Source characteristics of Peruvian deep focus seismic doublet of November 24, 2015

摘要

The Peruvian deep focus seismic doublet of November 24, 2015 is the largest event recorded on the Peru-Brazil border in the last 50 years, with hypocenter depth at 655 km (Mw 7.4) for the first event and 675 km (Mw 7.5) for the second event, both events were separated by a distance of 50 km and by a time of 5 min. There was no damage on the surface, but the earthquake was felt in part of Peru (IV MM in Esperanza Ucayali) and Brazil. The parameters that characterize the seismic source have been obtained from the inversion of teleseismic waveforms. For example, the duration of the rupture process was around 25 s for both events and the rupture velocity was between 2.5 and 2.8 km/s. The source time function is similar for both events: it starts with a small energy release before 10 s and then the greatest energy release between 10 s and 20 s. The focal mechanism is of normal fault type, corresponding to tensional tectonic regime of deep slab in the region.