An Avalanche Hazard Model for Bitlis Province, Turkey, Using Gis Based Multicriteria Decision Analysis

Abstract

Most avalanche fatalities in Turkey have occurred in Bitlis Province. The scope of this research was to identify the avalanche hazard area of that province, using geographical information system (GIS) based multicriteria decision analysis (MCDA) and to evaluate it by means of sensitivity and accuracy analysis. The model consists of 5 GIS layers: elevation, slope, aspect, vegetation density, and land use. The hazard model is obtained by using a comparison matrix where all identified criteria of GIS layers are compared against each other. The acceptability of the model was determined using historical events. All of these events plotted over the model showed that there is a remarkable coincidence with high hazard areas. Approximately 90% of avalanche events have occurred in the high and moderately high areas. Settlement areas cover approximately 39,741 ha of study area and just 41 settlement areas (villages and towns) have ideal topographic characteristics to prevent avalanche hazard, while 82% of them are not suitable. The avalanche hazard model shows that the southeast and southwest parts of Bitlis (Center), Tatvan, and Hizan counties have the highest avalanche hazard. Therefore, site planning, construction of supporting structures, and control programs should be effectively integrated with avalanche pathways in potential areas.