Vulnerability of the Atlantic Patagonian coast to tsunamis generated by submarine earthquakes located in the Scotia Arc region. Some numerical experiments

Abstract

The Scotia Arc is one of two regions in the Atlantic Ocean with greater potential for tsunami generation from seismic and volcanic sources. A numerical modeling study was undertaken to determine tsunami generation from postulated sources along the Arc and tsunami wave amplification or attenuation along the Patagonian continental shelf. Sea level oscillation represented by a simple sinusoidal wave function applied at the boundary of the numerical grid, which simulated the tsunami entering the computational domain, was implemented as forcing. The validation of this model was carried out by comparing the maximum amplitudes recorded and simulated at Santa Teresita and Mar del Plata (Buenos Aires province) after the occurrence of earthquake and subsequent tsunami in Sumatra (December 2004). From numerical simulations it can be seen that the tsunami propagation is highly affected by bathymetric refraction on the Patagonian continental shelf and the wave amplitude is significantly attenuated on the inner continental shelf. Maximum amplifications were obtained around Malvinas (Falkland) Islands and Burdwood bank because the wave propagates almost without refracting and the shoaling effect is highly significant there