{"id":29471,"date":"2018-12-14T07:46:40","date_gmt":"2018-12-14T07:46:40","guid":{"rendered":"https:\/\/blogs.agu.org\/landslideblog\/?p=29471"},"modified":"2018-12-14T07:46:40","modified_gmt":"2018-12-14T07:46:40","slug":"nyixoi-chongco-rock-avalanche","status":"publish","type":"post","link":"https:\/\/blogs.agu.org\/landslideblog\/2018\/12\/14\/nyixoi-chongco-rock-avalanche\/","title":{"rendered":"The Nyixoi Chongco rock avalanche in Tibet"},"content":{"rendered":"

The Nyixoi Chongco rock avalanche in Tibet<\/h4>\n

In a new paper in the journal Landslides<\/em><\/a>,\u00a0Wang et al.<\/em> (2018)<\/a> describe the Nyixoi Chongco rock avalanche in Tibet.\u00a0 I have not seen this spectacular rock avalanche<\/a> in the literature before this paper; it is an excellent addition to the inventory of such events.\u00a0 The dry, low vegetation environment of the Tibetan Plateau has meant that the rock avalanche is beautifully preserved in the landscape.\u00a0 Whilst the paper itself is a little vague on the exact location, I have managed to track it down to 29.534, 90.263, a spot that has excellent Google Earth imagery:-<\/p>\n

\"Nyixoi

Google Earth imagery of the the Nyixoi Chongco rock avalanche in Tibet<\/p><\/div>\n

.<\/p>\n

According to Wang et al.<\/em> (2018)<\/a>, the Nyixoi Chongco rock avalanche involved a mass of 28 million cubic metres descending a vertical distance of 885 metres, and traveling a total of 4.6 km horizontally, representing exceptional mobility.\u00a0 The landslide deposit is about 50 metres thick.\u00a0 The authors do not give an estimated age for the rock avalanche, nor a definite trigger mechanism, but the proximity to active faults makes them suspect that an earthquake might have been involved.\u00a0 Wang et al.<\/em> (2018)<\/a> note that a nearby fault is thought to have generated a magnitude 7.0 earthquake about 2,200 years BP; this would have induced sufficiently intense shaking to have triggered a rock avalanche of this type.<\/p>\n

The Nyixoi Chongco rock avalanche can be better appreciated in this Google Earth oblique view:-<\/p>\n

\"Nyixoi

Google Earth perspective view of the Nyixoi Chongco rock avalanche in Tibet<\/p><\/div>\n

.<\/p>\n

I have placed the marker at the crown of the landslide scar, which has a scoop morphology.\u00a0 Below this is a very clear transportation zone, stripped by the passage of the landslide.\u00a0 The deposit starts from the foot of the slope and extends down the valley.\u00a0 Note the clear hummocks in the landslide mass, which are very common for large rock avalanches.\u00a0 Wang et al.<\/em> (2018)<\/a> note that the landslide has many of the common characteristics of large rock avalanche masses, including a very coarse (i.e. boulder-rich) carapace (the surface layer), and a highly fragmented main landslide mass.\u00a0 The base of the landslide mass shows almost no mixing with the valley deposits, and has sedimentary structures that suggest that these deposits were unsaturated when the landslide was deposited.\u00a0 The authors suggest that the movement of the landslide was not associated with any of the complex mechanisms sometimes postulated for these huge rock avalanches, in this case involving simple shear between the landslide mass and the valley floor.<\/p>\n

It is interesting to note that this means that the landslide could have high mobility without needing liquefaction or anything more exotic, a finding that is important in the context of understanding other large events.<\/p>\n

Reference<\/h4>\n

Wang, YF., Cheng, QG., Shi, AW. et al.<\/em> 2018. Sedimentary deformation structures in the Nyixoi Chongco rock avalanche: implications on rock avalanche transport mechanisms<\/a>.\u00a0 Landslides<\/em> https:\/\/doi.org\/10.1007\/s10346-018-1117-7<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

The Nyixoi Chongco rock avalanche; a spectacular, very large ancient landslide in a tectonically active area of the Tibetan Plateau<\/p>\n","protected":false},"author":22,"featured_media":29476,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[69],"tags":[881,469,192,17,306,113],"class_list":["post-29471","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-landslide-images","tag-east-asia","tag-featured","tag-paper","tag-research","tag-rock-avalanche","tag-tibet"],"_links":{"self":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/29471","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=29471"}],"version-history":[{"count":0,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/29471\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media\/29476"}],"wp:attachment":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media?parent=29471"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/categories?post=29471"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/tags?post=29471"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}