{"id":26952,"date":"2018-02-22T06:51:19","date_gmt":"2018-02-22T06:51:19","guid":{"rendered":"https:\/\/blogs.agu.org\/landslideblog\/?p=26952"},"modified":"2018-02-22T06:52:40","modified_gmt":"2018-02-22T06:52:40","slug":"river-of-rock-1","status":"publish","type":"post","link":"https:\/\/blogs.agu.org\/landslideblog\/2018\/02\/22\/river-of-rock-1\/","title":{"rendered":"River of rock: a fantastic video of a granular flow from New Zealand"},"content":{"rendered":"<h4>River of rock: a fantastic video of a granular flow from New Zealand<\/h4>\n<p><a href=\"https:\/\/www.youtube.com\/watch?v=5AwFSSX34Wo\">From New Zealand comes a new video of a &#8220;river of rock<\/a>&#8220;, a somewhat beautiful granular flow.\u00a0 This was triggered by Ex Cyclone Gita, which made landfall across the central part of New Zealand, bringing heavy rainfall and, of course, landslides.\u00a0 The &#8220;river of rock&#8221; was captured on video by <a href=\"https:\/\/www.facebook.com\/pg\/Genesforprofit\/videos\/\">Donna Field on the Rakaia River<\/a>:<\/p>\n<iframe loading=\"lazy\" width=\"640\" height=\"360\" src=\"https:\/\/www.youtube.com\/embed\/5AwFSSX34Wo?feature=oembed\" frameborder=\"0\" allow=\"autoplay; encrypted-media\" allowfullscreen><\/iframe>\n<p>.<\/p>\n<p>This is a magnificent example of a granular flow.\u00a0 Whilst they appear to be very exotic, <a href=\"https:\/\/blogs.agu.org\/landslideblog\/2017\/06\/05\/terrifying-illgraben-debris-flow\/\">granular flows are quite common<\/a> and have been well-described in the literature.\u00a0 In essence the pebbles behave as particles, allowing behaviour that is akin to that of a fluid.\u00a0 Of course the density of the fluid is somewhat higher than that of a more familiar liquid, such as water, and the particles are many times larger, but the river of rock is still able to generate the sorts of flow structures that we see in water:-<\/p>\n<div id=\"attachment_26965\" style=\"width: 650px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-26965\" class=\"size-full wp-image-26965\" src=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2018\/02\/18_02-river-of-rock-1-e1519281478866.jpg\" alt=\"river of rock\" width=\"640\" height=\"333\" \/><p id=\"caption-attachment-26965\" class=\"wp-caption-text\">The river of rock granular flow on the Rakaia River in New Zealand. <a href=\"https:\/\/www.youtube.com\/watch?v=5AwFSSX34Wo\">Video captured by Donna Field in New Zealand in the aftermath of Ex Cyclone Gita<\/a>.<\/p><\/div>\n<p>.<\/p>\n<p>I suspect that this one comprises particles that are of a comparatively even size &#8211; Simon Cox from GNS suggested to me that the material is probably greywacke.\u00a0 It may be that this uniformity lies behind the unusual characteristics of this flow.<\/p>\n<p><a href=\"https:\/\/www.stuff.co.nz\/national\/101656977\/Canterburys-aptly-named-Terrible-Gully-turned-to-river-of-rock-by-ex-Cyclone-Gita?cid=app-android\">Stuff.co.nz has an article about the granular flow<\/a>. They note that:<\/p>\n<p><em>&#8220;A river of shingle rock flowing down Terrible Gully has left eight farms cut off from town in Rakaia, near Canterbury&#8217;s Mt Hutt.\u00a0 <\/em><em>Incredible video of the &#8220;rocky river&#8221; was captured by Donna Field of Cleardale Station as she surveyed the damage from former Cyclone Gita on Wednesday.\u00a0 <\/em><em>The flow of careering shingles closed Double Hill Run Rd which services the farms in the South Island region. It&#8217;s an event that has become a regular occurrence for the farmers in the area.<\/em><\/p>\n<p>I guess it may not be too hard to understand why this location was named &#8220;Terrible Gully&#8221;.<\/p>\n<p>Many thanks to the several people who pointed this one out to me.\u00a0 Much appreciated.<\/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>Ex Cyclone Gita has triggered a spectacular &#8220;river of rock&#8221; debris on the Rakaia River in New Zealand. This was captured on an amazing video by local farmer Donna Field<!-- 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":26965,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[29],"tags":[57,469,12341,963,7],"class_list":["post-26952","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-landslide-video","tag-debris-flow","tag-featured","tag-granular-flow","tag-landslide-video","tag-new-zealand"],"_links":{"self":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/26952","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=26952"}],"version-history":[{"count":0,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/26952\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media\/26965"}],"wp:attachment":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media?parent=26952"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/categories?post=26952"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/tags?post=26952"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}