{"id":28545,"date":"2018-09-05T22:39:27","date_gmt":"2018-09-05T22:39:27","guid":{"rendered":"https:\/\/blogs.agu.org\/landslideblog\/?p=28545"},"modified":"2018-09-05T22:39:27","modified_gmt":"2018-09-05T22:39:27","slug":"mw6-6-hokkaido-earthquake-in-japan-1","status":"publish","type":"post","link":"https:\/\/blogs.agu.org\/landslideblog\/2018\/09\/05\/mw6-6-hokkaido-earthquake-in-japan-1\/","title":{"rendered":"The Mw=6.6 earthquake in Hokkaido, Japan: early indications of significant landslides"},"content":{"rendered":"

The Mw=6.6 Hokkaido earthquake in Japan: early indications of significant landslides<\/h4>\n

The Mw=6.6 earthquake in Hokkaido, Japan at 3:08 am local time today<\/a> appears to have generated significant numbers of landslides.\u00a0 On Twitter, Jamie Gurney<\/a> has captured two images<\/a> from a live broadcast on the Japanese broadcaster NHK<\/a> that indicate that in at least a part of the earthquake-affected area, many large landslides have been triggered:-<\/p>\n

\"Mw=6.6

Landslides from the Mw=6.6 earthquake in Hokkaido, Japan. Image from a live broadcast by NHK<\/a>, via Jamie Gurney<\/a>.<\/p><\/div>\n

.<\/p>\n

These are classic co-seismic landslides, apparently being triggered at the ridge crest and then involving the entire length of the slope.\u00a0 Note the two landslides on the left of the image that appear to have run out a significant distance onto the flatlands.\u00a0 One of these appears to involve a substantially damaged building.<\/p>\n

The image below, also from NHK<\/a> via Jamie Gurney<\/a>, shows another area of earthquake-induced landslides:-<\/p>\n

\"Mw=6.6

Detail on one of the landslides from the Mw=6.6 earthquake in Hokkaido, Japan. Image from a live broadcast by NHK<\/a>, via Jamie Gurney<\/a>.<\/p><\/div>\n

.<\/p>\n

In this case there appears to be substantial damage to properties and a road.\u00a0 It seems likely that there will be casualties.<\/p>\n

Interestingly, as Sotiris Valkaniotis<\/a> has also pointed out on Twitter, the USGS Pager landslide model<\/a> appears to be doing a poor job of predicting this level of landsliding.\u00a0 The current first pass estimate of area susceptible to landsliding is very low:-<\/p>\n

\"Mw=6.6

USGS Pager estimate of landslide hazard and population exposure<\/a> for the Mw=6.6 earthquake in Hokkaido, Japan. Image from USGS.<\/p><\/div>\n

.<\/p>\n

That is not a criticism in any way of the model – this stuff is really, really hard.\u00a0 There are two obvious possible explanations.\u00a0 The first is that the PAGER model is not describing the ground shaking well at this stage, which was the point that we made in our recent paper about the Kaikoura earthquake in New Zealand<\/a> (Massey et al.<\/em> 2018<\/a>).\u00a0 The other is that the ground was saturated in the aftermath of Typhoon Jebi, and earlier rainfall events that have affected Japan this summer, leaving the ground much more susceptible to landslides.\u00a0 Such effects are really hard to capture.<\/p>\n

The picture from Hokkaido will become clearer over the next few hours.\u00a0 Please post comments (or send me a Tweet – @davepetley<\/a>) if you have any information or images.<\/p>\n

Reference<\/h4>\n

C. Massey, D. Townsend, E. Rathje, K. E. Allstadt, B. Lukovic, Y. Kaneko, B. Bradley, J. Wartman, R. W. Jibson, D. N. Petley, N. Horspool, I. Hamling, J. Carey, S. Cox, J. Davidson, S. Dellow, J. W. Godt, C. Holden, K. Jones, A. Kaiser, M. Little, B. Lyndsell, S. McColl, R. Morgenstern, F. K. Rengers, D. Rhoades, B. Rosser, D. Strong, C. Singeisen, M. Villeneuve. 2018. Landslides Triggered by the 14 November 2016 M<\/span>w<\/span><\/span><\/span><\/span><\/span><\/span>\u00a07.8 Kaikoura Earthquake, New Zealand<\/a>. Bulletin of the Seismological Society of America<\/em> doi: https:\/\/doi.org\/10.1785\/0120170305<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

Initial images from Japan indicated that the Mw=6.6 earthquake in Hokkaido today has induced significant numbers of landslides <\/p>\n","protected":false},"author":22,"featured_media":28548,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_members_access_role":[],"_members_access_error":""},"categories":[537],"tags":[16802,23,881,361,17148],"class_list":["post-28545","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-earthquake-induced-landslide","tag-coseismic-landslide","tag-earthquake","tag-east-asia","tag-japan","tag-pager"],"_links":{"self":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/28545","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=28545"}],"version-history":[{"count":0,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/posts\/28545\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media\/28548"}],"wp:attachment":[{"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/media?parent=28545"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/categories?post=28545"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blogs.agu.org\/landslideblog\/wp-json\/wp\/v2\/tags?post=28545"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}