Geological experts have alerted that the April 25 earthquake and its frequent aftershocks including the greatest magnitude-6.8 tremor on May 12, are likely to trigger a number of landslides in the affected region.
The American Geophysical Union (AGU) and the Earthquake Without Frontiers (EWF), a global network of earthquake scientists, have warned that a number of landslides may affect life in central and eastern regions of Nepal including Kathmandu Valley, while blocking road networks.
“Landslides are going to be a very real problem in those areas affected by the Nepal earthquake, and by its aftershocks,” the AGU wrote a day after the great tremor.
It highlighted that risks are higher due to complex geographical structures of the affected region.
“Further to the north the mountains become higher and the slopes longer. Note the terracing in the fields, the steep slopes and the large numbers of houses. There are many substantial villages, often located high on the slopes,” the Union wrote, “This is highly landslide-prone territory, and the impact of the earthquake in these regions is going to be dreadful.”
Tom Robinson, a geologist at the University of Canterbury, New Zealand, in his landslide hazard map, has identified that landslides are likely to “occur in the high Himalayas to the north of the epicentre and Kathmandu.”
The Tom Robinson map. Courtesy: EWB
The EWF analyses that the affected areas include the major river valleys of central Nepal, including the Kali Gandaki, Marsyandi, and Trisuli Rivers, as well as parts of the Sunkoshi River catchment.
“These areas also have high relief between valley floors and ridge crests, meaning that landslides there are potentially large enough to block the valleys,” it warned.
Another map developed by Rob Parker of Cardiff University also warned that landslides are most likely in north of the epicentral area. Landslides are also expected in the foothills and places like Chitwan, the EWF added.
Rob Parker map. Courtesy: EWB
Meanwhile, the National Society for Earthquake Technology-Nepal (NSET) has suggested concerned authorities and field workers to adopt specific measures to protect the affected areas from landslides.