Shallow SH-wave seismic refraction and reflection methodssite-specific seismic hazards applications

摘要

The SH-wave seismic technique is becoming more common in shallow engineering and environmental surveys, because of its insensitivity to ground-water masking, and its frequent capacity to provide higher resolution relative to the traditional P-wave method. In this paper, we show applications of the SH-wave method for earthquake site classification and shallow investigation of active faults in the Gansu Province of the Peoples Republic of China. The seismic S-wave velocities and thicknesses of the shallow nonlithified sediments have a significant role in sitespecific earthquake ground-motion response; thus are the basis for many of the empirical and theoretical earthquake hazard classifications in geotechnical earthquake engineering. The SH-wave refraction/reflection method has been shown to be effective in characterizing these dynamic site properties. In addition, SH-wave CMP profiles in urban areas underlain by low-velocity, watersaturated sediment can assist in the identification of shallow neotectonic structures (i.e. ≤ 50m) that are a primary input parameter to any seismic hazard analysis.