Unravelling Karachi’s Seismic Potential: Estimating Maximum Ground Shaking in Various Zones

Abstract

Karachi, a sprawling city spanning over 3500[Formula: see text]sq. km, exhibits significant variability in seismic hazard across its expanse. This study employs a deterministic approach for seismic hazard assessment due to the unavailability of a long-term seismic archive required for a probabilistic approach, given the city’s relatively young age. Furthermore, a novel methodology is employed in this study, utilizing all known faults within Karachi’s seismic vicinity for conducting Deterministic Seismic Hazard Assessment (DSHA). Individual hazards associated with each seismic source are estimated, enabling the determination of the most severe hazard for the development of a seismic zoning map. The resulting DSHA-based seismic hazard assessment categorizes Karachi into four seismic zones, ranging from Zone 2A to Zone 4. This paper concludes that for a vast city like Karachi, relying solely on a single fault source for DSHA does not accurately represent the realistic seismic hazard to the region.