{"id":10315,"date":"2022-07-05T17:45:00","date_gmt":"2022-07-05T22:45:00","guid":{"rendered":"http:\/\/all-geo.org\/highlyallochthonous\/?p=10315"},"modified":"2022-11-03T20:26:47","modified_gmt":"2022-11-04T01:26:47","slug":"the-long-term-seismic-impact-of-mega-thrust-earthquakes","status":"publish","type":"post","link":"https:\/\/all-geo.org\/highlyallochthonous\/2022\/07\/the-long-term-seismic-impact-of-mega-thrust-earthquakes\/","title":{"rendered":"The long-term seismic impact of mega thrust earthquakes"},"content":{"rendered":"\n<p><a href=\"https:\/\/temblor.net\/earthquake-insights\/megathrust-earthquakes-impact-surrounding-seismicity-for-centuries-14194\/\">Here\u2019s a very interesting analysis of aftershock patterns in the wake of M9+ megathrust events<\/a>: the aftershocks in a \u2018core\u2019 region closest to the rupture shut off within a few years of the main shock, after which seismicity might remain very low for centuries. However, within a larger \u2018corona\u2019 of stressed rocks around this core region, seismicity is boosted for decades.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"600\" height=\"390\" src=\"https:\/\/all-geo.org\/highlyallochthonous\/wp-content\/uploads\/2022\/11\/FW62OHAWQAAc-NG-600x390.jpeg\" alt=\"Graph of aftershock rate against time relative to background levels for 300 years after a large megathrust earthquake. Schematic in top right shows relative distribution of core (blue) and corona (red) zones, which are plotted separately. In the core, the blue line shows a period of activity below background starting within a few years and persisting for several centuries; in the corona the red line shows a decline to background within a few decades.\" class=\"wp-image-10316\" srcset=\"https:\/\/all-geo.org\/highlyallochthonous\/wp-content\/uploads\/2022\/11\/FW62OHAWQAAc-NG-600x390.jpeg 600w, https:\/\/all-geo.org\/highlyallochthonous\/wp-content\/uploads\/2022\/11\/FW62OHAWQAAc-NG-300x195.jpeg 300w, https:\/\/all-geo.org\/highlyallochthonous\/wp-content\/uploads\/2022\/11\/FW62OHAWQAAc-NG-768x499.jpeg 768w, https:\/\/all-geo.org\/highlyallochthonous\/wp-content\/uploads\/2022\/11\/FW62OHAWQAAc-NG.jpeg 1200w\" sizes=\"auto, (max-width: 600px) 100vw, 600px\" \/><figcaption>Model of aftershock rate against time relative to background levels for 300 years after a large megathrust earthquake. Schematic in top right shows relative distribution of core (blue) and corona (red) zones, which are plotted separately. From Stein &amp; Toda (2022).<\/figcaption><\/figure>\n\n\n\n<p>One think I like about this model is how it reconciles the known history of large earthquakes on the Cascadia megathrust with its historical lack of much seismicity at all, which for some time led us to&nbsp;<a href=\"https:\/\/all-geo.org\/highlyallochthonous\/2011\/06\/the-slowly-building-threat-of-cascadia-and-the-slow-realisation-it-was-there-book-review\/\">dangerously underestimate the risk it posed to the Pacific Northwest<\/a>. It\u2019s still recovering from&nbsp;<a href=\"https:\/\/all-geo.org\/highlyallochthonous\/2017\/01\/317-years-since-the-last-rupture-of-the-cascadia-megathrust\/\">the last rupture in 1700<\/a>. Furthermore, perhaps as it starts to evolve towards rupturing again in the future, we&nbsp;<em>might<\/em>&nbsp;expect to see a bit more low-level seismicity in the \u2018core\u2019 region.<\/p>\n\n\n\n<p>[collated from this <a href=\"https:\/\/twitter.com\/Allochthonous\/status\/1544372073077825544?s=20&amp;t=CAthtn6pAmawPS23DFkdFA\">Twitter thread<\/a>]<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Here\u2019s a very interesting analysis of aftershock patterns in the wake of M9+ megathrust events: the aftershocks in a \u2018core\u2019 region closest to the rupture shut off within a few years of the main shock, after which seismicity might remain &hellip; <a href=\"https:\/\/all-geo.org\/highlyallochthonous\/2022\/07\/the-long-term-seismic-impact-of-mega-thrust-earthquakes\/\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[13,5,4],"tags":[373,898,899],"class_list":["post-10315","post","type-post","status-publish","format-standard","hentry","category-earthquakes","category-geohazards","category-geology","tag-aftershocks","tag-megathrust-earthquakes","tag-subduction-zones"],"_links":{"self":[{"href":"https:\/\/all-geo.org\/highlyallochthonous\/wp-json\/wp\/v2\/posts\/10315","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/all-geo.org\/highlyallochthonous\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/all-geo.org\/highlyallochthonous\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/all-geo.org\/highlyallochthonous\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/all-geo.org\/highlyallochthonous\/wp-json\/wp\/v2\/comments?post=10315"}],"version-history":[{"count":2,"href":"https:\/\/all-geo.org\/highlyallochthonous\/wp-json\/wp\/v2\/posts\/10315\/revisions"}],"predecessor-version":[{"id":10318,"href":"https:\/\/all-geo.org\/highlyallochthonous\/wp-json\/wp\/v2\/posts\/10315\/revisions\/10318"}],"wp:attachment":[{"href":"https:\/\/all-geo.org\/highlyallochthonous\/wp-json\/wp\/v2\/media?parent=10315"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/all-geo.org\/highlyallochthonous\/wp-json\/wp\/v2\/categories?post=10315"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/all-geo.org\/highlyallochthonous\/wp-json\/wp\/v2\/tags?post=10315"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}