Landslide in rocks of Jodhpur Group at Masuria Hill in Jodhpur, Western Rajasthan, India: Its causes and threat to significant Georesources

Abstract The ever first disastrous landslide at Masuria Hill (MH) damaged many houses and properties on 4th October 2019 in surrounding residential colonies of Masuria area in the Jodhpur city, Western Rajasthan India. Present landslide not only created panic among people but also damaged properties and significant georesources which is a serious concern for future. Geologically, MH is represented by rhyolite of Malani igneous suite (MIS) of Cryogenian age which is overlain by siliciclastic rocks of Jodhpur Group (JG) of Ediacaran age of Marwar Supergroup (MSG). Landslide occur in horizontally disposed rocks of Umed Bhawan Formation (UBF) of JG. UBF is divided into 4-18m thick clay dominated soft sediments zone with sheet and release joints at the base. It is followed by 24-72m thick rigid sand zone having orthogonal jointing. This disposition of soft and rigid pattern of sedimentation of UBF is identified as the key horizons responsible for the landslide with shale horizon as the failure plane. Causes of landslide can be explain based on the model of BPSZ (Bedding Parallel Shear Zone). BPSZ is attributed to three main mechanisms: liquefaction, mass wasting and shear stresses that caused the landslide at MH. Study further reveal that residential area surrounding MH and other seven hills having similar geological disposition are under great threat to future landslide in Jodhpur. Paper also embodies characteristics of georesources having educational and cultural values which are under great threat to landslide along with appropriate hazard mitigation measures.