ARGENTINA

BRAZIL

CHILE PARAGUAY

URUGUAY

BOLIVIA

PERU

ECUADOR

COLOMBIA

PANAMA

COSTA RICA

NICARAGUA

HONDURAS

VENEZUELA

CURAÇAO

TRINIDAD AND TOBAGO

GRENADA

SAINT LUCIA

SAINT VINCENT AND THE GRENADINES

BARBADOS

ARUBA

GUYANA

SURINAME

FRENCH

GUIANA

FALKLAND ISLANDS

(ISLAS MALVINAS)

Sala y Gomez Ridge

Arabian

Basin

Falkand

Plateau

Santos

Plateau

Demerara Plain

Clark Basin

Chile Basin

Peru Basin

Cocos Ridge

Nazca Ridge

PERU-CHILE TRENCH

PERU-CHILE TRENCH

Chile Triple Junction

1906

1943

1985

1971

1918

1977

1906

1943

1966

1974

1908

1994 2007

1996

1963

1960

1940

1970

1922

1947

2001

1942

1913

1996

1966

1974

1985

1995

2005

1987

1976 1959

1966

1950

1983

2007

1918

1995

1908

1960

1960

1928

1953

1962

1914

1939

1975

1960

1970

1979

1942

1958

1934

1970

1979

1994 2007

1983

1992 1950

1983

1960

1942

2005

1906

1953

1921

1960

2005

1906

1971

1953

1928

1996

1963

1949

1918

1977

1960

1940

2005

1900

1970

1953

1922

1992

1987

1962

1947

1914

1976 1959

1939

2001

1966

1950

1921

1983

1960

1942

2007

1913

1975

1958

1934

1996

1963

1950

1918

Drake Passage

Tierra del Fuego

Ibague

La Plata

Santa Cruz de La Sierra

Santa Fe

Cochabamba

Manaus

Valencia

San Miguel De Tucuman

Santiago Valparaiso

Callao

Medellin

Belo Horizonte

Managua

Montevideo

Cuiaba

Sao Luis

Piura

Rio de Janeiro

Maracay

Concepcion

La Paz

Chiclayo

Cuzco

Barranquilla

Goiania

Maracaibo

Santos

Trujillo

Salta

Barquisimeto

Niteroi

Cartagena

Bogota

Brasilia

Cali

Campo Grande

Cordoba

Manizales

Quito

Arequipa

Lima

Porto Alegre

Rosario

Guayaquil

Belem

Asuncion

Buenos Aires

Cucuta

Sao Paulo

Curitiba

Bucaramanga

1906

2001

1922

2010

1960

A'

A

A'

B

B'

C C'

D' D

Caracas

Panama

San Jose

-30°

10°

-50°

80°W 70°W 60°W 50°W

40°W

Equator

Equator

10°N

10°S

20°S

40°S

50°S

40°S

30°S

20°S

100°W

100°W 90°W 80°W 70°W 60°W 50°W 40°W

90°W

South America Albers Equal Area Projection Scale 1:14,000,000

Digital map database and cartography by Greg Smoczyk

MAP EXPLANATION

Nucleation points and

 year of occurrence

Active volcanoes

Plate boundaries

Transform

Divergent

Inferred

Subduction

Depth of focus

!( Less than 69 km

!( 70–299 km

!

1960

( Greater than 300 km

Magnitude classes

5.5–5.7

5.7–6.0

6.0–6.3

6.3–6.6

6.6–6.9

6.9–7.1

7.1–7.4

7.4–7.7

7.7–8.0

Greater than 

 8.0

Mean slab depth

600

500

400

300

200

100

60 km

Aftershock zones*

Rupture zones*

Country 

Boundary

*Aftershock zones for large earthquakes represent the area over 

which significant aftershock activity was observed in the immediate 

vicinity of the main shock, within tectonic environments coupled to 

the main shock system. For example, for the 2011 M 9.0 Tohoku 

earthquake, extensive aftershocks occurred on the interplate thrust 

contact between the Pacific and North America plates, as well as in 

the overlying upper plate, and on faults within the Pacific plate 

outboard of the subduction zone. We do not include more distant 

triggered aftershocks such as those that occurred on upper plate 

faults within mainland Japan.

