Detection of Slope Instability in Hong Kong Based on Multi-baseline Differential SAR Interferometry Using ALOS PALSAR Data

The monitoring of slope instability requires detailed observations of mass movements, which generally cannot be obtained by geodetic methods or global positioning systems (GPS). Differential synthetic aperture radar (SAR) interferometry has proven to be an effective way of measuring land deformation with millimeter accuracy over wide areas. Using data from the newly launched L-band ALOS PALSAR interferometer and the multi-baseline differential SAR interferometry technique, slope instability in Hong Kong was analyzed by means of measured surface displacement along look vectors. Owing to its enhanced vegetation penetration, less temporal decorrelation enabled the L-band data to improve spaceborne radar sensor land-surface deformation measurements. The results were validated by ENVISAT ASAR-derived outcomes and other ground survey data.