATA COVERAGE

90°

90°

93°

93°

36°

36°

33°

33°

Distribution of Intensity for the December 16, 1811, northeast 

Arkansas, maximum intensity XI, magnitude 8.1 earthquake

KANSAS

MISSOURI

OKLAHOMA

ARKANSAS

MISSISSIPPI

TEXAS LOUISIANA

90°

90°

93°

93°

36°

36°

33°

33°

Distribution of intensity for the January 5, 1843, northeast 

Arkansas, maximum intensity VII, magnitude 6.0 earthquake

Base from U.S. Geological Survey 

National Elevation Dataset, National 

Hydrologic Database, and Digital 

Chart of the World (ESRI, 1993)

Albers equal-area conic projection, 

standard parallels 29°30’00” and 

39°30’00”, central meridian -90°

00’00”, latitude of origin 0°00’00”

Base from U.S. Geological Survey 

National Elevation Dataset, National 

Hydrologic Database, and Digital 

Chart of the World (ESRI, 1993)

Albers equal-area conic projection, 

standard parallels 29°30’00” and 

39°30’00”, central meridian -90°

00’00”, latitude of origin 0°00’00”

SCALE 1:5 000 000

0 50 100 150 200 KILOMETERS

0 50 100 150 200 MILES

EXTENT OF DATA COVERAGE

SCALE 1:5 000 000

0 50 100 150 200 KILOMETERS

0 50 100 150 200 MILES

New Madrid Seismic Zone

 and Liquefaction Area

Saline River

 Fault Zone

EL DORADO

ARKANSAS AREAS OF DEFORMATION, LIQUEFACTION, AND FAULTING

The U.S. Geological Survey Quaternary Faults Database (http://earthquake.usgs.gov/qfaults)

documents several areas of known and inferred recent deformation and faulting within the map area.

The word recent refers to events that are of Quaternary age (younger than 1.6 million years). These

areas in Arkansas are shown on the Earthquake Location Map (above) and described below.

As a result of strong ground shaking, liquefaction features often develop in the epicentral areas of

large earthquakes. Liquefaction features are ground-surface features that form when buried saturated

sand, under pressure due to the shaking, liquefies and vents upward, often in the form of sand and

water geysers, known as sand blows. The resulting sand deposits are typically circular in shape and

several meters in diameter. Over time, these sand deposits can themselves become buried forming

buried sand lenses. In regions having long seismic histories, paleoseismologists are sometimes able to

excavate these buried liquefaction features and date the sequential histories of past large earthquakes,

thereby determining approximate recurrence intervals of large events (see figures, left).

New Madrid Liquefaction Area

The New Madrid earthquake sequence of 1811–1812 produced subsidence and widespread

liquefaction (sand blows and sand-filled fissures) throughout the New Madrid seismic zone and

surface deformation at several locations (Crone and Schweig, 1994). The liquefaction features,

including depressed and submerged land (Jibson and Keefer, 1988), are concentrated in a 40–60-kmwide belt from near Charleston, Miss., to Marked Tree, Ark. (Obermeier, 1988), and are the

most widespread expression of recent strong earthquakes in the New Madrid region. Most of these

features formed at the time of the major 1811–1812 earthquakes. The resulting depressed and

submerged areas, referred to as sunken lands, are associated with surface deformation and the

impoundment of the Little and St. Francis rivers (Guccione and VanArsdale, 1995; and Guccione

and others, 2000), see map explanation above.

Evidence of Quaternary faulting in the New Madrid region is based on the occurrence of large

magnitude earthquakes in the 1811–1812 sequence, the abundant ongoing seismic activity, and

surface deformation associated with the Reelfoot fault scarp. Other than the faulting associated with the

Reelfoot scarp, individual seismogenic faults in the New Madrid seismic zone are not expressed at the

ground surface. The general subsurface locations of these seismogenic faults are inferred to be

associated with areas of abundant recorded microseismicity.

