{"id":32071,"date":"2019-09-06T06:11:47","date_gmt":"2019-09-06T06:11:47","guid":{"rendered":"https:\/\/blogs.agu.org\/landslideblog\/?p=32071"},"modified":"2019-09-06T06:11:47","modified_gmt":"2019-09-06T06:11:47","slug":"velsemannen-1","status":"publish","type":"post","link":"https:\/\/blogs.agu.org\/landslideblog\/2019\/09\/06\/velsemannen-1\/","title":{"rendered":"Veslemannen in Norway – major movement, and possibly a significant failure, reported"},"content":{"rendered":"

Veslemannen in Norway – major movement, and possibly a significant failure, reported<\/h4>\n

Over the last few days, the Velsemannen rockslide in Norway<\/a> has undergone another major movement event.\u00a0 This large rock mass has undergone repeated movement events in recent years<\/a>, responding in particular to phases of wet weather when the ground is not frozen.\u00a0 There has been a substantial impact on the local community – the 11 residents in the valley below the Velsemannen rockslide have been evacuated on 16 separate occasions over the last five years as movement crises have developed.<\/p>\n

This time though the events are clearly different.\u00a0 Yesterday (Thursday 5th September) the landslide showed movement rates far higher than had been recorded previously, with the lower part of the rock mass reportedly moving 70 cm.<\/a>\u00a0 In comparison, the mass moved a total of 58 cm in the whole of 2018.\u00a0 Rockfalls were repeatedly observed on the unstable mass, a sign that it was undergoing internal deformation and fracturing:-<\/p>\n

\"Velsemannen\"

A rockfall from the Velsemannen rockslide on 5th September 2019. Image from vg.no<\/a><\/p><\/div>\n

Overnight Thursday and into early Friday a large failure appears to have occurred<\/a>.\u00a0 News reports suggest that this might be in the order of 100,000 cubic metres, although more analysis is clearly needed to validate these numbers, and that the initial visual inspection indicates that a major part of the unstable mass has now failed and collapsed. Pleasingly, the properties at the foot of the slope do not seem to have been impacted so far.<\/p>\n

Forecasting the behaviour of Velsemannen has been extremely challenging as the rockslide has gone through repeated movement crises, without accelerating to final failure.\u00a0 A collapse event was inevitable, such that evacuations were essential, but the behaviour has been extremely unpredictable.\u00a0 The best case scenario appeared to be a collapse event in a series of smaller failures, preventing the long runout that would have destroyed the properties.\u00a0 So far, his appears to have been the outcome.<\/p>\n

Work will now be needed to monitor the remaining unstable rock mass, and to determine its susceptibility to a collapse.\u00a0 We have seen elsewhere that an initial event can sometimes trigger a further large failure<\/a>.\u00a0 But for the people living below Velsemannen, and for the geologists, this must be a major step towards resolving the problems.<\/p>\n","protected":false},"excerpt":{"rendered":"

After a phase of accelerated movement in the last few days, the large Velsemannen rockslide in Norway underwent a significant failure overnight <\/p>\n","protected":false},"author":22,"featured_media":32073,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[144,469,39,278,136],"class_list":["post-32071","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-landslide-report","tag-europe","tag-featured","tag-monitoring","tag-norway","tag-rockslide"],"_links":{"self":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/32071","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=32071"}],"version-history":[{"count":0,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/32071\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media\/32073"}],"wp:attachment":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media?parent=32071"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/categories?post=32071"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/tags?post=32071"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}