Investigating the Effects of Active Tectonics on Rockfall Susceptibility Along the Mountain Sector of Chalus Highway

Abstract

Numerous rockfalls occur along the southern foothills of the Alborz mountain range, particularly affecting the Chalus highway. This study aims to identify the key factors influencing rockfall events and to produce a susceptibility zoning map using GIS-based modeling techniques. A high-resolution 10-m DEM, geological maps, and field data were integrated to simulate rockfall frequency, velocity, height, and energy. The analysis identified nine high-risk zones along the highway corridor. Results indicate that while tectonic activity plays a role in rock fragmentation, climatic conditions particularly freeze–thaw cycles during winter are the main trigger for rockfalls. The generated susceptibility map provides essential information for road management and risk mitigation strategies.