Saline River Fault Zone Area

Quaternary deformation in the Saline River fault zone area is inferred and is thought to be associated

with a trend of earthquake epicenters following the Saline River in southeastern Arkansas (Cox and

VanArsdale, 1997). Cox and VanArsdale describe several small faults of various orientations

exposed in road cuts and in an exploratory trench. In addition, from shallow-seismic reflection data,

Cox and VanArsdale interpret the existence of sub-surface faults. However, the relationship of the

exposed features to the deeper structures and to the regional pattern of seismicity is not well

understood. Because there is no significant geomorphic expression of known or suspected faulting,

active deformation is questionable. This discussion of the Saline River fault zone area was derived,

in part, from a compilation by Crone, 1998.

Big Lake, sunken land that formed during the New Madrid earthquakes of 1811–1812.

Photograph by Pat Lendennie. Image source: The Encyclopedia of Arkansas History and

Culture, http://www.encyclopediaofarkansas.net/encyclopedia/entryInterpretative diagram of a sand blow and the liquefaction

process (after Obermeier and others, 1987).

Aerial view of sandblow liquefaction features within the New Madrid 1811–1812 meizoseismal

region. White spots are areas where sand vented onto the darker ground surface. The vented

sand formed cones that are 15 to 50 cm in height and tens of meters in width. Image source:

Obermeier, S.F., 1998, Seismic Liquefaction Features: Examples from Paleoseismic

Investigations in the Continental United States, USGS Open-File Report 98–488, slide 14.

http://pubs.usgs.gov/of/1998/of98-488/.

Typical small dike in vertical section. Image

source: Obermeier, S.F., 1998, Seismic

Liquefaction Features: Examples from

Paleoseismic Investigations in the Continental

United States, USGS Open-File Report 98–488,

slide 19, http://pubs.usgs.gov/of/1998/of98–488/.

Lake St. Francis, Ark., 1904. Cypress trees killed

by submergence resulting from the New Madrid

earthquakes of 1811–1812. Plate 4–B in U.S. Geological

Survey Bulletin 494, 1912. Photo by M.L. Fuller.

Image source: USGS Photographic Library,

http://libraryphoto.cr.usgs.gov/earth.htm

Compiled by Richard L. Dart1 and Scott M. Ausbrooks2

2011

Probable location of observers 

who felt the 1699 earthquake.

Western Lowlands 

Liquefaction Area

ARKANSAS SEISMIC NETWORK

The Arkansas Seismic Network (ASN) consists of six state-of-the-art permanent broadband

seismic stations strategically placed within selected State Parks across Arkansas. The ASN

was funded through the Arkansas Governor’s General Improvement Fund in response to the

Magnet Cove earthquake swarm in 2008. The goal of the ASN is to establish better and more

uniform earthquake detection outside of the New Madrid seismic zone (NMSZ). The network

was installed in spring of 2010 and is seamlessly integrated with the regional and national

seismic networks. The ASN is operated and maintained in cooperation with the Arkansas

Geological Survey (AGS), Center for Earthquake Research and Information (CERI) at the

University of Memphis and Arkansas State Parks (ASP). For additional information visit:

http://www.geology.ar.gov/geohazards/ark_seismic_network.htm. INTENSITY I II III IV V VI VII VIII IX X+

SHAKING

DAMAGE

None

None

Weak

None

Weak

None

Light

None

Moderate

Very

Light

Strong

Light

Very

Strong

Moderate

Severe

Moderate

Heavy

Violent

Heavy

Extreem

Very

Heavy

MAGNITUDE

EXPLANATION

Epicenter

MMI Observations

II

III

IV

V

VI

VII

VIII

IX

X

XI

Generalized MMI

I

II

III

IV

V

VI

VII

VIII

IX

X

XI

UrbanAreas

Image source: Arkansas Geological Survey.

OPEN-FILE REPORT 2011–1118

TENNESSEE

CONVERSION FACTORS

Multiply By To obtain

3.281 feet (ft)

0.6214 miles (mi)

meters (m)

kilometers (km)