Tsunami Dangeros in the Southern Ocean, Numerical Simulation

Abstract

We model tsunami generation and propagation from strong seismic events for the Southern Ocean. Two seismically hazardous zones of the Southern Ocean were studied - the South Sandwich Trench and the Macquarie Ridge area. The earthquake in the Sandwich Trench on August 12, 2021 (M=8.1) and the earthquake on the Macquarie Ridge on May 23, 1989 (M=8.0) were considered. For both earthquakes, based on data on the main parameters of the seismic process, the earthquake source was modeled and its dynamics were specified for each of the events under consideration. For modeling simulation, a keyboard model of the earthquake source was used, in which the area of ​​​​the rupture of the Earth's crust is represented in the form of sequentially moving keyboard blocks. For both events, numerical simulation of the tsunami source generation by the seismic source and the propagation of tsunami waves to the nearest island and continental coasts were performed. Histograms of maximum wave heights along these coasts were constructed and compared with available natural data.For the Sandwich earthquake (12.08.2021, M=8.1), the maximum tsunami height for the Chilean coast was 1.7 m, with an average arrival time of about 3 hours, for the Argentine coast, the maximum tsunami height was 2.5 m, with an average arrival time of about 3.5 hours. For the earthquake on the Macquarie Ridge on May 23, 1989, for Australia and Tasmania, the maximum wave heights are up to 1.3 meters and the arrival time is about 1.5 hours, for Antarctica, the corresponding values ​​are 0.3 m and 1.5-2 hours. In the case of earthquakes with M > 8.1, the generated tsunami waves may be a great danger.

Keywords: Tsunami, strong earthquakes, keyboard model, South Sandwich Trench, Macquarie Ridge