Combining active and passive multichannel analysis of surface waves for seismic soil classification through Vs30

Abstract

Surface wave methods are commonly used for seismic soil classification, however, their indirect nature implies a degree of uncertainty that needs to be described and constrained. Surface waves response is analyzed using active and passive sources. In passive test, linear and circular arrays were used. The f-k analysis, SPAC method, and Roadside MASW were used to evaluate the dispersive characteristics of each site. Our results show that the exploration of the first 30 meters of soil is not a trivial process. To obtain a reliable shear wave depth-profile, is necessary to have a high energy source, or combine dispersion curves obtained with standard-energy active source, passive linear and circular arrays. Results obtained through passive linear test do not guarantee the 30 m of exploration, especially when there are no roads or street close to explored site. We test the reliability of this approach in three end-member soil conditions of the Santiago basin (Chilean capital).