Land subsidence in the western part of Aizawl: a case study of Hunthar, Aizawl, India

Aim: To generate Landslide Susceptibility Map of Hunthar locality using AHP method, demarcating the study area Hunthar Landslide and interpreted with its physico-chemical properties of soil within the study area. Methodology: ArcGIS 10.4 was utilized to create Landslide Susceptibility Map through Analytic Hierarchy Process (AHP). Atterberg limit for liquid limit, plastic limit and plasticity index, samples were analyzed to ascertain the geotechnical characteristics of soil. Sieve analysis and hydrometer analysis were performed for soil texture classification. X-Ray Diffraction (XRD) was utilized for clay minerals identification in the soil samples. Results: Analytic Hierarchy Process (AHP)-based Landslide Susceptibility Consistency Ratio was 0.008. The plasticity chart classified the soil samples ranges to: low-plastic clay to low-plastic silt and clay of intermediate compressibility to low-compressive silt. Loamy soil was indicated by the classification of soil texture. Through X-ray, parent materials such as silica, micas, and feldspars were found alongside clay mineral groups like kaolinite, illite, and smectite. Quartz was the dominant mineral, montmorillonite and illite were common clay minerals. Interpretation: Physico-chemical characteristics of soils and interpretation of Hunthar landslide susceptibility map showed that the landslide is caused due to erosion of toe area during monsoon. High concentration of clay minerals like monmorillonite (swelling clay) contributes to landslide activity. Key words: Analytic hierarchy process, Atterberg, Clay minerals, Hunthar, Landslide