Using a Tank Model to Determine Hydro-Meteorological Thresholds for Large-Scale Landslides in Taiwan

Abstract

Rainfall thresholds for slope failures are essential information for establishing early-warning systems and for disaster risk reduction. Studies on the thresholds for rainfall-induced landslides of different scales have been undertaken in recent decades. This study attempts to establish a warning threshold for large-scale landslides (LSLs), which are defined as landslides with a disturbed area more massive than 0.1 km2. The numerous landslides and extensive rainfall records make Taiwan an appropriate area to investigate the rainfall conditions that can result in LSLs. We used landslide information from multiple sources and rainfall data captured by 594 rain gauges to create a database of 83 rainfall events associated with LSLs in Taiwan between 2001 and 2016. The corresponding rainfall duration, cumulative event rainfall, and rainfall intensity for triggering LSLs were determined. This study adopted the tank model to estimate conceptual water depths (S1, S2, S3) in three-layer tanks and calculated the soil water index (SWI) by summing up the water depths in the three tanks. The empirical SWI and duration (SWI–D) threshold for triggering LSLs occurring during 2001–2013 in Taiwan is determined as SWI = 155.20 − 1.56D and D ≥ 24 h. The SWI–D threshold for LSLs is higher than that for small-scale landslides (SSLs), those with a disturbed area smaller than 0.1 km2. The LSLs that occurred during 2015–2016 support this finding. It is notable that when the SWI and S3 reached high values, the potential of LSLs increased significantly. The rainfall conditions for triggering LSLs gradually descend with increases in antecedent SWI. Unlike the rainfall conditions for triggering SSLs, those for triggering LSLs are related to the long duration–high intensity type of rainfall event.

Aplicação do Tank Model como Ferramenta de Gestão na Bacia do Rio Perdizes – Cambará do Sul/RS

“…Matsuyama et al (2021) aplicaram 2 índices derivados do Tank (SWI e SWI-modificado) em uma bacia hidrográfica na Rússia para previsão de deslizamentos acarretados por neve, com bons resultados. Outros trabalhos também foram bemsucedidos na estimativa deslizamentos (Lin et al, 2020) e estabilidade de encostas (Matlan et al, 2018). Neste sentido, o TMI possui formulação mais robusta do que o SWI por adotar a média e mediana dos armazenamentos calculados pelo modelo, enquanto o SWI é calculado pelo simples somatório das alturas de armazenamento dos tanques.…”

Landslide susceptibility assessment and mapping using statistical and data mining models in Iran

“…Landslides are complex, isolated, and destructive natural hazards by which human lives are threatened, and considerable socioeconomic and environmental losses are incurred (Palmisano et al, 2016;Zhou et al, 2018;Ambrosi et al, 2018;Billah et al, 2019). Landslides occur owing to the interactive effect of different geoenvironmental factors including landform (Kim et al, 2015;Liucci et al, 2017;Chudý et al, 2019), geological evolution (Agostini et al, 2014;Niculiţă et al, 2019;Song et al, 2020), groundwater table oscillation (Peng et al, 2018;Cao et al, 2020), land uses/ land covers (Persichillo et al, 2017, Hao et al, 2020, precipitation (Chang et al, 2017;Segoni et al, 2018, Stanley et al, 2020, Lin et al, 2020, excessive irrigation (Hou et al, 2018;Cummins, 2019;Lacroix et al, 2020), seismic activities (Wang et al, 2018;Ojala et al, 2019;Hibert et al, 2019;Sha que, 2020), anthropogenic interferences (Mohammadi and Taiebat, 2016;Singh and Singh, 2020;Wu et al, 2020), and climate changes (Alvioli et al, 2018;Peres and Cancelliere, 2018;Rianna et al, 2019;Niculiţă, 2020).…”

Preface to the Special Issue “Rainfall Thresholds and Other Approaches for Landslide Prediction and Early Warning”

“…This is due mostly to the fact that the adopted physically-based model considers the antecedent soil hydrological conditions, which are known to have a primary role in slope instability. − Lin and co-authors [33] presented the definition of SWI-D (soil water index-duration) thresholds to define the condition of landslide triggering in Taiwan. In this paper, besides the classical rainfall thresholds, the authors proposed an approach based on the definition of soil water content, calculated by the use of a 3-layers tank model, where each tank represents a soil layer, from ground surface to the bedrock.…”