{"id":36483,"date":"2021-02-04T08:12:08","date_gmt":"2021-02-04T08:12:08","guid":{"rendered":"https:\/\/blogs.agu.org\/landslideblog\/?p=36483"},"modified":"2021-02-04T08:12:08","modified_gmt":"2021-02-04T08:12:08","slug":"white-cliffs-of-dover","status":"publish","type":"post","link":"https:\/\/blogs.agu.org\/landslideblog\/2021\/02\/04\/white-cliffs-of-dover\/","title":{"rendered":"The White Cliffs of Dover chalk cliff collapse"},"content":{"rendered":"<h4>The White Cliffs of Dover chalk cliff collapse<\/h4>\n<p>A really interesting video was widely circulated on social media yesterday showing a large cliff collapse on the White Cliffs of Dover in SE England.\u00a0 The coverage of the event was quite amusing, with the event being compared to the UK response to the Covid-19 crisis (everything is going downhill) or Brexit (even the White Cliffs are trying to closer to Europe).\u00a0 I have sympathy with both memes.<\/p>\n<p>But the event itself is interesting, not least because it was a large double event.\u00a0 <a href=\"https:\/\/twitter.com\/adamclarkitv\/status\/1357002525795352576\">The original video was included in a tweet<\/a>:-<\/p>\n<blockquote class=\"twitter-tweet\" data-width=\"500\" data-dnt=\"true\">\n<p lang=\"en\" dir=\"ltr\">A large part of the White Cliffs of Dover has collapsed this afternoon. This footage was filmed at Samphire Ho. <a href=\"https:\/\/t.co\/ycKVf93wiw\">pic.twitter.com\/ycKVf93wiw<\/a><\/p>\n<p>&mdash; Adam Clark (@adamclarkitv) <a href=\"https:\/\/twitter.com\/adamclarkitv\/status\/1357002525795352576?ref_src=twsrc%5Etfw\">February 3, 2021<\/a><\/p><\/blockquote>\n<p><script async src=\"https:\/\/platform.twitter.com\/widgets.js\" charset=\"utf-8\"><\/script><\/p>\n<p>.<\/p>\n<p>I guess everyone can now tell how it is that the White Cliffs of Dover stay white &#8211; and such collapses are not unusual.\u00a0 Indeed <a href=\"https:\/\/blogs.agu.org\/landslideblog\/2012\/03\/15\/the-dover-chalk-cliff-rockfall-in-the-context-of-other-such-events\/\">I wrote about another event like this in 2012<\/a>.<\/p>\n<p>The event sequence yesterday is interesting though, and the video is valuable.\u00a0 At the very start of the video some precursory rockfalls are seen splashing into the sea, followed by the initial, smaller (but not trivial) collapse.\u00a0 This is followed by the large event a few seconds later.<\/p>\n<p>The main collapse event is shown in the still below:-<\/p>\n<div id=\"attachment_36488\" style=\"width: 510px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-36488\" class=\" wp-image-36488\" src=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2021\/02\/21_02-White-Cliffs-1.jpg\" alt=\"White Cliffs of Dover rockfall\" width=\"500\" height=\"633\" srcset=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2021\/02\/21_02-White-Cliffs-1.jpg 717w, https:\/\/blogs.agu.org\/landslideblog\/files\/2021\/02\/21_02-White-Cliffs-1-237x300.jpg 237w\" sizes=\"auto, (max-width: 500px) 100vw, 500px\" \/><p id=\"caption-attachment-36488\" class=\"wp-caption-text\">The 3 February 2021 White Cliffs of Dover rockfall. <a href=\"https:\/\/twitter.com\/adamclarkitv\/status\/1357002525795352576\">Still from a video tweeted by Adam Clark<\/a>.<\/p><\/div>\n<p>.<\/p>\n<p>In the mid section of the cliff there is a large toppling failure, with a big slab of rock rotating away from the cliff.\u00a0 This releases a large volume of more weathered material from upslope:-<\/p>\n<div id=\"attachment_36490\" style=\"width: 510px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-36490\" class=\" wp-image-36490\" src=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2021\/02\/21_02-White-Cliffs-2.jpg\" alt=\"3 February 2021 White Cliffs of Dover rockfall.\" width=\"500\" height=\"760\" srcset=\"https:\/\/blogs.agu.org\/landslideblog\/files\/2021\/02\/21_02-White-Cliffs-2.jpg 719w, https:\/\/blogs.agu.org\/landslideblog\/files\/2021\/02\/21_02-White-Cliffs-2-198x300.jpg 198w, https:\/\/blogs.agu.org\/landslideblog\/files\/2021\/02\/21_02-White-Cliffs-2-674x1024.jpg 674w\" sizes=\"auto, (max-width: 500px) 100vw, 500px\" \/><p id=\"caption-attachment-36490\" class=\"wp-caption-text\">The latter stages of the 3 February 2021 White Cliffs of Dover rockfall. <a href=\"https:\/\/twitter.com\/adamclarkitv\/status\/1357002525795352576\">Still from a video tweeted by Adam Clark<\/a>.<\/p><\/div>\n<p>.<\/p>\n<p>Large rockfalls from chalk cliffs are well-documented.\u00a0 There is a considerable evidence that smaller falls occur throughout the year, but the largest collapses are associated with the wetter and cooler months.\u00a0 This is probably an indication that moisture in the chalk plays a key role in the development of failure, perhaps through cycles of wetting and drying.\u00a0 It is interesting to note that January in the UK was unusually cold (the coldest January in a decade) and unusually wet.<\/p>\n<p>My colleague here at the University of Sheffield, <a href=\"https:\/\/www.sheffield.ac.uk\/civil\/people\/academic\/elisabeth-bowman\">Dr Lis Bowman<\/a> (<a href=\"https:\/\/twitter.com\/lis_bowman\">@lis_bowman<\/a>) has studied these large cliff collapses.\u00a0 The largest coastal chalk collapses have unusual mobility (i.e. they travel large distances), a behaviour that <a href=\"https:\/\/link.springer.com\/article\/10.1007\/s10346-014-0472-2\">Bowman and Take (2015)<\/a> suggest may be associated with sturzstrom-like (i.e. rock avalanche) behaviour, which is usually seen in much larger rock slope failures.<\/p>\n<p>.<\/p>\n<h4>Reference<\/h4>\n<p>Bowman, E.T. and Take, W.A. 2015 <a href=\"https:\/\/link.springer.com\/article\/10.1007\/s10346-014-0472-2\">The runout of chalk cliff collapses in England and France\u2014case studies and physical model experiments.<\/a> <i>Landslides<\/i>\u00a0<b>12,\u00a0<\/b>225\u2013239 (2015). https:\/\/doi.org\/10.1007\/s10346-014-0472-2<\/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 3 February 2021 White Cliffs of Dover chalk cliff collapse in Kent, England, which was caught on a brilliant video.   <!-- 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":36488,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[29],"tags":[611,243,182,144,469,30010,963,56,133],"class_list":["post-36483","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-landslide-video","tag-chalk","tag-cliff","tag-england","tag-europe","tag-featured","tag-kent","tag-landslide-video","tag-rockfall","tag-uk"],"_links":{"self":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/36483","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=36483"}],"version-history":[{"count":0,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/36483\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media\/36488"}],"wp:attachment":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media?parent=36483"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/categories?post=36483"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/tags?post=36483"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}