{"id":37176,"date":"2021-03-29T07:55:34","date_gmt":"2021-03-29T07:55:34","guid":{"rendered":"https:\/\/blogs.agu.org\/landslideblog\/?p=37176"},"modified":"2021-03-29T13:02:05","modified_gmt":"2021-03-29T13:02:05","slug":"yarlung-tsangpo","status":"publish","type":"post","link":"https:\/\/blogs.agu.org\/landslideblog\/2021\/03\/29\/yarlung-tsangpo\/","title":{"rendered":"Yarlung Tsangpo: another giant, high mountain landslide on 22 March 2021"},"content":{"rendered":"

Yarlung Tsangpo: another giant, high mountain landslide on 22 March 2021<\/h4>\n

On Friday evening, as I was queueing to receive the first dose of the Oxford \/ Astra Zeneca vaccine for Covid-19 (a wonderful day), I received an email from G\u00f6ran Ekstrom of Columbia Universit<\/a>y making a small group of us aware that he had detected, using seismic instruments, a probable large-scale landslide in the vicinity of the Yarlung Tsangpo in Tibet.\u00a0 As always, the seismic data gives an indication of location, but not a precise grid reference, and an idea of the mass (in this case about 100 million tonnes – a very large one indeed).<\/p>\n

Fastest out of the blocks was Marten Geertsema<\/a>, who used partially cloudy Planet Labs satellite imagery<\/a> to identify a possible site.\u00a0 Yesterday, Planet Labs data<\/a> with low levels of cloud became available.\u00a0 Dan Shugar from the University of Calgary<\/a> was able to identify that the location was correct, and that a large landslide had occurred<\/a>:-<\/p>\n

https:\/\/twitter.com\/WaterSHEDLab\/status\/1376247670419808259<\/p>\n

.<\/p>\n

This is the Planet Labs<\/a> image of the site, captured yesterday:<\/p>\n

\"Planet

Planet Labs<\/a> image of the 22 March 2020 landslide at Tsangpo in Tibet. Image cop right of Planet Labs<\/a>, used with permission.<\/p><\/div>\n

.<\/p>\n

The coordinates of the site, 29.815, 94.932 are the centre of the landslide source.\u00a0 Note the scale in the bottom right corner.<\/p>\n

Dan and I slightly disagree with how this (and Chamoli<\/a>) should be described (which is fine of course).\u00a0 Dan describes this event as the collapse of hanging glaciers, whereas I consider it to be a rockslide that has taken some ice with it.\u00a0 Researchers love semantics!\u00a0 Either way, at Yarlung Tsangpo it is clear that a large amount of rock and ice have detached from the east side of the tributary valley, moving westwards and then to the south.\u00a0 Once again this has formed a catastrophic channelised flow that has travelled down the channel to deposit a large volume in the main channel.\u00a0 This was probably blocked briefly, but as the image above shows water is now flowing freely.<\/p>\n

Note the huge increase in turbidity of the water downstream of the blockage on the Yarlung Tsangpo.<\/p>\n

Stuart Dunning of Newcastle University<\/a> tweeted a very interesting aspect of this site yesterday<\/a> in response to a tweet from Dan:-<\/p>\n

\n

@davepetley<\/a> active place this! pic.twitter.com\/wdkPkZh1LM<\/a><\/p>\n

— Stuart Dunning (@Rock_Avalanches) March 28, 2021<\/a><\/p><\/blockquote>\n