Microtremor Survey Method is utilized to map the near surface velocity structure for a proposed subway construction project in Shenzhen, China. Three components broad-band seismometers are deployed in circular arrays on multiple survey points along the subway line. The recorded microtremor ‘noise’ is processed using SPAC method to obtain phase velocity dispersion curve for the fundamental mode of Rayleigh wave. HVSR is analyzed to probe potential anomalous geological structures. In this study it is demonstrated that phase velocities for frequency range from 5Hz to 40 Hz can provide reasonable solvability for structures down to 50 m and map the bedrock topography. Urban infrastructures buried at depth down to 10 m are detected as high phase velocity, high H/V ratio zones. Bedrock deposited in the depth of 25-35 m shows similar signature of signals. Profiling the phase velocity dispersion curve and HVSR along the survey line allows the provision of a snapshot of the geology structure beneath.
Presentation Date: Thursday, September 28, 2017
Start Time: 9:20 AM
Presentation Type: ORAL