{"id":37021,"date":"2021-03-15T08:22:50","date_gmt":"2021-03-15T08:22:50","guid":{"rendered":"https:\/\/blogs.agu.org\/landslideblog\/?p=37021"},"modified":"2021-03-15T08:22:50","modified_gmt":"2021-03-15T08:22:50","slug":"knappensee-1","status":"publish","type":"post","link":"https:\/\/blogs.agu.org\/landslideblog\/2021\/03\/15\/knappensee-1\/","title":{"rendered":"Knappensee: a large landslide at an old open cast mining site in eastern Germany"},"content":{"rendered":"<h4>Knappensee: a large landslide at an old open cast mining site in eastern Germany<\/h4>\n<p>On Thursday 11 March 2021 a large landslide occurred on the banks of an abandoned and flooded open case coal mine site at Knappensee in eastern Germany.\u00a0 The images after the event are impressive:-<\/p>\n<div id=\"attachment_37024\" style=\"width: 810px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-37024\" class=\" wp-image-37024\" src=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2021\/03\/21_03-Knappensee-1.jpg\" alt=\"The aftermath of the landslide at Knappensee on 11 March 2021\" width=\"800\" height=\"446\" srcset=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2021\/03\/21_03-Knappensee-1.jpg 2468w, https:\/\/blogs.agu.org\/landslideblog\/files\/2021\/03\/21_03-Knappensee-1-300x167.jpg 300w, https:\/\/blogs.agu.org\/landslideblog\/files\/2021\/03\/21_03-Knappensee-1-1024x571.jpg 1024w, https:\/\/blogs.agu.org\/landslideblog\/files\/2021\/03\/21_03-Knappensee-1-768x428.jpg 768w, https:\/\/blogs.agu.org\/landslideblog\/files\/2021\/03\/21_03-Knappensee-1-1536x857.jpg 1536w, https:\/\/blogs.agu.org\/landslideblog\/files\/2021\/03\/21_03-Knappensee-1-2048x1143.jpg 2048w\" sizes=\"auto, (max-width: 800px) 100vw, 800px\" \/><p id=\"caption-attachment-37024\" class=\"wp-caption-text\">The aftermath of the landslide at Knappensee on 11 March 2021. <a href=\"https:\/\/www.bild.de\/regional\/dresden\/dresden-aktuell\/erdrutsch-knappensee-kann-sich-so-etwas-an-anderen-seen-wiederholen-75721408.bild.html\">Image by HY-photo Gernot Menzel via Bild<\/a>.<\/p><\/div>\n<p>.<\/p>\n<p>The event was captured on a remarkable video that has been posted to <a href=\"https:\/\/www.youtube.com\/watch?v=xhLew-dqPGA\">Youtube<\/a>.\u00a0 This video starts with an orientation problem that is soon resolved:-<\/p>\n<iframe loading=\"lazy\" title=\"12. M\u00e4rz 2021\" width=\"640\" height=\"360\" src=\"https:\/\/www.youtube.com\/embed\/xhLew-dqPGA?feature=oembed\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture\" allowfullscreen><\/iframe>\n<p>.<\/p>\n<p>Judging by news reports, the banks of the Knappensee have been undergoing remediation to allow the site to become a recreation attraction.\u00a0 This bank had been undergoing work recently &#8211; I note the various vessels in the video &#8211; and was a site with known geotechnical problems.\u00a0 The unslipped areas in the image above have little or no vegetation, suggesting engineering works since the last growing season.<\/p>\n<p><a href=\"https:\/\/www.mdr.de\/sachsen\/bautzen\/bautzen-hoyerswerda-kamenz\/knappensee-ursache-rutschung-100.html\">MDR.de reports that<\/a>:<\/p>\n<p><em>The landslide at Knappensee was probably triggered by renovation work in the bank area.\u00a0Experts from the Saxon Mining Authority have come to this conclusion.\u00a0In the past few weeks, the first careful security measures have been carried out in this area.\u00a0Among other things, dump material has been removed and work has been prepared in the bank area, said the Mining Authority.\u00a0This was also the case on the day of the landslide, which is why this work is suspected to be the trigger.<\/em><\/p>\n<p>The landslide appears to have been retrogressive, starting with a small failure at the toe.