1 July 2015

An updated landslide density map from the Nepal earthquakes from the EWF project

Posted by Dave Petley

An updated landslide density map from the Nepal earthquakes from the EWF project

The Earthquakes Without Frontiers project has published a revised landslide density map for the Nepal earthquakes,  This map includes landslides triggered by both the 25th April and the 12 May earthquakes:-


Note the shaded areas are those obscured by cloud, so the dataset is not quite complete. The full landslide dataset is available to download from here:


EWF highlight the following key points:

  • Approximately 5,600 landslides have been identified to date, including new landslides triggered by the 25 April 2015 Gorkha earthquake and the 12 May 2015 Dolakha earthquakes, as well as reactivations of landslides that were present before the earthquake sequence began.
  • Major or disruptive landsliding is limited to a zone that runs east-west, approximately parallel to the transition between the Lesser and High Himalaya. This zone includes parts of the districts of Gorkha, Dhading, Nuwakot, Rasuwa, Sindhupalchok, Dolakha, Ramechhap, and Khavre.
  • Landslides triggered by the 12 May Dolakha earthquake are included in this data set for the first time. The area of landslides triggered by the Dolakha earthquake overlaps with the eastern end of the area affected by landslides in the Gorkha earthquake. In general, locations that suffered from high landslide intensities after the Dolakha earthquake also suffered from widespread landsliding in the Gorkha earthquake. These areas have suffered damaging levels of shaking in two successive large (Mw 7+) earthquakes, and must be viewed as having a very high risk of failure during the 2015 monsoon season.
  • There have been numerous reports of cracked ground in the affected areas. There is no single interpretation of cracks in slopes generated during earthquakes and how these cracks are likely to develop through the monsoon. We recommend establishing simple monitoring (distance measurements between stakes positioned across cracks), to establish if cracks are widening or if movement of the slope has ceased. Areas that exhibit continued or accelerating movement should be treated with extreme caution.

Full details are available on the EWF blog.