Bering Sea

PACIFIC OCEAN

R U S S I A

A L A S K A ( U . S . A . )

G u l f o f A l a s k a

Bristol

Bay

C

o

o

k

I

n

l

e

t

O. Bering

Attu

Agattu

Shemya

Amchitka

Semisopochnoi

Kiska

R

A

T

I S L A N D S

N

E

A

R

I

S L A N D S

A N D R E A N O F I S L A N D S

Atka I.

Amlia I.

Great

Sitkin I. Adak I. Tanaga I.

Islands of

Four Mountains

Saguam I. Yunaska I.

Umnak I.

Unimak I.

Unalaska I.

K o d i a k

I s

l a

n

d

Afognak I.

Montague

I.

Hinchinbrook I.

Nunivak I.

(Alaska)

St. Matthew I.

(Alaska)

Pribilof Islands (Alaska)

St. Paul I.

St. George I.

St. Lawrence I.

(Alaska)

COMMANDER

ISLANDS

(Russia)

O. Mednyy

A

L

E

U

T

I

A

N

T R E N C H

A L E U T I A N

T R E N C H

Bristol Canyon

Bering Canyon

Umnak

Basin

Unalaska Basin

Davidson BankSanak

Bank

S h u m a g i n

B

a

n

k

Guide Ridge

P a t t o n S e a m o u n t s

Surveyor Channel

Surveyor Gap

Pratt Guyot

S h i r s

h

o

v

R

i

d g

e

V i t y

a

z

V

a

l

l

e

y

Komandor Basin

K a n a g a B a s i n

Aleutian Terrace

Hawley Ridge

Atka Basin

Amlia Basin

Amukta

Canyon

Umnak Canyon

Umnak

Plateau

Pribylov Canyon

B o w e r s B a s i n

Ulm

Plateau

Petrel

Bank

Kiska Knoll

Tahoma

Reef

Stalemate

Bank

A l e u t i a n

R i s e

Detroit Rise

Tenji

Guyot

Basin

Aleutian

Bowers Ridge

Rude Knoll

B'

A

A'

B

C

C'

A

A'

D'

D

E'

E

60

100

200

200

100

50

100

50

RAT 

ISLANDS

ANDREANOF

ISLANDS

1900

1916

1917

1929

1929

1965

1965

1979

1986

1987

1988

1996

2003

2006

1906

1938

1946

1957

1964

1965

172°

172° 148° 146° 144° 142° 140°

150°

150°

152°

152°

154°

154°

156°

156°

158°

158°

160°

160°

162°

162°

164°

164°

166°

166°

168°

168°

170°

170°

174°

174°

176°

176°

178°

178°

180°

180°

178°

178°

176°

176°

174°

174°

172°

172°

170°

162° 164° 166° 168° 170°

62°

60°

60°

58°

58°

56°

56°

54°

54°

52°

52°

50°

50°

48°

48°

46°

0 100 200 300 400 500 600 700 800

KILOMETERS

Scale

NORTH AMERICA PLATE

PACIFIC PLATE

UNITED STATES

RUSSIA

75

74

73 71

68

63

60

56

66

75

74

73 71

68

63

60

56

66

B e r i n g S e a

PA C I F I C O C E A N

A

L

E U T I A N

T R E N C H

A L E U T I A N

T R E N C H

150° 145°

155°

155°

160°

160°

165°

165°

170°

170°

175°

175°

180°

180°

175°

175°

170°

160° 165° 170°

60°

60°

55°

55°

50°

50°

SEISMIC HAZARD AND RELATIVE PLATE MOTION

U.S. DEPARTMENT OF THE INTERIOR

U.S. GEOLOGICAL SURVEY

Seismicity of the Earth 1900–2010

Aleutian Arc and Vicinity

Compiled by Harley M. Benz,1 Richard L. Dart,1 Antonio Villaseñor,2 Gavin P. Hayes,1 Arthur C. Tarr,1 Kevin P. Furlong,3 and Susan Rhea1

