A Compact Ground-Based Interferometric Radar for Landslide Monitoring: The Xerem Experiment

A real-time monitoring system based on groundbased synthetic aperture radar interferometry (GB-InSAR) were developed and deployed with the objective to gain understanding of landslide dynamics in an area in Xerem (district of Duque de Caxias -RJ, Brazil). The area is subjected to landslide risk and the deployed system aims to provide subsidies to the authorities to prepare actions related to prevention and evacuation, and serve as the basis for a future early-warning system in the framework of the Civil Defense of Duque de Caxias. The system consists of a compact and rugged X-band GB-InSAR newly developed by Bradar, Brazil. The processing and monitoring methodology are proposed. Two campaigns, totaling six days, were carried out. The acquisitions of the first campaign occurred without rain. In the second campaign, rain events, varying from light to torrential rainfall, occurred for a period of time, in subsequent days, during the radar acquisitions. New insights on landslide dynamics are revealed. The monitoring data show that, approximately 10 h after heavy rainfall, the terrain movement on a slope reached 4 mm/h during ca. 5 to 8 h, resulting in velocities of 20 to 32 mm/day.