CHARACTERISTICS OF SAR BACKSCATTERED INTENSITY AND ITS APPLICATION TO EARTHQUAKE DAMAGE DETECTION

SAR images obtained before and after a natural disaster are considered to be useful for emergency response due to its all-weather and sunlight-independent characteristics. Recently, the spatial resolutions of SAR systems have been improved significantly. In this paper, SAR intensity images acquired before and after the 2008 Iwate-Miyagi, Japan, earthquake from ALOS/PALSAR (L-band) and TerraSAR-X (X-band) are employed to investigate the radar backscattering characteristics for various acquisition and surface conditions. The spatial resolution, radar frequency, flight path, and incidence angle were shown to affect SAR backscattering echo, depending on surface materials and roughness. Since the spatial resolution of TerraSAR-X is much higher than that of PALSAR, more detailed surface condition could be seen from the TerraSAR-X images. It is also observed that the difference of the backscattering coefficients at the pre- and post-event times gets large and their correlation coefficient becomes small at the locations of landslides and slope failures