Site-Dependent Response Spectral Attenuation Modelling

Abstract

A site-dependent response spectral attenuation model is an important element in a site-dependent seismic hazard assessment. Seismic attenuation behaviour is controlled by a large number of wave modification mechanisms, some of which have characteristics specific to a local area or a particular site, whilst others can be generalised to the entire seismic region. Factors representing these mechanisms are often not resolved. An attenuation modelling approach is demonstrated in this paper, to evaluate individual regional and local wave modification factors. The upper-crust amplification factor computed from the modelled rock shear wave velocity profile was then combined with predicted attenuation parameters to determine the upper-crust modification filter function associated with Singaporean geological formations. Stochastic simulations of the seismological model for the magnitude 9.3 Aceh earthquake (Indonesia) on the 26th of December in 2004, were performed and compared with the response spectra recorded on a rock site in Singapore.