Characterizing Anomalous Ground For Engineering Applications Using Surface-based Seismic Methods

摘要

Seismic surface-wave methods can be successful for developing meaningful velocity profiles, even in the near surface, which is notoriously complex. As site conditions increase in complexity, the use of independent prior information becomes ever more critical. Integration of surface-wave based methods, active and passive, with other geological, geophysical, and geotechni-cal information can improve both resolution of estimated shear-wave velocity profiles and depth of penetration.rnOur current approach for developing a detailed shear-wave velocity model involves acquiring and processing MASW and SASW data from passive and active sources. We apply an interpretation scheme that incorporates a-priori information such as judicious search constraints based on geology. We also perform data fitting with an optimal forward modeling scheme.rnOver recent years, widespread research has advanced the use of surface-wave methods such as SASW and MASW for site characterization. Still, there remains considerable opportunity for development to obtain better results with surface waves. One category is extending the applicability of these methods for mapping lateral heterogeneities such as tectonic faults, caliche lenses, fissures, cavities, facies boundaries, lost or forgotten utilities, and abandoned mines.rnRegarding seismic response studies for the Las Vegas Valley, the next step is to finalize the velocity model and incorporate it into ground-shaking simulations. By doing so, we will be enhancing our understanding of earthquake hazards in a rapidly developing, major city that has a significant earthquake risk.