In recent years, sediment disaster has frequently been caused by heavy rainfall and has cost many human lives and great property losses. To estimate such risks, Wakai et al. [1] proposed a simplified prediction method to calculate the variation of groundwater levels in natural slopes both at the time of rainfall in wide areas and in real time. To calculate the variation of groundwater levels using this method, the slope conditions (such as material constant and initial conditions) must be determined in advance. This study takes the 2017 heavy rainfall in Northern Kyushu as an example to analyze surface layer thickness, one of the slope conditions that most significantly influences slope stability, over wide areas. The findings reveal that the prediction of slope failure distribution differs depending on how the surface layer thickness and sliding surface are determined.
Measuring the amount of rainfall is essential for a wide-area evaluation of the risk of landslide disaster using a real-time simulation. In Thailand, located in Monsoon Asia, point observation is conducted using a rain gauge. Interpolation calculation is crucial for obtaining the planar rainfall intensity for the wide-area analysis from scattered point observation data. In this study, to accurately calculate rainfall intensity using the inverse distance weighting (IDW) method, the parameters affecting the results are examined. Additionally, using obtained rainfall data, a simple prediction calculation of groundwater level fluctuation by Wakai et al. [1] and Ozaki et al. [2] is performed. Finally, the relationship between the rainfall intensity and the fluctuation of groundwater level will be discussed.
Every year, especially in the rainy season, landslides occur quite often in Lao Cai – a northern mountainous province of Vietnam. Specifically, in the year 2019, several landslides were observed to occur near the Sapa Ancient Rock Field in Hau Thao commune, Sapa town, Lao Cai province. In December 2019, a landslide investigation was conducted to examine the mechanism and possible causes of the landslides. Besides that, as the landslide distribution in this area is still unclear, this study will also aim to show the landslide denseness in a 700 m × 700 m square map as well as survey results in 2019 of two main landslides in such map. According to the survey, the landslide is the main phenomenon of geomorphological development in this area, being a combination of multiple different landslides with varying sizes and dissimilar triggers. The first survey landslide is about 50 m wide and 350 m long and has still been going on in recent years, with annual horizontal displacement being around 0.8 m. Meanwhile, the second one is a typical flash-landslide caused by rainfall. Despite being quite small in scale, about 15 m × 40 m, its characteristics indicate a dangerous implication in the future. This information will be the basis for further ongoing studies.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.