On the selection of ground-motion attenuation relations for seismic hazard assessment of the Peninsular Malaysia region due to distant Sumatran subduction intraslab earthquakes

Abstract

The assessment of seismic hazard from seismicity especially those induced by either subduction interface or intraslab earthquakes requires appropriate ground-motion attenuation relations that are tuned to a suitable magnitude-distance range. The Peninsular Malaysia region could be subject to a remarkable seismic hazard due to the large-magnitude, long-distance earthquakes from the Sumatran subduction zone. The earthquakes from Sumatran subduction intraslab zone have not been taken into special consideration in terms of applying the applicable ground-motion relations in the most previous probabilistic seismic hazard assessment (PSHA) studies for the region. This study has attempted first to derive response spectral ground-motion attenuation relations for distant subduction intraslab earthquakes based on the ground-motion data recorded in Peninsular Malaysia, Japan, and Iran. The response spectra database has been compiled from hundreds of ground motions from subduction intraslab events of moment magnitude (M) 5.0-7.7 recorded at sites with hypocentral distance (Rhyp) of about 120 up to 1400 km. The proposed empirical relations are for peak ground acceleration (PGA), peak ground velocity (PGV), and 5% damped pseudo-acceleration (PSA) for four site classes (i.e., National Earthquake Hazards Reduction Program (NEHRP) site classes B, C, D, and E). Second, an evaluation of the applicability of the present study, the global and overseas regional ground-motion relations to the Sumatran subduction intraslab earthquakes has been presented in order to develop ground-motion logic tree for seismic hazard assessment in the Peninsular Malaysia region.