Sediment thickness and average V s prediction using HVSR of ambient seismic noise: case studies in Singapore

The thickness of sediment and average shear-wave velocity ( V s ) are crucial information for geotechnical site investigation and engineering geology. The horizontal-to-vertical spectral ratio (HVSR) approach has become an appealing complementary tool due to its convenience and simplicity in field acquisition and processing. This study discusses essential technical details for acquiring and processing HVSR data and provides recommendations based on case studies in Singapore. We conducted 51 HVSR tests using a multi-component 4.5-Hz geophone coupled with a reference borehole to identify sediment thickness. By establishing such database, we produced three high-level colormaps on sediment characteristics, including resonance frequency f 0 , thickness, and estimated average V s . These high-level colormaps agree with the general trend of local terrain and the location of the Bukit Timah Fault. Additionally, we established empirical functions to estimate sediment thickness and average V s , allowing geologists and engineers to quickly assess two crucial geotechnical design parameters.