Landslide Potential Evaluation Using Fragility Curve Model

Abstract

The geological environment of Taiwan mainly contains steep topography and geologically fragile ground surface. Therefore, the vulnerable environmental conditions are prone to landslides during torrential rainfalls and typhoons. The rainfallinduced shallow landslide has become more common in Taiwan due to the extreme weathers in recent years. To evaluate the potential of landslide and its impacts, an evaluation method using the historical rainfall data (the hazard factor) and the temporal characteristics of landslide fragility curve (LFC, the vulnerability factor) was developed and described in this chapter. The LFC model was based on the geomorphological and vegetation factors using landslides at the Chen-Yu-Lan watershed in Taiwan, during events of Typhoon Sinlaku (September 2009) and Typhoon Morakot (August 2009). The critical hazard potential (Hc) and critical fragility potential (Fc) were introduced to express the probability of exceeding a damage state of landslides under certain conditions of rainfall intensity and accumulated rainfall. Case studies at Shenmu village in Taiwan were applied to illustrate the proposed method of landslide potential assessment and the landslide warning in practice. Finally, the proposed risk assessment for landslides can be implemented in the disaster response system and be extended to take debris flows into consideration altogether.

The Effect of Temporal Characteristics on Developing a Practical Rainfall-Induced Landslide Potential Evaluation Model Using Random Forest Method

“…Factors that describe the environmental conditions and triggering behavior of landslides were usually used in the LSA method. The LSA-based models can be divided into qualitative and quantitative methods [1,2]. The approaches of statistical analysis, geotechnical engineering analysis (deterministic and probability), artificial intelligence [3][4][5][6][7][8][9], and data mining were commonly used for quantitative LSA modeling.…”

“…The concept of the risk triangle, proposed by Crichton [16], including hazard, vulnerability, and exposure, is usually used to develop an LRA model, in which probability assessment is performed to describe the risk level. A recently developed landslide evaluation model using the landslide fragility curves (LFC) was a model of LRA [1,2,17]. LFC model used spatial statistics and GIS for data processing on the grid base.…”

“…Fragility curves were built for each combination of factors in the model. With the fragility curves, the critical hazard potential and critical fragility potential were determined to express the probability of exceeding a damage state of landslides under certain conditions of rainfall intensity and accumulated rainfall [2].…”

“…In addition to rainfall factors, previous studies [1,2,20,21] on landslides usually used other annual factors of each year to establish a potential evaluation model. The variation of the same factors between each year was typically assumed to be independent and uncorrelated.…”

“…Reference rainfall station: Nan Tian Chih (0601 event); San Di Men (Typh. Nesat and Haitang) 2. at Nantou County, coordinate using TWD97 3.…”