Seismic hazard vulnerability based on probabilistic seismic hazard approach in Bengkulu City, Indonesia

Abstract

Bengkulu City is an area in Indonesia that has a high seismic intensity. This area is very vulnerable to undergo earthquakes. Therefore, there is a necessity to study the hazard assessment in this area. This paper presents a seismic hazard vulnerability study in Bengkulu City based on seismic ground response analysis combined with the probabilistic seismic hazard assessment. The soil profiles around Bengkulu City are investigated using a geophysical survey by microtremor and seismic ground response analysis. The ground motion of soft soil is implemented. Soil responses such as peak ground acceleration (PGA) at the surface, spectral accelerations (SA) at 0.2 s and 1 s, and the amplification factors of sites are observed. Those parameters are then processed to be presented in microzonation maps. The results show that PGA in Bengkulu City ranges from 0.2 to 0.5g. SA at 0.2 s and 1 s ranges from 0.4 to 1.3g and 0.4 to 0.7g, respectively. The results also exhibit that the propagated wave could amplify up to 1.6 times at the ground surface. The results bring a recommendation to reconsider the seismic design code for the structural buildings in Bengkulu City.