26 March 2020
The Imom rockslide in Central Asia
Central Asia is probably the finest place on Earth to view and understand giant rockslides and rock avalanches. The combination of young, rugged mountains, high uplift rates, previous glaciation and very active seismicity means that it is the ideal terrain for these giant landslides. Furthermore, the arid climate means that the rates of removal of the landslide deposits, and the rate of weathering of the landslide scars, results in exceptional preservation of them in the landscape. My friend Alexander Strom has worked tirelessly on the documentation of these landslides, and on their analysis, as well as introducing them to the landslide community via his field trips. It is to my eternal regret that I have been unable to attend as yet.
A very detailed analysis of these landslides is available in a detailed and lavishly illustrated book (Strom and Abdrakhmatov 2018), which provides large numbers of case studies. Unfortunately, at US$180 per copy this is beyond the reach of most of us, but substantial sections are available online via Google Books. This provides staggering insight into the diversity of giant landslides in Central Asia.
One nice example is the Imom rockslide. This is located at 37.692, 72.327 and is beautifully clear in Google Earth:-
This is a large landslide – Strom and Abdrakhmatov (2018) suggest it is about 15 million cubic metres – with a very clear scar and a large deposit, a part of which is on the valley floor. The landslide is about 2.4 km from the scar to the front edge of the deposit, and the height difference is about 700 metres. Interestingly, the authors hypothesise that the material at the front of the landslide may be moraine that was perched on the hillside and that has been bulldozed by the landslide to form a part of the deposit.
Strom, A. and Abdrakhmatov, K. 2018. Rockslides and Rock Avalanches of Central Asia – Distribution, Morphology, and Internal Structure. Elsevier, 1st Edition. ISBN: 9780128032046.