Assessment and simulation of potential landslide caused by the rainfall intensity in Batu City during 2021

Abstract

Rain is the main factor causing landslides; rainwater can enter the soil through rock gaps and then accumulate in the impermeable layer; the layer then becomes a slip plane that triggers the landslide. This study aims to determine the level of influence of rainfall on landslide events in Batu City in 2021. Batu City is one of the main tourist cities in Indonesia, so security and safety are the main factors that must be considered. The method used in this research is a descriptive analysis of rainfall and landslide data. The analysis process was approached with a literature review and simple mathematical calculations visualized on a 2D map using GIS and Geostudio to simulate groundwater infiltration and safety factors. The results showed that the number of landslide events increased with increasing rainfall. The rainfall for Batu City is between 1749.15-2238.73 mm, while most landslides occur in January and February. Landslides in Batu City in 2021 occurred 78 times, most of which occurred in Songgokerto Village (15 incidents). The intensity of rainfall greatly influences the occurrence of massive landslides; apart from changing the physical properties of the soil or rock, the mechanical properties also change rapidly. The wetting-drying process will make the properties of soil particles and rock aggregates more vulnerable or the durability index of the soil and rock layers will decrease due to continuous rainfall.