Estimation of the Seismic Source of the 1974 Lima Peru Earthquake and Tsunami (Mw 8.1)

Abstract

In this investigation, we have conducted a long period teleseismic and tsunami waveform inversion to obtain the slip distribution of the 1974 Lima-Perú earthquake occurred in the central region of Peru. According to teleseismic inversion, the rupture process was complex with a duration of 90 s approximately and the main asperity was located in the northern side of the rupture geometry, offshore Lima and Callao. According to tsunami waveform inversion the main asperity was located in the southern side of the fault plane, offshore Cañete. However, a joint inversion of teleseismic and tsunami waveforms averaged the contribution of the two datasets and could give a better result. The maximum slip from the joint inversion was 7.25 m, and the moment magnitude was Mw 8.1. Despite the occurrence of this earthquake (almost 50 years ago), there is a high seismic potential to trigger a tsunamigenic earthquake in the central region of Peru. According to the interseismic coupling the next earthquake in the central region of Peru is ready to occur and it would be of 8.5–8.8 Mw.