Investigation of Active Geomorphological Processes and Landslide Mapping Using Advanced UAV Data around the Kopili Fault Zone, in the Northeast Himalayan region of India

Active geomorphological processes such as landslides, surface deformation, fluvial erosion, and structural reactivation pose serious geohazards in tectonically and climatically dynamic regions. Accurate identification and monitoring of these processes require high‐resolution surface information capable of capturing spatial variability and short‐term geomorphic changes. In this study, high‐resolution unmanned aerial vehicle (UAV) based optical imagery is used to investigate active geomorphological processes, structural controls, and geohazard distribution in a seismically active region of the northeastern Himalaya of India.

The study is conducted in the Kopili Fault Zone (KFZ), in the Northeast of India. It is a major active tectonic corridor located at the junction of the Himalayan and Indo-Burman plate boundary systems. The region is characterised by steep slopes, intense monsoonal rainfall, dense vegetation, frequent moderate earthquakes, and widespread slope instability. These combined tectonic and climatic conditions result in recurring landslides, rapid landscape modification, and complex interactions between tectonic structures and surface processes.

UAV-derived optical images are processed using photogrammetric techniques to generate high‐resolution orthomosaics and digital surface models. These datasets are used for detailed landslide inventory mapping, identification of scarps, crown cracks, debris accumulation zones, and assessment of landslide geometry and spatial distribution. Structural mapping of lineaments, fault traces, and fracture patterns is carried out through visual interpretation and GIS-based analysis of UAV imagery, enabling evaluation of tectonic controls on slope instability and drainage development.

The results include the generation of a high-resolution landslide inventory, improved delineation of structurally controlled instability zones, and enhanced identification of active deformation and erosion hotspots. The study is expected to demonstrate clear spatial relationships between landslide occurrence, active fault segments, and geomorphic anomalies. Overall, this research highlights the effectiveness of UAV-based optical remote sensing for resolving fine-scale geomorphological processes and improving geohazard characterisation, thereby supporting hazard mitigation, land-use planning, and risk reduction strategies around the Kopili Fault Zone and similar tectonically active regions.