The November 24, 2015 22:45 UTC M 7.6 earthquake was the first of two similarly sized events near the Peru-Brazil border in southeast Peru. Both earthquakes occurred as the result of normal faulting at the depth of approximately 600 km, almost 1000 kilometers east of the Peru-Chile Trench within the subducted oceanic lithosphere of the Nazca plate. Focal mechanisms indicate rupture occurred on either the north or south-southeast striking, moderately dipping normal fault. At the location of the earthquakes, the Nazca plate subducts to the east under the South America plate at the velocity of about 69 mm/yr.
The 22:45 UTC event preceded another M 7.6 earthquake (22:50 UTC) by 5 minutes; the events were separated by approximately 50 km horizontally, slightly more than typical location uncertainties of global earthquakes and just 6 km vertically. The two events also had approximately the same focal mechanism. The latter earthquake was most likely triggered by the earlier event. Seismologists sometimes refer to a pair of similarly sized earthquakes that occur at nearly the same time and location as an earthquake "doublet."
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