The Attabad landslide in N. Pakistan - some initial images from my field visit this week

I am now back from my comparatively short but very interesting trip to the Attabad landslide in N. Pakistan. I will make a series of posts about this serious but very interesting landslide over the next few days. As a taster, here a few images of the site. The first image was taken from the top of the 1858 Salmanabad landslide deposit, looking upstream to the Attabad slide. The scar of the landslide is on the left and extends beyond the snowline. The main landslide deposit is on the right, coated with a layer of black clay-silt sediment that was scooped up from the river bed by the slide. In the valley bottom the secondary flow is also visible - this was a mudflow of riverbed sediment that travelled about 1.5 km. Look carefully on the full image (click on the image below to see this) and you will see the ruins of some buildings on the left side of the mudflow, at the junction with the rock cliff. This is the place where the 19 victims of the landslide died, struck by the mudflow:

The image below shows the spillway under construction. At the moment the spillway is still being excavated in the black mudflow deposit, although this will shortly break through to the underlying colluvium. The army are optimistic that the spillway will survive the summer flood - others may have a different opinion...

This final image is a view from the top of the landslide deposit looking upstream. In the foreground is the landslide deposit - note the lack of black clay here. In the background is the lake and, beyond that, the rock walls of the main river valley. If the landslide does survive then a new section of the Karakoram Highway will need to be built through this section. This will take some time.

More to follow.

Problems at the Hattian Bala landslide dam in Pakistan

The largest landslide in the 2005 Kashmir earthquake occurred at Hattian, 25 km or so from Muzaffarabad:


My colleagues and I wrote a paper on this landslide a few years ago (you can download the pdf here). It was notable for the fact that it blocked the valley - in the aftermath the Pakistan Army built a spillway to ensure that uncontrolled overtopping did not occur. The landslide has been stable since, although many of us have warned that this area is far from out of the woods, with the first really intense precipitation event being a key test.

In the last few days this area has suffered a very heavy rain and snowfall event - as in fact has a vast area of the Himalayan Arc - indeed I have never seen a 1 day TRMM landslide potential map like this - it is quite bizarre:

Late tonight, media sources in Pakistan are suggesting that the lake has broken its banks, flooding 23 houses. So far the dam is holding, but clearly this event will ask substantial questions of it. Hopefully, the spillway engineers have got this right!

Elsewhere in the Muzaffarabad area, heavy rain is reported to have triggered many landslides. I have not yet seen any reports of the situation at Attabad, but this is not likely to be helping.