A Preliminary Result of Seismic Hazard Analysis in Eastern Part of Bali Island, Indonesia

Abstract

Bali Island is one of the main tourist destinations in Indonesia. However, Bali Island is also prone to earthquakes, as evidenced by several historical destructive earthquakes, especially in the eastern part of Bali. A probabilistic seismic hazard modeling is undertaken to analyse the earthquake hazard, as well as studying the contribution of local geological conditions to earthquake ground motion. We use seismic waveforms retrieved from 23 temporary seismic stations across the eastern part of Bali Island from December 2018 to June 2019 and 5 permanent seismic stations around Mount Agung and Batur. The recording data were processed using the Horizontal to Vertical Spectral Ratio (HVSR) method. Our preliminary result shows local geological conditions for each station, represented by the value of the average shear-wave velocity on rocks to a depth of 30 meters (Vs30) and the total thickness of sediments above the bedrock (basin depth). These initial results will then be developed as site parameter input for probabilistic seismic hazard analysis in the eastern part of Bali.