SCALE 1:14,000,000 

200

KILOMETERS

0 400 600 800 1,000

200

MILES

0 400 600 800 1,000

TECTONIC SUMMARY

DATA SOURCES

REFERENCES

U.S. DEPARTMENT OF THE INTERIOR

U.S. GEOLOGICAL SURVEY

Seismicity of the Earth 1900–2013

Seismotectonics of South America (Nazca Plate Region)

Compiled by Gavin P. Hayes,1 Gregory M. Smoczyk,1 Harley M. Benz,1 Antonio Villaseñor,2

and Kevin P. Furlong3

3

Department of Geosciences, Pennsylvania State University, University Park, Pa., USA

1

U.S. Geological Survey

2

Institute of Earth Sciences, Consejo Superior de Investigaciones Científicas, (CSIC), Barcelona, Spain

2014

Publishing support provided by: 

Denver Publishing Service Center

Manuscript approved for publication February 11, 2015

Any use of trade, firm, or product 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 must be secured from the copyright owner. 

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/. 

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This report is available at:

http://pubs.usgs.gov/of/2015/1031/e

For more information concerning this publication, contact:

Center Director, USGS Geologic Hazards Science Center

Box 25046, Mail Stop 966

Denver, CO 80225

(303) 273-8579

Or visit Geologic Hazards Science Center Web site at:

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

Suggested citation:

Hayes, G.P., Smoczyk, G.M., Benz, H.M., Villaseñor, Antonio, 

and Furlong, K.P., 2015, Seismicity of the Earth 1900–2013,

Seismotectonics of South America (Nazca Plate Region):

U.S. Geological Survey Open-File Report 2015–1031-E, 1 sheet,

scale 1:14,000,000 http://dx.doi.org/10.3133/of20151031E. 

ISSN 2331-1258 (online)

http://dx.doi.org/10.3133/of20141031E

The South American arc extends over 7,000 kilometers (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 

millimeters/year (mm/yr) in the south, to approximately 65 mm/yr in the north. Although the rate of subduction varies little along 

the entire arc, there are complex changes in the geologic processes along the subduction zone that dramatically influence volcanic 

activity, crustal deformation, earthquake generation and occurrence all along the western edge of South America.

Most of the large earthquakes in South America are constrained to shallow depths of 0–70 km as a result of both crustal and 

interplate deformation. Crustal earthquakes are caused by deformation and mountain building in the overriding South America plate 

and generate earthquakes as deep as approximately 50 km. Interplate earthquakes occur due to slip along the dipping interface 

between the Nazca and the South America plates. Interplate earthquakes in this region are frequent and often large, and occur 

between depths of approximately 10–60 km. Since 1900, numerous magnitude (M) 8 or larger earthquakes have occurred on this 

subduction zone interface that were followed by devastating tsunamis, including the 1960 M9.5 earthquake in southern Chile, the

largest instrumentally recorded earthquake in the world. Other notable shallow tsunami-generating earthquakes include the 1906 

M8.5 earthquake near Esmeraldas, Ecuador, the 1922 M8.5 earthquake near Coquimbo, Chile, the 2001 M8.4 Arequipa, Peru 

earthquake, the 2007 M8.0 earthquake near Pisco, Peru, and the 2010 M8.8 Maule, Chile earthquake located just north of the 1960

event.

Large intermediate-depth earthquakes (those occurring between depths of approximately 70 and 300 km) are relatively limited in 

size and spatial extent in South America, and occur within the Nazca plate as a result of internal deformation within the subducting 

plate. These earthquakes generally cluster beneath northern Chile and southwestern Bolivia, and to a lesser extent beneath northern 

Peru and southern Ecuador, with depths from 110 to 130 km. Most of these earthquakes occur adjacent to the bend in the coastline 

between Peru and Chile. The most recent large intermediate-depth earthquake in this region was the 2005 M7.8 Tarapaca, Chile, 

earthquake.

Earthquakes can also be generated to depths greater than 600 km as a result of continued internal deformation of the subducting

Nazca plate. Deep-focus earthquakes in South America are not observed from a depth range of approximately 300–500 km. Instead, 

deep earthquakes in this region occur at depths of 500–650 km and are concentrated into two zones: one that runs beneath the 

Peru-Brazil border and another that extends from central Bolivia to central Argentina. These earthquakes generally do not exhibit 

large magnitudes. An exception to this was the 1994 Bolivian earthquake in northwestern Bolivia. This M8.2 earthquake occurred 

at a depth of 631 km, which was until recently was the largest deep-focus earthquake instrumentally recorded (superseded in May

2013 by a M8.3 earthquake 610 km beneath the Sea of Okhotsk, Russia), and was felt widely throughout South and North America.

