We tested four topographic models for predicting locations of debris-slide sources: 1) slope; 2) proximity to stream; 3) SHALSTAB with “standard ” parameters; and 4) debris-slide-prone landforms, which delineates areas similar to “inner gorge ” and “headwall swale ” using experience-based rules. These approaches were compared in three diverse study areas of northwestern California having multiple inventories of historical non-road-related debris slides in a variety of topographic settings. We implemented the models in a GIS using USGS 10-m digital elevation models (DEMs). The topographic models show moderate predictive success. Slope performs comparatively well in all study areas. SHALSTAB is rarely superior. The proximity-to-stream model is competitive in one area but falls short in the others. The landforms model performs somewhat better than the others for nearly all the debris-slide data sets in all three areas, and appears especially effective for large debris slides that deliver sediment to streams. Large landslide deposits also influence the propensity for debris sliding in some areas. The areal density of historical debris-slide sources in steep ground within large, geomorphically fresh landslide deposits can be more than twice that in steep ground outside landslide deposits. Thus, prediction of debris-slide sources can be improved using maps of geomorphically fresh large landslide deposits
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