{"id":8051,"date":"2014-02-19T09:04:31","date_gmt":"2014-02-19T09:04:31","guid":{"rendered":"http:\/\/blogs.agu.org\/landslideblog\/?p=8051"},"modified":"2014-02-19T09:04:31","modified_gmt":"2014-02-19T09:04:31","slug":"jupille-fly-ash-landslide","status":"publish","type":"post","link":"https:\/\/blogs.agu.org\/landslideblog\/2014\/02\/19\/jupille-fly-ash-landslide\/","title":{"rendered":"Jupille 1961: an extraordinary fly ash landslide"},"content":{"rendered":"<h5>The Jupille fly ash landslide of 1961<\/h5>\n<p>The Jupille fly ash landslide is a little-known but quite extraordinary mine waste disaster.\u00a0 It occurred in the town of Jupille in Belgium on 3rd February 1961, killing 11 people, consisting of seven children and four women.\u00a0 The landslide originated from a dump of fly ash that was about 29 m high and covered an area of 4 hectares; the disaster was caused by a collapse of about 550,000 tonnes of the fly ash deposit.\u00a0 The remarkable aspect of the landslide though is the rate of movement &#8211; the slide traveled about 700 m in about 60 seconds, despite moving down a very low angled slope (about 3 degrees).\u00a0 The landslide impacted the town at the foot of the valley, burying several houses.\u00a0 There is an account of the landslide <a href=\"http:\/\/obelix-mbm.skynetblogs.be\/archive\/2009\/08\/22\/un-vendredi-noir-a-jupille-le-3-fevrier-1961.html\">here<\/a>, from which this image of the aftermath is taken:<\/p>\n<div id=\"attachment_8052\" style=\"width: 367px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2014\/02\/14_02-jupille-1.jpg\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-8052\" class=\"size-full wp-image-8052\" alt=\"fly ash landslide\" src=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2014\/02\/14_02-jupille-1.jpg\" width=\"357\" height=\"480\" srcset=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2014\/02\/14_02-jupille-1.jpg 357w, https:\/\/blogs.agu.org\/landslideblog\/files\/2014\/02\/14_02-jupille-1-223x300.jpg 223w\" sizes=\"auto, (max-width: 357px) 100vw, 357px\" \/><\/a><p id=\"caption-attachment-8052\" class=\"wp-caption-text\">http:\/\/obelix-mbm.skynetblogs.be\/archive\/2009\/08\/22\/un-vendredi-noir-a-jupille-le-3-fevrier-1961.html<\/p><\/div>\n<p>..<\/p>\n<p>This <a href=\"http:\/\/www.youtube.com\/watch?v=dixF5xKVwjk\">short but desperately sad video<\/a> shows the aftermath of the landslide and the attempts to rescue the victims.\u00a0 At the end it includes a shot of the slope down which the landslide flowed:<\/p>\n<p><iframe loading=\"lazy\" title=\"de ramp van Jupille   1961\" width=\"500\" height=\"375\" src=\"https:\/\/www.youtube.com\/embed\/dixF5xKVwjk?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe><\/p>\n<p>..<\/p>\n<h5>The mechanics of the Jupille fly ash landslide<\/h5>\n<p>Since the disaster there has been a great deal of interest in the mechanics of the landslide, and in particular its exceptional mobility.\u00a0 Whilst the initial failure is quite easy to explain (little more than a rising water table), the high rate of flow requires a more nuanced explanation.\u00a0 It is certainly true that the landslide was unusually mobile.\u00a0 Investigations at the time suggested that the base of the landslide was not water saturated, which led to the suggestion by Calembert and Dantinne (1964) that the flow was caused by air fluidization.\u00a0 In a nutshell the idea is that the particles of ash became suspended in air, allowing the mass to flow like a liquid with very low viscosity. You can get an idea of the process by watching <a href=\"http:\/\/www.youtube.com\/watch?v=tzbIdE51jcg\">a video of a pyroclastic flow<\/a> (though remember that pyroclastic flows are very hot, which was not the case here):<\/p>\n<p><iframe loading=\"lazy\" title=\"Pyroclastic Flow followed by series of Tornados, Sinabung Volcano\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/tzbIdE51jcg?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe><\/p>\n<p>..<\/p>\n<p>However, whilst air fluidization this is widely agreed to be a key mechanism is pyroclastic flows, more recent work has rejected it as a process occurring within landslides.\u00a0 This has been in part because exceptional mobility is also observed in landslides in which air fluidization is unlikely to be important, and in part because it has been believed that entrapping sufficient air within the mass is unlikely.\u00a0 But, the Jupille fly ash landslide is essentially unique, so it has been worth revisiting it with modern analytical techniques.\u00a0 <a href=\" http:\/\/dx.doi.org\/10.1016\/j.geomorph.2014.01.020\">In a paper that is online for the journal <em>Geomorphology<\/em><\/a>, Stilmant <em>et al.<\/em> (2014) have reanalysed the Jupille fly ash landslide using a new numerical model.\u00a0 This model, combined with field observations of the landslide and its constituent materials, suggest that most likely mechanism was indeed air fluidization.\u00a0 Thus, the landslide started with an initial collapse of the spoil heap, which then caused diffusion of the pressurized air through the mass, allowing it to flow at high velocity.\u00a0 This mechanism can explain the observed morphological features of the landslide and the high degree of observed mobility.<\/p>\n<p>Like many others I suspect I had assumed that the air fluidization theory for landslide mobility had been debunked.\u00a0 It is fascinating to see a case in which this may well be the mechanism that explains the observed behaviour.<\/p>\n<h5>References<\/h5>\n<p>Calembert, L. and Dantinne R. 1964. L&#8217;avalanche de cendres volantes survenue \u00e0 Jupille (Li\u00e8ge) le 3 f\u00e9vrier 1961. In: Spronck, R. (Ed.), <em>Amici et Alumni &#8211; Hommage \u00e0 Ferdinand Campus, Georges Thone<\/em>, Li\u00e8ge, Belgium (1964), pp.41-57.<\/p>\n<p>Stilmant, F., Pirotton, M., Archambeau, P., Erpicum, S. and Dewals, B. 2014. Can the collapse of a fly ash heap develop into an air-fluidized flow? &#8211; Reanalysis of the Jupille accident (1961). Geomorphology: <a href=\"http:\/\/dx.doi.org\/10.1016\/j.geomorph.2014.01.020\">http:\/\/dx.doi.org\/10.1016\/j.geomorph.2014.01.020<\/a><\/p>\n<!-- AddThis Advanced Settings generic via filter on the_content --><!-- AddThis Share Buttons generic via filter on the_content -->","protected":false},"excerpt":{"rendered":"<p>The 1961 fly ash landslide at Jupille in Belgium killed 11 people. A new paper resurrects the idea that air fluidization may have been the key mechanism<!-- AddThis Advanced Settings generic via filter on wp_trim_excerpt --><!-- AddThis Share Buttons generic via filter on wp_trim_excerpt --><\/p>\n","protected":false},"author":22,"featured_media":8052,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[770,144,469,769,959,299,192],"class_list":["post-8051","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorized","tag-belgium","tag-europe","tag-featured","tag-fluidization","tag-landslide-report","tag-mine","tag-paper"],"_links":{"self":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/8051","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=8051"}],"version-history":[{"count":0,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/8051\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media\/8052"}],"wp:attachment":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media?parent=8051"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/categories?post=8051"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/tags?post=8051"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}