Preliminary Neo-Deterministic Seismic Hazard Assessment in Pakistan and Adjoining Regions

The regional seismic hazard in Pakistan and adjoining regions is assessed using the Neo-deterministic seismic hazard assessment approach (NDSHA). Synthetic seismograms are generated by the modal summation technique at the nodes of a grid that covers the studied area. The main input for the computations consists of a set of earthquake sources and of the structural model where the seismic waves propagate. The earthquake sources are parameterised within the active seismogenic areas by defining the focal mechanism, the depth and the magnitude, obtained through the analysis and re- elaboration of the past seismicity. The peak displacement (Dmax), peak velocity (Vmax) and design ground acceleration (DGA) are then extracted from the synthetic signals and plotted on the 0.2° x 0.2° grid to construct the seismic hazard map of the studied area. There are few probabilistic hazard maps available for Pakistan, however, this is the first study aimed at producing a neo-deterministic seismic hazard map for Pakistan and adjoining regions.The most severe hazard is found in the epicentral zone of the great Muzaffarabad earthquakes of 2005 and its surroundings, where the DGA estimate falls in the highest range 0.60 g – 1.2 g. The peak velocity and displacement in the same region are estimated as 60−120 cm s−1 and 30−60 cm, respectively.