A simple approach of enhancing ambient noise array analysis as bedrock depth proxy

Subsurface geometry, particularly the depth of bedrock, is crucial in many applications i.e. site effects studies, hydrogeologic studies and site characterization projects. Estimating the bedrock surface using ambient seismic noise analysis has been practiced by many researchers with most studies focusing on utilizing site resonance frequency. This study proposes a simple approach of applying ambient noise array analysis for estimating bedrock depth. To examine the approach, array ambient noise data have been acquired at two sites. Analysis of ambient noise data was carried out. Shear wave velocity of the sites was inverted and bedrock depth was estimated. A comparison of the bedrock depth predictions using this study approach with boreholes drilled in close proximity to the measured sites demonstrates that the approach provides a comparable bedrock depth estimation. This suggests that the method provides reasonable results as a bedrock depth proxy at study sites.