17:15 〜 18:45
[AAS07-P05] Assessment of Landslide Susceptibility under the Climate Change in the future in the Chishan River Watershed in Southwestern Taiwan
キーワード：landslide susceptibility, climate change, frequency ratio method, Chishan river watershed, Taiwan
The influence of climate change on the East Asia is the change of rainfall characteristic based on the Assessment Report Sixth (AR6) proposed by Intergovernmental Panel on Climate Change (IPCC). The rainfall characteristics in Taiwan due to climate change gradually change to short-duration and high-intensity. The high-intensity rainfall in Taiwan with high landslide proneness will result in more landslide cases during heavy rainfall events. The study focuses on the assessment and evolution of landslide susceptibility in the Chishan river watershed under the climate change in the future in Southwestern Taiwan. The Chishan river watershed was a landslide-prone mountainous watershed, and 2009 Typhoon Morakot caused serious sediment disasters, including the severe Xiaolin deep-seated landslide. The study uses the geomorphological data, rainfall data and landslide inventory after Typhoon Matmo in 2014 as the basis for building the landslide susceptibility assessment model, and uses the landslide inventory after Typhoon Sinlaku in 2008 as a model verification. The study combines the landslide susceptibility assessment model and the daily rainfall in the future in Taiwan which was proposed in the Assessment Report Sixth by Intergovernmental Panel on Climate Change to predict the landslide susceptibility in the Chishan river watershed in Southwestern Taiwan.
This study selected a total of 10 factors as the basis for building the landslide susceptibility assessment model. These factors include elevation, slope, geology, land use, distance to rivers, distance to faults, the topographic roughness index, topographic Wetness Index, landslide frequency, and daily rainfall. The methodology for building the landslide susceptibility model in the study was the Frequency Ratio Method (FR). The daily rainfall during Typhoon Matmo in 2014 in the Chishan river watershed ranged from 112.5 to 408.5 mm, and it resulted in 1 landslide cases. The AUC value (Area Under the ROC curve) of the landslide susceptibility model based on the landslide inventory after Typhoon Matmo in 2014 in the Chishan river watershed exceeded 0.7, and the correct ratio by using the error matrix was 0.70. Furthermore, the model was validated using the landslide inventory after Typhoon Sinlaku in 2008, and the verification results also demonstrated a 70% accuracy rate.
This study combines the landslide susceptibility assessment model with the daily rainfall in the future under climate change to predict the distribution of landslide susceptibility in the Chishan river watershed. Using the future (2024-2100) daily rainfall data provided by Taiwan Climate Change Estimation Information and Adaptation Knowledge Platform (TCCIP), the climate change scenarios include SSP126, SSP245, SSP370 and SSP585, and compare them with the past (2000-2023) daily rainfall. Based on the analysis of past rainfall data, approximately 82% to 93% of the annual rainfall occurs during the rainy season (May to October), indicating that the rainfall in this region is mainly concentrated in the rainy season.
This study selected a total of 10 factors as the basis for building the landslide susceptibility assessment model. These factors include elevation, slope, geology, land use, distance to rivers, distance to faults, the topographic roughness index, topographic Wetness Index, landslide frequency, and daily rainfall. The methodology for building the landslide susceptibility model in the study was the Frequency Ratio Method (FR). The daily rainfall during Typhoon Matmo in 2014 in the Chishan river watershed ranged from 112.5 to 408.5 mm, and it resulted in 1 landslide cases. The AUC value (Area Under the ROC curve) of the landslide susceptibility model based on the landslide inventory after Typhoon Matmo in 2014 in the Chishan river watershed exceeded 0.7, and the correct ratio by using the error matrix was 0.70. Furthermore, the model was validated using the landslide inventory after Typhoon Sinlaku in 2008, and the verification results also demonstrated a 70% accuracy rate.
This study combines the landslide susceptibility assessment model with the daily rainfall in the future under climate change to predict the distribution of landslide susceptibility in the Chishan river watershed. Using the future (2024-2100) daily rainfall data provided by Taiwan Climate Change Estimation Information and Adaptation Knowledge Platform (TCCIP), the climate change scenarios include SSP126, SSP245, SSP370 and SSP585, and compare them with the past (2000-2023) daily rainfall. Based on the analysis of past rainfall data, approximately 82% to 93% of the annual rainfall occurs during the rainy season (May to October), indicating that the rainfall in this region is mainly concentrated in the rainy season.