6 July 2011

Serious landslide impacts in China

Posted by Dave Petley

The Summer monsoon is now well and truly underway in China, with heavy rainfall  resulting in severe landslide and flood impacts.  Xinhua reports that on Tuesday heavy rainfall triggered a landslide at Lueyang County in Shaanxi Province, killing 18 people and injuring a further two.  The image below shows the slope that failed – it is a rather notably steep feature.  The landslide, which reportedly had a volume of 5000 cubic metres, buried 12 houses:

This event comes on the back of major landslides in the Yingxiu area of Sichuan Province that I mentioned yesterday, and another landslide on Sunday at a chemical works in Maoxian County of Sichuan Province that killed eight people in a dormitory building.

A year ago, landslides into the rivers in Yingxiu led to a diversion of the flow into newly constructed areas of the town:

Interestingly, an article on the Xinhua news site today indicates that the rivers have once again been severely hit by landslides: “Mudslides into the Yuzixi River, which flows through Yingxiu, raised the riverbed by between 3 and 5 meters and continuing rain has brought down more and more slides of mud and rock.  So far, no casualties have been reported. However, locals are worried that the river will become blocked and flood the town, according to Wenchuan county’s meteorological bureau.  Downstream, 30 meters of riverbank has been washed away. A team of more than 300 people arrived on Monday with at least 60 pieces of heavy equipment and began to remove debris from the river and repair broken riverbanks with huge rocks wrapped in steel nets. They said on Tuesday the reconstruction of the riverbanks was almost complete.”

All of which is apparently causing a growing realisation of the likely longterm impacts of landslides in the earthquake affected areas.  The same Xinhua news item has the following “Wang Lei, manager of Yingxiu-Wenchuan Highway Administration Company, said the 8.0-magnitude earthquake in 2008 was likely responsible for the recent mudslides. “The earthquake in 2008 destroyed the integrity of the surface, making it much easier for the rain to flush away earth and rocks,” Wang said.  His view was repeated by Ma Dongtao, an expert on earthquake aftermath prevention at the Chinese Academy of Sciences.  Ma predicted that the mudslides and landslides in Wenchuan are just the beginning of a phase that could last for 100 years.  “Landslide prevention work will be the most important issue in dealing with the aftermath,” the Shanghai Morning Post quoted Ma as saying.”