Identification and determination of avalanche speed by using radar interferometry –A case study in Varangah Rud at Chalous Road, Iran

Avalanche is one of the natural disasters that annually inflicts heavy casualties on human societies, especially the world's transportation systems, especially in mountainous areas. The use of remote sensing and radar interference knowledge is one of the expanding and efficient methods in identifying changes in the earth's surface, especially avalanches. In this study, radar imaging interference and offset tracking techniques were used to identify the avalanche incident on Chalus Road. The basis of this method is to determine the extent of changes in the characteristics of the Earth's surface, which is determined by changes in radar redistribution. This process is done by comparing the Sentinel-۱ radar images before and after the event. After ensuring the results of radar interference by matching it in the Google Earth environment, using the histogram diagram, the frequency changes of radar distribution pixels, the average velocity of avalanche mass displacement in the domain were determined. Based on this, the maximum velocity of Avalanche mass was ۴۵ cm and the maximum displaced volume of Avalanche mass was determined on a slope with a velocity of ۵ cm per day, which indicates that the snow mass forming Avalanche has been moved in several stages and along with geomorphological characteristics. The area, the snowfall, and the increase in its volume on the slope have gradually overcome the frictional force between the slope surface and the lower part of the snow mass, causing the avalanche mass to move down the road.