## 3 Materials and Methods  
Determination of the most relevant debris flow conditioning factors, as well as the factor classes, is essential to susceptibility analyses. Global coverage of fourteen conditioning factor datasets (aridity, climate, precipitation, elevation, fault density, landform, lithology, depth to bedrock, slope, soil thickness, soil type, topsoil percent clay, soil drainage, and landcover) were acquired from various sources. A European continent boundary dataset was used to clip each factor and create a Europe-only coverage. The landslide inventory was sourced from NASA [15]. The inventory contains 99 debris flows and mudslides within the continent of Europe. Mudslides are included in this study as it is a common misnomer for debris flows. It is noteworthy that landslide classification itself may be a source of data uncertainty. The event inventory contains a \"location accuracy\" attribute for each event. The locational accuracies associated with the 99 debris flows in Europe range from an \"exact\" known location to 50 km (Table 1), plus six events that were identified with a location accuracy of \"unknown\". Figure 1 shows the distribution of this model training data depicted with locational uncertainty buffers for the 93 events with defined locational uncertainties. The predisposing factors were analyzed for Pearson's correlation coefficient (r) with Excel Correl function and found to have a weak to very weak correlation among all factors \begin{table}
\begin{tabular}{c c c c|c c c|c c c} \hline \hline
**Locational** & \begin{tabular}{c} **Frequency** \\ **Distribution** \\ **Radius (km)** \\ \end{tabular} & \begin{tabular}{c} **Percent of** \\ **Total Debris** \\ **Flow Events** \\ \end{tabular} & \begin{tabular}{c} **Cum** \\ **Percent of** \\ **Flow Events** \\ \end{tabular} & \begin{tabular}{c} **Frequency** \\ **Distribution** \\ **Flow Events** \\ \end{tabular} & \begin{tabular}{c} **Percent of** \\ **Total Debris** \\ **Flow Events** \\ \end{tabular} & \begin{tabular}{c} **Cum** \\ **Flow Events** \\ \end{tabular} & \begin{tabular}{c} **Frequency** \\ **Distribution** \\ **Flow Events** \\ \end{tabular} & \begin{tabular}{c} **Percent of** \\ **Distribution** \\ **Flow Events** \\ \end{tabular} & \
\begin{tabular}{c} **Cum** \\ **Percent** \\ **(World All)** \\ **Landside Types** \\ \end{tabular} &
\begin{tabular}{c} **Cum** \\ **Events** \\ \end{tabular} \\ \hline
**exact** & 5 & 5.1 & 5.1 & 174 & 7.6 & 7.6 & 1386 & 12.6 & 12.6 \\ \hline
**1** & 19 & 19.2 & 24.3 & 620 & 27.0 & 34.6 & 2185 & 19.8 & 32.4 \\ \hline
**5** & 31 & 31.3 & 55.6 & 763 & 33.3 & 67.9 & 3178 & 28.8 & 61.2 \\ \hline
**10** & 20 & 20.2 & 75.8 & 277 & 12.1 & 79.9 & 1435 & 13.0 & 74.2 \\ \hline
**25** & 12 & 12.1 & 87.9 & 240 & 10.5 & 90.4 & 1470 & 13.3 & 87.5 \\ \hline
**50** & 6 & 6.1 & 93.9 & 125 & 5.4 & 95.9 & 794 & 7.2 & 94.7 \\ \hline
**100** & 0 & & 9 & 0.4 & 96.3 & 25 & 0.2 & 94.9 \\ \hline
**250** & 0 & & 4 & 0.2 & 96.4 & 16 & 0.1 & 95.1 \\ \hline “unknown” & 6 & 6.1 & 99.9 & 82 & 3.6 & 100.0 & 546 & 4.9 & 100.0 \\ \hline
**Total** & **99** & & **2294** & & & **11,033** & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Locational uncertainty frequency distribution of global inventory: Europe debris flows (left), world debris flows (center), and world-all landslide types (right). The Europe debris flows are used for this study. Figure 1: 93 (of 99) European debris flow events with a buffered “known” locational uncertainty. Some larger buffers overlap and occlude nearby smaller buffers. Base map is from ArcGIS®, the intellectual property of Esri, used herein under license. Copyright® Esri. (Table 2). Analysis of the predisposing factor contributions, from a Maximum Entropy model of the original 99 events, resulted in precipitation, fault density, and soil with the highest relative contributions at 42%, 27.6%, and 8.6%, respectively. Thus, for purposes of this study, the location uncertainty impact is analyzed and demonstrated for only these three factors.