{"id":22009,"date":"2017-02-27T07:40:30","date_gmt":"2017-02-27T07:40:30","guid":{"rendered":"http:\/\/blogs.agu.org\/landslideblog\/?p=22009"},"modified":"2017-02-27T07:40:30","modified_gmt":"2017-02-27T07:40:30","slug":"niwa-1","status":"publish","type":"post","link":"https:\/\/blogs.agu.org\/landslideblog\/2017\/02\/27\/niwa-1\/","title":{"rendered":"NIWA maps huge submarine landslides triggered by the Kaikoura earthquakes"},"content":{"rendered":"
NIWA maps huge submarine landslides triggered by the Kaikoura earthquakes<\/h5>\n

NIWA<\/a>, the National Institute of Water and Atmospheric Research in New Zealand, has put out a press release today regarding submarine landslides triggered by the Kaikoura earthquakes<\/a>.\u00a0 We know that the main shock, and the aftershocks, triggered large numbers of landslides onshore<\/a>.\u00a0 The picture on the seafloor was less certain, and is of course harder to determine.\u00a0 The interesting aspect of this is that offshore Kaikoura lies a submarine canyon – the Kaikoura Canyon –\u00a0 which is rather beautifully depicted in this NIWA press release from 2011<\/a>:<\/p>\n

\"NIWA\"

The Kaikoura Canyon, via NIWA<\/a><\/p><\/div>\n

.<\/p>\n

The interest in this canyon, and hence in its landslides, is more than merely academic.\u00a0 As the 2011 press release notes<\/a>:<\/p>\n

The Kaikoura Canyon is one of the most productive benthic (ocean floor) deep-sea habitats yet described, exceeding by 100 times the highest biomass measured for large invertebrates in at depths below 500 m at similar habitats, except for around hydrothermal vents. This productivity may contribute significantly to the surrounding ecosystem, which includes deep commercial fisheries for hoki and orange roughy.<\/p>\n

The research showed very dense populations of large invertebrates, burrowing sea cucumbers, spoon worms, bristle worms and irregular urchins at depths of 900-1100 m.<\/p><\/blockquote>\n

It is this biodiversity that attracts the whales for which Kaikoura is known.\u00a0 The impact of large submarine landslides in the canyon is thus of critical importance.<\/p>\n

NIWA have undertaken two research cruises to the canyon since the Kaikoura earthquake.\u00a0 They have found evidence of large landslides through the canyon<\/a>:<\/p>\n

…the latest post-quake surveys found not one instance of an organism living on or in the seabed.\u00a0 NIWA marine geologist Dr Joshua Mountjoy said a huge slipping event caused by the earthquake had removed the mud – where organisms had flourished – from the canyon’s upper slope.<\/p>\n

“[Previously] everything at the head of the canyon was smooth and draped in mud. Our new data shows … almost every part of the upper slope had mud removed from it.”<\/p>\n

The amount of material that had cascaded through the canyon was massive, he said.<\/p>\n

“Some individual landslides are more than three times the size of the landslides that damaged the road to the north of Kaik\u014dura.”<\/p><\/blockquote>\n

NIWA have released a before and after image of the landslides:<\/p>\n

\"NIWA\"

Pre-earthquake image of Kaikoura Canyon, via NIWA<\/a><\/p><\/div>\n

\"NIWA\"

Post earthquake submarine landslides in the Kaikoura Canyon, via NIWA<\/a><\/p><\/div>\n

.<\/p>\n

Whilst the scale on these images is absent (which is frustrating), the amount of change is clear.\u00a0 It will be interesting to see how an inventory of submarine landslides compares with one for the terrestrial environment.\u00a0 I am not sure that such a comparison has been made previously.\u00a0 Others will be able to comment on the short and long term implications for marine organisms.<\/p>\n","protected":false},"excerpt":{"rendered":"

In New Zealand, two research cruises by NIWA have mapped massive submarine landslides triggered by the Kaikoura earthquakes<\/p>\n","protected":false},"author":22,"featured_media":22041,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_members_access_role":[],"_members_access_error":""},"categories":[537],"tags":[23,469,1213,7,129],"class_list":["post-22009","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-earthquake-induced-landslide","tag-earthquake","tag-featured","tag-kaikoura","tag-new-zealand","tag-submarine-landslide"],"_links":{"self":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/22009","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=22009"}],"version-history":[{"count":0,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/22009\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media\/22041"}],"wp:attachment":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media?parent=22009"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/categories?post=22009"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/tags?post=22009"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}