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[HDS11-P05] Topography, geology, rainfall and land-use of the landslide areas in northwestern Vietnam
Keywords:landslide, land-use, mountain road, NW-Vietnam
Seven typhoons made landfall on or approached the central region of Vietnam in October to November 2020 and caused rainfall-induced landslides and sediment disasters, which attracted global attention (Tien et al. 2021). However, according to the statistics for 1991-2015 (JICA 2018), the highest fatality rate of sediment disaster is found in the northwestern region, the most mountainous area in the country, suggesting the significance of landslide occurrence and vulnerability to disasters of the area (FFPRI 2021). Recent Google Earth images and other satellite images in the northwestern region of Vietnam show occurrence of (1) shallow landslides in the left bank of the middle reaches of the Da River (Lao Cai and Yen Bai provinces) on mountain slopes in higher altitudes where igneous rocks (granite and rhyolite) are predominant and (2) relatively large landslides in the left bank of the upper reaches of the Da River (Lai Chau province) on mountain slopes on lower altitudes where sedimentary rocks are underlain (Furuichi et al. 2021).
A previous study, hosted by a research team of the Vietnam Institute of Geosciences and Minerals, made an extensive landslide inventory mapping in 14 provinces in northern Vietnam based on aerial photos and DEM data, in which 10149 landslides were identified (Hung et al. 2017). Another research group undertook in-depth fieldwork in various areas across Vietnam and discussed the factors and mechanisms of landslide occurrence by examining geological structure, rock types and regolith characteristics (Tien et al. 2016; Abe et al. 2021).
In this paper, we report our updated analysis on recent landslides in northwestern Vietnam, particularly by focusing on the factors, that are topography, geology, rainfall and land-use, of shallow landslide occurrence. The analysis will partly include results of fieldwork scheduled in February 2022.
A previous study, hosted by a research team of the Vietnam Institute of Geosciences and Minerals, made an extensive landslide inventory mapping in 14 provinces in northern Vietnam based on aerial photos and DEM data, in which 10149 landslides were identified (Hung et al. 2017). Another research group undertook in-depth fieldwork in various areas across Vietnam and discussed the factors and mechanisms of landslide occurrence by examining geological structure, rock types and regolith characteristics (Tien et al. 2016; Abe et al. 2021).
In this paper, we report our updated analysis on recent landslides in northwestern Vietnam, particularly by focusing on the factors, that are topography, geology, rainfall and land-use, of shallow landslide occurrence. The analysis will partly include results of fieldwork scheduled in February 2022.