## 4 Results and Discussion  
### Analysis of Prediction Statistics of Historical Landslide Data  
In this study, we ran simulations of the SEM-LEWS operation to generate a series of landslide early warning level maps for the Busan area during the rainy season (June to October) over an eight-year period (2009-2016). During this period, the city of Busan experienced eight days in which at least one landslide was recorded. The previously introduced historical data of 186 slope failures and 36 debris \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Occurrence Date**} & \multicolumn{2}{c}{**Number of GIS**} & \multicolumn{2}{c}{**Number of Classified Data Points According to Spatial Precision**} \\ \cline{3-5}  & **Landslide Data Points** & **1 st Class** & **2 nd Class** & **3 rd Class** \\ \hline
6 September 2005 & 2 & - & 1 & 1 \\
9 July 2006 & 12 & 2 & 1 & 9 \\
10 July 2006 & 12 & 3 & 9 & - \\
15 August 2008 & 1 & - & 1 & - \\
16 August 2008 & 1 & - & 1 & - \\
7 July 2009 & 13 & 8 & 5 & - \\
16 July 2009 & 148 & 69 & 55 & 24 \\
27 July 2011 & 60 & 17 & 22 & 21 \\
15 July 2012 & 13 & 2 & 10 & 1 \\
18 August 2014 & 1 & 1 & - & - \\
25 August 2014 & 41 & 12 & 18 & 11 \\
4 July 2016 & 2 & 1 & 1 & - \\
5 October 2016 & 1 & - & 1 & - \\ Total & 317 & 117 & 125 & 75 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: _Cont._ \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Landslide Type**} & \multicolumn{6}{c}{**Number of Historical Landslide Data Points**} \\ \cline{2-10}  & **IC Zone 1** & **IC Zone 2** & **IC Zone 3** & **IC Zone 4** & **IC Zone 5** & **IC Zone 6** & **IC Zone 7** & **IC Zone 8** \\ \hline Slope failure & 4 & 2 & 68 & 60 & 9 & 24 & 17 & 2 & 186 \\ Debris flow & - & 1 & 10 & 18 & 4 & 1 & 2 & - & 36 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Reclassification of 1 st and 2 nd class historical landslide data recorded from 2009 to 2016, according to the infiltration characteristic (IC) zone and landslide type. flows in Figure 8b and Table 3 were all recorded during these eight days. Ideally, the timing information of each historical landslide forms the basis of the model's evaluation, for example, an evaluation of the prediction results from the SEM-LEWS model. Especially in terms of rainfall-induced landslides, hourly-, or minute-scale timing information is necessary, as most landslide-triggering rainfall in Korea tends to be concentrated over a few hours, and therefore, landslide hazards can vary greatly over an hour. However, it is almost impossible to obtain minute-scale individual occurrence times for such a large number of historical landslides. This is primarily due the majority of primary sources used for constructing the historical landslide database being compiled by public officials and thus, in most cases, only containing information on the occurrence date or period and not the exact time of occurrence. Such uncertainties arising from the lack of the accurate landslide occurrence time information have been reported by various landslide-modelling researchers [36; 37; 38]. In our study, we obtained minute-scale time information for only a limited number of the 222 historical landslide data points, and these were mostly sourced from internet news archives.