M 7.4 - 33 km S of Champerico, Guatemala

Tectonic Summary

The November 7, 2012, M 7.4 earthquake south of Champerico, Guatemala, occurred as a result of shallow thrust faulting on or near the subduction zone interface between the subducting Cocos plate and the overlying Caribbean and North America plates, near their triple junction. At the location of this earthquake, the Cocos plate moves north-northeast relative to the Caribbean and North America plates at a velocity of about 70–80 mm/yr and subducts beneath Central America at the Middle America Trench southwest of the November 7th earthquake.

Over the past 40 years, the region within 250 km of the November 7th earthquake has experienced 50 earthquakes with M 6+; 2 of these were larger than M 7. The first was a M 7.1 in December of 1983, in approximately the same location as the November 7th event, and resulted in no documented fatalities. The second had a magnitude of 7.2, and struck about 100 km to the northwest offshore Mexico in September 1993. One known fatality was associated with the 1993 event. A M 6.8 earthquake in October 1979, 120 km to the east-southeast of the November 7th earthquake, resulted in seven fatalities in Guatemala.

Hayes et al. (2016) Tectonic summaries of magnitude 7 and greater earthquakes from 2000 to 2015, USGS Open-File Report 2016-1192. (5.2 MB PDF)