{"id":25302,"date":"2017-08-25T01:08:14","date_gmt":"2017-08-25T01:08:14","guid":{"rendered":"http:\/\/blogs.agu.org\/landslideblog\/?p=25302"},"modified":"2017-08-25T02:35:17","modified_gmt":"2017-08-25T02:35:17","slug":"pizzo-cengalo-rock-avalanche-1","status":"publish","type":"post","link":"https:\/\/blogs.agu.org\/landslideblog\/2017\/08\/25\/pizzo-cengalo-rock-avalanche-1\/","title":{"rendered":"Pizzo Cengalo rock avalanche &#8211; Planet satellite imagery captured the landslide in motion"},"content":{"rendered":"<h5>Pizzo Cengalo rock avalanche &#8211; Planet satellite imagery captured the landslide in motion<\/h5>\n<p>The Pizzo Cengalo rock avalanche in Switzerland on Wednesday has <a href=\"http:\/\/www.bbc.com\/news\/world-europe-41036851\">attracted considerable attention<\/a>, not least because of the two amazing videos that were captured of the event.\u00a0 The <a href=\"https:\/\/www.youtube.com\/watch?v=40_vZFHyZ-A\">first caught the initiation of the collapse<\/a> and the initial development of the avalanche itself:-<\/p>\n<iframe loading=\"lazy\" width=\"640\" height=\"360\" src=\"https:\/\/www.youtube.com\/embed\/40_vZFHyZ-A?feature=oembed\" frameborder=\"0\" allowfullscreen><\/iframe>\n<p>.<\/p>\n<p>And second the <a href=\"https:\/\/www.youtube.com\/watch?v=4OyOfMI_4pA\">extraordinarily destructive nature of the flow some 5 km downstream<\/a>:-<\/p>\n<iframe loading=\"lazy\" width=\"640\" height=\"360\" src=\"https:\/\/www.youtube.com\/embed\/4OyOfMI_4pA?feature=oembed\" frameborder=\"0\" allowfullscreen><\/iframe>\n<p>.<\/p>\n<p>This is of course <a href=\"https:\/\/blogs.agu.org\/landslideblog\/2016\/09\/19\/piz-cengalo\/\">far from the first event on this mountain<\/a>, although with eight people recorded missing it may be the most tragic.\u00a0 Given that it is well-studied I will allow others to write in detail about it, but would point out one fascinating aspect of the first video.\u00a0 This is an apparent shock wave (?) that appears to travel ahead of the main dust cloud immediately after the mass strikes the valley floor.\u00a0 I have tried to capture it in this screenshot:-<\/p>\n<div id=\"attachment_25303\" style=\"width: 650px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-25303\" class=\"size-full wp-image-25303\" src=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2017\/08\/17_08-Pizzo-1-e1503620421527.jpg\" alt=\"Pizzo Cengalo rock avalanche\" width=\"640\" height=\"726\" \/><p id=\"caption-attachment-25303\" class=\"wp-caption-text\">Possible shock wave from the Pizzo Cengalo rock avalanche? Via <a href=\"https:\/\/www.youtube.com\/watch?v=40_vZFHyZ-A\">Youtube<\/a><\/p><\/div>\n<p>.<\/p>\n<p>I am no expert in these events, but given the speed with which this moves downslope I am hypothesising that this might be a shock wave?\u00a0 Can anyone else comment?<\/p>\n<p>Perhaps even more interesting than that is a set of images from <a href=\"https:\/\/www.planet.com\/\">Planet Labs<\/a>.\u00a0 One of their constellation of satellites was overhead at the time, and remarkably has captured the landslide in motion.\u00a0 This is an image taken on 4th August of the site of the Pizzo Cengalo rock avalanche:-<\/p>\n<div id=\"attachment_25312\" style=\"width: 650px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-25312\" class=\"size-full wp-image-25312\" src=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2017\/08\/17_08-Pizzo-2-e1503621202494.png\" alt=\"Pizzo Cengalo rock avalanche\" width=\"640\" height=\"654\" \/><p id=\"caption-attachment-25312\" class=\"wp-caption-text\"><a href=\"https:\/\/www.planet.com\/\">Planet Labs<\/a> image of the site of the Pizzo Cengalo rock avalanche site, dated 4th August.<\/p><\/div>\n<p>.