Deterministic seismic hazard assessment of a long mountainous road tunnel: a case study of Lowari Tunnel, Pakistan

This study aimed to perform a comprehensive Deterministic Seismic Hazard Assessment (DSHA) to quantify the Peak Ground Acceleration (PGA) values for the Lowari Tunnel region. Twelve thrust faults in the vicinity of the tunnel were evaluated using an updated earthquake catalog from 25AD to 2022. The PGA values were calculated for each thrust fault and compared with the designed value of 0.5 g from the feasibility stage of the tunnel. The study demonstrated that all twelve thrust faults exhibited PGA values below 0.5 g, indicating a low-to-moderate seismic hazard in the region. The maximum PGA value obtained in this study was 0.4 g, which is well below the maximum designed value, indicating that the tunnel is expected to withstand the ground motion values projected to result from high-magnitude earthquakes in the region. These findings hold significant importance as they provide crucial insights into assessing the long-term sustainability of the Lowari Tunnel, situated in one of the world's most seismically active zones.