Preliminary Results of Horizontal to Vertical Spectral Ratio (HVSR) Across Lembang Fault, Bandung, Indonesia

Abstract

Lembang Fault is located in the Bandung basin with is a thick sedimentary of volcanic rocks and the depositional remnants of an ancient lake. Bandung region has a dense population and infrastructure that possible to be vulnerable of seismic hazard. Based on geological studies, Lembang fault is an active fault that possibility to produce a magnitude more than 6.0. Seismic hazard estimation is one of some method to identification of hazard potential due to the Lembang Fault activity. Horizontal to Vertical Spectral Ratio (HVSR) method is one of way to seismic microzonation that identified the dominant frequency (F0). We deployed 6 seismometers across Lembang Fault area for about 3 months observation. Then we computed the seismic response that corelated with physical properties inside the basin. The variation of seismic susceptibility index around Lembang area indicates the vulnerability of seismic hazard. LEM01 and LEM06 have relatively lower of natural frequency, its about 1.22 (LEM01) and 1.49 (LEM06). The number of natural frequency indicate thick of sediment and vulnerable of seismic hazard.