FAULT-BASED DETERMINISTIC SEISMIC HAZARD ASSESSMENT FOR KHALABAT TOWNSHIP, HARIPUR, KPK, PAKISTAN

Abstract

The present study was carried out based on the identification and characterization of major active faults within 200 km radius of Khalabat Township Haripur, for preparation of a Deterministic Seismic Hazard Analysis (DSHA). Estimates of seismic demand were made based on evaluation of the source parameters: fault mechanism, maximum moment magnitude (Mw) and closest source-to-site distance. Peak Ground Acceleration (PGA) was chosen as the governing ground motion parameter, and was computed from two Ground Motion Prediction Equations (GMPEs), the attenuation relationship from Cornell-Banon et al. (1977) and the Boore and Atkinson (2008) model. The results show that the Panjal Fault has been controlling the seismic hazard at the study site as it is located at a close distance of 40 km and has a seismic capacity of Mw 7.5 and results in a maximum PGA of 0.295 g using Cornell model and 0.155 g using the Boore and Atkinson model. The deterministic estimate was compared with Building Code of Pakistan (BCP 2007) which has set the area under Seismic Zone 2B where the PGA values are 0.18–0.24 g, finding the values to be around 23% above the upper limit of the code. Results were clearly highlighting the advantage of local seismic hazard assessment over generalized seismic zoning to ensure safer and more reliable seismic design of the rapidly developing northern Pakistan, and show the importance of incorporating site-specific hazard evaluation in such seismic design.