Search

This study investigates the backscattering properties of C-band RADARSAT (SAR) signal over sloping mountainous areas, and evaluates the utility of RADARSAT in natural disaster areas (e.g., forest fires), geological mapping, monitoring of natural hazards, natural and associated Earths environmental changes. Conventional change detection techniques in remote sensing are adequate for most applications. However, the changes in backscattering coefficients (σ0) before and after, for example, forest fires are not apparent in certain cases, mainly because of the effects of steeply sloping target scattering surface areas. The slopes of a mountainous test site can be divided into two cases with respect to the incident SAR signal look direction: the front and back slopes, where local incidence angles can vary significantly. Depending on the slope of the scattering surface, the backscattering coefficient increases to the maximum of 3.3. dB in the front-slope, but decreases 4.5 dB in back-slope after forest fires. Forest fire burnt areas provide a good example of a natural sloping scattering surface, which exhibits subtle changes in backscattering coefficients similar to the lithological changes in nature. The April 2000 forest fire in Kangwon province, Korea, burned for several weeks and was one of the worst ones in recent years. Among several firedamaged sites, an area near Samchuk city was investigated in detail with a set of multi-temporal RADARSAT Synthetic Aperture Radar (SAR) data to estimate the fire damages as compared to the unburnt background. [ABSTRACT FROM AUTHOR]

Space-borne Synthetic Aperture Radar (SAR) techniques have recently become one of the most flexible and cost-effective Earth-observation tools for monitoring surface processes, including natural hazard monitoring and management tasks such as landslides, volcanic activities, and earthquake-related problems. This study investigates the feasibility of applying space-borne SAR interferometry to the monitoring of earthquake hazards and investigation of the earthquake-related tectonic processes, focusing on the investigation of the geological setting and associated tectonic processes in the Nahanni Earthquake area, NWT, Canada. Investigation of seismotectonics in the Nahanni area was carried out in two stages: traditional analysis of remote-sensing data, including both optical and microwave data, for static aspects of tectonic processes (Moon et al., 1991); and new SAR interferometry using RADARSAT, ERS-1/2, and JERS-1 SAR data to study relative movements of several active geological tectonic blocks. Preliminary results indicate that (1) conventional geological remote-sensing methods provide us with important basic information on the tectonic setting associated with local earthquake activities, including several newly discovered structural features, and remain important as Earth-observation tools, (2) the newly discovered tectonic features correlate well with the earthquake focal plane solutions obtained from teleseismic data, (3) multi-temporal SAR interferometric (or differential InSAR) analysis can provide us with detailed tectonic moeements and understanding of the earthquake processes in the study area, but (4) availability of suitable space-borne SAR data suitable for differential SAR interferometry may pose more problems than the technical development. [ABSTRACT FROM AUTHOR]