<\/p>\n<div id=\"attachment_25308\" style=\"width: 650px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-25308\" class=\"wp-image-25308\" src=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2017\/08\/17_08-Pizzo-3.png\" alt=\"Pizzo Cengalo rock avalanche\" width=\"640\" height=\"654\" srcset=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2017\/08\/17_08-Pizzo-3.png 705w, https:\/\/blogs.agu.org\/landslideblog\/files\/2017\/08\/17_08-Pizzo-3-294x300.png 294w\" sizes=\"auto, (max-width: 640px) 100vw, 640px\" \/><p id=\"caption-attachment-25308\" class=\"wp-caption-text\"><a href=\"https:\/\/www.planet.com\/\">Planets Labs<\/a> image of the Pizzo Cengalo rock avalanche in motion.<\/p><\/div>\n<p>.<\/p>\n<p>An even more fascinating aspect of this data is that the way in which the Planet Labs satellites collect imagery means that the near infrared (NIR) image is collected separately from the optical (RGB) imagery, with a 0.5 second gap between them.\u00a0 On this basis, Bas Altena from University of Oslo suggested that the movement might be visible in the imagery.\u00a0 The gap between these two images can be seen below &#8211; if you look carefully you can see that the dust clouds have moved in that 0.5 second period.\u00a0 This is the NIR image (which has a lower resolution):-<\/p>\n<div id=\"attachment_25307\" style=\"width: 650px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-25307\" class=\"size-full wp-image-25307\" src=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2017\/08\/17_08-Pizzo-4-e1503621762146.png\" alt=\"Pizzo Cengalo rock avalanche\" width=\"640\" height=\"421\" \/><p id=\"caption-attachment-25307\" class=\"wp-caption-text\"><a href=\"https:\/\/www.planet.com\/\">Planet Labs<\/a> NIR image of the Pizzo Cengalo rock avalanche in motion.<\/p><\/div>\n<p>.<\/p>\n<p>And this, half a second later, is the Red band of the optical imagery:<\/p>\n<div id=\"attachment_25306\" style=\"width: 650px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-25306\" class=\"size-full wp-image-25306\" src=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2017\/08\/17_08-Pizzo-5-e1503621932980.png\" alt=\"Pizzo Cengalo rock avalanche\" width=\"640\" height=\"420\" \/><p id=\"caption-attachment-25306\" class=\"wp-caption-text\"><a href=\"https:\/\/www.planet.com\/\">Planet Labs<\/a> Red band image of the Pizzo Cengalo rock avalanche in motion<\/p><\/div>\n<p>&nbsp;<\/p>\n<p>.<\/p>\n<h4>Acknowledgement<\/h4>\n<p>Planet Team (2017). Planet Application Program Interface: In Space for Life on Earth. San Francisco, CA.\u00a0<a href=\"https:\/\/api.planet.com\/\">https:\/\/api.planet.com<\/a><\/p>\n<p>Thanks in particular to Joe Mascaro of <a href=\"https:\/\/www.planet.com\/\">Planet Labs<\/a>, who pointed out that this event had been captured, Bas Altena from University of Oslo who suggested the RGB\/NIR trick, and to various friends who have tweeted, left comments and emailed me about this amazing event.<\/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>Planet Labs imagery has captured the enormous Pizzo Cengalo rock avalanche, which has left eight people missing in Switzerland, in motion<!-- 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":25308,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7203],"tags":[144,469,963,306,25,444],"class_list":["post-25302","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-planet-labs","tag-europe","tag-featured","tag-landslide-video","tag-rock-avalanche","tag-satellite","tag-switzerland"],"_links":{"self":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/25302","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=25302"}],"version-history":[{"count":0,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/25302\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media\/25308"}],"wp:attachment":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media?parent=25302"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/categories?post=25302"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/tags?post=25302"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}