Near-Surface Velocity Models in Davao City, Philippines using Multi-Channel Analysis of Surface Waves and Seismic Refraction

Abstract

A study of property of soil layer in Davao city, the Philippines by using the Multi-channel Analysis of Surface Wave (MASW) and Seismic refraction techniques. The aims of the study are to generate a shear wave and primary wave velocity model, and obtain Vs30 Contour map. Both 2D Vs and Vp model can be divide into 3 layers base on boreholes data. The top layer be related to clay layer and sand clay and/or sand silt layer. The second layer corresponds to gravels with clay layer. The bottom layer corresponds to volcanic breccia. The Vs30 contour map from MASW (WaveEq), estimate Vs30 (Wang & Wang, 2015), seismic refraction, and lithologic logs were obtained. According to the NEHRP standard, all Vs30 contour map can be classified into Class C as the very dense soil or soft rock.