{"id":31186,"date":"2019-06-12T06:21:42","date_gmt":"2019-06-12T06:21:42","guid":{"rendered":"https:\/\/blogs.agu.org\/landslideblog\/?p=31186"},"modified":"2019-06-12T06:22:04","modified_gmt":"2019-06-12T06:22:04","slug":"nayong-rock-avalanche","status":"publish","type":"post","link":"https:\/\/blogs.agu.org\/landslideblog\/2019\/06\/12\/nayong-rock-avalanche\/","title":{"rendered":"The 2017 Nayong rock avalanche: an analysis using drone and seismic data"},"content":{"rendered":"

The 2017 Nayong rock avalanche: an analysis using drone and seismic data<\/h4>\n

On 28 August 2017 a catastrophic landslide (now known as the Nayong rock avalanche) occurred in Guizhou Province, China, causing multiple fatalities<\/a>.\u00a0 I covered this event at the time, noting that remarkable footage had been collected of the event both from the ground<\/a> and, astonishingly, from a drone<\/a>.\u00a0 This rock avalanche has been analysed in detail in a new paper (Zhu et al.<\/em> 2019<\/a>) published in the journal Engineering Geology<\/a>.<\/em>\u00a0 Interestingly, the authors have combined the seismic data with the drone video to understand the dynamics of the failure.\u00a0 I believe that this is the first time an analysis like this has been undertaken.<\/p>\n

This is an image from Zhu et al.<\/em> (2019)<\/a>\u00a0 showing the aftermath of the Nayong rock avalanche:-<\/p>\n

\"The

The aftermath of the Nayong rock avalanche. Image from Zhu et al.<\/em> (2019)<\/a>.<\/p><\/div>\n

.<\/p>\n

The image shows that this was a catastrophic collapse of a limestone rock slope. The landslide occurred as five discreet events recorded by the drone, with the fifth being the largest. According to Zhu et al.<\/em> (2019)<\/a>, this had a volume of about 490,000 m\u00b3, which then entrained a further 310,000 m\u00b3 from the slope.\u00a0 The rock avalanche descended a total vertical distance of 280 m, and travelled for a total distance of 820 m.\u00a0 It killed 35 people.<\/p>\n

I think the most interesting aspect of this paper is seen in the seismic signal, and corroborated by the drone footage:-<\/p>\n

\"Seismic

The seismic signal generated by the Nayong rock avalanche in China in 2017. Diagram from Zhu et al.<\/em> (2019)<\/a>.<\/p><\/div>\n

.<\/p>\n

The seismic signal shows the first detected collapse event occurring shortly before 10:18, before the first major event, seen in the drone footage, just after 10:20. The seismic signal shows that the landslide was generating a series of small seismic signals, which are presumably indications of fracture and collapse occurring within the landslide mass as it began to fail.\u00a0 We have seen this pattern previously<\/a>, and once again emphasises that rock slope failure is a time dependent process in which the final collapse is simply the final manifestation of long-term deformation and rock fracture.\u00a0 It is this phenomenon that allows the forecasting of some rock collapse events, if suitable instrumentation is deployed.<\/p>\n

Reference<\/h4>\n

Zhu, Y., Xu, S., Zhuang, Y., Dai, X and Xing, A. 2019. Analysis of characteristics and runout behaviour of the disastrous 28 August 2017 rock avalanche in Nayong, Guizhou, China<\/a>. Engineering Geology. Doi: https:\/\/doi.org\/10.1016\/j.enggeo.2019.105154<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

An analysis by Zhu et al (2019) of the dynamics of the 2017 Nayong rock avalanche in China, using a combination of seismic data and drone imagery<\/p>\n","protected":false},"author":22,"featured_media":31187,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[544],"tags":[16,2349,881,469,192,17,306,588],"class_list":["post-31186","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-review-of-a-paper","tag-china","tag-drone","tag-east-asia","tag-featured","tag-paper","tag-research","tag-rock-avalanche","tag-seismic"],"_links":{"self":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/31186","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=31186"}],"version-history":[{"count":0,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/31186\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media\/31187"}],"wp:attachment":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media?parent=31186"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/categories?post=31186"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/tags?post=31186"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}