Implementation of seismic hazard mitigation on the basis of ground shear strain indicator for spatial plan of Bengkulu city, Indonesia

Abstract

Bengkulu, a city on west coast of Sumatra Island Indonesia, is very vulnerable to undergo earthquake and other natural hazards. A seismic hazard mitigation should be prioritised in this developing city. This paper presents the seismic hazard mapping on the basis of shear strain indicator for spatial plan in Bengkulu City, Indonesia. The values of ground shear strain can be the indicator for the possible damage that could occur in an area. This study was initiated by performing geophysical measurements using microtremor to obtain the geophysical description of study area. The analysis of horizontal to vertical spectral ratio (H/V) was further performed to determine peak amplitude (A0) and predominant frequency (f0). From those parameters, the empirical analyses of vulnerability indices (Kg) and ground shear strain (γ) were conducted. All results such as A0, f0, Kg, and γ were depicted in microzonation maps. The results showed that Bengkulu City was generally vulnerable to undergo seismic impact. The concern was focused along coastal area of Bengkulu City since the liquefaction damage could occur in this area. Results of this study could bring a recommendation to stakeholders to consider seismic hazard mitigation for Bengkulu City.