Pre and Post Earthquake Seismo-Tectonic Scenario of Hazara-Kashmir Terrain of Pakistan

Abstract

 The Hazarn-Kashmir(HK) terrain is located on the northwestern margin of the Lesser Himalaya. The Hazara Kashmir Syntaxis (HKS) is one of the bold tectonic scars, which physically seperate this terrain from rest of the Himalaya.The major tectonic features  sculpturing this terrain in the shape of folds and faults are: Hazara-Kasmir Syntaxis (HKS), Main Mantle Thrust (MMT), Main BoundaryThust (MBT), Panjal Thrust (PT), Hazara Thrust (HT) and Indus Valley Faults (IVF). All these mega-structures are the abode of variablc seismicity and generate earthquakes of low to moderate magnitudes. Among them, thc MMT, MBT, PT and the IVF have hazardous seismic history. The earthquake of October, 8, 2005 of magnitude 7.6 with its epicenter, located south of  Balakot is linked with one of these faults, the MBT, Which traverses the eastern and western flanks of the HKS.The deep mega-crustal deformations beneath the Hazara-Kashmir terrain monitored through seismicity arc: Indus-Kohistan Seismic Zone (IKSZ), Hazara Lower Scismic Zone (HLSZ) and Tarbela Seismic Zone (TSZ). The epicenter of earthquakes generally lies between 10-60 km depth in the seismic zonc of the mega-crustal deformations in the HK terrain. The earthquakes generated at this depth are categorized as shallow and usually more hazardous. The successive events in the seismic profle betwcen years 2003-2005 were a reliable precursor to predict accumulation of energy, which ultimately caused the earthquake on October 8, 2005.