A new paper (Yao et al. 2023) examines a 29 million cubic metre rockslide that has the potential to create a large landslide dam
The Landslide Blog is written by Dave Petley, who is widely recognized as a world leader in the study and management of landslides.
An article in the journal Natural Hazards (Yao et al. 2023) examines the Woda landslide on the Jinsha River. The study tries to determine the potential impact of the failure of a slope that would block a major river, potentially inducing a dam break event. The paper highlights a very interesting slope hazard.
The Woda landslide is located at [31.4364, 98.8281] (as an aside, I still find it frustrating that this information is not routinely provided in decimal form in papers – surely this is essential information?). This is the slope in question:-
The landslide is reasonably easy to see in the image above. The crown of the slope is at 4,000 metres elevation, and the elevation difference to the toe is about a kilometre. Yao et al. (2023) note that the slope angle is about 30 degrees, the landslide is about 1.9 kilometres long and the width is about 1.7 km. The volume is about 29 million cubic metres.
This is an ancient landslide, but the central section has reactivated. Yao et al. (2023) include monitoring data that indicates that the central portion of the slope is moving at about 10 cm per year. Thus, the concern about a potential major collapse is well founded.
In their paper, Yao et al. (2023) model the failure of the landslide under a range of scenarios. The study shows that the landslide has the potential to create a major dam that could be extremely damaging downstream should it breach catastrophically through overtopping.
There are many sites of this type in high mountain areas, and back in 2010 we saw the challenges of managing a valley-blocking landslide in real time. Whilst there is always multiple uncertainties in these types of studies, including whether failure of the landslide will occur at all, there is real value in trying to determine the range of scenarios if and when a major event does occur.
Yao, S., Lei, Y., Liu, D. et al. 2023. Assessment risk of evolution process of disaster chain induced by potential landslide in Woda. Natural Hazards. https://doi.org/10.1007/s11069-023-06214-4