The earthquake occurred on thrust faults along the boundary of the Nazca and South American plates . The region frequently produces large earthquakes , and 15 others of magnitude 7 or higher have taken place within 400 km of the epicenter over the past 100 years . The last big quake that occurred in this region was the 1943 Ovalle earthquake , reaching a magnitude in the range 7.9 – 8.2 ; however , comparisons of the associated source time function ( the time history of release of seismic moment ) show that the 2015 event was significantly larger than the 1943 earthquake , in terms of duration , up-dip rupture extent and tsunami size
1943 Ovalle earthquake
1943 Ovalle earthquake
2015 Illapel earthquake