Albers Equal Area Conic Projection

Digital map database and cartography by Susan Rhea and Arthur Tarr

Manuscript approved for publication Nov. 16, 2011

TECTONIC SUMMARY

This map shows details of the Aleutian arc not visible in an earlier publication (Tarr and others,

2010).The Aleutian arc extends about 3,000 km from the Gulf of Alaska to the Kamchatka

Peninsula. It marks the region where the Pacific plate subducts into the mantle beneath the

North America plate. This subduction is responsible for the generation of the Aleutian Islands

and the deep offshore Aleutian Trench. Relative to a fixed North America plate, the Pacific

plate is moving northwest at a rate that increases from about 55 mm per year at the arc's eastern

edge to 75 mm per year near its western terminus. In the east, the convergence of the plates is

nearly perpendicular to the plate boundary. However, because of the boundary's curvature, as

one travels westward along the arc, the subduction becomes more and more oblique to the

boundary until the relative plate motion becomes parallel to the arc at the Near Islands near its

western edge.

Subduction zones such as the Aleutian arc are geologically complex and produce numerous

earthquakes from multiple sources. Deformation of the overriding North America plate

generates shallow crustal earthquakes, whereas slip at the interface of the plates generates

interplate earthquakes that extend from near the base of the trench to depths of 40 to 60 km. At

greater depths, Aleutian arc earthquakes occur within the subducting Pacific plate and can

reach depths of 300 km. Since 1900, six great earthquakes have occurred along the Aleutian

Trench, Alaska Peninsula, and Gulf of Alaska: M8.4 1906 Rat Islands (Okal, 2005); M8.6

1938 Shumagin Islands (Estabrook and others, 1994); M8.6 1946 Unimak Island (Lopez and

Okal, 2006); M8.6 1957 Andreanof Islands (Johnson and Satake, 1993); M9.2 1964 Prince

William Sound (Kanamori, 1970); and M8.7 1965 Rat Islands (Wu and Kanamori, 1973).

Several relevant tectonic elements (plate boundaries and active volcanoes) provide a context

for the seismicity presented on the main map panel. The plate boundaries (Bird, 2003) are most

accurate along the axis of the Aleutian Trench and more diffuse or speculative in extreme

northeastern Russia. The active volcanoes (Siebert and Simkin, 2002) parallel the Aleutian

Trench from the Gulf of Alaska to the Rat Islands.

The earthquakes portrayed on the main map and the depth profiles are taken from two sources: (a) the Centennial

earthquake catalog (Engdahl and Villaseñor, 2002) and annual supplements for the interval 1900–2007, where the

magnitude floor is 5.5 globally, and (b) a catalog of earthquakes having high-quality depth determinations for the

period 1964–2002 and a magnitude range of 5.0≥M≤5.4 (Engdahl, personal commun., 2009.)

The nucleation points of great earthquakes (M≥8.3) are designated with a label showing the year of occurrence.

Their rupture areas are shown as pale reddish polygons. Major earthquakes (7.5≥M≤8.2) are labeled with the year of

occurrence, while earthquakes (8.0≥M≤8.2) are labeled with the year of occurrence and also denoted by a white

outline (Tarr and others, 2010).

The Seismic Hazard and Relative Plate Motion map displays the generalized seismic hazard of the region (Giardini

and others, 1999) and representative relative plate motion vectors of the Pacific plate relative to the adjacent North

America plate using the NUVEL–1A model (DeMets and others, 1994).

Pre-instrumental seismicity for the Aleutian arc was obtained from the NOAA National Geophysical Data Center

(2010) database of significant earthquakes; locations are approximate, based on macro-seismic reports and field

investigations. We selected earthquakes with associated reports of moderate to major damage, 10 or more deaths, an

estimated magnitude of 7.5 or greater (if known), Modified Mercalli Intensity at least X, or tsunami generation.

