DETERMINISTIC SEISMIC HAZARD ANALYSIS FOR WAH CANTT, PAKISTAN: A SITE-SPECIFIC ASSESSMENT

Abstract

Seismic hazard assessment is essential for the safe design of strategic infrastructure in tectonically active regions. This paper presents a site-specific deterministic seismic hazard analysis (DSHA) for Wah Cantt, Pakistan (33.77∘N,72.75∘E), with emphasis on the Main Boundary Thrust (MBT) as the controlling seismic source. The analysis considers active fault systems within approximately 100 km of the site. It estimates the median horizontal peak ground acceleration (PGA) using the Boore and Atkinson (2008) ground-motion prediction equation (GMPE) under reference-rock conditions (Vₛ₃₀ = 760 m/s). The MBT is identified as the governing source due to its proximity and a maximum credible magnitude of Mw 8.1. The resulting median PGA of 0.267g exceeds the upper limit of Seismic Zone 2B in the Building Code of Pakistan (BCP 2007), indicating that generalized zoning may understate near-source hazard at strategic facilities. A 5%-damped site-specific response spectrum is also presented, with peak spectral acceleration of 0.452g at T = 0.15s.

Keywords- Deterministic Seismic Hazard Analysis, Main Boundary Thrust, Peak Ground Acceleration, Response Spectrum.