Numerical modelling of the 1970 intraslab Peru earthquake and tsunami (Mw 7.9)

In this research paper, we have modelled the tsunami source of the 1970 Peruvian earthquake. The rupture geometry (of dimensions 150×75 km²) was obtained from the aftershocks distribution. The fault plane geometry was divided into 2 subfaults: the biggest (of 112.5-km length to the northern side) of normal fault plane and the smallest (37.5-km length to the south) of reverse fault plane, due to the seismic event had a complex rupture process. The slip was constrained from the tsunami waveform amplitudes and seismic moment using an iterative approach method, since a data inversion is impossible due to the scarcity of available tsunami data. The simulated vertical deformation field has a particular pattern, it is composed of 4 lobes of alternated uplift and subsidence, the maximum subsidence was 38 cm, and the maximum uplift was 57 cm. We have obtained a seismic moment of 8.92× 10²⁰ Nm and the corresponding moment magnitude was Mw 7.9. The maximum slip was calculated in 1.59 m (reverse fault) and 1.32 m (normal fault). The simulated maximum tsunami height was 93 cm at Salaverry and 73 cm at Chimbote stations.