{"id":16211,"date":"2015-09-22T06:05:08","date_gmt":"2015-09-22T06:05:08","guid":{"rendered":"http:\/\/blogs.agu.org\/landslideblog\/?p=16211"},"modified":"2015-09-23T04:54:17","modified_gmt":"2015-09-23T04:54:17","slug":"touzhai-rock-avalanche-1","status":"publish","type":"post","link":"https:\/\/blogs.agu.org\/landslideblog\/2015\/09\/22\/touzhai-rock-avalanche-1\/","title":{"rendered":"The 1991 Touzhai rock avalanche in China"},"content":{"rendered":"
The Touzhai rock avalanche<\/h5>\n

On 23rd September 1991, at 18:10 local time, the catastrophic Touzhai rock avalanche occurred\u00a0 Zhaotong, Yunnan Province in SW China. This was a large event – the estimated volume of the Touzhai rock avalanche is 15 million cubic metres, and the landslide had a runout distance of over 3.5 km.\u00a0 After descending a vertical distance of about 950 m the landslide destroyed 202 houses in the village of Touzhai, killing 216 people.\u00a0 In a paper in the journal Landslides<\/a>, Xing et al.<\/em> (2015)<\/a> (and with a stellar list of authors) have provided a detailed description of this landslide, and have modeled its movement using DAN-W software..<\/p>\n

The landslide occurred after a prolonged period of heavy rainfall.\u00a0 Failure occurred on a steep slope in basalt over an area that was 900 m long (in terms of the slide direction) and up to 700 m, with a thickness of between 5 and 120 m. This is the headscarp are as shown in the paper:-<\/p>\n

 <\/p>\n

\"The<\/a>

The headscarp of the Touzhai rock avalanche, from Xing et al.<\/em> 2015<\/a><\/p><\/div>\n

.<\/p>\n

The structural control of pre-existing joints is quite clear.\u00a0 This looks to be a rather complex wedge type failure.\u00a0 This mass fragmented and transitioned into a rapid flow that travelled down the valley to hit the village below.\u00a0 The modelling of the landslide suggests that it had a peak velocity of just under 50 m\/sec and an average velocity of 21 m\/sec, giving a duration of the Touzhai rock avalanche of 175 seconds from the initial rupture event.\u00a0 This is the image of the landslide itself from the paper:<\/p>\n

\"Touzhai<\/a>

The headscarp of the Touzhai rock avalanche, from Xing et al.<\/em> 2015<\/a><\/p><\/div>\n

.<\/p>\n

This landslide highlights one of the major issues managing the hazard associated with rock avalanches.\u00a0 The flow initiated in hard rock, but not on a near vertical cliff, over 3 km from the village.\u00a0 Identifying those areas that might be susceptible to such a failure is really difficult, and forecasting the likely runout speed and distance of the flow is also an enormous challenge.\u00a0 We still have a lot of work to do in this area, but detailed studies such as this are a great help.<\/p>\n

Reference<\/h5>\n

Xing, A, Wang, G., Yin, Y. Tang, C., Xu, Z., and Li, W. 2015. Investigation and dynamic analysis of a catastrophic rock avalanche on September 23, 1991, Zhaotong, China.<\/a> Landslides<\/em>, 13 pages. Published online 11th August 2015.<\/p>\n","protected":false},"excerpt":{"rendered":"

In September 1991 the Touzhai rock avalanche in China killed over 200 people. In a paper just published, Xing et al. (2015) provide a detailed description and the outcomes of modeling of the runout of the landslide<\/p>\n","protected":false},"author":22,"featured_media":16214,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_members_access_role":[],"_members_access_error":""},"categories":[3,544],"tags":[16,469,959,192,306],"class_list":["post-16211","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-landslide-report","category-review-of-a-paper","tag-china","tag-featured","tag-landslide-report","tag-paper","tag-rock-avalanche"],"_links":{"self":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/16211","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=16211"}],"version-history":[{"count":0,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/16211\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media\/16214"}],"wp:attachment":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media?parent=16211"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/categories?post=16211"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/tags?post=16211"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}