ABSTRACT Landslides pose considerable threats to infrastructure, communities and the geoenvironment, particularly in geologically fragile regions like Jammu and Kashmir. The present study focuses on the landslide that took place on 25 April 2024 in a small hamlet of the village Pernote in Ramban District of the Union Territory of Jammu and Kashmir, employing an integrated geomorphological, geological and geophysical approach to assess its characteristics and primary causes. A field investigation in Pernote village suggests that the landslide-affected terrain covers an area of 0.8 km2. It has been observed that the interplay of geomechanical properties of soil material exacerbated by the hydrogeology of the slope leads to the occurrence of such devastating landslides. The field observations confirmed that the Pernote event is a complex landslide with a deep circular motion. The sub-surface study of the slide through Ground Penetrating Radar (GPR) suggests a thick cover of slope material, demonstrating a huge vertical load. The GPR profile of a 16-80 MHz multi low frequency antenna demonstrates a soil cover of around 15 m at the crown that significantly increases downslope towards the zone of accumulation. The high-resolution GPR images of a 200 MHz antenna show a sharp signal interface at a depth of 3m, revealing the zone of saturation and shallow groundwater conditions. The soil of Pernote slope yields high swelling property, swelling index (18%), porosity (31%), water absorption (29.52%), plastic index (11.08%) and specific gravity (2.4), when got oversaturated, resulting in the loss of cohesion that triggers the slope failure. Based on the terrain characteristics, field study and sub-surface GPR imaging, we concluded that the Pernote landslide is of a deep circular nature that took place along a curved slip surface with a rotational component, as suggested by backward tilting residential buildings and other structures like agricultural fields, trees, and electric poles. The slide took place as a reactivated slope failure on a pre-existing failure plane on a fossil-landslide, as suggested by terrain characteristics as well as residents that probably was of the same magnitude and intensity.
Singh et al. (Sun,) studied this question.