A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Geotechnical and Earth Resources Engineering

Thesis (M. Sc.) - Asian Institute of Technology, 2023

Over the years, many landslides and debris flows have occurred in Thailand's northern and southern regions, resulting in the loss of lives as well as damage to property. Are Di Village was one such area hit by landslides and flash floods in September 2020, leading to destruction of public utilities, buildings, and houses. Therefore, it is essential to comprehend the mechanism of landslides in the area and establish a susceptibility map to mitigate potential risks. The landslide susceptibility map can serve as a guide for the residents of the surrounding area for the residents of the surrounding area to prevent damage and reduce the risk of future events. This research aimed to assess the stability of slopes and potential for landslides in the region using a Fortran program named Transient Rainfall Infiltration and Grid-Based Regional Slope-Stability Analysis (TRIGRS). The TRIGRS model utilized data on geotechnical soil properties, topography, and rainfall patterns to simulate the effects of rainfall on the soil and calculate the Factor of Safety (FS) values for different locations within the area. A FOS map was generated, which can be used to identify areas that are at high risk of landslides and develop strategies for mitigating the risk. The validation of landslide susceptibility map was performed using the LR class index, which showed good performance in predicting potential landslide areas. Overall, the results of this study provide valuable information for the development of effective landslide risk management strategies in the study area.