Investigation of Site Condition Using Elliptical Curve Inversion from Horizontal-to-Vertical Spectral Ratio (HVSR)

Abstract

This study aims to investigate site conditions based on the dominant period and elliptical curve inversion of Horizontal-to-Vertical Spectral Ratio (HVSR). The data were taken using a seismometer portable short period in the minimum time span of data retrieval for 30 minutes. The Nakamura method as known as Horizontal-to-Vertical Spectral Ratio (HVSR) is used to obtain the value of the dominant frequency and amplification factor. The dominant frequency is changed to the dominant period which can indicate the type of soil. HVSR processing use Geopsy software with a guide from the SESAME Project. The results of processing show that the dominant frequency and the amplification factor. In Geopsy there are several modules and packages. This processing uses TFA Module and Max2curve Package and Dinver Package. Waveform can be inversed based on the elliptical curve of HVSR model to produce a shear wave velocity model (Vs) uses that modules and packages. From the velocity model, we can know Vs30 to determine the type of soil layer. The shear wave velocity model obtained can show the estimation of sediment thickness in the area under investigation.