The 23 July 2019 Shuicheng County landslide: a first scientific report

On 23 July 2019 a large landslide occurred at Pingdi village in Shuicheng County, in Guizhou Province, China. The landslide, which occurred after a spell of heavy rain, killed an estimated 42 people after it destroyed 20 houses.  Eleven people were rescued.  I blogged about this landslide at the time, but now a first scientific account of this landslide (Li et al. 2020) has been published in the journal Landslides.

This was a large slide – Li et al. (2020) estimate that it had a total length of about 1,300 m, a vertical extent of about 120 m, a surface area of about 370,000 m² and a volume of about 2 million m³.  The authors have generated this annotated orthophoto of the landslide site, which clearly shows the source area of the slip, the transportation and entrainment zone and the landslide deposit:-

An annotated orthophoto of the 23 July 2019 Shiucheng County landslide in China. Image from Li et al. (2020).

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Interestingly, Li et al. (2020) describe this as being a rotational landslide, with an initial thickness of about 20 m.  This would not have been obvious to me.  The authors note that a road passed through the source area, but they do not comment as to whether this might have been a factor in the failure. In the seven days prior to the failure the area experienced three heavy spells of rainfall, totaling about 154 mm.  Whilst this is undoubtedly intense, it seems unlikely that this was particularly exceptional.

Finally, Li et al. (2020) note that this slope continues to represent a hazard:

“The field investigation suggests that this slope may fail again in the future under rainfall/earthquake events. Hence, to avoid any secondary disaster and protect people’s lives and properties, it is crucial to strengthen the monitoring and early warning systems of landslide by the local government.”

A key question remains though.  That is, could it have been anticipated in advance that this slope, rather than any other in the area, was close to failure.  And if so, how?

Reference

Li, H., Xu, Y., Zhou, J. et al. 2020.  Preliminary analyses of a catastrophic landslide occurred on July 23, 2019, in Guizhou Province, China. Landslides. https://doi.org/10.1007/s10346-019-01334-0