Mapping Geo-Hazard by Satellite Radar Interferometry

This paper describes the application examples of satellite interferometric synthetic aperture radar (InSAR) in exploring potential geo-hazards and mapping geo-related disasters, including earthquakes, landslides, and land subsidence, triggered by natural forces and/or human activities. Satellite images were acquired from the Japan Aerospace Exploration Agency´s (JAXA´s) ALOS-PALSAR satellite, the Euroeapn Space Agency´s (ESA´s) Envisat-ASAR satellite, and the German Aerospace Center´s (DLR´s) TerraSAR-X satellite, covering frequency bands of L, C, and X, respectively. The study areas include Taiwan and Vietnam because both regions are prone to greater risks of geo-hazards and natural disasters. A series of C-band and L-band both ascending and descending mode SAR imagery data were used to map the deformation and subsidence of the environmentally sensitive areas. With the historical information and fast updated data sets, long-term and short-term subsidence patterns can be effectively and efficiently obtained. Excellent agreements were obtained as compared with Global Positioning System (GPS) and leveling measurements. Stacking of dual-beam mode as ascending and descending mode could extract the vertical displacement more easily and reduce the influence from the horizontal displacement. In summary, the advance of satellite radar interferometry provides a vital mapping to detect and identify geo-hazard and potential geo-disaster in general.