Aaron et al.<\/em> (2017)<\/a> model the runout behaviour of the landslide using two well-documented and highly regarded models for the dynamic analysis of landslides – DANW (which is a 2 dimensional model) and DAN3D (the three dimensional equivalent), both developed by Oldrich and his colleagues.\u00a0 The approach that they have used has been to model the landslide in two dimensions first to understand the parameters that control the landslide behaviour, and then to use these to model the landslide in three dimensions.\u00a0 They have calibrated the models on the basis of detailed mapping of the landslide deposit – in other words, they required that the models were able to account for the spatial distribution of different remnants of the landslide as well as the overall morphology of the deposit.\u00a0 In particular, they observe three distinct zones of the landslide mass post-failure (quoted from Aaron et al.<\/em> (2017)<\/a>:<\/p>\n 1. The source zone, which contains a nearly intact although heavily deformed block at the head, bordered by highly sheared but massive blocks that appear to have travelled for a limited distance down a sloping, steplike surface from a higher elevation;<\/em><\/p>\n 2. The valley floor, which consists of widely spread fluid deposits bearing rafts of intact sand and clay; and<\/em><\/p>\n 3. Distal splash zone, which consists only of fluidized material and organic debris.<\/em><\/p><\/blockquote>\n These features can be quite readily identified on the Google Earth imagery of the landslide:-<\/p>\n Google Earth imagery of the Oso landslide. The regions that form the basis of the dynamic analysis are readily identifiable.<\/p><\/div>\n .<\/p>\n I noted above the controversy about the failure mechanisms of the landslide.\u00a0 Aaron et al.<\/em> (2017)<\/a> note this controversy, but observe that the various mechanisms make little difference to the runout analysis.\u00a0 I suspect that this may be a point of contention.\u00a0 The models proposed by Aaron et al.<\/em> (2017) are reported to be able to reproduce the key features noted above, and many of the fine-grained elements such as the location of various displaced rafts containing identifiable trees.\u00a0 The most important aspect of this model is that not all of the landslide material is assumed to have undergone liquefaction.\u00a0 In the model presented here, material in the upper part of the landslide, consisting of overconsolidated glaciolacustrine silt and clay, underwent brittle failure but did not undergo liquefaction.\u00a0 Material on the lower part of the slope, consisting of colluvium (effectively debris from earlier landslide events) failed as a result of the impact and loading of the upper portion of the landslide, and underwent “significant undrained strength loss (liquefaction)<\/em>“, allowing it to travel more than 1.4\u00a0km across the valley floor.\u00a0 It was this mobility that caused the landslide to induce such heavy loss of life.<\/p>\n Aaron et al.<\/em> (2017)<\/a> note that their analysis does not explain why this colluvial material was so prone to liquefaction; further laboratory testing is going to be needed to explore this behaviour, and thus to provide evidence for what is likely to be a controversial mechanism. But the approach described in this paper, and the use of detailed mapping, evidence from previous high mobility failures and high quality 2d and 3D modelling is a fitting tribute to the skills, knowledge and contributions of Oldrich Hungr and of course his co-authors.<\/p>\n Aaron, J., Hungr, O., Stark, T. and Baghdady, A. 2017. Oso, Washington, Landslide of March 22, 2014: Dynamic Analysis<\/a>, Journal of Geotechnical and Geoenvironmental Engineering<\/em>, 10.1061\/(ASCE)GT.1943-5606.0001748, 143:9, (05017005).<\/p>\n Stark, T. D., Baghdady, A., Hungr, O., and Aaron, J. 2017. \u201cCase study: Oso landslide on 22 March 2014\u2014Material properties and failure mechanism<\/a>.\u201d Journal of Geotechnical and Geoenvironmental Engineering<\/em>, 10.1061\/(ASCE)GT.1943-5606.0001615<\/a>, (05017001).<\/p>\n","protected":false},"excerpt":{"rendered":" In one of his last contributions, a paper by Oldrich Hungr and his colleagues provides a dynamic analysis of the 2014 Oso landslide, which killed 43 people<\/p>\n","protected":false},"author":22,"featured_media":25229,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[544],"tags":[145,7727,469,725,780,17,788],"class_list":["post-25226","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-review-of-a-paper","tag-analysis","tag-dynamic","tag-featured","tag-north-america","tag-oso","tag-research","tag-review-of-a-paper-2"],"_links":{"self":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/25226","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=25226"}],"version-history":[{"count":0,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/25226\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media\/25229"}],"wp:attachment":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media?parent=25226"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/categories?post=25226"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/tags?post=25226"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}![\"dynamic](\"https:\/\/blogs.agu.org\/landslideblog\/files\/2017\/08\/17_08-Oso-Hungr-1-e1503187450420.jpg\")
References<\/h4>\n