106° 105° 104° 103° 102°

106° 105° 104° 103° 102°

17°

18°

19°

20°

21°

17°

18°

19°

20°

21°

M i d d l e A m e r i c a T r e n c h

Lago de Chapala

B a h i a d e B a n d e r a s

1911

1997

1986

19851973

19411934

1995

19321932

1900

Jalisco

Michoacan

Colima

Nayarit Nayarit

Guerrero

Guanajuato

Guanajuato

0

AMECA

Pomaro

Ostula

Aquila

Capire

Zamora

COLIMA

Comala

Tonila

Tuxpan

Alista

AUTLANCOTIJA

SAYULA

AtaceoZAMORAATOYAC

Ayutla

Ixtlan

COCULA

TECOMANARMERIA

URUAPAN

Chamela Zirosta

TolimanParacho

SAUHAYO

CHAPALA

OCOTLAN

Mixtlan

Mascota

La Vega

ARANDAS

Tequila

Monteon

Cuyutlan

Z MorenoSantiago

Juluapan

Patamban

PureperoTomaltan

Cacaluta

LA BARCA

El Tuito

ETZATLANTesistan

AMATITAN

Las Pinas

COALCOMAN

El Colomo

Cihuatlan

Tancitaro

Los Reyes

El Grullo

CayacapamJIQUILPAN

JUCHITLAN

La Cuesta

YURECUARO LA PIEDAD

Poncitlan

Mazatepec

Playa Azul

MANZANILLO

APATZINGAN

Buenavista

TECALITLANZapotitlan

Zapotiltic

Tinguindin

Ecuandurea

Tlajomulco

San MarcosTEPATITLANPUNTA MITA

San Isidro

Los Tepames

Coquimatlan

Tuxcacuesco

TENAMAXTLAN

Jesus MariaZapotlanejo

GUADALAJARA

Purificacion

Los Volcanes

CIUDAD GUZMAN

TangamandapioUnion de Tula

Melchor Ocampo

Villa Victoria

Calla de Campos

Valle de Juarez

Santa GertrudisTizapan el Alto

PUERTO VALLARTA

TALPA DE ALLENDE

Casimiro Castillo

ZACOALCO DE TORRES

ATOTONILCO EL ALTO

Espinazo del Diablo

San Jose de Bazarte

TAMAZULA DE GORDIANO

Atemajac de Brizuela

La Cofradia de Ostula

AHULALULCO DE MERCADO

San Ignacio Cerro Gordo

Colima

Mascota Volc Field

Michoacan-Guanajuato

Map prepared by U.S. Geological SurveyNational Earthquake Information Center4 February 2003Map not approved for release by Director USGS

DATA SOURCES

EARTHQUAKES AND SEISMIC HAZARD USGS, National Earthquake Information Center UN Office for the Coordination of Humanitarian Affairs IASPEI, Centennial Catalog (1900 - 1999) Handbook of Seismology and Earthquake Engineering Global Seismic Hazard Assessment Program

PLATE TECTONICS Smithsonian Institution, Global Volcano Program

BASE MAP NIMA and ESRI, Digital Chart of the World USGS, EROS Data Center

General Interest Product xxxU.S. Department of the InteriorU.S. Geological Survey

DISCLAIMER

Base map data, such as place names and politicalboundaries, are the best available but may not be current or may contain inaccuracies and thereforeshould not be regarded as having official significance.

Seismic hazard is expressedas peak ground acceleration(PGA) on rock or firm soil,in meters/sec**2, expected in a 50-yr period with a probability of 10 percent.

RELATIVE PLATE MOTIONS

The relative motion of adjacent tectonicplates is depicted on the map by short vectors located at selected locationson the plate boundary. In this present-ation, one plate is assumed to be rigid and fixed. The vector therefore repre-sents the direction of the moving platerelative to the fixed plate. The rate of relative motion is labelled next tothe vector.

The components of the vector perpendic-ular and parallel to the plate margin approximate convergent/divergent and transverse direction of motion between the plates, respectively. As viewed from the fixed plate, an inward directed com-ponent suggests convergence at and near the plate boundary that may be expressedas crustal folding, uplift, thrustfaulting, or plate subduction. Similar-ly, an outward directed component sug-gests plate divergence such as would be expected at a zone of crustal spreading.Transcurrent or transform faultingwould be expected when the predominantvector component is parallel to theplate margin.

