Site-specific response spectra developed by considering near-fault motion with finite-fault simulation in Taiwan

A new methodology is proposed for developing a scenario-based site-specific response spectrum (RS) considering near-fault effects in Taiwan. First, source parameters, together with reference rock site conditions, are defined according to the available geological and geophysical information at a target site close to a potential active fault in northern Taiwan. Secondly, the scenario-based response spectrum for a reference rock site condition is developed theoretically through an empirical approach by using a ground motion prediction equation (GMPE). The effect of the pulse period and the occurrence probability of near-fault pulse-like ground motion on RS is evaluated by using the ground motion simulation (GMS) technique, in which the stochastic finite-fault simulation method is validated and applied for evaluating velocity pulse. Third, site-specific site amplification is incorporated into RS through a site transfer function calculated from the measured horizontal-to-vertical Fourier spectral ratio through the microtremor (MHVR) of the target site. Finally, the design spectrum of the target site is compared with the derived site-specific RS to evaluate the impact of the neighbor fault on the structure of the target site.