{"id":29678,"date":"2018-12-29T10:25:49","date_gmt":"2018-12-29T10:25:49","guid":{"rendered":"https:\/\/blogs.agu.org\/landslideblog\/?p=29678"},"modified":"2019-01-01T02:31:56","modified_gmt":"2019-01-01T02:31:56","slug":"anak-krakatau-2","status":"publish","type":"post","link":"https:\/\/blogs.agu.org\/landslideblog\/2018\/12\/29\/anak-krakatau-2\/","title":{"rendered":"First visual satellite images of Anak Krakatau show the enormous extent of the landslide"},"content":{"rendered":"<h4>First visual satellite images of Anak Krakatau show the enormous extent of the landslide<\/h4>\n<p>The <a href=\"https:\/\/www.sentinel-hub.com\/\">ESA Sentinel-2 satellite<\/a> today captured the first visible band imagery of the <a href=\"https:\/\/blogs.agu.org\/landslideblog\/2018\/12\/26\/anak-krakatau-1\/\">Anak Krakatau landslide scar<\/a>.&nbsp; This is the image, from <a href=\"https:\/\/www.sentinel-hub.com\/\">Sentinel Hub<\/a>:-<\/p>\n<div id=\"attachment_29680\" style=\"width: 650px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-29680\" class=\"size-full wp-image-29680\" src=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2018\/12\/18_12-Anak-Krakatau-3-e1546078730603.jpg\" alt=\"Anak Krakatau\" width=\"640\" height=\"480\"\/><p id=\"caption-attachment-29680\" class=\"wp-caption-text\">ESA Sentinel-2 True Colour image of Anak Krakatau collected on 29th December 2018.<\/p><\/div>\n<p>.<\/p>\n<p>For reference, this is an image also collected by Sentinel-2, of the island before the landslide:-<\/p>\n<div id=\"attachment_29689\" style=\"width: 650px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-29689\" class=\"size-full wp-image-29689\" src=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2018\/12\/18_12-Anak-Krakatau-4-e1546079962212.jpg\" alt=\"Anak Krakatau\" width=\"640\" height=\"498\"\/><p id=\"caption-attachment-29689\" class=\"wp-caption-text\">ESA Sentinel-2 True Colour image of Anak Krakatau collected on 1st November 2018.<\/p><\/div>\n<p>.<\/p>\n<p>I have tried to improve the Sentinel-2 image to bring out the main features:-<\/p>\n<div id=\"attachment_29698\" style=\"width: 650px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-29698\" class=\"size-full wp-image-29698\" src=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2018\/12\/18_12-Anak-Krakatau-3b-1-e1546080276800.jpg\" alt=\"Anak Krakatau\" width=\"640\" height=\"893\"\/><p id=\"caption-attachment-29698\" class=\"wp-caption-text\">ESA Sentinel-2 True Colour image of Anak Krakatau collected on 29th December 2018.<\/p><\/div>\n<p>.<\/p>\n<p>So, there appears to be a huge scar on the west side of the island.&nbsp; This is consistent with the reported deformation from the radar images, <a href=\"https:\/\/twitter.com\/Sutopo_PN\/status\/1078661984277585920\">as analysed by PVMBG<\/a> and <a href=\"https:\/\/www.bbc.co.uk\/news\/science-environment-46707731\">reported by the BBC<\/a>.&nbsp; They report that the landslide had a volume of 150-170 million cubic metres, which is a huge landslide.&nbsp; Note that most of the slide was a terrestrial (i.e. above water) slide, not the underwater event that was initially reported.&nbsp; A very substantial proportion of the volcanic cone is missing, including all of the higher elements.&nbsp; PVMBG report that the come elevation has decreased from 338 metres to about 100 metres.&nbsp; Around the southwest part of the island there appears to be an extensive shallow marine deposit &#8211; is this landslide material, perhaps moved by the currents, or ash fall from the volcanic eruptions? Or both of course.<\/p>\n<p>It seems likely that this failure was a single large event, although it might have had several phases in short succession.&nbsp; The seismic data, once properly analysed should help with the interpretation of the failure sequence. A key question will be whether INSAR data could have detected precursory deformation of this flank prior to the main landslide 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>The ESA Sentinel 2 satellite today caught an image of the remains of Anak Krakatau. A huge landslide scar is visible, profoundly changing the island <!-- 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":29680,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[469,346,141,959,314,20063,107],"class_list":["post-29678","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-landslide-report","tag-featured","tag-flank-collapse","tag-indonesia","tag-landslide-report","tag-se-asia","tag-sentinel","tag-volcano"],"_links":{"self":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/29678","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=29678"}],"version-history":[{"count":0,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/29678\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media\/29680"}],"wp:attachment":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media?parent=29678"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/categories?post=29678"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/tags?post=29678"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}