Co-seismic landslide damming in the Indian Himalayas

In mountainous terrains, coseismic landslide dams are catastrophic geological hazards that induce devastating and cascading effects on humanity. Identification of historical landslide dams is necessary to mitigate the long-term effects it may cause in the future. If not controlled or necessary mitigation measures are not appropriately applied, the landslide dam deposits may have longer implications in generating cascading hazards through geological time. Coseismic landslide dams in the Indian Himalayas are not explored more except for very few studies. Here, we propose a framework to examine the potential for coseismic landslide damming and analyze the possible mitigation strategies to minimize the effects. We use the framework to analyze the potential of coseismic landslide damming in Uttarakhand, India, in the western part of the Himalayas. In addition, to make a coseismic landslide dam susceptibility map, we identified around a dozen landslide dams along major river systems in Uttarakhand which were not mapped or identified earlier. We found that many landslides during the Chamoli 1999 earthquake triggered many dams. While major earthquakes after 1999 did not occur in Uttarakhand, the possibility of coseismic landslide disasters should not be overlooked, and preparedness and mitigation strategies become inevitable to avoid cascading damages by landslide damming.