P

E

R

U - C

H I L

E

T R

E

N

C

H

C O L O M

B I A

N T R E N C H

P

E

R

U - C

H

I L

E

T R E N C H

P A N A

G U Y A

N

A

S U R I N A M E

F R E N C H

G U I A N A

C O L O M B I A

G U Y A

N

A

B R A Z I L

P E R U

E C U A D O R

B O L I V I A

C H I L E

C H I L E

PA R A G U A Y

A R G E N T I N A U R U G U A Y

ta Cruz

dor

Isla San Cristóbal

Isla Española

Isla del Coco

(Costa Rica)

I. Coiba

C a r n e g i e R i d g e

A l v a r a d o R i d g e

G r i j a l v a R i d g e

A r g e n nit e

B a s i n

A r g e n t i n e R i s e

C h i l e R i s e

C

h i l e

 B

a

s

i n

S o u t h e a s t

P a c i f i c

B a s i n

J u a n F e r n a n d e z R i d g e

P A C I F I C O C E A N

P e r u B a s i n

A T L A N T I C

O C E A N

N a z c a R i d g e

A l v a r a d o R i d g e

S a r m i e n t o R i d g e

D

60

0

300

200

200

100

60

600

400

200

100

60

60

500

400

100

500

200

V EN E Z U E L A

A

A'

B

B'

C

C'

D

D'

1906

1908

1913

1914

1918

1918

1928

1934

1939

1940

1942

1942

1943

1947

1953

1953

1958

1959

1960

1960

1960

1960

1962

1966

1966

1971

1974

1975

1977

1979

1983

1983

1985

1987

1995

1996

1996

2001

2007

2007

1921

1963

1963

1970

1994

1906

1922

1960

2001

Ibague

Cali

Quito

Belem

Guayaquil

Manaus

Piura

Chiclayo

Trujillo

Callao

Cuzco

Cuiaba

Brasilia

Arequipa La Paz

Goiania

Cochabamba Santa Cruz

de La

Sierra

Campo

Grande

Sao

Paulo

Santos

Salta

Asuncion

Curitiba

San Miguel

De Tucuman

Porto

Alegre

Cordoba

Santa Fe

Rosario

Valparaiso

Santiago

Montevideo

Concepcion

Bogota

Buenos

Aires

Lima

La Plata

Bucaramanga

Medellin

Manizales

2010

55°

55°

65°

65°

50°

50°

60°

60°

70°

70°

75°

75°

80°

80°

85°

85°

100° 95° 90° 45°

5°

5°

0°

0°

5°

5°

10°

10°

15°

15°

20°

20°

25°

25°

30°

30°

35°

35°

40°

40°

45°

SOUTH AMERICA PLATE

COCOS 

PLATE

NAZCA

PLATE

BRAZIL

COLOMBIA

PERU

ECUADOR

GUYANA

CHILE

ARGENTINA

BOLIVIA

URUGUAY

PARAGUAY

ANTARCTIC

PLATE

SURINAME

FRENCH

GUIANA

65 VENEZUELA

GUYANA

58

79

80

80

80

79

77

73

68

50°

50°

60°

60°

70°

70°

80°

80°

100° 90°

0°

0°

10°

10°

20°

20°

30°

30°

40°

40°

0 100 200 300 400 500 600 700 800

Kilometers

Seismicity of the Earth 1900–2007

Nazca Plate and South America

Compiled by Susan Rhea, Gavin Hayes, Antonio Villaseñor1, 

Kevin P. Furlong2, Arthur C. Tarr, and Harley Benz

1

Institute of Earth Sciences, CSIC, Lluis Solé i Sabarîs s/n, 08028 Barcelona, Spain

2

Department of Geosciences, Pennsylvania State University, State College, PA 16802 USA

Scale 1:12,000,000

OPEN-FILE REPORT 2010–1083-E

Version 1.0

TECTONIC SUMMARY

The South American arc extends over 7,000 km, from the Chilean margin triple junction offshore of southern

Chile to its intersection with the Panama fracture zone, offshore of the southern coast of Panama in Central

America. It marks the plate boundary between the subducting Nazca plate and the South America plate, where

the oceanic crust and lithosphere of the Nazca plate begin their descent into the mantle beneath South America.

The convergence associated with this subduction process is responsible for the uplift of the Andes Mountains,

and for the active volcanic chain present along much of this deformation front. Relative to a fixed South America

plate, the Nazca plate moves slightly north of eastwards at a rate varying from approximately 80 mm/yr in the

south to approximately 70 mm/yr in the north.

Subduction zones such as the South America arc are geologically complex and generate numerous earthquakes

from a variety of tectonic processes that cause deformation of the western edge of South America. Crustal

deformation and subsequent mountain building in the overriding South America plate generate shallow

earthquakes. Slip along the dipping interface between the two plates generates frequent and often large interplate

earthquakes between depths of approximately 10 to 60 km. Since 1900, numerous magnitude 8 or greater

earthquakes have occurred on the interface between the Nazca and South America plates, including the 1960

M9.5 earthquake in southern Chile, the largest instrumentally recorded earthquake in the world (large yellow area

on main map from 37°S to 45°S) and the 2010 M8.8 earthquake north of the 1960 quake. Earthquakes can also

be generated to depths greater than 600 km from internal deformation of the subducting Nazca plate. Although

the rate of subduction varies little along the entire subduction zone, there are complex changes in geologic

processes along the subduction zone that dramatically influence volcanic activity, earthquake generation and

occurrence. For example, an extended zone of crustal seismicity in central-northern Argentina highlights a wellknown ‘flat-slab’ region of this subduction zone, where the Nazca plate moves horizontally for several hundred

kilometers before continuing its descent into the mantle. This transition in slab structure is coincident with a

marked break in the Andes volcanic chain. (see profile C–C')

DATA SOURCES

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 comm. 2003)

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 yellow polygons. Major earthquakes (7.5≤M≤8.2) are labeled with the year

of occurrence. Slab contours are from Hayes and Wald (2010).

