Abstract

In this study, two kinds of tsunami numerical models based on the shallow water equations were employed to simulate the South Pagai Island, Sumatra earthquake tsunami which occurred in 25 October 2010. The models consist of generation, propagation and arrival times along affected coasts in Mentawai islands. Post event tsunami calculations were performed in order to better represent the event and identify more in detail the affected locations. The numerical models were performed by using nonlinear and dispersive long wave tsunami models (TUNAMI N2 and SWAN) with GEBCO30 and ETOPO2 bathymetry data in a coarse 2′ and 4′ basin scale grid. The simulated waves were particulary high on the South shore of the islands of Mentawai where they reached. This is in agreement with the locations indicated by the survey reports as most affected. The simulated waves were also compared with the available deep ocean pressure sensors and tide gauge records. Results of the numerical simulations except for the Padang2 tide gauge measurement are in reasonable agreement with data of observations. In this regard, numerical simulations are important for the purpose of providing mitigation measures to reduce the potential impacts and risks on local communities in the islands. Therefore, the main purpose of this study was conducted to contribute to reveal the effects of the earthquake in the region by using the tsunami simulation models considering the occurrence of tsunami in the future at the same area.

Key words: Mentawai Islands, earthquake source parameters, tsunami, tsunami simulation, bathymetry.