Rainfall thresholds for shallow landslides considering rainfall temporal patterns

Recent advancements in rainfall observation and forecasting have enabled the real-time identification of rainfall temporal patterns, thereby enhancing the prediction of landslides by accounting for their temporal dynamics. However, conventional landslide prediction methodologies rely on average rainfall characteristics, such as intensity (I) and duration (D), overlooking the influence of rainfall temporal details. To overcome this limitation, this study proposes an innovative approach to defining rainfall thresholds that integrate rainfall temporal patterns. These thresholds are designed to provide probabilistic estimations of landslide occurrences for rainfall events characterized by constant intensity and duration, while considering the temporal dynamics. Investigating the impact of rainfall temporal patterns on landslide occurrences reveals that the initiation of landslides is primarily influenced by the infiltrated rainfall rather than the total rainfall amount. Specifically, rainfall temporal patterns characterized by fewer high-intensity values tend to result in greater infiltration, thereby increasing the likelihood of landslide triggering. Furthermore, rainfall concentrated in the early and middle stages of an event is associated with a higher probability of landslide occurrence. This study's findings underscore the importance of incorporating rainfall temporal patterns into landslide early warning systems, thereby facilitating more effective risk mitigation strategies.