{"id":18721,"date":"2016-05-19T07:12:13","date_gmt":"2016-05-19T07:12:13","guid":{"rendered":"http:\/\/blogs.agu.org\/landslideblog\/?p=18721"},"modified":"2016-05-19T07:12:13","modified_gmt":"2016-05-19T07:12:13","slug":"aranayake-1","status":"publish","type":"post","link":"https:\/\/blogs.agu.org\/landslideblog\/2016\/05\/19\/aranayake-1\/","title":{"rendered":"The Aranayake landslide in Sri Lanka"},"content":{"rendered":"
The Aranayake landslide in Sri Lanka<\/h5>\n

Aranayake landslide in Sri Lanka is now thought to have killed about 140 people, from which the remains of 19 victims have been recovered to date.\u00a0 The landslide was triggered by exceptional rainfall associated with a slow moving tropical cyclone.\u00a0 Some reports suggest more than 350 mm may have fallen.\u00a0 The best overview image of the landslide that I have seen to date is this one, by AP and posted on the BBC website<\/a>:<\/p>\n

\"Aranayake

The Aranayake landslide in Sri Lanka via the BBC<\/a> and AP<\/p><\/div>\n

.<\/p>\n

This is a complex landslide.\u00a0 It appears to have started as a small landslide high on the hillslope – is there a hint of bedrock in that area?\u00a0 I suspect so, which might suggest regolith sliding on a bedrock interface.\u00a0 That then appears to have induced a much more substantial failure on the steeper sections downslope, with three main portions.\u00a0 There is certainly bedrock evident in this area, but the mobile material appears to be deeply weathered soil \/ regolith.\u00a0 Finally, the displaced material appears to have turned into a highly mobile flow that has channelised.\u00a0 It is this portion of the landslide that is likely to have caused the loss of life.\u00a0 I would also note from this image that the underlying geological structure here might be highly complex – note the different inclinations of the rock surface visible on the ridge to the left compared with the bedrock visible in the slide itself.\u00a0 This suggests that there could be a structural element to this as well, perhaps.<\/p>\n

More detail is available about the sliding surface in this image, which was tweeted by the Sri Lanka Red Cross<\/a> yesterday:<\/p>\n

\"Aranayake

The Sliding surface of the Aranayake landslide, via the Sri Lanka Red Cross<\/a><\/p><\/div>\n

.<\/p>\n

In this image it is clear that the main landslide on the steeper slopes consisted of regolith sliding on a bedrock interface.\u00a0 The Sri Lanka Red Cross<\/a> have also tweeted this helicopter image of the lower portion of the landslide, which illustrates the highly mobile nature of the mass movement:<\/p>\n

\"Aranayake

Sri Lanka Red Cross<\/a> image of the lower portion of the Aranayake landslide<\/p><\/div>\n

.<\/p>\n

Reports today suggest that rescue operations have been suspended today due to further landslide movement associated with heavy rainfall.\u00a0 This will be a very dangerous site until the weather clears up and the ground dries out.\u00a0 The monsoon is not far away.<\/p>\n

I believe that this Google Earth image shows the location of the landslide:<\/p>\n

\"Aranayake

Google Earth image of the Aranayake landslide in Sri Lanka<\/p><\/div>\n

.<\/p>\n

Pallebage (location: 6.9639, 80.4209) is reported to be one of the communities destroyed by the landslide.\u00a0 However, so far I have been unable to pin the location down more precisely.\u00a0 Viewing the Google Earth image from directly above leaves me with a suspicion that this might not have been the first major landslide on this hillside.\u00a0 I have indicated the location of a possible large, much older landslide:<\/p>\n

\"Aranayake

Google Earth image of a possible older landslide site close to the Aranayake landslide location<\/p><\/div>\n

.<\/p>\n","protected":false},"excerpt":{"rendered":"

The Aranayake landslide in Sri Lanka is now thought to have killed about 140 people. Images are becoming available of this complex landslide<\/p>\n","protected":false},"author":22,"featured_media":18723,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[1122,523,469,959,72,82],"class_list":["post-18721","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-landslide-report","tag-complex-landslide","tag-cyclone","tag-featured","tag-landslide-report","tag-south-asia","tag-sri-lanka"],"_links":{"self":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/18721","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=18721"}],"version-history":[{"count":0,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/18721\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media\/18723"}],"wp:attachment":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media?parent=18721"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/categories?post=18721"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/tags?post=18721"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}