Landslide and Tsunami in Karrat Fjord, Greenland, 2017; the Event, the Response and the Future
Abstract
On the evening of 17 June 2017, a landslide released from a rock slope in the Karrat Fjord, West Greenland. A section 800 m in breadth detached from an elevation of 1000 m a.s.l. and plunged into the fjord below causing a tsunami. The result was loss of life and injury, devastation and evacuation of local villages, and the revelation that the mountain side is unstable in other places. The humanitarian effort, both locally and international to ease the situation for locals has been outstanding. Here we describe how the sequence of events surrounding the landslide unfolded and, thanks to the rapid response and cooperation by a multi-disciplinary, international team of geoscientists, crucial information could be provided to the Greenlandic authorities that supported and aided decision making. Photography and video from the first response teams showed the path of the landslide. Initial analysis of optical (Planet Cubesat constellation, Sentinel-2), SAR (Sentinel-1) and photogrammetric data from before and after the event confirmed the location of the landslide and the area that had detached. By extending the time series of Sentinel-1 data, it was possible to show that the section had been active since March 2017 with displacement accelerating towards failure. The new ArcticDEM was used to give an estimate of area and volume displacement in the main slide. The area where material was lost covered 760 x103 m2 and amounted to a displaced volume of >50 mio m3. These approaches all identified other parts of the mountain side that are in motion. Tsunami modelling was used to predict the on land inundation with simulations based on the landslide dimensions and a bathymetry model from multi beam surveys. The model results matched extremely well with reconstructed run-up heights manually interpreted from video and photographic footage and seismic analyses. For optimizing the guidance of the Greenlandic authorities, all results and experience from the many involved scientists and institutions were summarized in a number of memos. This knowledge provided information crucial for the response team, their activities and decisions regarding the future of the evacuated villages. A detailed understanding of the landslide and other areas of high risk is of importance in discussions of future mapping and monitoring of geohazards in Greenland.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFMPA11C..05L
- Keywords:
-
- 1918 Decision analysis;
- INFORMATICS;
- 6304 Benefit-cost analysis;
- POLICY SCIENCES;
- 6314 Demand estimation;
- POLICY SCIENCES;
- 6620 Science policy;
- PUBLIC ISSUES