Base map data sources include GEBCO (2008), Volcanoes of the World dataset (Siebert and Simkin, 2002), plate

boundaries (Bird, 2003), Digital Chart of the World (1992), and ESRI (2002). Slab contours are from Hayes and Wald

(2010).

Bird, Peter, 2003, An updated digital model of plate boundaries: Geochemistry Geophysics Geosystems,

.

v. 4, no. 3, 52 p.

DeMets, Charles, Gordon, R.G., Argus, D.F., and Stein, Seth, 1994, Effects of recent revisions to the geomagnetic time

.

scale on estimates of current plate motions: Geophysical Research Letters, v. 21, p. 2191–2194.

Digital Chart of the World, 1992: http://earth-info.nga.mil/publications/specs/printed/89009/89009_DCW.pdf, last .

accessed Mar. 9, 1996.

Engdahl, E.R., and Villaseñor, Antonio, 2002, Global seismicity 1900–1999, in Lee, W.H.K., Kanamori, Hiroo, .

Jennings, P.C., and Kisslinger, Carl, eds, International Handbook of Earthquake and Engineering Seismology, .

International Association for Earthquake Engineering, v. 81(A), chap. 41, p. 1–26.

ESRI, 2002, ESRI data and maps: Redlands, Calif., ESRI. Available at http://www.esri.com/data/data-maps/index.html.

Estabrook, C.H., Jacob, K.H., and Sykes, L.R., 1994, Body wave and surface wave analysis of large and great

.

earthquakes along the eastern Aleutian arc, 1923–1993, Implications for future events: Journal of Geophysical .

Research, v. 99, no. B6, p. 11643–11662.

GEBCO, 2008, The GEBCO_08_Grid, ver. 20091120: http://www.gebco.net/, last accessed January 8, 2010.

Giardini, D., Grünthal, G., Shedlock, K., Zhang, P., and Global Seismic Hazards Program, 1999, Global seismic .

hazards map: http://seismo.ethz.ch/GSHAP, last accessed January 9, 2007. .

Hayes, Gavin, and Wald, David, 2010, Slab models for subduction zones: U.S. Geological Survey Earthquake Hazards

Program, last accessed July, 22, 2010 at http://earthquake.usgs.gov/research/data/slab/.

Johnson, J.M. and Satake, Kenji, 1993, Source parameters of the 1957 Aleutian earthquake from tsunami

.

waveforms: Geophysical Research Letters, v. 20, no. 14, p. 1487–1490.

Kanamori, Hiroo, 1970, The Alaska earthquake of 1964: Radiation of long-period surface waves and source

.

mechanism: Journal of Geophysical Research, v. 75, no. 26, p. 5029–5040.

Lopez, A.M., and Okal, E.A., 2006, A seismological reassessment of the source of the 1946 Aleutian ‘tsunami’

.

earthquake: Geophysical Journal International, v. 165, no. 3, p. 835–849.

NOAA, 2010, National Geophysical Data Center: National Oceanic and Atmospheric Administration,

accessed on March 31, 2010 at http://www.ngdc.noaa.gov/hazards.

Okal, E.A., 2005, A re-evaluation of the great Aleutian and Chilean earthquakes of 1906 August 17: Geophysical

.

Journal International, v. 161, no. 2, p. 268–282.

Siebert, Lee, and Simkin, Thomas, 2002, Volcanoes of the world: An illustrated catalog of Holocene volcanoes and their

.

eruptions: Smithsonian Institution, Global Volcanism Program Digital Information series, GVP-3: .

http://www.volcano.si.edu/world/, last accessed January 9, 2007.

Tarr, A.C., Villaseñor, Antonio, Furlong, K.P., Rhea, Susan, and Benz, H.M., 2010, Seismicity of the Earth 1900–2007:

.

U.S. Geological Survey Scientific Investigations Map 3064, scale 1:25,000,000.

Wu, F.T., and Kanamori, Hiroo, 1973, Source mechanism of February 4, 1965, Rat Island earthquake: Journal of

Geophysical Research, v. 78, no. 26, p. 6082–6092.

