Spatial distribution analysis of mass movements triggered by the 2005 Kashmir earthquake in the Northeast Himalayas of Pakistan

Distribution of the mass movements triggered by the 2005 Kashmir earthquake was analysed in the vicinity of Jhelum Valley, Neelum Valley, and Muzaffarabad in the Northeast Himalayas of Pakistan. Mass movements were mapped using SPOT satellite imagery and field investigations. Geographic information systems (GIS) were used to analyse the relations of the distribution of these mass movements using various parameters, such as distance from an earthquake source (epicentre and fault), topographic parameters (slope steepness, slope aspect, and elevation) and geological units. The results of the analysis indicate that the mass movement concentration decreases with increased distance from the earthquake epicentre and the reactivated Muzaffarabad Fault. The maximum concentration of mass movements is near the epicentre and a fault. A significant occurrence and concentration of mass movements were evident at slope angles between 31-40 degrees. The preferred orientations of the mass movements were in southerly directions. The concentrations of mass movements differ substantially among various geological units. Mass movements are widely distributed in the Miocene Murree Formation, whereas the concentration of mass movements is higher in the Cambrian Muzaffarabad Formation. The median mass movement concentration inflicted by the epicentre and the Muzaffarabad Fault exhibited no significant differences (KS = 0.505; p = 0.961). The results of the PCA reveal that the largest variance in mass movement concentration is attributed to the distance from the epicentre and the Muzaffarabad Fault. The findings suggest that the mass movement concentration is primarily dependent on the distance from the earthquake source. In addition, the topographic parameters and geological units played subordinate roles in the distribution of mass movements. (C) 2013 Elsevier B.V. All rights reserved.