M7.4 EARTHQUAKE STRIKES NEAR ACAPULCO, MEXICO

March 19, 2012

Walter Hays, Global Alliance for

Disaster Reduction, University of North Carolina, USA

REGIONAL LOCATION MAP

LOCATION

The 20 km (12.4 miles) deep,

M7.4 earthquake occurred as the result of thrust faulting on or

near the interface between the Cocos and North American

tectonic plates

COCOS PLATE SUBDUCTION ZONE

INITIAL REPORTS• The ground shook for about 1 minute

(very short compared with 10 minutes for the December 26, 2004 M9.0 Indonesia quake)• 500 homes in the state of Guerrero

collapsed • Bridge collapsed in Mexico City• No deaths

BRIDGE COLLAPSED IN MEXICO CITY, OVER 330 KM FROM SOURCE

REMEMBERING PAST EARTHQUAKE DISASTERS

IN MEXICO

September 19, 1985

PAST NOTABLE DISASTERS

• MEXICO CITY • 1985

EARTHQUAKE

• 10,000 CASUALTIES• $ 4,000 M LOSS

(1985 VALUES)• $ 275 M

INSURED LOSS

MEXICO CITY IS WELL KNOWN FOR 2-SEC PERIOD

SOIL AMPLIFICATION AT SITES IN THE OLD LAKE

BED

EXAMPLE OF SOIL AMPLIFICATION

SCHOOL: MEXICO; SEPT. 19, 1985