M7.8 Tecomán, Colima, Mexico Earthquake of 22 January 2003

EXPLANATIONMain Shock

22 January 2003

22 - 23 January 2003

M < 4.5

4.5 - 4.9

5.0 - 5.4

5.5 - 5.9

6.0 - 6.5

Earthquakes 1900 - 2003

5.5 - 5.9

6.0 - 6.4

6.5 - 6.9

7.0 - 7.4

7.5 - 8.0

Volcanoes

State Boundary

Urbanized Area

Populated Places

Roads

Railroads

0 20 40 60 8010

Kilometers

SCALE 1:1,100,000Albers Equal-Area Projection

120° 115°

110° 105° 100° 95° 90°

120° 115°

110° 105° 100° 95° 90°

15°

20°

25°

30°

15°

20°

25°

30°

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

C O C O S P L A T E

RIVERAPLATE

P A C I F I C P L A T E

N O R T H A M E R I C A N P L A T E

CARIBBEAN PLATE

U N I T E D S T A T E S

M E X I C O

GUA.HON.

G u l f o f M e x i c o

Dallas

New Orleans

Houston

Phoenix

Mexico City

M e x i c oB a s i n

M i d d l e A m e r i c a T r e n c h

G o l f o d e C

a l i f o r n i a

Islas Revillagigedo

MathematiciansSeamounts

Camp

eche B

ank

Austin

BELIZE

Tectonic Setting

SCALE 1:18,000,000Lambert Conformal Conic Projection

20 mm/yr

46 mm/yr

Sierra Madre del Sur

Sierra M

adre Occidental

Sierra M

adre Oriental

B a j a C

a l i f o r n i a

DETAILED MAP

48 mm/yr

0 200 400 600 800100

Kilometers

120° 115°

110° 105° 100° 95° 90°

120° 115°

110° 105° 100° 95° 90°

15°

20°

25°

30°

15°

20°

25°

30°

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

C O C O S P L A T E

RIVERAPLATE

P A C I F I C P L A T E

N O R T H A M E R I C A N P L A T E

CARIBBEAN PLATE

U N I T E D S T A T E S

M E X I C O

GUA.HON.

G u l f o f M e x i c o

Dallas

New Orleans

Houston

Phoenix

Mexico City

G o l f o d e C

a l i f o r n i a

Islas Revillagigedo

Austin

BELIZE

Generalized Seismic Hazard

SCALE 1:18,000,000Lambert Conformal Conic Projection

DETAILED MAP

2003

190119001921

19831970 19501935

194419171903

19761912199619021978

1931 19651928

199519951957

191419501909

19111908

1905 19371959 19161911

19431985 1908

19801997 1964 19731925 1985

193719411934

199519321932

19001906

1902

1915

1934

1968

120° 115°

110° 105° 100° 95° 90°

120° 115°

110° 105° 100° 95° 90°

15°

20°

25°

30°

15°

20°

25°

30°

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

C O C O S P L A T E

RIVERAPLATE

P A C I F I C P L A T E

N O R T H A M E R I C A N P L A T E

CARIBBEAN PLATE

U N I T E D S T A T E S

M E X I C O

GUA.HON.

G u l f o f M e x i c o

Dallas

New Orleans

Houston

Phoenix

Mexico City

G o l f o d e C

a l i f o r n i a

Islas Revillagigedo

Austin

BELIZE

Earthquake History 1900 - 2003

SCALE 1:18,000,000Lambert Conformal Conic Projection

DETAILED MAP

A1'

A1

A2

A3

A2'

A3'

