{"id":27245,"date":"2018-03-22T07:57:04","date_gmt":"2018-03-22T07:57:04","guid":{"rendered":"https:\/\/blogs.agu.org\/landslideblog\/?p=27245"},"modified":"2018-03-22T19:52:24","modified_gmt":"2018-03-22T19:52:24","slug":"wairoa-1","status":"publish","type":"post","link":"https:\/\/blogs.agu.org\/landslideblog\/2018\/03\/22\/wairoa-1\/","title":{"rendered":"Wairoa: a significant valley-blocking landslide in New Zealand"},"content":{"rendered":"

Wairoa: a significant valley-blocking landslide in New Zealand<\/h4>\n

A significant valley-blocking landslide<\/a> has occurred on a tributary of the Wairoa River, to the west of Gisborne, in the North Island of New Zealand.\u00a0 The landslide is large – Radio New Zealand reports<\/a> about 80 million tonnes (presumably about 30 million m\u00b3) [see the comment at the bottom of the article – this is more likely to be about 8 million tonnes], and Google Earth indicates that it is over 1 km long.\u00a0 The Mangapoike River, the specific tributary of the Wairoa Rver, is blocked.\u00a0 The impounded lake is currently about 50 m deep and is rising at 60 cm per day.\u00a0 There is a significant risk of a breach, but fortunately this is a sparsely populated area of New Zealand.\u00a0 Reports suggest<\/a> that it was triggered by a localised earthquake earlier in March 2018.<\/p>\n

This is the site of the landslide on Google Earth.\u00a0 I have placed the market at the approximate crown of the landslide.\u00a0 The image was collected in early 2011:-<\/p>\n

\"Wairoa

Google Earth image of the site of the Wairoa River landslide in New Zealand.<\/p><\/div>\n

.<\/p>\n

This image shows that this was a pre-existing landslide that has been creeping.\u00a0 Lateral scarps are evident on both flanks, and the area on the left of the landslide shows clear evidence of tension cracks.\u00a0 It appears that there was active erosion occurring at the toe of the slope.<\/p>\n

This is a Planet Labs image<\/a> of the landslide, collected on 12th March 2018 and used with permission:-<\/p>\n

\"Wairoa

Planet Labs image<\/a>, collected on 12th March 2018, showing the landslide on the Mangapoike River near to Wairoa in New Zealand.<\/p><\/div>\n

.<\/p>\n

The image clearly shows the landslide scar and the deposit at the toe that has blocked the river. The lake is also clearly evident.\u00a0 Note that at present this is not large in terms of extent, but it has the potential to generate a significant flood event.\u00a0 Fortunately New Zealand has very considerable experience in dealing with these types of events.<\/p>\n

Reference<\/h4>\n

Planet Team (2017). Planet Application Program Interface: In Space for Life on Earth. San Francisco, CA.\u00a0https:\/\/api.planet.com<\/a><\/p>\n

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

A significant valley-blocking landslide has occurred near to Wairoa in New Zealand. The Mangapoike River is blocked and a lake estimated to be 50 m deep has formed<\/p>\n","protected":false},"author":22,"featured_media":27251,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[469,959,7,898,688],"class_list":["post-27245","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-landslide-report","tag-featured","tag-landslide-report","tag-new-zealand","tag-planet","tag-valley-blocking-landslide"],"_links":{"self":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/27245","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=27245"}],"version-history":[{"count":0,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/27245\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media\/27251"}],"wp:attachment":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media?parent=27245"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/categories?post=27245"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/tags?post=27245"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}