DATA SOURCES

1:5,000,000

REFERENCES

OPEN-FILE REPORT 2010–1083-B

Revised September, 2011

2011

PROFILE E

-500 -400 -300 -200 -100 0

-300

-200

-100

0

E E'

TRENCH AXIS

PROFILE D

-400 -300 -200 -100 0 100

-200

-100

0

D D'

PROFILE C

-300 -200 -100 0 100

-300

-200

-100

0

C C'

TRENCH AXIS

TRENCH AXIS

PROFILE B

-300 -200 -100 0 100

-300

-200

-100

0

TRENCH AXIS

B' B

PROFILE A

 -100 0 100 200

 -100

 0

A A'

TRENCH AXIS

1899

1897

1899

1899

1899

1899

1898

1896

1786

1883

1880

1880

1879

1788

1868

1899

1867

1843

1835

1818

1826

1878

1817

R U S S

A L A S K A ( U S A )

I A

PRE-INSTRUMENTAL SEISMICITY 1500–1899

Modified Mercalli Intensity (MMI) ≥ 4

.

X X'

Profiles of earthquake and volcano

locations are constructed from the mapped

data. Locations of the profile intersection

with the surface are drawn on the map and

labeled to coincide with the profile label.

Box defines extent of earthquakes

included in the profile. Length of the

profile graphic is the same as on the map.

Distance in kilometers from the trench

axis is indicated in the X direction, depth

in kilometers is indicated in the Y

direction. There is no vertical

exaggeration. See Explanation at side for

color key. Not all earth layers, earthquake

depths or magnitude, are visible on every

profile.

PROFILE X

TRENCH AXIS

-100 0 100 200 300 400 500 600

 -800

 -700

 -600

 -500

 -400

 -300

 -200

 -100

 0

Depth (km)

DEPTH PROFILE EXPLANATION Distance (km)

B

FIGURE EXPLANATION

Peak ground acceleration

0–0.2 m/s2

0.2–0.4

0.4–0.8

0.8–1.6

1.6–3.2

3.2–6.4

6.4–9.8

Relative plate motion

11.0–19.9 mm/yr

20.0–39.9

40.0–59.9

60.0–79.9

80.0–100.0

Plate boundaries

Divergent

Transform

Inferred

Subduction

Convergent

Magnitude classes

4–5.9

6–6.4

6.5–6.9

7–7.4

7.5

7.6

7.7

7.8

7.9

8.0

8.1

8.2

Depth of focus

0–69 km

70–299 km

300–700 km

Earth structure

Air

Crust

Upper mantle

Transition zone

Lower mantle

Active volcanoes

Nucleation points

of M>8.3 events

MAP EXPLANATION

Magnitude classes

4–5.9

6–6.4

6.5–6.9

7–7.4

7.5

7.6

7.7

7.8

7.9

8.0

8.1

8.2

Depth of focus

0–69 km

70–299 km

300–700 km

Nucleation points

Active volcanoes

Mean slab depth

50 km

100

200

300

600

Plate boundaries

Divergent

Rupture zones

Transform

Inferred

Convergent

Subduction

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is in the public domain, it also contains copyrighted 

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use must be secured from the copyright owner

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This report is available at:

http://pubs.usgs.gov/of/2010/1083/b

For more information concerning this publication, contact:

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Or visit Geologic Hazards Science Center Web site at:

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Suggested citation:

Benz, H.M., Tarr, A.C., Hayes, G.P., Villaseñor, Antonio, Hayes, G.P., 

Furlong, K.P., Dart, R.L., and Rhea, Susan, 2011, Seismicity of the Earth 

1900–2010 Aleutian arc and vicinity: U.S. Geological Survey Open-File 

Report 2010–1083-B, scale 1:5,000,000.

1

U.S. Geological Survey

2

Institute of Earth Sciences, CSIC, Barcelona, Spain

3

Department of Geosciences, Pennsylvania State University, 

State College, PA 16802 USA