Determination of ground motion parameters of urban centers of Balochistan province

Abstract

Ground motion prediction equations (GMPEs) are cornerstone of Probabilistic Seismic Hazard Assessment. A big pool of GMPEs is available nowadays for active crustal and subduction zone categories which are derived from dataset of different regions including the database of Middle East, Europe (non-NGA) and NGA WEST 2 database. For countries like Pakistan which do not have local GMPEs, selection of GMPE is difficult and is merely based on hit and trial. A Comparative analysis of latest set of GMPEs for these respective categories on seismic hazard of Pakistan is unknown. In this study, Probabilistic Seismic Hazard analysis is conducted on urban centers (Gwadar and Quetta) of Balochistan province, a sample from Pakistan is given their potential to become economic hubs as rapid infrastructure development is expected in the region. The analysis is based on area source approach along with the modelling of major active crustal faults of the region. Three sets of GMPEs are selected where first set consists of GMPEs developed by NGA WEST 2, the second set consists of non-NGA based GMPEs while the third set is a hybrid set in which NGA WEST 2 and non-NGA based GMPEs are used together. Logic tree method is employed in this work to take into consideration of the epistemic uncertainty in different GMPEs for each tectonic zone and the seismic source models as well. For 10% probability of exceedance in 50 years (return period 475 years), updated hazard maps for PGA and spectral acceleration for structural period of 0.1 s, 0.2 s, and 1 s are created. These results can be effectively used to reduce seismic risk, to develop effective disaster mitigation, and management strategies.