Landslide Movement at Lokanthali during the 2015 Earthquake in Gorkha, Nepal

Abstract

The Gorkha earthquake (Mw=7.8) of April 25, 215, caused widespread damage in the Kathmandu Valley. At a gently sloping site, known as Lokanthali, large ground fissures and tension cracks with vertical offsets in excess of 1 m, were observed along a ridge for a distance of about 1 km. The authors conducted a postearthquake engineering field reconnaissance of the affected areas, surveyed the topography of the site, performed subsurface explorations, conducted in situ shear strength tests, and performed dynamic simple shear as well as bender element tests, on soil samples from the site. Additionally, numerical analyses were performed to understand the seismic vulnerability of the site. The numerical geomechanical modeling showed that the site was most likely affected by seismically induced landslide movements. Results of this study provide a valuable case history of moderate seismic shaking and landslide movement, which may be used by researchers for the calibration of simplified Newmark models.