Subduction of the Nazca plate is geometrically complex and influences the geology and seismicity of the western edge of South 

America. The intermediate-depth regions of the subducting Nazca plate can be segmented into five sections based on their angle of 

subduction beneath the South America plate. Three segments are characterized by steeply dipping subduction; the other two by 

near-horizontal subduction. The Nazca plate beneath northern Ecuador, southern Peru to northern Chile, and southern Chile 

descend into the mantle at angles of 25° to 30°. In contrast, the slab beneath southern Ecuador to central Peru, and under central 

Chile, is subducting at a shallow angle of approximately 10° or less. In these regions of “flat-slab” subduction, the Nazca plate 

moves horizontally for several hundred kilometers before continuing its descent into the mantle, and is shadowed by an extended

zone of crustal seismicity in the overlying South America plate. Although the South America plate exhibits a chain of active 

volcanism resulting from the subduction and partial melting of the Nazca oceanic lithosphere along most of the arc, these regions of 

inferred shallow subduction correlate with an absence of volcanic activity.

The tectonics of the Antarctica triple junction in southern Chile (Chile triple junction), are controlled by the interactions of the 

Antarctica, South America, and Scotia plates. Immediately south of the Chile triple junction, the Antarctica plate subducts beneath 

South America at a rate of approximately 16 mm/yr. There have been no moderate-to-large earthquakes associated with this 

convergence over the past century. Moving south and east through Patagonia, plate motions between the South America and the 

Scotia plates are predominantly left-lateral, at rates of 5–10 mm/yr. This plate boundary hosted two M7.8 earthquakes in December 

1949, near the Chile-Argentina border in Tierra del Fuego. Farther south, the Antarctica plate moves towards the east with respect 

to the Scotia plate at rates of less than 10 mm/yr, decreasing towards the south. Several M6–6.5 earthquakes have been observed in 

the Drake Passage region over the past half-century, all with left-lateral strike-slip faulting mechanisms.

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 5.0–5.4 (Engdahl, written commun., 2003)

 

The nucleation points of great earthquakes larger than M8.3 are designated with a label showing the year of occurrence. Their 

rupture areas are shown as light gray polygons. Major earthquakes (M7.5–8.2) are labeled with the year of occurrence, whereas 

earthquakes (M8.0–8.2) 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 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 National Oceanic and Atmospheric Administration (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, deaths, estimated magnitude of VIII 

or greater (if known), Modified Mercalli Intensities VIII 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 (1992), 

and Esri (2002). Slab contours are from Hayes and others (2012).

Bird, Peter, 2003, An updated digital model of plate boundaries: Geochemistry, Geophysics, Geosystems, v. 4, no. 3, 52 p., doi: 

 10.1029/2001GC000252.

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

 on estimates of current plate motions: Geophysical Research Letters, v. 21, no. 20, p. 2191–2194.

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

 March 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., Environmental Systems Research Institute (Esri). [Also available at

http://www.esri.com/data/data-maps/index.html.]

GEBCO, 2008, The EBCO_08_Grid, ver. 20091120: UNESCO, General Bathymetric Chart of the Oceans, UNESCO, accessed Jan. 8, 

 2010 at http:/www.gebco.net/.

Giardini, Domenico, Grünthal, Gottfried, Shedlock, K.M., Zhang, Peizhen, and Global Seismic Hazards Program, 1999: Global 

 seismic hazards map, accessed February 18, 2014, at http://www.seismo.ethz.ch/static/GSHAP/.

Hayes, G.P., Wald, D.J, and Johnson, R.L., 2012, Slab 1.0—A three-dimensional model of global subduction zone geometrics: Journal 

 of Geophysical Research, v. 117, doi: 10.1029/2011JB008524.

National Oceanic and Atmospheric Administration (NOAA), 2010, National Geophysical data center: National Oceanic and 

Atmopheric Administration, accessed March 31, 2010, at http://www.ngdc.noaa.gov/hazard/hazards.shtml.

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, last accessed Jan. 9, 2007, at 

http://www.volcano.si.edu/world/.

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. [Available at http://pubs.usgs.gov/sim/3064/.]

