Landslide Movement Detection Using DInSAR and Sentinel-1A Imagery in a Tropical Volcanic Highland

Abstract

Landslides are major geological hazards in tropical mountainous regions, where steep topography, weathered materials, geological structures, and rainfall promote slope instability. This study evaluates Differential Interferometric Synthetic Aperture Radar (DInSAR) to detect and quantify post-landslide surface deformation in a tropical volcanic highland affected by a catastrophic landslide in December 2014. A single Sentinel-1A interferometric pair acquired on 4 August 2017 and 1 May 2026 from the same ascending relative orbit was processed using a standard DInSAR workflow. Line-of-Sight (LOS) displacement was interpreted with geological and geomorphological data. Results show LOS displacement of −0.69 to −0.40 m accumulated over 8.74 years (3,192 days), equivalent to an interval-average rate of approximately 46–79 mm/year. The displacement is spatially associated with structurally controlled volcanic terrain, weathered lithologies, fault and joint systems, and slopes of 30–40%. This study quantifies post-2014 deformation at Telagalele using DInSAR. However, the estimates derive from a single 8.74-year interferometric pair without independent validation and should therefore be interpreted cautiously. The findings indicate DInSAR's potential for post-landslide deformation assessment in tropical mountainous environments.