\u00a0 That in turn may have been triggered by a slip under the water, but that is speculation at this point.\u00a0 The final scar is reported to be 500 m by 200 m.<\/p>\n<p>The landslide generated a displacement wave &#8211; reported to be about 1.5 metres high.\u00a0 Whilst this would be small in a marine environment, in a non-tidal lake this is significant event.\u00a0 \u00a0This tsunami damaged properties on the other side of the lake:-<\/p>\n<div id=\"attachment_37026\" style=\"width: 809px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-37026\" class=\" wp-image-37026\" src=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2021\/03\/21_03-Knappensee-2.jpg\" alt=\"Damage caused by the displacement wave at Knappensee in Germany\" width=\"799\" height=\"478\" srcset=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2021\/03\/21_03-Knappensee-2.jpg 1918w, https:\/\/blogs.agu.org\/landslideblog\/files\/2021\/03\/21_03-Knappensee-2-300x179.jpg 300w, https:\/\/blogs.agu.org\/landslideblog\/files\/2021\/03\/21_03-Knappensee-2-1024x612.jpg 1024w, https:\/\/blogs.agu.org\/landslideblog\/files\/2021\/03\/21_03-Knappensee-2-768x459.jpg 768w, https:\/\/blogs.agu.org\/landslideblog\/files\/2021\/03\/21_03-Knappensee-2-1536x919.jpg 1536w\" sizes=\"auto, (max-width: 799px) 100vw, 799px\" \/><p id=\"caption-attachment-37026\" class=\"wp-caption-text\">Damage caused by the displacement wave at Knappensee in Germany. Image by Torsten Richter-Zippack via <a href=\"https:\/\/www.lr-online.de\/lausitz\/hoyerswerda\/erdrutsch-am-knappensee-flutwelle-verursacht-zahlreiche-schaeden-_-anwohner-haben-angst-55615336.html\">LR Online<\/a>.<\/p><\/div>\n<p>.<\/p>\n<p>The level of the lake has been raised by 32 cm as a result of the landslide.\u00a0 This is now being lowered, but slowly because of the fear that rapid drawdown will trigger further instability.<\/p>\n<p>Large failures in open cast coal mines, or in coal mine waste piles, are not rare,\u00a0 Recent examples include:-<\/p>\n<ul>\n<li><a href=\"https:\/\/blogs.agu.org\/landslideblog\/2020\/02\/04\/mina-pecket\/\">The 2014 Mina Pecket landslide in Chile<\/a><\/li>\n<li><a href=\"https:\/\/blogs.agu.org\/landslideblog\/2013\/03\/04\/new-images-of-the-hatfield-colliery-coal-mine-landslide-in-northern-england\/\">The 2013 Hatfield Colliery landslide in the UK<\/a><\/li>\n<li><a href=\"https:\/\/blogs.agu.org\/landslideblog\/2017\/02\/26\/kakanj-1\/\">The 2017 Kakanj landslide in Bosnia<\/a><\/li>\n<\/ul>\n<p>&nbsp;<\/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>Knappensee: a large landslide at an old open cast mining site in eastern Germany on 11 March 2020, which was captured on video, generated a 1.5 m high tsunami that damaged property on the far side of the lake<!-- 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":37024,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[144,30625,162,31,299,205,128],"class_list":["post-37021","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-landslide-report","tag-europe","tag-fatured","tag-germany","tag-lake","tag-mine","tag-mining","tag-tsunami"],"_links":{"self":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/37021","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=37021"}],"version-history":[{"count":0,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/37021\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media\/37024"}],"wp:attachment":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media?parent=37021"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/categories?post=37021"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/tags?post=37021"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}