부산대학교 도서관

This study produced an inventory of the 2,523 potential large-scale landslide areas (PLSLAs) in southern Taiwan. These PLSLAs were delineated using LiDAR DEM of 1m resolution after the 2009 Typhoon Morakot by other institutes. Using the inventory, we conducted a statistical analysis of the important geologic and geomorphologic factors possibly related to a PLSLA. The statistical analyses reveal that, among the 2,523 PLSLAs, (1) 82% of elevation are between 750 and 2,750 m, (2) 79% of the area are between 10 and 40 hectares, (3) 76% of the slope height are between 200 and 600 m, (4) 86% of the slope are between 25 and 40 degrees and (5) 83 percent of stream order are less than 3. Rock formations of these PLSLAs range from Oligocene to Miocene; 67% of the strata are slate, and 12% are interbedded of sandstone and shale. This study selected 24 medium to high risk cases of the 2,523 PLSLAs, and interpreted the micro-geomorphological features from 1m LiDAR DEM. The following three patterns were present: (1) PLSLA with clear features of gravitational slope deformation in slope height more than 500 m condition, (2) PLSLA with the relic of paleo landslides induced by gravitational buckling, toppling, or plane sliding, (3) PLSLA with river bank erosion on slope toe and head-cut erosion induced by gully development. Based on statistics, the stream order of the PLSLAs with gravitational slope deformation usually would exceed 3; 83% of PLSLAs are the areas also with paleo large-scale landslide.