Impact of the landslide for a Relationship between Rainfall Condition and Land Cover in North Vietnam

This paper aims to evaluate the probability of landslide hazards using a physical model(TRIGRS:Transient Rainfall Infiltration and Grid-Based Region Slope-Stability)for a regional scale considering the variations of a triggering rainfall condition and land-cover under the climate change.There are certain uncertainties raising from the soil properties and soil depth determination,assumption of groundwater,as well as the same root cohesion for all tree cover in the forest-related region.However,the application of TRIGRS model in a regional scale would provide important references for the distribution of landslide prone area regarding scenarios about changes of weather condition and land cover situation.It thus would support local authorities in obtaining more adequate land planning strategies in a river basin to mitigate potential hazard from the slope failure issue.

Evaluation of Landslide Susceptibility in Cau River Basin Using a Physical-Based Model under Impact of Climate Change

This paper evaluated the probability of landslide susceptibilities through the applica-tion of the Transient Rainfall Infiltration and Grid-Based Region Slope-Stability model in Cau river basin (Vietnam) using the scenarios-based approach under the influence of the warming climate. The tested cases were developed based on various options including rainfall amount and distribution, soil depth determination, and land-cover conditions. Input data for extreme rain events included historical rainstorm in 2013, the Probable Maximum Precipitation (PMP) with the durations of 24 hours and 48 hours. The results illustrated the reduction of slope stability when the land cover changed from land-use data in 2007 (Ha12) to land-use data in 2015 (Ha22). When the whole region was assumed to be replaced by soil (Ha02), the factor of safety (Fs) decreased to lower magnitude when compared to Fs value regarding to changes in land cover condition (Ha12 & Ha22) and changes in soil-depth (Ha33). The model simulations demonstrated the agreement with the slope-failure hazard association with the destabilizing factor such as slope-cutting activities at historical landslide events. Under the same land-cover and soil depth condition, the average value of factor of safety regarding to the historical rainstorm in 2013 (Ha32) declined by 0.069 and 0.189 when compared to Fs of the 24-hour PMP with the storm distribution type 3 (1332) and Fs of the 48-hour PMP with the storm distribution type 3 (2332), respectively. The results reveal that in a warming climate, changes in extreme precipitation in terms of rain-total, rain-duration, and rain-distribution would result in the expansion of slope instability in the hilly region. This application is considered as a prevailing method for landslide susceptibility analysis and would provide important information for authorities in developing adequate land-management in the river basin.