Abstract ID: 3.13565 | Accepted as Talk | Talk/Oral | TBA | TBA

Manikaran, located in Kullu district, Himachal Pradesh, NW Himalaya, India, is a renowned tourist destination, famous for its hot springs, ancient Ram Mandir, and Gurudwara Sahib. The region has seen an exponential increase in tourists, drawn to its natural and cultural attractions. However, the area is also prone to frequent rockfall events, which pose a significant risk to public safety. A major rockfall disaster occurred in August 2015, when a rockfall hit the Gurudwara, destroying its four-story building, killing around 10 people, and injuring 15 others who were asleep in the Gurudwara’s Sarai. The town and surrounding areas are regularly affected by rockfall activity, especially during the monsoon season, making it critical to study and predict future rockfall hazards. This study combines geological field investigations, geomorphic mapping, field-based rockfall datasets (rock shape and volume), high-resolution digital elevation models (DEM) using drone survey, and numerical simulations using the open-source SICONOS software. Field investigations revealed that the August 2015 rockfall event was not due to a single rock block, but rather a chain reaction, where a primary rockfall event triggered the remobilization of static blocks along the slope’s runout path. A novel rockfall propagation model was developed to incorporate rock-rock interactions and simulate realistic rockfall events, which may better predict future hazards. This model, the first to account for the impact of pre-fragmented rock mass as a source area on static blocks in rockfall propagation, enables a comparative hazard assessment by simulating rockfall trajectories both with and without the presence of static blocks on the slope. The findings of this study offer new insights into rockfall dynamics and provide valuable predictive capabilities, which can be applied to rockfall-prone regions worldwide, particularly those with large static rock blocks in the run-out paths of moving rock blocks.