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

Jiménez C.; Miguel Saavedra J.; Zamudio Y.; Olcese D. · Journal of Seismology (2023) · DOI: 10.1007/s10950-022-10119-3

Resumen

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.

Instituciones: Universidad Nacional Mayor de San Marcos; Universidad Nacional de Ingeniería