Review on landslide monitoring technology in space-air-ground-sea framework

As a type of geological hazard induced by multiple interacting factors, landslides take place frequently in high complexity and large uncertainty, thereby necessitating the development of an efficient and integrated monitoring system. Therefore, this systematic overview on advances in landslide monitoring technology was made under “space-air-ground-sea” framework. At present, monitoring of subaerial landslides has been relatively well developed, covering ground-based geodetic measurements, three-dimensional laser scanning, subsurface displacement monitoring, and multiphysics monitoring. In parallel, spaceborne InSAR, GNSS, and optical remote sensing have facilitated the capture of macroscopic deformation signals; and airborne platforms using UAVs and LiDAR further improved high-precision detection and compensated for observational blind spots in critical areas. It is important to note that submarine landslide monitoring is still in early phase, which depends primarily on multibeam surveys, side-scan sonar, and shallow profiling in shallow waters, whereas monitoring of deep-sea seafloor landslides relies mainly on field investigation, in situ observation, physical modeling, and numerical modeling. Given the marked differences among various landslide types in their hazard-prone environments, key monitoring objects, and technical constraints, we conceptualized the “space-air-ground-sea” system as a platform coordination framework for different application scenarios. The purpose of this framework is to selectively mobilize and integrate spaceborne, airborne, ground-based, and sea-based technologies according to landslide type and monitoring objectives across different scenarios, and ultimately to support risk detection, data analysis, and early warning publish.