Response spectral attenuation relations for shallow crustal earthquakes in Taiwan

In this study, a local set of response spectral attenuation equations, developed for seismic hazard analysis in Taiwan, are introduced as an example for determining the local strong motion attenuation relationship for a region. Strong ground-motion data for shallow crustal earthquakes are obtained from the Taiwan Strong-motion Instrumentation Program (TSMIP). These data are used to establish peak ground acceleration (PGA) and response spectral acceleration (SA) attenuation equations taking into consideration both hanging-wall effects and site conditions. The obtained results show that the local set of attenuation equations gives significantly lower values of PGA and SA for structural periods shorter than 0.3 s as compared to a set of global relations obtained from international data. The SAs obtained for structural periods longer than 0.3 s are similar to those obtained for global sets. This indicates that developing a local set of ground-motion attenuation equations is necessary for more accurate prediction of ground motion values.

Research highlights
► A local set of response spectral attenuation equations is necessary for more accurate prediction of ground motion values.
► The local attenuation is faster than NGA models for short period motions.
► Faster attenuation may be a character in a young orogen like in Taiwan.
► The 1981 Campbell form is still valid for use in this Taiwan case except soil de-amplification under large strain is not considered.