Establishing the landslide-triggering rainfall thresholds for the Kashmir Himalaya

The Himalaya is frequently impacted by precipitation-triggered landslides. When assessing the threat and potential consequences of landslides, it is important to understand the triggering mechanism and the associated rainfall thresholds. However, no such study has been carried out in the Kashmir Himalaya, irrespective of the fact that the region has a history of catastrophic precipitation triggered landslides. The study focuses on establishing rainfall thresholds for the Kashmir valley and a stretch of Jammu-Srinagar National Highway (NH-44) from Udhampur to Banihal. Using an empirical and automatic lower bound algorithm approach, the relationship between rainfall intensity and duration was investigated for 220 landslides in the Kashmir valley and 190 along the NH-44 for the period 1990-2021. The results show that rainfall intensities of 9.4 mm/day in the valley and 14.35 mm/day along the NH-44 can trigger landslides. Moreover, the effect of antecedent rainfall on landslides was analyzed and it was observed that 55 mm of minimum rainfall over 15 days and 53 mm of rainfall over 20 days is required to trigger landslides in the Kashmir valley and along the NH-44, respectively. These results provide valuable insight into the relationship between rainfall and landslides which can be utilized to anticipate future landslide events and reduce their effects in the region.