Reconnaissance of the effects of the M7.8 Gorkha (Nepal) earthquake of April 25, 2015

The M7.8 earthquake of 25th April, 2015 caused widespread damage in the Nepal region by destroying many residential, public, religious and cultural heritage buildings and roads due to intense shaking, surface fissures and landslides. This earthquake provided an opportunity to study the vulnerability of the built environment and reassessment of the risk exposure of the region. The reconnaissance trip was aimed at surveying the Kathmandu valley region in Nepal and adjoining districts of Bihar state in India due to their high population density and rapid urbanization. The observed damage in Kathmandu and the northern districts of Bihar were consistent with the intensity reported in these regions. Complete collapse was observed in RC buildings and old unreinforced masonry buildings due to inherent structural defects in regions of MM intensity VIII and IX. Significant number of cultural heritage structures suffered partial to complete collapse. These observations provide a perspective on the widespread lack of preparedness even when the seismic hazard of the Himalayan region is well established. This letter cites some of the poor construction practices that are followed in the Kathmandu valley region which make the built environment vulnerable to unacceptable levels of damage under expected design levels of shaking