31 January 2010
The latest news from the site of the Attabad landslide in Hunza, Pakistan, as relayed by the Pamir Times, is somewhat mixed. There is now a very helpful video of the landslide site on Youtube, which gives a proper view of the slide and its deposit from the scarp area:
The scarp area appears to be highly fractured and unstable.
Meanwhile, this report states that the lake continues to rise as about 2.8 feet (85 cm) per day, which is pretty high. The lake is now 11 km long. Two houses were submerged on Friday, another three will be lost imminently. The helicopter service to the areas upstream has been suspended for two days due to the weather. Interestingly, the article also reports the impact statistics of the landslide itself:
- 19 fatalities plus 6 people missing
- Seven people injured
- 54 houses destroyed
- 60 houses damaged
- 1652 people displaced
- 1.3 km of the Karakoram highway blocked.
On the plus side, the work to create a drainage channel is now well underway. The Pamir Times has printed this image of the site:
I have two observations to make:
- The along valley thickness of the dam, as shown on the video, should mean that it the chances of failure by piping or slope instability of the dam itself is not high;
- The images all show a dam that is made up of mostly quite fine-grained material, with some blocks. I hope that the core is rather more coarse-grained as preventing rapid erosion of the dam will not be easy if the material is as shown above.