58 mm/yr

65 mm/yr

BOLIVIA

BARBADOS

CHILE

NICARAGUA

HAITI

ARGENTINA

SAINT LUCIA

VENEZUELA

URUGUAY

PANAMA

EL SALVADOR

TRINIDAD AND

TOBAGO

COLOMBIA

CAYMAN ISLANDS

PARAGUAY

HONDURAS

BELIZE

PERU

CURAÇAO

ECUADOR

SURINAME FRENCH

GUIANA

JAMAICA

BRAZIL

GUADELOUPE MEXICO

VIRGIN

ISLANDS, U.S.

GUYANA

GUATEMALA

DOMINICAN REPUBLIC

65 mm/yr

65 mm/yr

58 mm/yr

65 mm/yr

74 mm/yr

71 mm/yr

73 mm/yr

51 mm/yr

74 mm/yr

71 mm/yr

73 mm/yr

51 mm/yr

NAZCA PLATE

COCOS PLATE

SOUTH AMERICA

 PLATE

ANTARCTIC PLATE

SCOTIA PLATE

FIGURE EXPLANATION

10% in 50 year peak ground

 acceleration

Relative plate motion

Plate boundaries

0−0.2 m/s2

7−20 mm/yr

21−40

41−60

61−80

81−110

Subduction

Transform

0.2−0.4

0.4−0.8

0.8−1.6

1.6−3.2

3.2−6.4

6.4−9.8

Divergent

Others

FALKLAND ISLANDS

(ISLAS MALVINAS)

100°W

120°W 100°W 80°W 60°W 40°W 20°W

20°N

20°S

40°S

20°N

20°S

40°S

80°W 60°W 40°W

Equator

Equator

200

KILOMETERS

0 400 600 800 1,000

200

MILES

0 400 600 800 1,000

CURAÇAO

ARGENTINA

VENEZUELA

SURINAME

COSTA RICA

Chile

GUYANA

PANAMA

BARBADOS

PERU

PARAGUAY

NICARAGUA

BRAZIL

COLOMBIA

URUGUAY

FRENCH

GUIANA

GRENADA

BOLIVIA

ECUADOR

HONDURAS

FALKLAND ISLANDS

(ISLAS MALVINAS)

1513

1586

1619

1716

1751

1822

1868

1575

1604

1687

1730

1819

1837

1877

1513

1586

1619

1716

1751

1822

1868

1575

1604

1687

1730

1819

1837

1877

80°W 60°W 40°W

100°W 80°W 60°W 40°W 20°W

40°S

20°S

20°S

40°S

Equator

Equator

8.5

8.0

Magnitude

MAP EXPLANATION

200

KILOMETERS

0 400 600 800 1,000

200

MILES

0 400 600 800 1,000

OPEN-FILE REPORT 2015–1031-E

This report supplements Open-File Report 2010–1083-E

PRE-INSTRUMENTAL SEISMICITY 1500 – 1899

Deaths, tsunami, MMI VIII+, or M 8

M 8.5 labeled with year 

SEISMIC HAZARD AND RELATIVE PLATE MOTION

1837

PROFILE A

0 200 400 600 800 1,000 1,200

–600

–400

–200

0

TRENCH AXIS

A A'

PROFILE B

0 200 400 600 800 1,000 1,200

–800

–600

–400

–200

0

TRENCH AXIS

B B'

PROFILE C

–200 0 200 400 600 800 1,000

–600

–400

–200

0

C C'

TRENCH AXIS

PROFILE D

–200 0 200 400 600

–400

–200

0

TRENCH AXIS

D D'

–200 0 200 400

DEPTH PROFILE EXPLANATION

Nucleation point

Magnitude classes

Earth structure

Air

Crust

Upper mantle

Transition zone

Lower mantle

Active volcanoes

Depth of focus

!( Less than 69 km

!( 70–299 km

!( Greater than 300 km

>!

Less than 6.0

6.0–6.5

6.5–7.0

7.0–7.5

7.5

7.6

7.7

7.8

7.9

8.0

8.1

Greater then

or equal to 8.2

8.0-8.2 Magnitude

earthquake location

7.5-8.2 Magnitude

earthquake location

1935

1911

PROFILE X

TRENCH AXIS

 0

 –200

 –400

Distance (km)

Depth (km)

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 Y direction.

There is no vertical exaggeration. See 

explanation at side for color key. Not all

Earth layers and earthquake depths or

magnitude are visible on every profile.

X X'

Pacific Ocean

Atlantic Ocean

CARIBBEAN PLATE

MAP LOCATION