Numerous methods have been developed to evaluate site effects during strong earthquakes. In areas of low to moderate seismicity, no strong motion recordings are available and site effect studies must rely on weak motion records and numerical modeling. Numerical modeling requires good knowledge of the geophysical structure, and needs cheap and fast methods to measure important physical parameters. Ambient vibration techniques have therefore become very important: they provide information on the eigen-vibrations of the geological structure and estimates of S-wave-velocities as a function of depth. This presentation will give examples of work done in Switzerland on site-specific hazard studies, site characterization of seismic stations, and possible applications for building codes.
