Academic Affiliation: Syracuse University
Probabilistic analysis of rainfall thresholds for Western Oregon
In western Oregon, many rainfall thresholds have not been analyzed systematically. As a result, landslide prediction is uncertain. This project examined rainfall thresholds throughout western Oregon to estimate the percentage of threshold exceedance events that will produce landslides. For this study, the geologic characteristics, precipitation data, and historical events of western Oregon were collected and analyzed. After filtering the data, we compared the results of the threshold exceedances with landslide occurrences to test the accuracy of the predictions made by the thresholds. Landslides were found to occur both when the threshold was exceeded and also when it was not exceeded. Since rainfall data and landslide data have an incomplete record, only preliminary threshold values were determined. More extensive analysis of the rainfall data and landslide events needs to be performed to determine rainfall threshold values for western Oregon.