Earthquake-induced landslide hazard assessment using ground motion parameters: A case study for Bhagirathi Valley, Uttarakhand, India

The Himalayan region has endured devasting earthquakes, triggering secondary hazards like landslides. Mapping earthquake-induced landslide susceptibility is crucial in seismically active areas. Reliable seismic ground motion parameters are essential for accurate landslide hazard zonation (LHZ) study. This study integrates seismic ground motion parameters with a static LHZ map to assess earthquake-induced landslide hazard zonation using a random forest model. Probabilistic seismic hazard assessment has been employed to generate scenario ground motion parameters, specifically peak ground acceleration (PGA) corresponding to return periods of 475 and 2475 years. Results revealed that seismic parameters significantly enlarge the high-hazard area, especially in seismic active regions in the Himalayas. Based on the static factors, only 7.07% of the regions are categorized within the very high-hazard zone. However, when considering seismic parameters for a 475-yr. return period (LHZ-475), 26.82% of the area comes under the high and very high susceptibility zones. For the 2475 yr. (LHZ-2475), 33.02% of the area comes under the high and very high-susceptible zones. Emphasizing dynamic factors like PGA underscores the importance of evaluating seismic hazards in assessing susceptibility to landslides, particularly in seismic activity regions. This comprehensive approach offers valuable insight into reducing landslide risk and strengthening resilience to disaster in multi-hazard prone areas.