The updated zonation of seismic vulnerability index and ground shear strain at Bengkulu City, Indonesia

Abstract

Seismic Vulnerability Index and Ground shear strain have been updated to increase the resolution of seismic hazard analysis in Bengkulu City. A total of about 400 sites are studied. The measurement of the sites is performed to obtain the amount of information such as amplification and predominant frequency. Those parameters are empirically analyzed to determine the seismic vulnerability index (Kg and Ground shear strain (γ). The results showed that the highest value of Kg is identified on the alluvium terraces Qat formation, especially in Rawa Makmur, a densely populated housing area. The highest value of γis also identified in Rawa Makmur, which is dominated by soft rock sites. The observation reveals that the dynamic behavior of soil properties in the site tends to be generally categorized as elastic. However, the possibility of elastoplastic material is identified on minor sites in Rawa Makmur. It would reflect that during the strong earthquake, the geotechnical impacts, such as crack and settlement, would have been possible to happen in Rawa Makmur.