2003

190119001921

19831970

1950193519931944

1917

197619121996 19021978

192819651928

1968 19951995195719141950

190719091911

19081905

1962 19371959

19161911

19431985

190819811997 1964

197319861925 1999

1934

1995193219321900

1906

1902

1915

1934

19681940

EXPLANATIONMain Shock

22 January 2003

Plate Boundary

Convergent

Diffuse

Divergent

Transform

Volcanoes

State Boundary

Urbanized Areas

EXPLANATIONSeismic Hazard

0 - 0.2 m/sec**2

0.2 - 0.4

0.4 - 0.8

0.8 - 1.6

1.6 - 3.2

3.2 - 6.4

6.4 - 9.8

Magnitude Classes

5.5 - 5.9

6.0 - 6.4

6.5 - 6.9

7.0 - 7.4

7.5 - 8.0

Depth Classes

0 - 69 km

70 - 300 km

0 200 400 600 800100

Kilometers

0 200 400 600 800100

Kilometers

22 January 2003 02:06:34.07 UTC18.837 N., 103.817 W.Depth 24 km (Geophysicist USGS)MW = 7.8 (USGS)

This earthquake killed 29 people (26 in Colima State, two in Jalisco State, and one in Michoacan State), injured about 300, and left about 10,000 homeless. The Federal Government of Mexico declared a state of emergency in ten municipalities in Colima State and four in Jalisco State. The most affected municipality was Villa de Alvarez near Colima city. In Colima State, approximately 8,820 houses were damaged in-cluding 2,005 that were totally destroyed. The heaviest damage was to structures built of unreinforced adobe and brick which commonly collapsed. Some casualties and damage were reported in Guadalajara. Power outages, road damage, and bridge damage were widespread throughout Colima State. The main shock was felt strongly in Mexico City (495 km to the east) where tall buildings swayed and power out-ages were widespread.

EXPLANATIONMain Shock

22 January 2003

Magnitude Classes

5.5 - 5.9

6.0 - 6.4

6.5 - 6.9

7.0 - 7.4

7.5 - 8.0

Depth Classes

0 - 69 km

70 - 300 km

Plate Boundary

Convergent

Diffuse

Divergent

Transform

Volcanoes

State Boundary

Urbanized Areas

LARGEST EARTHQUAKES 1900 - 2003 M GE 7.5 MEXICO AND VICINITY

YR MO DY LAT LON DEPTH MAG

1902 4 19 14.000 -91.000 0 7.50 1902 9 23 16.000 -93.000 0 7.80 1907 4 15 17.000 -100.000 0 7.90 1908 3 26 18.000 -99.000 80 7.70 1909 7 30 17.000 -100.500 0 7.60 1911 6 7 17.500 -102.500 0 7.60 1911 12 16 17.000 -100.500 50 7.60 1917 12 29 15.000 -97.000 0 7.50 1928 3 22 16.127 -96.505 35 7.50 1928 6 17 16.028 -97.036 35 7.70 1928 10 9 16.229 -97.550 35 7.50 1931 1 15 16.053 -96.614 35 7.80 1932 6 3 19.457 -104.146 25 7.90 1932 6 18 19.452 -103.632 54 7.90 1941 4 15 18.677 -102.957 35 7.60 1942 8 6 13.780 -90.913 35 7.70 1950 10 23 14.500 -91.500 0 7.50 1957 7 28 16.881 -99.297 37 7.80 1973 1 30 18.455 -102.960 37 7.60 1976 2 4 15.297 -89.145 12 7.50 1978 11 29 16.012 -96.602 25 7.80 1979 3 14 17.759 -101.222 25 7.50 1985 9 19 18.444 -102.361 22 8.00 1985 9 21 17.827 -101.622 18 7.60 1995 10 9 19.052 -104.208 26 8.00 1999 9 30 16.055 -96.905 40 7.50 2003 1 22 18.837 -103.817 24 7.80

DISCUSSION

This shallow earthquake occurred in a seismically active zone near thecoast of central Mexico. The earthquake occurred near the junction ofthree tectonic plates: the North American Plate to the north-west, theRivera Plate to the north-east, and the Cocos Plate to the south. Boththe Rivera Plate and the Cocos Plate are being consumed beneath theNorth American Plate in a north-west direction. The slower movingRivera Plate is moving north-west at about 2 cm per year relative tothe North American Plate and the faster moving Cocos plate ismoving in a similar direction at a rate of about 4.5 cm per year.

There have been several significant earthquakes near the recent event.In 1932 a magnitude 8.4 thrust earthquake struck about 100 km to thenorth-west. More recently, on October 9th 1995, a large earthquake struckabout 20 km to the north-west. This magnitude 8.0 shock on Oct 9thkilled at least 49 people and left 1,000 homeless. The most deadly earthquake in the region occurred about 170 km to the south-east on September 19,1985. This magnitude 8.0 earthquake killed at least 9,500 people, injured about 30,000, and left 100,000 people homeless.

100 km 0 km 100 km 200 km 300 km 400 km

100 km 0 km 100 km 200 km 300 km 400 km

200 km

100 km

0 km

200 km

100 km

0 km

Depth Profile A1 - A1'

0 km 100 km 200 km 300 km 400 km 500 km

0 km 100 km 200 km 300 km 400 km 500 km

200 km

100 km

0 km

200 km

100 km

0 km

Depth Profile A2 - A2'

0 km 100 km 200 km 300 km 400 km 500 km

0 km 100 km 200 km 300 km 400 km 500 km

200 km

100 km

0 km

200 km

100 km

0 km

Depth Profile A3 - A3'