{"id":17233,"date":"2015-12-22T08:41:58","date_gmt":"2015-12-22T08:41:58","guid":{"rendered":"http:\/\/blogs.agu.org\/landslideblog\/?p=17233"},"modified":"2015-12-22T08:41:58","modified_gmt":"2015-12-22T08:41:58","slug":"the-shenzhen-guangdong-landslide-a-massive-flowslide-in-construction-waste","status":"publish","type":"post","link":"https:\/\/blogs.agu.org\/landslideblog\/2015\/12\/22\/the-shenzhen-guangdong-landslide-a-massive-flowslide-in-construction-waste\/","title":{"rendered":"The Shenzhen, Guangdong landslide: a massive flowslide in construction waste"},"content":{"rendered":"
The Shenzhen, Guangdong landslide: a massive flowslide in construction waste<\/h5>\n

The well-reported, enormous landslide in Shenzhen earlier this week was a most interesting, and of course deeply tragic, event.\u00a0 It is now clear that the Guangdong landslide was a very large flowslide<\/a> from a pile of construction waste in a quarry above the industrial estate.\u00a0 Some reports suggest that there was heavy rainfall at the time.\u00a0 The Chinese news agency Xinhua has the best images of the landslide that I have seen to date<\/a>, including this one showing the landslide mass and a part of the source in the background:-<\/p>\n

\"Guangdong<\/a>

The Shenzhen, Guangdong landslide in China. Image from Xinhua<\/a>,<\/p><\/div>\n

.<\/p>\n

As of this morning the number of people reported missing<\/a> in the landslide is 85, with just one body recovered<\/a>.\u00a0 There can be little hope of any survivors now.\u00a0 Xinhua report<\/a>s that the landslide has covered an area of 380,000 square metres to a depth of 10 metres, giving a volume of 3.8 million cubic metres.\u00a0 This is an unusually large man-made slide.\u00a0 In essence the event appears to be almost identical in mechanism and outcome to a mine waste flowslide, of which China has had many of course.\u00a0 The best recent example is probably the Hpakant flowslide in Burma<\/a> a couple of weeks ago, which also had a tragic outcome.<\/p>\n

Of course in addition to the rescue operations, the focus is on how this can have happened.\u00a0 The International Business Times has a nice article<\/a> that outlines the situation as of yesterday:<\/p>\n

Residents told Xinhua the Hongao Construction Waste Dump had built up for nearly two years\u00a0and\u00a0stood at\u00a0nearly 20 stories high when it collapsed. It also had overly steep slopes, making it unstable, the Ministry of Land and Natural Resources said.\u00a0 Documents published on the Guangming New District website showed officials had conducted monthly inspections of the dump, the South China Morning Post reported. In February 2014, officials gave the dump approval to operate for just 12 more months, but found in July \u2014\u00a0five months after it should have closed \u2014\u00a0that it\u00a0was still in operation. At that time, the site was not following agreed safety or maintenance plans.\u00a0 Officials told the dump managers to improve its conditions and reapply for a license by September, which it also failed to do, according to the documents. \u201cIllegal dumping of earth is strictly forbidden,\u201d a statement in the documents said, according to the South China Morning Post.<\/p><\/blockquote>\n

The location of the landslide is 22.718, 113.933.\u00a0 There is excellent Google Earth imagery of the site.\u00a0 The most recent image of the quarry, taken\u00a0 on 29th September 2015, shows a large amount of dumped construction waste in the pit, retained by very steep, benched slopes:<\/p>\n

\"Guangdong<\/a>

The Shenzhen, Guangdong landslide in China on 29 September 2015. Image via Google Earth.<\/p><\/div>\n

.<\/p>\n

This was quite literally a disaster waiting to happen, and there can be no excuse for this.\u00a0 Zooming back a year, this was the site on 23rd November 2014:<\/p>\n

\"Guangdong<\/a>

The Shenzhen, Guangdong landslide in China on 23 November 2015. Image via Google Earth.<\/p><\/div>\n

.<\/p>\n

Note the extensive work going on around the lower slopes.\u00a0 There are large numbers of dumper trucks hauling waste in this area. But a year earlier the site looks quite different.\u00a0 On 25th November 2013 the site was an abandoned, flooded quarry with no haul roads and no waste:-<\/p>\n

\"The<\/a>

The Shenzhen, Guangdong landslide in China on 25 November 2013. Image via Google Earth.<\/p><\/div>\n

.<\/p>\n

It is notable that there is very little drainage evident in the debris pile in the most recent images.\u00a0 I suspect that a key part of the investigation may well be to ascertain what measures were in place to prevent the build up of excess pore water pressures in the spoil.\u00a0 The presence of water in the quarry before the dumping began suggests that the natural drainage through the bedrock was probably limited.<\/p>\n

I would also draw your attention to one aspect of the most recent image that is not obvious at first inspection.\u00a0 The image is a composite, with the join running through the quarry.\u00a0 The more recent image is the lower portion – note the change in colour balance.\u00a0 I have drawn a line below to show the approximate location of the joint between the two images:<\/p>\n

\"Guangdong<\/a>

The most recent Google Earth image of the Guangdong landslide. The lower portion of this image is more recent, the line marks the point at which the two images are stitched<\/p><\/div>\n

.<\/p>\n

The lower (newer) portion of the image suggests that there was a new phase of dumping occurring on the waste at the very top of the slope, in effect to infill the remainder of the quarry.\u00a0 This will have steepened the waste pile dramatically, and may be the reason why the failure occurred now, rather than in the wet season.<\/p>\n

I will post again tomorrow with a compilation of the amazing videos of the landslide event.<\/p>\n","protected":false},"excerpt":{"rendered":"

It is now clear that the Guangdong landslide was a flowslide from a huge pile of construction waste in a quarry about the industrial park.<\/p>\n","protected":false},"author":22,"featured_media":17234,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[16,1039,881,469,14,825],"class_list":["post-17233","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-landslide-report","tag-china","tag-construction-waste","tag-east-asia","tag-featured","tag-flowslide","tag-landslide-treport"],"_links":{"self":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/17233","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/users\/22"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/comments?post=17233"}],"version-history":[{"count":0,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/17233\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media\/17234"}],"wp:attachment":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media?parent=17233"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/categories?post=17233"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/tags?post=17233"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}