Determination of Susceptibility to Occurrence of Slope Instability around the Benaravan Fault using Logistic Regression

At present, the question of identification, control, and prevention of human, economic, and social losses resulting from natural events such as earth tremors, floods, and earthquakes have attracted special interest in scientific-research communities and in responsible authorities of most countries around the world. In recent decades, considering the upward trend in losses and damages caused by natural events (especially landslides), prediction of damages and losses and introduction of solutions and methods for controlling and avoiding them have been addressed in earnest. This research evaluated the region around the Benaravan fault using logistic regression (logit regression or logit model) to determine regions that face slope instability hazard. Field surveys were made, previous research was reviewed, and the prevailing conditions in the region was studied first and, using the Idrisi software, it was found that the nine factors of altitude class, slope, dip direction, lithology, distance from the fault, distance from the waterway, distance from the road, land use, and vegetation influenced occurrence of slope instability. After performing slope instability hazard zonation, percentages of slope instability in each class were calculated. Results indicated that areas with high hazard zonation in the study region constituted the smallest part of it. In this research, which used logistic regression, the elevation factor with the highest coefficient was the best variable for predicting the occurrence probability of slope instability in the region. The highest incidence of slope instability occurred at high altitudes with slopes of 23-32 degrees because of gravity force.