Shear wave velocity profiling and ground response analysis in Phuentsholing, Bhutan

Shear wave velocity is directly related to earthquake energy characteristics and is a useful parameter in estimating the surface motion parameters. Shear wave velocities can be obtained from geophysical investigation or by empirical correlations. In the present paper, combinations of both approaches are used to estimate shear wave velocity for some locations in Bhutan. Although some measurements based on the multispectral analysis of surface waves are available for the depth up to 22 m, the deep subsoil geology is still unknown in Bhutan. This study estimates the shear wave velocity for the depth until elastic rock (V_S> 800 m/s) is found. The results highlight that the elastic rock is found at the depth between 150 and 400 m in Phuentsholing region of Bhutan. Furthermore, one-dimensional equivalent-linear ground response analysis is conducted using equivalent-linear earthquake site response analyses program to estimate shear wave profile, and surface ground motion parameters are obtained.