MODELING AND SIMULATION OF GLACIER AVALANCHE: A CASE STUDY OF GAYARI SECTOR GLACIERS HAZARDS ASSESSMENT

Abstract

Glacier avalanches are natural hazard that could damage infrastructures and threaten lives in high altitude mountainous terrains. On 7 April 2012 a massive ice avalanche struck a Pakistani military base at Gayari sector, Saltoro Valley and buried/killed 148 soldiers and civilians. Keeping in view the catastrophe a study was designed with the objectives to (1) model and simulate the Gayari sector glacier avalanche incident in terms of height, extent, velocity, pressure and momentum, (2) generate hazard risk assessment of possible other glacier avalanches in the Saltoro Valley through modeling & simulation and (3) suitability analysis of current military camp sites and recommendation of new safe camps sites locations in the Saltoro valley. To simulate the Gayari sector glacier event and other Glacier possible avalanches, a physical process based Glacier Avalanche Model (GAM) was used. The GAM has two main components i.e. Voellmy Salm (VS) and Random Kinetic Energy (RKE) which deals with variables like avalanche height and the mean avalanche velocity during the course of simulation. The suitability analysis of current military camp sites were achieved using weighted overlay analysis with different constraints in ArcGIS Spatial Analyst. The GAM model simulation of Gayari avalanche event predicted maximum velocity of 74ms-1 generating a pressure of 5074 kPa and attaining height of 45 m while the predicted debris volume on the ground was 3.8145 million m3. A good agreement was found between actual debris height and extent as compared with the GAM model output. The GAM model simulated all the potential tributary glacier avalanches of Saltoro valley very well. The weighted overlay analyses in ArcGIS Spatial Analyst revealed that the existing camp sites are safe and were not threaten by the glacier avalanche hazard. However, it was recommended that the Gayari HQ camp should not be constructed at the same location and should be relocated to proposed safe camp sites identified in this research study. The proposed methodology developed in the current study could be applied in the Siachen conflict zone for avalanche hazard/risk analysis of all the camp sites located in the valley.