Abstract: One of the most important tasks in the prevention and control of geohazards in large reservoir areas is to identify the amount and location of geohazards on the reservoir banks before impoundment. Many geohazards are typically missed by manual or single-technique survey methods. Interferometry synthetic aperture radar (InSAR) and unmanned aerial vehicle (UAV) optical remote sensing techniques were used to identify geohazards on the reservoir banks in the Xiangbiling-Yezhutang section of the Baihetan reservoir area. Comprehensive remote sensing technology identified 114 geohazards, with 89 and 39 geohazards identified by UAV optical remote sensing and InSAR technology, respectively, an increase of 72 beyond manual investigation. Combining ascending and descending images helps alleviate the geometric distortion of SAR data, increases the visible area of SAR, and improves the effectiveness of geohazard identification results. Due to image precision and timeliness, InSAR technology can detect newly deformed geohazards. But optical remote sensing has a tough time detecting them. In terms of macroscopic features, geohazards that have been deformed in the past can be recognized using both UAV optical remote sensing and InSAR, and observable deformations that occur within the SAR data cycle can also be identified using InSAR technology. Due to data accuracy limits, InSAR technology and optical remote sensing are both successful in recognizing geohazards over broad areas, while InSAR technology is not useful in identifying geohazards over smaller areas. By using multi-source remote sensing including InSAR and UAV optical remote sensing and other technologies, we can obtain information of the surface deformation of geohazards, understand the characteristics of geohazards, overcome the limitations posed by satellite optical remote sensing interpretation, and effectively avoid the missing error of manual investigation or single technical method for geohazard identification in high mountain and canyon areas.

Key words: geohazards, Interferometry Synthetic Aperture Radar (InSAR), Unmanned Aerial Vehicle (UAV), multi-source remote sensing, Baihetan reservoir area