Fig. 13

Classification results of risk levels in Evaluation 4. The red and green areas represent the classified “ high-risk” and “ low-risk” slopes, respectively. The blue curve represents the predictive slip mean, while the blue-shaded area represents the confidence interval corresponding to the risk probability threshold \(p_{threshold}\). The dashed line represents the slip threshold value \(y_{threshold}=0.6\) with which the risk level was classified. The red and green points represent the data of high and low risk, respectively. The slip regression model was trained from the target data on slopes shallower than 5\(^\circ\). Lower \(p_{threshold}\) makes the risk level boundary shift to a shallower slope and provides more conservative risk prediction. Results for the rough sand surface class are presented