A STUDY ON QUANTITATIVE EXTRACTION OF TERRAIN CHANGES CAUSED BY SLOPE FAILURE USING PALSAR-2 DATA AND ANALYSIS OF CHARACTERISTICS OF EXTRACTED AREAS

Abstract

 In this study, the study area is selected the regions that happened slope failure accompanied by topographical changes caused by Northern Kyushu heavy rain in July 2017 and take ALOS-2/PALSAR-2 data is used as the satellite information. Under the same conditions, the results show that firstly, single-polarization backscatter differential analysis ex-tracts the terrain changes more accurately than the coherence analysis. Secondly, based on the slope angle, aspect angle and local incident angle, we also classify the slope failure that is able to extracted, incorrectly extracted and unextracted. As a result, slope angle less than 15° can be extracted well by the backscatter differential analysis with almost no error. Finally, the aspect angle is well extracted in the east-west direction using the coherence analysis. In contrary, the south direction is well extracted by the backscatter differential analysis. Furthermore, the larger of off nadia angle, the easier to extract the areas where the local incident angle is small.