Numerical modelling of the 1996 Chimbote-Peru tsunami earthquake (Mw 7.5)

The earthquake of Chimbote occurred on February 21, 1996 in the northern region of Peru. Despite its relatively small magnitude, it generated a tsunami of 2–3 m height in Chimbote, taking the lives of 12 people. We conducted the signal processing of 31 broadband teleseismic stations, and waveform inversion to obtain the slip distribution and source time function, which indicated a multiple rupture process. The rupture process had a duration of 70 s, a rather high value for a relatively small earthquake. The calculated scalar seismic moment was $2.19\times {10}^{20}$ Nm, corresponding to a moment magnitude of Mw 7.5. The slip distribution was heterogeneous, with a maximum slip of 8.9 m around the main asperity concentrated in an area of $30\times 30{\mathrm{km}}^2$, for an constrained rigidity of $1.46\times {10}^{10}N/m^2$. We also calculated the vertical coseismic deformation for 45 subfaults, which was used as an initial condition for the tsunami propagation modelling. Simulated tsunami waveforms were calculated for Salaverry ($H_{\max }=0.81$ m), Santa ($H_{\max }=4.62$ m) and Chimbote ($H_{\max }=2.67$ m) tidal stations.