Friday, 26 July 2013

At least nine dead following landslide in Gansu Province, northwest China.

At least nine people are known to have died, and another four are missing, after a landslide in Nanyu Village in the Qinzhou District of Gansu Province, in northwest China, that took place at about 9.30 local time (1.30 am GMT) on Thursday 25 July 2013, following heavy rains and flooding. Another four people are still missing following a second landslide in the nearby Yongguang Village. This is the same area that was hit be a series of Earthquakes on Sunday 21 July, causing widespread damage to infrastructure and killing at least 95 people.

The approximate location of the 25 July 2013 Nanyu landslide. Google Maps.

The area of southern Gansu where this occurred has a landscape largely made up of loess hills; which is to say loosely consolidated (but very fertile) fine soils comprised of material blown in from the Gobi Desert, a formerly fertile area that had its rainfall cut off by the impact of India into southern Asia and subsequent rise of the Himalayas. The area is cut through by the Yellow River (Huang He), which is fed by glaciers in the Himalayas, but is highly prone to flash flooding and landslides during the seasonal monsoon (another effect of the Himalayas). Landslides are a common problem after severe weather events, as excess pore water pressure can overcome cohesion in soil and sediments, allowing them to flow like liquids. The combination of fertile soil, frequent flooding and unstable hillsides has led to the Yellow River also being known as the China's Sorrow and Scourge of the Sons of Han, as historically the area has always had a high population, vulnerable to such events.

A landslide cutting through terraced fields in Minxian County, Gansu, following the Earthquakes of 21 July 2013. Reuters.


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