FIELD SURVEY ON SINKHOLES IN POKHARA, NEPAL, BASED ON UAV AND SURFACE WAVE TEST

Abstract

Since November 2013, a number of sinkholes have been observed in the Armala area of Pokhara Valley, Central Nepal, affecting the farming lands and the local residents. According to the local people, more than

200 sinkholes have been occurred. The authors have investigated the affected area six times from 2014 through

2016. The topographic data was obtained by using UAV and the subsurface soil structures were investigated through surface wave test and cone penetration tests. The results indicates that an erosion of weak soil layers in buried old river channels along the main river, Seti River, may have caused the sinkhole damages.