13 August 2015
Shanyang landslide: a very complex slide
Posted by Dave Petley
Very little information has emerged in the last 24 hours about the Shanyang landslide in Shaanxi, China, which I covered yesterday. Xinhua has a news item on it, confirming that 65 people remain missing. There appears to have been no success in finding victims or survivors since the initial rescue effort. The chances of finding anyone alive now must be remote.
The best new information comes in the form of a gallery of photographs from China Foto Press that are being distributed by Getty Images. As these are commercial images I will show just one here, simply because it provides so much insight into the Shanyang landslide:
This image appears to show the source area of the landslide in the centre background, in which an entire section of ridge seems to have collapsed. I think that the rocks dip in the direction of initial sliding, perhaps suggesting that this is a dipslope failure? The landslide appears to have been quite mobile, turning through 90 degrees. Movement appears to have ceased when the landslide impacted another valley wall.
Eye witness reports suggest that the survivors ran up the valley to escape the landslide. Those who ran down the valley were reportedly hit by the Shanyang landslide. This would make sense if they were located near to the toe of the initial failure as movement started.
There is a notable lack of debris from buildings in the image, suggesting that the structures were completely buried. I am unsure as to whether the crushed car in the bottom left of this image was associated with the Shenyang landslide or is left from an earlier event.
Nothing here changes my view that, although I cannot comment on this specific case, there is evidence that slopes are being inadequately managed in some mines in China. Dipslope failures are a well-known hazard.