TerraSAR-X and ALOS/PALSAR data for soil stability monitoring in Malaysia

Early warning systems for tsunami are typically run by national rescue authorities or natural disaster centers. These centers have to operate round the clock, which is costly. Therefore it is practical to combine many hazard types in these centers. Techniques of SAR interferometry were used in image analysis. These techniques included computation of coherence between a pair of scenes and its generalization to the case of three scenes, the so called triherence. Amplitude and coherence images were ortho-rectified with a digital elevation model (DEM). Coherence and triherence in TerraSAR-X high-resolution spotlight data were lower in periods with high soil movement. Amplitude in ALOS PALSAR data showed changes in the Penang site, especially in agricultural areas. TerraSAR-X data – due to its high spatial resolution - seem suitable for monitoring the stability of forest-free hill slopes provided that movements are in the order of some tens of centimeters.