M 7.7 - 36 km ESE of Tocopilla, Chile

Tectonic Summary

The November 14, 2007, M 7.7 earthquake near Antofagasta, Chile, occurred as the result of shallow thrust faulting in northern Chile about 100 km east of the Peru-Chile Trench, where the oceanic Nazca plate begins its subduction beneath the South America plate. At the location of the earthquake, the Nazca plate moves to the east-northeast relative to the South America plate at a velocity of about 79 mm/yr. The location, depth, and focal mechanism solutions of the earthquake indicate that this event likely resulted from subduction-related thrusting on the interface between these two plates.

While commonly plotted as points on maps, earthquakes of this size are more appropriately described as slip over a larger fault area. Thrust-faulting events of the size of the November 14, 2007, earthquake are typically about 100x50 km (length x width); modeling of this earthquake implies dimensions of about 120x80 km, predominantly surrounding and to the south of the hypocenter.

This earthquake occurred at the southern end of the rupture area of the great-sized M 8.8 earthquake of 1877, which produced a destructive tsunami and whose source region has since the late 1970s been recognized as a potentially dangerous seismic gap. In July 1995, a M 8.0 earthquake occurred approximately 200 km farther south of the November 14th event and caused at least 3 fatalities, injuried to 58 people, and widespread damage from landslides, tsunami impact, and building collapse.

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)