Inversion of shallow subsurface structure from Rayleigh ellipticity beneath a station in Tangerang, Indonesia

Abstract

Horizontal to vertical spectral ratio (HVSR) method has been widely used for estimating site effects and soil properties beneath a station. Recent studies have shown that it is possible to extract Rayleigh wave ellipticity from the record of seismic noise or vibration. In this study, we applied HVSR method to obtain frequency resonance and site amplification beneath a seismic station in Tangerang, Indonesia. We applied time frequency analysis (HVTFA) using a continuous wavelet transform to extract Rayleigh ellipticity. We carried out inversion from the computed Rayleigh ellipticity to estimate shallow subsurface structure. We applied non linear inversion using two layers as initial model to obtain the best fit subsurface structure. We obtained that the layer boundary between two layer model is found at depth of about 100 m.