Probabilistic Seismic Hazard Analysis of Baluchistan and Hazard Deaggregation of Quetta using Geoinformatics Techniques

Abstract

Seismic Hazard Assessment (SHA) is most fundamental part of earthquake risk mitigation and management. Pakistan has quite a complex Seismo tectonic environment, with Arabian, Eurasian, and Indian plates colliding at different rates. In this research, probabilistic seismic hazard assessment and deaggregation approach for Baluchistan has been performed using area source model. For model development, an earthquake catalogue has been updated by compiling the events from national and international databases from year 1900 to 2020. For surface level hazard assessment, ground motion prediction equations (GMPEs) are appropriately used. To cope with uncertainty in Equations, the Logic Tree Approach is also used. Surface hazard maps are developed for Peak ground acceleration at 2%, 5%, 10%, 25% and. 69% probability of exceedance in 50 years. The Uniform. Hazard spectra (UHS) has been generated for major cities of Baluchistan. Surface level Uniform hazard spectra (UHS) graphs for Quetta and Gawadar city are developed at 69% 10% and 2% probability of exceedance which is SLE, DBE and MCE Level respectively. Hazard Deaggregation Analysis for Quetta is also carried out to estimate the percentage of hazard contribution of all the seismic source (faults, tectonic plates) to the city. Results of Deaggregation Analysis gives better understanding of seismic risk to cities. Surface Hazard PGA Maps, uniform hazard spectra (UHS) and hazard deaggregation Analysis have many practical applications in structural designing and performance evaluation of existing structures. These curves and maps would help for disaster risk mitigation and management policies.