{"id":26820,"date":"2018-02-12T08:04:50","date_gmt":"2018-02-12T08:04:50","guid":{"rendered":"https:\/\/blogs.agu.org\/landslideblog\/?p=26820"},"modified":"2018-02-12T08:04:50","modified_gmt":"2018-02-12T08:04:50","slug":"juneau-1","status":"publish","type":"post","link":"https:\/\/blogs.agu.org\/landslideblog\/2018\/02\/12\/juneau-1\/","title":{"rendered":"Juneau: a very large rockslope failure in Alaska in December 2016"},"content":{"rendered":"

Juneau: a very large rockslope failure in Alaska in December 2016<\/h4>\n

KTOO<\/a> has a very interesting article about a large rockslope failure that occurred at Cowee Creek to the north of Juneau on 30th December 2016.\u00a0 This rockslope collapse has been investigated by Rick Edwards of the U.S. Forest Service\u2019s Pacific Northwest Research Station<\/a> after it was detected as a M=3.4 seismic event.\u00a0 It had a volume of about 540,000 m\u00b3 according to their analysis, so was a substantial event.\u00a0 The rockfall descended into a lake at the foot of the slope, displacing 460,000 m\u00b3 of water.\u00a0 This forced a 9 m high wave down the valley, cutting a 90 m wide swathe as it went.\u00a0 The wave was recorded to be almost 2 m high some 13 km downstream.\u00a0 The wave destroyed 1,500 trees.\u00a0 KTOO have this image of the site<\/a>, including the rockfall scar in the background and the path of the displacement wave in the foreground:-<\/p>\n

\"Juneau\"

The aftermath of the 30th December 2016 rockfall and displacement wave near to Juneau in Alaska. Image via KTOO<\/a>, courtesy of Rick Edwards\/United States Forest Service<\/p><\/div>\n

.<\/p>\n

This is a Planet Labs image<\/a> of the aftermath of the rockslope failure, collected on 9th August 2017.\u00a0 The slope that failed is difficult to see, but the path of the displacement wave is clear in the imagery:-<\/p>\n

\"Juneau\"

Planet Labs<\/a> image of the aftermath of the 30th December 2016 rockslope failure at Cowee Creek north of Juneau.<\/p><\/div>\n

.<\/p>\n

The timing of the slope collapse is quite interesting – this would have been the middle of winter, when the slopes were frozen.\u00a0 Analyses suggest that most of the very large rockslope failures in Alaska occur in the spring and early summer<\/a>. For comparison, this is a 5 m resolution RapidEye image of the same area, collected on 25th August 2015, before the rockslope collapse:<\/p>\n

\"Juneau\"

RapidEye image of the site of the December 2016 rockslope failure at Cowee Creek near to Juneau. Image dated 25th August 2015, obtained via Planet Labs<\/a>.<\/p><\/div>\n

.<\/p>\n

Reference<\/h4>\n

Planet Team (2017). Planet Application Program Interface: In Space for Life on Earth. San Francisco, CA.\u00a0https:\/\/api.planet.com<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

A large rockslope failure occurred at Cowee Creek near to Juneau in Alaska in December 2016, inducing a 9 m high, 90 m wide displacement wave that travelled at least 13 km down the valley<\/p>\n","protected":false},"author":22,"featured_media":26830,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7203],"tags":[340,469,725,1408,128,48,352],"class_list":["post-26820","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-planet-labs","tag-alaska","tag-featured","tag-north-america","tag-rockslope","tag-tsunami","tag-usa","tag-wave"],"_links":{"self":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/26820","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=26820"}],"version-history":[{"count":0,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/26820\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media\/26830"}],"wp:attachment":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media?parent=26820"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/categories?post=26820"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/tags?post=26820"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}