Abstract
Because landslides with long-travel distance (so-called long-travelling landslides) can cause severe damages, it is important for disaster-prevention works to find slopes prone to long-travelling landslide in advance. In this study, we collected 77 landslides induced by snowmelt, and conducted topographic analyses of source and transfer-deposition areas of the landslides to find features correlated with occurrence of long-travelling landslides. The topographic analyses using 10-m DEM revealed that long-travelling landslides, which traveled longer than their slope lengths, tended to occur at the slopes with following three features : 1) preexisting landslide slope (reactivation), 2) coupling with steep valley topography (more than 0.15m m-1 or 9 degrees), and 3) sharp inflow angle (less than 70 degrees) of sliding mass to the valley topography. Then, simple discriminant test using the features was developed. By using all the three features, 12cases of 14 long-travelling landslides (86％ of positive predictive value) and 58 cases of 63 normal landslides (92％ of negative predictive value) were correctly distinguished, and correctness of the test attained 91％, suggesting the above three topographic features were effective to find slopes prone to long-travelling landslide.
