{"id":34777,"date":"2020-08-03T06:43:36","date_gmt":"2020-08-03T06:43:36","guid":{"rendered":"https:\/\/blogs.agu.org\/landslideblog\/?p=34777"},"modified":"2020-08-03T16:13:50","modified_gmt":"2020-08-03T16:13:50","slug":"yigongxiang-1","status":"publish","type":"post","link":"https:\/\/blogs.agu.org\/landslideblog\/2020\/08\/03\/yigongxiang-1\/","title":{"rendered":"Yigongxiang: a valley blocking debris flow in Tibet"},"content":{"rendered":"

Yigongxiang: a valley blocking debris flow in Tibet<\/h4>\n

On 2 August 2020 a Twitter user named Swapna (@swapna_apsrsac<\/a>), a specialist in remote sensing, tweeted news of a valley-blocking debris flow high in the mountains<\/a> of Tibet<\/a>.  The location is extremely remote, located upstream of Yigongxiang in Nyingchi, Tibet.  This event is reported in the Arunachal Times in some detail<\/a>.  This reports that the landslide was spotted from satellite imagery – if so that was a very shrewd piece of detective work.  The article is by Chintan Sheth (@blueczkfox<\/a>), who suggests that it might have been triggered by recent seismic activity in this area.<\/span><\/p>\n

This part of Tibet is very difficult to image in August due to extensive cloud cover.  It is located at 30.428, 94.547 if you wish to see the location – this is close to the termination of a glacier in rugged mountain terrain.  The only optical satellite to have captured it as far as I am aware is an ESA Sentinel 2 image from 27 July 2020:-<\/p>\n

\"Yigongxiang

ESA Sentinel 2 image of the Yigongxiang landslide in Tibet. Image captured on 27 July 2020, copyright ESA, image via Sentinel Hub.<\/p><\/div>\n

.<\/p>\n

The debris flow appears to have come from the western side of the valley.  It is large – the barrier appears to be about 500 m wide, and probably over a kilometre long.  A lake has developed upstream (to the north).  This appears to have been about 1.5 km long on 27 July.<\/p>\n

The images are partially obscured by cloud.  A better understanding can be gained from a false colour image, in which vegetation shows as red, bare rock as a light brown and water as cyan.  Cloud is still white:-<\/p>\n

\"Yigongxiang

ESA Sentinel 2 False colour image of the Yigongxiang landslide in Tibet. Image captured on 27 July 2020, copyright ESA, image via Sentinel Hub.<\/p><\/div>\n

.<\/p>\n

For reference, this is the site on 2 July 2020:-<\/p>\n

\"Yigongxiang

ESA Sentinel 2 image of the site of the Yigongxiang landslide in Tibet. Image captured on 2 July 2020, copyright ESA, image via Sentinel Hub.<\/p><\/div>\n

.<\/p>\n

There is a risk here of a breach of the landslide dam and a subsequent flood downstream.  It is not possible to estimate the magnitude of the risk at this site, but further investigation and monitoring is needed urgently.<\/p>\n

.<\/p>\n

Quickslide 1: Deadly landslides in South Korea<\/h4>\n

South Korea is suffering a spell of heavy rainfall that has triggered extensive flooding and landslides<\/a>.  The spell of poor weather is expected to extend into Tuesday.<\/p>\n

.<\/p>\n

Quickslide 2: Continued landslide losses in Nepal<\/h4>\n

The toll from fatal monsoon-induced landslides in Nepal continues to rise in a manner that is alarming. In the most recent incident, eight people appear to have been killed in a landslide at Melamchi in Sindhupalchok<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"

In the high, remote mountains of Tibet a debris flow, possibly induced by recent seismic activity, has created a valley-blocking landslide dam <\/p>\n","protected":false},"author":22,"featured_media":34784,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[23,469,521,20063,72,113,688],"class_list":["post-34777","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-landslide-report","tag-earthquake","tag-featured","tag-satellite-image","tag-sentinel","tag-south-asia","tag-tibet","tag-valley-blocking-landslide"],"_links":{"self":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/34777","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=34777"}],"version-history":[{"count":0,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/34777\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media\/34784"}],"wp:attachment":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media?parent=34777"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/categories?post=34777"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/tags?post=34777"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}