Earthquake Source Characterization for Tsunami zoning (Case study of the Bengkulu 12 September 2007 Tsunami and the 2 June 1994 Banyuwangi Tsunami)

摘要

The aim of this study is to characterize the earthquake generating tsunami in Indonesia, that influenced by the magnitude in the source. This study consists of the catalog and data of NOAA, Russian Tsunami Laboratory, BMKG observation, Global CMT, USGS and GEBCO bathymetry. Characterization of earthquakes based on Wphase method and the ratio of energy-seismic moment. Wphase widely applied in the global tsunami early warning using a group of P wave teleseismic with very low frequencies below 0005 Hz but yield an accurate result closed to Global CMT. The ratio of energy produced from seismic moment of broadband velocity waveform that give a threshold of the tsunamigenic earthquake with Θ ratio between -4.9 to -5.7 and the tsunami earthquake that Θ below -5.7. Further the characterization parameter used as an input tsunami modelling to give 2.2 m run-up height in case of Bengkulu 2007 tsunami and the highest run-up in Bali 5 m with inundation distance of 711 m in case of Banyuwangi 1994 tsunami. Tsunami zoning prone area is affected by tsunami source consisting of earthquake magnitude, distance to subduction trenches, geological conditions as hypocenter depth, bathymetry and coastal morphology exciting tsunami amplification.