Earthquake vulnerability assessment through spatial multi-criteria analysis: a case study of Quetta city, Pakistan

Abstract

Vulnerability assessment of an urban area to earthquake hazards is the requirement to attaining sustainable urban resilience. Quetta city is the capital of the province of Balochistan surrounded by mountains with the existence of many active faults. The main objective of the current study was to assess the earthquake vulnerability in Quetta valley. A total of 400 households were selected for the primary household survey. A simple random sampling technique is employed using proportionate allocation method because of the heterogeneity of the area in terms of population. Secondary data was taken from the Geological Survey of Pakistan (GSP), the Pakistan Bureau of Statistics (PBS), and the United States Geological Survey (USGS). Analytical Hierarchal Process (AHP) & Weighted Linear Combination (WLC) methods are used to identify earthquake vulnerability. The results of the study reveal that the Northwestern and Southeastern parts of Quetta are seismically vulnerable to earthquake hazard; its geology coupled with the human dimension indicates a more disastrous future events. Results of the composite earthquake vulnerability show that seven out of thirteen Zones of Quetta city are highly vulnerable to all four components of vulnerability. Four Zones have a medium level of vulnerability and only two Zones are considered low earthquake vulnerable Zones in the study area. The topmost influential factors that make Quetta city highly earthquake-vulnerable are the soil type (0.45), peak ground acceleration (0.34), proximity to the hospitals and fire service stations (0.22, 0.21), elderly population (0.22) and fault lines (0.21) as shown in Fig. 12. This research study has significant implications for urban planners and provides a risk reduction platform in order to reduce future earthquake losses and make Quetta city more resilient and sustainable.