Remote sensing for landslide investigations: A progress report from China

China has a significant portion of land in landslide-prone areas, and remote sensing technologies are becoming a tool of choice to investigate and monitor landslides. Although much progress has been made with remote sensing technologies and their applications in China, there is no systematical summary report. Thus, we summarize Synthetic Aperture Radar (SAR), optical remote sensing, and laser technologies currently being used in China, and their associated platforms (space-borne, air-borne, and ground-based). Multi-temporal optical images and time series SAR are often used to detect active landslides at time scales of years and months. The latest optical images and SAR intensity images are usual adopted to map fresh landslides, especial for coseismic landslides. LiDAR technology has been widely applied to identify ancient landslides. Combining advantages and limitations of every technology, an integrated space-air-ground collaborative investigation strategy has been proposed for early identification and early warning of landslides. Additionally, a comprehensive landslide investigation integrating multidisciplinary approaches, including remote sensing, geology, and geophysical exploration, could be a further developing trend, because remote sensing technologies just provide surface information, while a complete understanding of landslides requires more than surface information - knowledge of geotechnical parameters, geological features, and field conditions is also needed.