The Development of a 2‐Dimensional Microtremor Survey Method Based on SPAC Method Using Sequential Linear Arrays

Abstract

The demand to quickly and economically obtain S‐wave velocity profiles in geotechnical and seismic engineering fields has been increasing recently. In order to satisfy this need, many types of surface wave methods have been developed and have become widespread. It is, however, not easy to find survey methods which rapidly provide cross sections of the shear‐wave velocities at depths of greater than about 30m. In order to overcome this limitation, we have developed a new 2‐dimensional microtremor survey method based on the SPAC method using sequential linear arrays. We call this survey method “2‐Dimensional Linear Array Microtremor Survey (2D‐LAMS) Method”. We applied this new method to field surveys and evaluated the results. Consequently, we confirmed that the cross sections of the shear‐wave velocities obtained by this new method were consistent with the cross sections obtained by such conventional geophysical survey methods as 2D‐MASW, seismic reflection surveys and electrical resistivity surveys. The 2‐Dimensional Linear Array Microtremor Survey Method has advantages in terms of the depths of investigation in comparison with MASW. In addition, this method is less susceptible to ambient noises when compared with the other conventional survey methods.