On November 12, 1996, an earthquake of magnitude 7.7 Mw occurred in front of the Nazca Ridge, South of the Peruvian Central region, its origin has been associated with the subduction process of the Nazca plate under the South American plate. The focal mechanism parameters of the earthquake are determined from the P-wave polarity and body-wave modeling method (P and SH-wave). The focal mechanism corresponds to an inverse fault with fault planes oriented in direction NW-SE, with a dip in the NE direction, next to the horizontal (δ = 16°). The focus depth is estimated to be 18 km. The source time function (STF) has a 50 second duration and a scalar seismic moment of 4.4 × 10 20Nm. It describes a complex rupture process associated with three points of energy release on the same fault plane, two of them having greater size than the third one. Focal mechanisms computed for three after-shocks, of magnitude greater than 5.4 mb, present similar characteristics to the principal earthquake and suggest three rupture stop points located at depths of 11, 21 and 25 km and distributed on a fault plan with a 24° dip in the NE direction. The rupture processes of these aftershocks are simple and of short duration. The earthquake of 1996 is the sixth of the large earthquakes that occurred in the Central Peru region since the 1940s. This inter-plate earthquake is located in the same area where the August 24, 1942 (Mw = 8.2) earthquake occurred: in front of the Nazca Ridge, showing the important role that this structure plays in earthquake generation in the region. The results obtained for the 1942 and 1996 earthquakes suggest that the last earthquake is a repetition of the first one.