PE

RU

-

C

HI

LE

T

RE

NC

H

CO

LO

MB

I AN

TR

EN

CH

PE

RU

- C

HI L

E T

RE

NC

H

P A N A

GU

YA

NA

S U R I N A M E

F R E N C HG U I A N A

C O L O M B I A

GU

YA

NA

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 AY

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

ta Cruzdor

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 va r a

d o Ri d

g eG r i j a

l va R i d

g e

A r g e n nit eB 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

Ch

i le

Ba

si 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 eP 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 CO C E A N

Na z c a R

i dg e

A l va r a

d o Ri d

g e

S a r mi e

n t o R

i dg e

D

600

300

200

200100

60600

400

200

100

60

60

500

400

100

500

200

V E N E Z U E L A

A

A'

B

B'

C

C'

DD'

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

CochabambaSanta Cruzde LaSierra

CampoGrande

SaoPaulo

Santos

Salta

Asuncion

Curitiba

San MiguelDe Tucuman

PortoAlegre

CordobaSanta Fe

Rosario

ValparaisoSantiago

Montevideo

Concepcion

Bogota

BuenosAires

Lima

La Plata

Bucaramanga

Medellin

Manizales

2010

55°

55°

65°

65°

50°

50°

60°

60°

70°

70°

75°

75°

80°

80°

85°

85°

90°95° 45°100°

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

NAZCAPLATE

BRAZIL

COLOMBIA

PERU

ECUADOR

GUYANA

CHILE

ARGENTINA

BOLIVIA

URUGUAY

PARAGUAY

ANTARCTICPLATE

SURINAMEFRENCHGUIANA

65 VENEZUELAGUYANA

5879

80

80

80

79

77

73

68

50°

50°

60°

60°

70°

70°

80°

80°

90°100°

0°

0°

10°

10°

20°

20°

30°

30°

40°

40°

0 100 200 300 400 500 600 700 800Kilometers

Seismicity of the Earth 1900–2007Nazca Plate and South America Compiled by Susan Rhea, Gavin Hayes, Antonio Villaseñor1, Kevin P. Furlong2, Arthur C. Tarr, and Harley Benz1Institute of Earth Sciences, CSIC, Lluis Solé i Sabarîs s/n, 08028 Barcelona, Spain2Department of Geosciences, Pennsylvania State University, State College, PA 16802 USA

1:12,000,000Scale

OPEN-FILE REPORT 2010–1083-EVersion 1.0

TECTONIC SUMMARY

The South American arc extends over 7,000 km, from the Chilean margin triple junction offshore of southernChile to its intersection with the Panama fracture zone, offshore of the southern coast of Panama in CentralAmerica. It marks the plate boundary between the subducting Nazca plate and the South America plate, wherethe 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 Americaplate, the Nazca plate moves slightly north of eastwards at a rate varying from approximately 80 mm/yr in thesouth to approximately 70 mm/yr in the north.

Subduction zones such as the South America arc are geologically complex and generate numerous earthquakesfrom a variety of tectonic processes that cause deformation of the western edge of South America. Crustaldeformation and subsequent mountain building in the overriding South America plate generate shallowearthquakes. Slip along the dipping interface between the two plates generates frequent and often large interplateearthquakes between depths of approximately 10 to 60 km. Since 1900, numerous magnitude 8 or greaterearthquakes have occurred on the interface between the Nazca and South America plates, including the 1960M9.5 earthquake in southern Chile, the largest instrumentally recorded earthquake in the world (large yellow areaon main map from 37°S to 45°S) and the 2010 M8.8 earthquake north of the 1960 quake. Earthquakes can alsobe generated to depths greater than 600 km from internal deformation of the subducting Nazca plate. Althoughthe rate of subduction varies little along the entire subduction zone, there are complex changes in geologicprocesses along the subduction zone that dramatically influence volcanic activity, earthquake generation andoccurrence. For example, an extended zone of crustal seismicity in central-northern Argentina highlights a well-known ‘flat-slab’ region of this subduction zone, where the Nazca plate moves horizontally for several hundredkilometers before continuing its descent into the mantle. This transition in slab structure is coincident with amarked 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 Centennialearthquake catalog (Engdahl and Villaseñor, 2002) and annual supplements for the interval 1900–2007, where themagnitude floor is 5.5 globally, and (b) a catalog of earthquakes having high-quality depth determinations for theperiod 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 yearof 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 ofsignificant earthquakes; locations are approximate, based on macro-seismic reports and field investigations. Weselected for earthquakes with associated reports of moderate to major damage, deaths, estimated magnitude of 8or 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), plateboundaries (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 timescale 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 SeismicHazards 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 EarthquakeHazards 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 theireruptions: 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 Earth1900–2007: 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 onlyand 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 ServicesBox 25286, Federal Center, Denver, CO 802251-888-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

PERUECUADOR

COLOMBIA

VENEZUELA GUYANA

SURINAME

BOLIVIA

PARAGUAY

URUAGUAY

1875

1868

1837

1822

1819

17511751

1730

1716

1716

1687

1619

1609

1604

1586

1575

1513

PRE-INSTRUMENTAL SEISMICITY 1500–1899Deaths, 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 volcanolocations are constructed from themapped data. Locations of the profileintersection with the surface are drawnin the map and labeled to coincide withthe profile label. Box defines extent ofearthquakes included in the profile.Length of the profile graphic is the sameas in the map. Distance in kilometersfrom the trench axis is indicated in the Xdirection, depth in kilometers isindicated in the Y direction. There is novertical exaggeration. See Explanation atside for color key. Not all earth layers,earthquake depths or magnitude, arevisible 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 INTERIORU.S. GEOLOGICAL SURVEY

C C'

B B'

A A'

DD '

Distance (km)

Dep

th (k

m)

X'X

FIGURE EXPLANATION

Peak ground acceleration0–0.2 m/s²0.2–0.40.4–0.80.8–1.61.6–3.23.2–6.46.4–9.8

Relative plate motion11.0–19.9

20.0–39.9

40.0–59.9

60.0–79.9

80.0–100.0

Plate boundariesSubductionTransformDivergentOthers

MAP EXPLANATION

Magnitude classes4–5.9

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 focus0–69 km70–299 km300–700 km

Nucleation points

Rupture zones

Active volcanoes

Mean slab depth60 km100200300400500600

Plate boundariesSubduction

TransformDivergentOthers

Magnitude classes4–5.96–6.46.5–6.97–7.47.57.67.7

7.8

7.9

8.0

8.1

8.2

Depth of focus0–69 km70–299 km300–700 km

Nucleation points

Earth structureAirCrustUpper mantleTransition zoneLower mantle

Active volcanoes