Bowing
The Landslide Blog is written by Dave Petley, who is widely recognized as a world leader in the study and management of landslides.
I was recently pondering some of the most interesting landslides on which I have worked during my career, and was reminded of the 8 October 2005 Hattian Bala landslide in Kashmir, Pakistan. This was the largest landslide triggered by the appalling Mw=7.6 Kashmir Earthquake that day, which killed over 87,000 people. The Hattian Bala landslide is believed to have accounted for about 1,000 fatalities.
As a result of our work on the landslides triggered by the Kashmir Earthquake, we write a paper (Dunning et al. 2007) about the Hattian Bala landslide. The remains of the failure are still visible on Google Earth – it’s located at [34.1393, 73.7232]:-
The scale of this landslide is enormous – we estimated the volume to be 68 million cubic metres, with a length of 2.6 km and an average thickness of 63 metres. This image shows the lower part of the landslide deposit:-
The landslide blocked the valley, creating two lakes, the largest of which caused considerable concern regarding a breach event. As a consequence, attempts were made to construct a spillway to manage the lake level:-
The dam did finally breach in 9 February 2010. This was subsequently described in a paper (Konagai and Sattar 2011) in the journal Landslides. They estimate that the breach released 36 million cubic metres of water. This image, which was sent to me by Ken Hewitt, shows the aftermath of the breach:-
The flood caused a great deal of damage downstream, but this was undoubtedly reduced by the presence of the spillway.
As the Google Earth image shows, the remains of the landslide dam continue to impound a significant volume of water.
References
Konagai, K. and Sattar, A. 2012. Partial breaching of Hattian Bala Landslide Dam formed in the 8th October 2005 Kashmir Earthquake, Pakistan. Landslides 9, 1–11 (2012). https://doi.org/10.1007/s10346-011-0280-x
Dunning, S.A., Mitchell, W.A., Rosser. N.J. and Petley, D.N. 2007. The Hattian Bala rock avalanche and associated landslides triggered by the Kashmir Earthquake of 8th October 2005. Engineering Geology 93 (3–4), 130–144. doi:10.1016/j.enggeo.2007.07.00
