HVSR Data Processing

Panduan pengolahan data seismik pasif HVSR menggunakan GEOPSY.

The method that records seismic noise is the Horizontal-to-Vertical Spectral Ratio (HVSR) method. This method is widely used to find the depth to bedrock in areas with surface sedimentary layers. Depth to bedrock is necessary for earthquake hazard assessments and for construction projects. This method uses a single three-component seismometer. The seismometer records ambient energy for about 30-60 minutes. For analysis, the spectral ratio of the horizontal and vertical components is calculated for some window length of about 30-60 seconds. The next step is to find the dominant frequency component of this ratio. This frequency (f0) is set as the resonance frequency of the overlying sedimentary layer. Its thickness is $V_{s}/4f0$, which is essentially a quarter of the wavelength. Often the shear wave velocity is unknown at a specific location. In this case, an empirical relationship between the resonance frequency and the layer thickness is used. This relationship must be known at the depth to bedrock within the study domain.