Site-specific shear wave velocity investigation for geotechnical engineering applications using seismic refraction and 2D multi-channel analysis of surface waves

Abstract

In order to quantify the near-surface seismic properties (P- and S-wave velocities, and the dynamic elastic properties) with respect to the depth at a specific area (6th of October club), we conducted a non-invasive and low cost active seismic survey. The primary wave velocity is determined by conducting a P-wave shallow seismic refraction survey. The dispersive characteristics of Rayleigh type surface waves were utilized for imaging the shallow subsurface layers by estimating the 1D (depth) and 2D (depth and surface location) shear wave velocities. The reliability of the Multi-channel Analysis of Surface Waves (MASW) depends on the accurate determination of phase velocities for horizontally traveling fundamental mode Rayleigh waves. Consequently, the elastic properties are evaluated empirically. The Vs30 (average shear wave velocity down to 30m depth), which is obtained from the MASW technique, plays a critical role in evaluating the site response of the upper 30m depth. The distribution of the obtained values of Vs30 through the studied area demonstrates site classes of C and D, according to the NEHRP (National Earthquake Hazard Reduction Program) and IBC (International Building Code) standards.