{"id":15429,"date":"2015-07-06T07:04:15","date_gmt":"2015-07-06T07:04:15","guid":{"rendered":"http:\/\/blogs.agu.org\/landslideblog\/?p=15429"},"modified":"2015-07-06T07:04:15","modified_gmt":"2015-07-06T07:04:15","slug":"lac-du-chambon-landslide-2","status":"publish","type":"post","link":"https:\/\/blogs.agu.org\/landslideblog\/2015\/07\/06\/lac-du-chambon-landslide-2\/","title":{"rendered":"Lac du Chambon landslide: accelerated movement may indicate approaching failure?"},"content":{"rendered":"
Lac du Chambon landslide<\/h5>\n

Yesterday, French newspapers reported significantly increased rates of movement<\/a> of the Lac du Chambon landslide<\/a> in Isere, France.\u00a0 This is the landslide that has caused a diversion of one of the key mountain sections of the 2015 Tour de France race<\/a>.\u00a0 For example, Europe 1<\/a> (in French) reported that movement of the Lac du Chambon landslide had increased to 2 metres per day.\u00a0 On Saturday the landslide early warning sirens were set off to warn of imminent collapse, but as of the time of the articles this had not occurred.\u00a0 However, several thousand tonnes of rock have been released from the slope, which may well indicate precursory activity as the mass actively deforms.<\/p>\n

Various news outlets have images of the landslide, which has deformed greatly since I write about it last. However, the best source of information is the SAGE Ingeniere twitter feed<\/a>: @SAGE_INGE (in French), from which the images below are taken<\/p>\n

This first image shows the whole deforming mass of the Lac du Chambon landslide:<\/p>\n

\"Lac<\/a>

Via Twitter<\/a><\/p><\/div>\n

.<\/p>\n

Note the large rear tension crack and the extensive rockfall activity on the lateral shear.\u00a0 Meanwhile, this higher resolution image shows the deforming landslide body in more detail:<\/p>\n

\"Lac<\/a>

Via Twitter<\/a><\/p><\/div>\n

.<\/p>\n

The tension cracks running almost directly downslope are interesting – these appear to be controlled by the rock mass structure, and probably indicate very high levels of internal deformation and shearing.<\/p>\n

Last night @SAGE_INGE tweeted:<\/p>\n

Cf mod\u00e8le \u00e9tabli, le ph\u00e9nom\u00e8ne de rupture amorc\u00e9 hier soir s’est prolong\u00e9 avec une fracturation importante du massif en mouvement<\/p><\/blockquote>\n

Which translated indicates that the models have established that the phenomenon of rupture began the previous evening and that significant fracturing was occurring.\u00a0 This should indicate that failure could occur reasonably soon, although predicting the time of collapse in such a complex rock mass is far from trivial.<\/p>\n","protected":false},"excerpt":{"rendered":"

In the last few hours the Lac du Chambon landslide has shown substantially increased rates of movement, possibly indicating that collapse in near <\/p>\n","protected":false},"author":22,"featured_media":15432,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[144,469,274,959,136],"class_list":["post-15429","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-landslide-report","tag-europe","tag-featured","tag-france","tag-landslide-report","tag-rockslide"],"_links":{"self":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/15429","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=15429"}],"version-history":[{"count":0,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/15429\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media\/15432"}],"wp:attachment":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media?parent=15429"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/categories?post=15429"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/tags?post=15429"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}