{"id":40505,"date":"2022-03-29T06:26:25","date_gmt":"2022-03-29T06:26:25","guid":{"rendered":"https:\/\/blogs.agu.org\/landslideblog\/?p=40505"},"modified":"2022-03-29T06:26:25","modified_gmt":"2022-03-29T06:26:25","slug":"mount-talakmau-1","status":"publish","type":"post","link":"https:\/\/blogs.agu.org\/landslideblog\/2022\/03\/29\/mount-talakmau-1\/","title":{"rendered":"Mount Talakmau: landslides from the 25 February 2022 Sumatra Earthquake"},"content":{"rendered":"<h4>Mount Talakmau: landslides from the 25 February 2022 Sumatra Earthquake<\/h4>\n<p>On 25 February 2022 a <a href=\"https:\/\/en.wikipedia.org\/wiki\/2022_Sumatra_earthquake\">M=6.1 earthquake struck West Sumatra in Indonesia at a depth of just 4.9 km<\/a>.\u00a0 The epicentre of the earthquake was about 20 km from the peak of <a href=\"https:\/\/volcano.si.edu\/volcano.cfm?vn=261130\">Mount Talakma<\/a>u, a c.3,000 m elevation compound volcano thought to have been active in the Holocene.<\/p>\n<p>In the aftermath of the earthquake, the ever impressive <a href=\"https:\/\/twitter.com\/SotisValkan\/status\/1500071155188879360\">Sotoris Valkaniotis tweeted imagery of landslides triggered on the flanks of Mount Talakmau<\/a>:-<\/p>\n<blockquote class=\"twitter-tweet\" data-width=\"500\" data-dnt=\"true\">\n<p lang=\"en\" dir=\"ltr\">And a 3D view of the debris flows &amp; landslides on Mt Talakmau, using Sentinel-2 imagery. View towards south-southwest <a href=\"https:\/\/t.co\/MURG3Hu0Wj\">pic.twitter.com\/MURG3Hu0Wj<\/a><\/p>\n<p>&mdash; Sotiris Valkaniotis (@SotisValkan) <a href=\"https:\/\/twitter.com\/SotisValkan\/status\/1500071155188879360?ref_src=twsrc%5Etfw\">March 5, 2022<\/a><\/p><\/blockquote>\n<p><script async src=\"https:\/\/platform.twitter.com\/widgets.js\" charset=\"utf-8\"><\/script><\/p>\n<p>.<\/p>\n<p>Wow!\u00a0 Subsequently, <a href=\"https:\/\/twitter.com\/UNOSAT\/status\/1501530107399352321\">UNOSAT has published a map of the landslides<\/a>:-<\/p>\n<p>https:\/\/twitter.com\/UNOSAT\/status\/1501530107399352321<\/p>\n<p>.<\/p>\n<p>Their assessment is that the landslide area covered about 6 square kilometres.\u00a0 So, I have taken a look at the <a href=\"https:\/\/www.planet.com\/\">Planet imagery<\/a> of the flanks of Mount Talakmau in the aftermath of the earthquake.\u00a0 The image below was collected on 26 March 2022:-<\/p>\n<div id=\"attachment_40508\" style=\"width: 810px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-40508\" class=\" wp-image-40508\" src=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2022\/03\/22_03-Talakmau-1.jpg\" alt=\"Satellite image of the landslides triggered by the 25 February 2022 Sumatra earthquake.\" width=\"800\" height=\"498\" srcset=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2022\/03\/22_03-Talakmau-1.jpg 1174w, https:\/\/blogs.agu.org\/landslideblog\/files\/2022\/03\/22_03-Talakmau-1-300x187.jpg 300w, https:\/\/blogs.agu.org\/landslideblog\/files\/2022\/03\/22_03-Talakmau-1-1024x638.jpg 1024w, https:\/\/blogs.agu.org\/landslideblog\/files\/2022\/03\/22_03-Talakmau-1-768x478.jpg 768w\" sizes=\"auto, (max-width: 800px) 100vw, 800px\" \/><p id=\"caption-attachment-40508\" class=\"wp-caption-text\">Satellite image of the landslides triggered by the 25 February 2022 Sumatra earthquake. Image copyright <a href=\"https:\/\/www.planet.com\/\">Planet Team<\/a>, used with permission. Image collected on 26 March 2022.<\/p><\/div>\n<p>.<\/p>\n<p>Hopefully, you will be able to use a Juxtapose slider below to compare images from before and after the earthquake:-<\/p>\n<div class=\"juxtapose\"><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2022\/03\/22_03-Talakmau-1.jpg\" alt=\"Satellite image of the landslides triggered by the 25 February 2022 Sumatra earthquake. \" width=\"800\" height=\"510\" \/><img loading=\"lazy\" decoding=\"async\" src=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2022\/03\/22_03-Talakmau-2.jpg\" alt=\"Satellite image of the site of the landslides triggered by the 25 February 2022 Sumatra earthquake.\" width=\"800\" height=\"510\" \/><\/div>\n<p>.<\/p>\n<p>There are many interesting aspects of these landslides.\u00a0 On the upper part of the slopes they appear to be very many shallow, disrupted failures in the volcanic soils.\u00a0 The vast majority have entered the drainage system, although there are also many isolated landslides too.\u00a0 The landslides appear to have transitioned to become channelised flows with a long runout, presumably driven by the steep topography and a large amount of entrainment.\u00a0 Some of the flows have travelled at least 10 km, with evidence of small amounts of material moving considerably further.<\/p>\n<p>Interestingly, most of the landslides are on the east and northeast sides of Mount Talakmau, with a smaller but still significant cluster to the northwest.\u00a0 This could be a topographic effect, a directional effect associated with the seismic waves or simply a reflection of the fact that the epicentre was to the northeast of the volcano.<\/p>\n<p>It is intriguing that an earthquake has triggered highly mobile, presumably saturated landslides.\u00a0 But this is a humid tropical environment and the soils are made from volcanic materials.\u00a0 Thus, it is likely that they had a high moisture content at the time of the earthquake, allowing some form of liquefaction to occur.\u00a0 These landslides might be described as <a href=\"https:\/\/blogs.agu.org\/landslideblog\/?s=lahar&amp;submit.x=0&amp;submit.y=0&amp;mswhere=blog\">lahars<\/a>.<\/p>\n<p>As an aside, there is no evidence of a valley-blocking event that I can see.<\/p>\n<p>This is a fascinating event, worthy of much more detailed investigation.\u00a0 I hope that someone is able to undertake detailed mapping and analysis &#8211; it is certainly worthwhile.<\/p>\n<p>.<\/p>\n<h4>Acknowledgement<\/h4>\n<p>Planet Team (2022). Planet Application Program Interface: In Space for Life on Earth. San Francisco, CA. <a href=\"https:\/\/www.planet.com\/\">https:\/\/www.planet.com\/<\/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>An earthquake on 25 February 2022 triggered multiple landslides on the flanks of Mount Talakmau in west Sumatra, Indonesia.<!-- 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":40508,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[537],"tags":[23,469,141,34,1205,8,314,107],"class_list":["post-40505","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-earthquake-induced-landslide","tag-earthquake","tag-featured","tag-indonesia","tag-lahar","tag-planet-labs","tag-satellite-imagery","tag-se-asia","tag-volcano"],"_links":{"self":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/40505","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=40505"}],"version-history":[{"count":0,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/40505\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media\/40508"}],"wp:attachment":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media?parent=40505"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/categories?post=40505"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/tags?post=40505"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}