The April 16, 2016 M 7.8 earthquake, offshore of the west coast of northern Ecuador,
occurred as the result of shallow thrust faulting on or near the plate boundary
between the Nazca and Pacific plates. At the location of the earthquake, the Nazca
plate subducts eastward beneath the South America plate at a velocity of 61 mm/yr.
The location and mechanism of the earthquake are consistent with slip on the primary
plate boundary interface, or megathrust, between the two major plates. Subduction
along the Ecuador Trench to the west of Ecuador, and the Peru-Chile Trench further south,
have led to the uplift of the Andes mountain range and produced some of the largest
earthquakes in the world, including the largest earthquake on record,
the 1960 M 9.5 earthquake in southern Chile.