March 20, 2012 Earthquake: Guerrero, Oaxaca, Mexico

Felt Reports

At least two people killed in Guerrero, 11 people injured in Oaxaca and two injured at Mexico. At least 800 houses collapsed at Igualapa, Guerrero. Felt (VIII) at Pinotepa Nacional; (VI) at Acatzingo, Chilpancingo and Nezahualcoyotl; (V) at Acapulco, Coatzacoalcos, Mexico, Minatitlan, Ometpec, Tehuacan and Tlaxcala. Felt widely in central and southern Mexico as far as Campeche, Ciudad Madero, Puerto Vallarta and San Luis Potosi. Felt (III) at Antigua Guatemala and Guatemala, Guatemala. Felt in much of western Guatemala. A seiche was observed in a swimming pool at Santa Fe, New Mexico, USA.

Tectonic Summary

The March 20, 2012 earthquake occurred as a result of thrust-faulting on or near the plate boundary interface between the Cocos and North America plates. The focal mechanism and depth of the earthquake are consistent with its occurrence on the subduction zone interface between these plates, approximately 100 km northeast of the Middle America Trench, where the Cocos plate begins its descent into the mantle beneath Mexico. In the region of this earthquake, the Cocos plate moves approximately northeastwards at a rate of 60 mm/yr.

Historically, there have been several significant earthquakes along the southern coast of Mexico. In 1932, a magnitude 8.4 thrust earthquake struck in the region of Jalisco, several hundred kilometers to the northwest of today's event. On October 9, 1995 a magnitude 8.0 earthquake struck in the Colima-Jalisco region, killing at least 49 people and leaving 1,000 homeless. The deadliest nearby earthquake occurred in the Michoacan region 470 km to the northwest of today's event, 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. More recently, a 2003 magnitude 7.6 Colima, Mexico earthquake 640 km to the northwest of today's event killed 29 people, destroyed more than 2,000 homes and left more than 10,000 homeless.

(above from reference #1053)

A powerful earthquake that shook Mexico from its massive capital to its resort-studded southern coast damaged hundreds of homes and sent thousands of panicked people fleeing from swaying office buildings, yet apparently didn't cause a single death. As of early Wednesday, there were still no reports of deaths from Tuesday's magnitude-7.4 quake centered near the border between the southern states of Oaxaca and Guerrero, even after 10 aftershocks. Interior Secretary Alejandro Poire said Tuesday night that nine people were injured in Oaxaca and two in Mexico City. (reference #9777)

Two people caught in this week's big earthquake died Thursday, the first deaths reported from the magnitude-7.4 temblor that damaged hundreds of homes in southern Mexico and caused panic far off in the national capital. Salvador Cruz Castro, mayor of the Cuajinicuilapa municipality in Guerrero state, said one of the victims died from injuries caused by a wall falling on him and the other died of complications for a heart attack suffered during the quake. Tuesday's earthquake was centered near the border between the southern states of Guerrero and Oaxaca. It caused about 60 houses to collapse and damaged about 800 more homes. (reference #9780)

<600m USD in total damage (reference #13034)

108m USD in economic loss (reference #13727)

320m USD in total damage (reference #1250)