18 April 2010
Worrying signs on the landslide at Attabad in Hunza
Posted by Dave Petley
The water level at the landslide dam at Attabad in Pakistan continues to rise (see the data on my Hunza landslide monitoring site), with the reported freeboard being less than 30 metres. However, I have to report a very much more worrying development. Dr Michele Comi and Dr Chiara Calligaris from Ev-K2-CNR are just returning from a visit to the site, and have sent me the picture below (reproduced with permission):
This sinkhole has apparently opened up on the upstream side of the dam. The most likely cause of a sinkhole is that erosion is occurring in the core of the dam, although this could be localised. However, given that seepage is now accelerating again, the signs are worrying.
Dave Petley is the Vice-Chancellor of the University of Hull in the United Kingdom. His blog provides commentary and analysis of landslide events occurring worldwide, including the landslides themselves, latest research, and conferences and meetings.
I've made a Google Earth Overlay with that NASA Earth Observatory image that Daniel posted on your Hunza landslide monitoring site. The registration isn't perfect but I did my best to line up the highway trace in the Google Earth roads layer with the trace in the satellite image, focusing on the area immediately surrounding the lake and landslide. There's more mismatch at higher altitudes, but I don't have the means to orthorectify the photo to clean this up. Feel free to point to this KMZ file if you find it useful: http://ron.outcrop.org/kml/Attabad.kmz