A remote-sensing-based intensity–duration threshold, Faifa Mountains, Saudi Arabia

摘要

Construction of intensity–duration (ID) thresholds andearly-warning and nowcasting systems for landslides (EWNSLs) are hampered bythe paucity of temporal and spatial archival data. This work representssignificant steps towards the development of a prototype EWNSL to forecastand nowcast landslides over the Faifa Mountains in the Red Sea Hills. Thedeveloped methodologies rely on readily available, temporal, archival GoogleEarth and Sentinel-1A imagery, precipitation measurements, and limited fielddata to construct an ID threshold for Faifa. The adopted procedures entailthe generation of an ID threshold to identify the intensity and duration ofprecipitation events that cause landslides in the Faifa Mountains, and thegeneration of pixel-based ID curves to identify locations where movement islikely to occur. Spectral and morphologic variations in temporal GoogleEarth imagery following precipitation events were used to identifylandslide-producing storms and generate the Faifa ID threshold (I =4.89D−0.65). Backscatter coefficient variations in radar imagery wereused to generate pixel-based ID curves and identify locations where massmovement is likely to occur following landslide-producing storms. Thesemethodologies accurately distinguished landslide-producing storms fromnon-landslide-producing ones and identified the locations of theselandslides with an accuracy of 60 %.