Heavy Rain Types for Triggering Shallow Landslides in South Korea

The Effects of Different Geological Conditions on Landslide-Triggering Rainfall Conditions in South Korea

“…The mean annual temperature and mean annual precipitation vary regionally from 6.6 to 16.6 • C and from 825.6 to 2007.3 mm, respectively [30]. More than 50% of the annual precipitation occurs during heavy rainfall in the summer season, i.e., June to September [18,29]. This is consistent with the monthly distribution of landslide occurrences, indicating that rainfall is the primary triggering factor in landslides [18].…”

“…According to Rosi et al [41], reasonable criteria must be established to exclude the possibility of subjective intervention when defining the starting point at which rainfall thresholds responsible for the initiation of landslides are identified. However, this is difficult to achieve because multiple rainfall patterns coexist [41] and landslides are triggered by various types of heavy rain in South Korea [29]. Therefore, we determined the start of the landslide-triggering rainfall event for each landslide by delimiting it by at least 24 h of no rainfall (Figure 3), as has been conducted in several studies [15,[44][45][46].…”

“…To investigate the I-D relationship in each geological condition, a quantile regression method was applied to determine the landslide-triggering rainfall threshold using the R statistical software package (ver. 3.4.3) [47], as performed in several previous studies [15,18,29]. Quantile regression analysis was performed at the 2nd, 50th, and 90th percentile levels, according to the methods propounded by Guzzetti et al [11] and Saito et al [15].…”

“…In South Korea, shallow landslides frequently occur in the surficial layer above bedrock in diverse geological settings during the summer rainy season from June to September [18,21,29], suggesting that understanding the influence of different geological conditions and rainfall on landslides is critically important in the establishment of a landslide warning system and can provide a good opportunity to explore the influence of different geological conditions. This study is aimed at (1) investigating the differences and variations in I-D conditions and rainfall characteristics for three major geological conditions (gneiss, GN; granite, GR; sedimentary rock, SR) using data from 476 shallow landslides in South Korea and (2) assessing the influence of these geological conditions on rainfall-triggered landslides in terms of occurrence exceedance probability and landslide susceptibility.…”

Assessment of critical rainfall scenarios for slope stability analyses based on historical rainfall records in Singapore

“…They concluded that 5-day antecedent rainfall affects the stability of slopes in Taiwan. Studies on the threshold of rainfall-induced landslides have been conducted in other countries in Asia, such as: Bhutan (Dikshit et al, 2019); Japan (Hong et al,2005); Bangladesh (Khan et al, 2012); South Korea (Kim et al, 2015).…”