{"id":16050,"date":"2015-09-09T05:30:15","date_gmt":"2015-09-09T05:30:15","guid":{"rendered":"http:\/\/blogs.agu.org\/landslideblog\/?p=16050"},"modified":"2015-09-09T02:42:54","modified_gmt":"2015-09-09T02:42:54","slug":"west-salt-creek-landslide-colorado-geological-survey-report","status":"publish","type":"post","link":"https:\/\/blogs.agu.org\/landslideblog\/2015\/09\/09\/west-salt-creek-landslide-colorado-geological-survey-report\/","title":{"rendered":"West Salt Creek Landslide: Colorado Geological Survey report"},"content":{"rendered":"
West Salt Creek Landslide report<\/h5>\n

The Colorado Geological Survey has produced a report<\/a> on the catastrophic West Salt Creek landslide<\/a>, which killed three men on 25th May 2014.\u00a0 The report (White et al. <\/em>2015<\/a>), which is available for download from the Colorado Geological Survey website, is an excellent piece of work.\u00a0 It provides a high level of insight into the conditions that led to the landslide, its behaviour during movement (which was very complex) and the long term hazards that the site now presents.\u00a0 It also provides some beautiful and enlightening images of the landslide, such as this one:<\/p>\n

\"West<\/a>

West Salt Creek landslide from White et al.<\/em> (2015)<\/a><\/p><\/div>\n

.<\/p>\n

There is so much in this report that I cannot do it justice here.\u00a0 I particularly like the forensic approach that has been taken to understanding the morphology and to draw inferences into the mechanisms of motion.<\/p>\n

The landslide was initiated by a rotational failure in a large block, as seen in this image from the report:<\/p>\n

\"West<\/a>

West Salt Creek landslide from White et al.<\/em> (2015)<\/a><\/p><\/div>\n

.<\/p>\n

The white dashed line in the image above shows the location of a prehistoric landslide identified in the imagery.\u00a0 A small part of the rotational block detached and fragmented, turning into a high energy debris\/rock avalanche event.\u00a0 The yellow dashed lines show the points of detachment.\u00a0 This high energy flow is interesting and intriguing, extending the landslide to a total crown to toe distance of about 4.5 km.\u00a0 The maximum velocity of this component of the landslide is estimated to have been between 18 m\/sec and a peak at about 40 m\/sec.\u00a0 This is perhaps surprisingly high, but the methods used are credible.\u00a0 The outcome is that the landslide showed a high level of mobility in terms of runout distance given its volume and elevation change, as shown in this plot:-<\/p>\n

\"West<\/a>

West Salt Creek landslide mobility from White et al.<\/em> (2015)<\/a><\/p><\/div>\n

.<\/p>\n

But perhaps the most surprising aspect of this behaviour is that the landslide appears to have been a comparatively dry flow event. White et al. (2015) note that:<\/p>\n

Overall the rock avalanche was a markedly dry deposit; during the field investigation, no water or mud was seen seeping or fanning out from the steeply sided edge of the avalanche toe.<\/p><\/blockquote>\n

 <\/p>\n

White et al. <\/em>(2015)<\/a> identify three phases of movement of the West\u00a0 Salt Creek landslide, creating a very complex and in some ways very beautiful deposit, as this image shows:<\/p>\n

\"West<\/a>

West Salt Creek landslide deposit, from White et al. <\/em>(2015)<\/a><\/p><\/div>\n

.<\/p>\n

Note the evidence for the late stage surge movement of the landslide on the left (as shown above) side of the deposit.\u00a0 The red dot is on the margin of this flow.\u00a0 So, White et al. <\/em>(2015)<\/a>) conclude that after the initial rotational failure, the West Salt Creek consisted of a series of dry rock avalanche surges that achieved high velocity and a long runout.\u00a0 This will have implications for landslide hazard management in this landscape.<\/p>\n

Reference<\/h5>\n

White, J.L., Morgan, M.L. and\u00a0 Berry, K.A. 2015. The West Salt Creek Landslide: A Catastrophic Rockslide and Rock\/Debris Avalanche in Mesa County.<\/a> Colorado Colorado Geological Survey, 45 pp.<\/p>\n

 <\/p>\n

 <\/p>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

The Colorado Geological Survey has produced a detailed report on the 2014 West Salt Creek landslide, which killed three men. Surprisingly, this was a high mobility rock avalanche that initiated as a rotational landslide.<\/p>\n","protected":false},"author":22,"featured_media":16054,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[469,155,959,952,306,151,369],"class_list":["post-16050","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-landslide-report","tag-featured","tag-investigation","tag-landslide-report","tag-mobility","tag-rock-avalanche","tag-rotational-landslide","tag-runout"],"_links":{"self":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/16050","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=16050"}],"version-history":[{"count":0,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/16050\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media\/16054"}],"wp:attachment":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media?parent=16050"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/categories?post=16050"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/tags?post=16050"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}