Rainfall intensity–duration conditions for mass movements in Taiwan

Abstract

Mass movements caused by rainfall events in Taiwan are analyzed during a 7-year period from 2006 to 2012. Data from the Taiwan Soil and Water Conservation Bureau reports were compiled for 263 mass movement events, including 156 landslides, 91 debris flows, and 16 events with both landslides and debris flows. Rainfall totals for each site location were obtained from interpolated rain gauge data. The rainfall intensity-duration (I-D) relationship was examined to establish a rainfall threshold for mass movements using random sampling: I = 18.10(±2.67)D −0.17(±0.04) , where I is mean rainfall intensity (mm/h) and D is the time (h) between the beginning of a rainfall event and the resulting mass movement. Significant differences were found between rainfall intensities and thresholds for landslides and debris flows. For short-duration rainfall events, higher mean rainfall intensities were required to trigger debris flows. In contrast, for long-duration rainfall events, similar mean rainfall intensities triggered both landslides and debris flows. Mean rainfall intensity was rescaled by mean annual precipitation (MAP) to define a new threshold: I MAP = 0.0060(±0.0009)D −0.17(±0.04) , where I MAP is rescaled rainfall intensity and MAP is the minimum for mountainous areas in Taiwan (3000 mm). Although the I-D threshold for Taiwan is high, the I MAP -D threshold for Taiwan tends to be low relative to other areas around the world. Our results indicate that Taiwan is highly prone to rainfall-induced mass movements. This study also shows that most mass movements occur in high rainfall-intensity periods, but some events occur before or after the rainfall peak. Both antecedent and peak rainfall play important roles in triggering landslides, whereas debris flow occurrence is more related to peak rainfall than antecedent rainfall.

Relação Intensidade-Duração De Precipitações Capazes De Desencadear Escorregamentos Em Porto Alegre - Rs

“…Em seu trabalho, Caine (1980) propôs uma relação limiar global entre intensidade e duração de precipitação capaz de desencadear escorregamentos utilizando 73 eventos de escorregamentos e fluxo de detritos. Apesar de a abordagem empírica negligenciar importantes aspectos hidrológicos atuantes no solo, fornece um meio simples de emissão de alertas a movimentos de massa baseado apenas em precipitação (CHEN et al, 2015).…”

A Rainfall Intensity-Duration Threshold for Mass Movement in Badulla, Sri Lanka

“…The I-D threshold for mass movements is identified on an I-D plot as the minimum rainfall for which a landslide could occur (Chen, 2015). Average rainfall intensity, duration, and cumulative rainfall for debris flow/mud flow were 49 mm/h, 7 h, and 260 mm respectively, and those for landslides were 41 mm/h, 5 h, and 210 mm respectively (Table 1).…”

“…International literature revealed that various methods have been used to establish the relationship between rainfall intensity and duration [12] [37], however the general form of the relationship between rainfall intensity and duration…”

“…These studies have been focused on rainfall parameters such as rainfall intensity, duration, cumulative rainfall, and antecedent rainfall [12]. Relationships between rainfall intensity and duration are the most common estimate of rainfall thresholds for landslides [14] [15] [16].…”

Evaluating critical rainfall conditions for large-scale landslides by detecting event times from seismic records

“…However, with the assistance of seismic records, the time information for estimating critical rainfall can be acquired. 25 By applying various rainfall factors into statistical analysis, a statistical threshold can be built to explore the critical rainfall conditions of landslide occurrences, such as using rainfall intensity and duration to define rainfall threshold curves (Caine, 1980;Guzzetti et al, 2008;Saito et al, 2010;Chen et al, 2015).…”