The Seismic Hazard and Relative Plate Motion panel displays the generalized seismic hazard of the region

(Giardini and others, 1999) and representative relative plate motion vectors using the NUVEL-1A model

(DeMets, and others, 1994.)

Pre-instrumental seismicity 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 for earthquakes with associated reports of moderate to major damage, deaths, estimated magnitude of 8

or greater, Modified Mercalli Intensities 8 or greater, 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, and ESRI (2002).

REFERENCES

Bird, Peter, 2003, An updated digital model of plate boundaries: Geochemistry Geophysics Geosystems, v. 4, no.

3, 52 p.

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

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

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

Kisslinger, C., and Kanamori, H., eds, International Handbook of Earthquake and Engineering Seismology, v.

81(A), chap. 41, p. 1–26.

ESRI, 2002, ESRI Data and Maps: ESRI, Redlands, CA.

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://www.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/.

NOAA National Geophysical Data Center, 2010, http://www.ngdc.noaa.gov/hazards, last accessed March 31,

2010.

Siebert, L., and Simkin, T., 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.

South America Albers Equal Area Projection

Digital map database and cartography by Susan Rhea and Art Tarr

Manuscript approved for publication July 28, 2010

Any use of trade 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.

This map was produced on request, directly from 

digital files, on an electronic plotter

For sale by U.S. Geological Survey Information Services

Box 25286, Federal Center, Denver, CO 80225

1-888-ASK-USGS

A PDF for this map is available at 

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

Suggested citation:

Rhea, Susan, Hayes, Gavin, Villaseñor, Antonio, Furlong, 

K.P., Tarr, A.C., and Benz, H.M., Seismicity of the earth 

1900–2007, Nazca Plate and South America: 

U.S. Geological Survey Open-File Report 2010–1083-E, 

1 sheet, scale 1:12,000,000.

BRAZIL

ARGENTINA

CHILE

PERU ECUADOR

COLOMBIA

VENEZUELA GUYANA

SURINAME

BOLIVIA

PARAGUAY

URUAGUAY

1875

1868

1837

1822

1819

1751

1751

1730

1716

1716

1687

1619

1609

1604

1586

1575

1513

PRE-INSTRUMENTAL SEISMICITY 1500–1899

Deaths, tsunami, MMI ≥ 8, or M ≥ 8

M ≥ 8.5 labled with year

PROFILE A

 -100 0 100 200 300 400 500 600 700 800 900 1000 1100 1200

 -700

 -600

 -500

 -400

 -300

 -200

 -100

 0

PROFILE B

 -100 0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300

 -800

 -700

 -600

 -500

 -400

 -300

 -200

 -100

 0

PROFILE C

 -200 -100 0 100 200 300 400 500 600 700 800 900 1000

 -600

 -500

 -400

 -300

 -200

 -100

 0

PROFILE C

 -200 -100 0 100 200 300 400 500 600 700 800 900 1000

 -600

 -500

 -400

 -300

 -200

 -100

 0

PROFILE A

 -100 0 100 200 300 400 500 600 700 800 900 1000 1100 1200

 -700

 -600

 -500

 -400

 -300

 -200

 -100

 0

PROFILE A

 -100 0 100 200 300 400 500 600 700 800 900 1000 1100 1200

 -700

 -600

 -500

 -400

 -300

 -200

 -100

 0

PROFILE B

 -100 0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300

 -800

 -700

 -600

 -500

 -400

 -300

 -200

 -100

 0

PROFILE C

 -200 -100 0 100 200 300 400 500 600 700 800 900 1000

 -600

 -500

 -400

 -300

 -200

 -100

 0

PROFILE D

 -200 -100 0 100 200 300 400 500 600

 -400

 -300

 -200

 -100

 0 .

Profiles of earthquake and volcano

locations are constructed from the

mapped data. Locations of the profile

intersection with the surface are drawn

in 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 in 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

 -700

 -600

 -500

 -400

 -300

 -200

 -100

 0

 100

DEPTH PROFILE EXPLANATION

SEISMIC HAZARD AND RELATIVE PLATE MOTION

U.S. DEPARTMENT OF THE INTERIOR

U.S. GEOLOGICAL SURVEY

C C'

B B'

A A'

D D'

Distance (km)

Depth (km)

X X'

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

20.0–39.9

40.0–59.9

60.0–79.9

80.0–100.0

Plate boundaries

Subduction

Transform

Divergent

Others

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

Rupture zones

Active volcanoes

Mean slab depth

60 km

100

200

300

400

500

600

Plate boundaries

Subduction

Transform

Divergent

Others

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

Earth structure

Air

Crust

Upper mantle

Transition zone

Lower mantle

Active volcanoes