## 4 Experimental Results
### Obtain and Compare the Target and Uncertainty Patterns via Equal-Area Ranks  
By cross-validating the target and uncertainty patterns with the 70 active landslides, **70 atm7**, the relationship between target and uncertainty ranks were visualized, conveniently expressed in \"1000 units (for instance, rank 900 corresponds to the top 10% equal-area rank). Figure 6 shows as an example the relationship between the target ranks, in descending order on the horizontal axis, and the respective uncertainty ranks, in ascending order on the vertical axis. It was obtained from the cross-validation process **FZ_70m7 at_ulpACDIS**. In the illustration, the diagram shows that the 70 points are distributed so that the higher target ranks on the horizontal axis appear to correspond to relatively lower uncertainty ranks. It is worth noting that there are five encircled points corresponding to areas of relatively high uncertainty ranks and the lowest target ranks. They are occurrences that contribute to the shallow part of the prediction-rate curves in Figure 4. They could be considered outliers amongst the occurrences used as DSP. Such a tendency for the patterns from the five models can also be visualized by sequencing the target ranks of the 70 occurrences in decreasing order, constructing histograms with pair of columns of target and corresponding uncertainty ranks. This is accomplished  
Figure 6: Target ranks in *1000 for the FZ model on the horizontal axis versus uncertainty ranks on the vertical axis, for the 70 active landslides, **70 at**, in the Tirano South study area. The five encircled points have the lowest target ranks. See text for explanation. in Figure 7 that shows in blue the target ranks and in red the corresponding uncertainty ranks for each occurrence. For all models, the histograms express a preferential distribution of higher uncertainty ranks for lower target ranks. We may wonder whether that tendency is visible also in the target patterns (or in the prediction patterns). This can be observed by generating combination patterns that relate uncertainty and target ranks by tentatively thresholding the uncertainty patterns. We have  
Figure 7: Histograms of decreasing target ranks (blue columns) and corresponding uncertainty ranks (red columns) for models FZ, LI, LO, LR, and BP from (**a**-**e**), respectively, using the cross-validation process **70 atm7_ulpACDIS**. generated the 50% combination patterns for each target pattern, as shown in Figure 8. A threshold value was arbitrarily set at the lower 50% uncertainty ranks in the study area to select the corresponding target ranks (or alternatively, we could have used prediction ranks from the respective prediction patterns). Figure 8: The 50% combination patterns, **704 nm7**, using the different models FZ, LI, LO, LR, and BP in (**a–e**), respectively. Black patches are the oversized trigger zones of the 70 active landslides, **704t**. The dark-gray areas represent 50% of the study area with relatively higher uncertainty. The remaining 50% show the target pattern ranks for areas with lower uncertainty. Colors in the legend indicate groups of ranks of % of SA in ascending order. By comparing the uncertainty pattern in Figure 5 with the prediction patterns in Figure 3, we can infer that the combination patterns in Figure 8 have retained high values in the southern part of the SA that shows low uncertainty (lower 50% uncertainty ranks). In the northeastern part, however, uncertainty is relatively high (upper 50% uncertainty ranks) so that the high target ranks are not visible in the combination patterns. What are then the characteristics of the 50% combination patterns? How is the uncertainty range threshold shaping them? Let us consider some revealing details of the rank distribution in a small window of the 50% combination patterns, as shown in Figure 9. Seven landslide trigger areas are displayed as black contours in the illustration. Some are predicted as uncertain and fall on gray areas, in Figure 9b,c,e by LI, LO, and BP models.