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Bits of 50 Chinese cities are falling over thanks to subsidence

CityMetric, staffed as it is by young Londoners, frequently enjoys a good whine about the horrors of not owning your own home. (Regular readers have probably noticed this.) Once in a while, then, it’s good to be reminded that being the owner of large chunks of real estate isn’t always all it’s cracked up to be either.

Consider, for example, how the owners of this block in Guangxi province, southern China, must be feeling right about now. Last night three adjacent residential buildings in the town of Guilin unexpectedly decided to adopt this jaunty, but presumably entirely unwelcome, new style.

Closer inspection suggests that they’re now leaning at an angle of 10 degrees. We checked:

Nobody was hurt, although several nearby roads did rupture and are now closed for repair.

The cause of this unexpected reorientation was our old enemy subsidence, a catch-all term for any incident in which a chunk of land suddenly decides it’d be more comfortable several feet below its current position.

There are a number of things that can cause this phenomenon. Some are industrial processes (mining, oil extraction); others are natural ones, such as erosion. This graphic from Wikipedia helpfully explains a few of the most likely causes:

Subsidence explained, graphically. Image: MPetty1/Wikimedia Commons.

Chinese cities seem particularly prone to subsidence. In 2012, China Central Television reported that it was afflicting buildings in more than 50 cities. The main cause seems to be the over-extraction of ground water, which is causing the ground beneath the cities to dry out and then settle in new positions.

At any rate, a disproportionate number of the pictures that our photo archive, Getty, brings up when you search for “subsidence” happen to have been taken in China. There’s this road in Chenzhou, last month:

A 100m2 hole in the road in Chuzhou on 13 July. Image: China Foto Press/Getty.

Or this one in Zhengzhou last May:

And again. Image: China Foto Press/Getty.

Then there are pictures of this town in Jilin Province, which was evacuated in 2007, after coal mining caused large chunks of it to start caving in:

Former residents of the town of Jiaohe. Image: Getty. 

There are also quite a lot of pictures of Barbara Windsor:

Told you. Image: Getty.

But she was planting a “Barbara Windsor variety of rose” (no, really) to launch an appeal to raise £100,000 to repair subsidence in the gardens of St Paul’s church in London’s Covent Garden. So we’re assuming that’s unrelated.

If you’re worried about subsidence happening in your building, look out for cracks in walls and ceilings, especially those which are wider at the top than the bottom.

The good news is that, in most cases, it can be repaired.

The bad news is that we suspect those houses in Guilin probably aren’t “most cases”.
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