{"id":12152,"date":"2016-05-09T18:54:59","date_gmt":"2016-05-09T16:54:59","guid":{"rendered":"http:\/\/www.laterredufutur.com\/accueil\/?p=12152"},"modified":"2016-05-09T18:54:59","modified_gmt":"2016-05-09T16:54:59","slug":"il-y-a-36-ans-le-mont-st-helens-explosait-et-aujourdhui-que-se-passe-t-il","status":"publish","type":"post","link":"https:\/\/www.laterredufutur.com\/accueil\/il-y-a-36-ans-le-mont-st-helens-explosait-et-aujourdhui-que-se-passe-t-il\/","title":{"rendered":"Il y a 36 ans, le Mont St Helens explosait et aujourd&rsquo;hui que se passe t-il ?"},"content":{"rendered":"<div class=\"1665f18d14f35dd9e7566e1a8ac9a3e9\" data-index=\"1\" style=\"float: none; margin:10px 0 10px 0; text-align:center;\">\n<script async src=\"https:\/\/pagead2.googlesyndication.com\/pagead\/js\/adsbygoogle.js\"><\/script>\r\n<ins class=\"adsbygoogle\"\r\n     style=\"display:block; text-align:center;\"\r\n     data-ad-layout=\"in-article\"\r\n     data-ad-format=\"fluid\"\r\n     data-ad-client=\"ca-pub-2860849627502538\"\r\n     data-ad-slot=\"3019501113\"><\/ins>\r\n<script>\r\n     (adsbygoogle = window.adsbygoogle || []).push({});\r\n<\/script>\n<\/div>\n<p style=\"text-align: justify;\">En 1980, survenait dans l\u2019ouest des Etats-Unis l\u2019une des \u00e9ruptions les plus violentes de ces derniers mill\u00e9naires. Le Mont St Helens \u00e9tait en activit\u00e9 depuis quelques semaines lorsque, le 18 mai 1980 au matin, toute la partie sommitale explosa, changeant l\u2019aspect du volcan et de la r\u00e9gion pour les ann\u00e9es \u00e0 venir&#8230;<\/p>\n<p style=\"text-align: justify;\">Mais depuis le d\u00e9but de 2016, le Mt. St. Helens a connu une s\u00e9rie d&rsquo;activit\u00e9 sismique sous sa surface. Les scientifiques de l&rsquo;United States Geological Survey (USGS) ont \u00e9t\u00e9 interpell\u00e9s par cet essaim de tremblements de terre, quelques 130 petites secousses sur une p\u00e9riode de huit semaines, c&rsquo;est comme une p\u00e9riode de \u00abrecharge\u00bb du volcan &#8211; cela implique la mont\u00e9e du magma dans le volcan car il \u00e9tait calme auparavant.<\/p>\n<p style=\"text-align: justify;\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" data-attachment-id=\"12153\" data-permalink=\"https:\/\/www.laterredufutur.com\/accueil\/il-y-a-36-ans-le-mont-st-helens-explosait-et-aujourdhui-que-se-passe-t-il\/mont-st-helens\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2016\/05\/mont-st-helens.jpg?fit=637%2C426&amp;ssl=1\" data-orig-size=\"637,426\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"mont-st-helens\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2016\/05\/mont-st-helens.jpg?fit=637%2C426&amp;ssl=1\" class=\"alignnone size-full wp-image-12153\" src=\"https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2016\/05\/mont-st-helens.jpg?resize=637%2C426\" alt=\"mont-st-helens\" width=\"637\" height=\"426\" srcset=\"https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2016\/05\/mont-st-helens.jpg?w=637&amp;ssl=1 637w, https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2016\/05\/mont-st-helens.jpg?resize=300%2C201&amp;ssl=1 300w\" sizes=\"auto, (max-width: 637px) 100vw, 637px\" \/><\/p>\n<p style=\"text-align: justify;\">Mais est ce que cela signifie que le Mt. St. Helens va entrer en \u00e9ruption ? Selon Zach Johnston Uproxx, il nous dit qu&rsquo;il est peu probable qu&rsquo;il entre en \u00e9ruption. Johnston affirme que, selon les donn\u00e9es compil\u00e9es de l&rsquo;USGS, le volcan a connu ces p\u00e9riodes de micro-tremblements de terre en dessous de la surface plusieurs fois par le pass\u00e9, \u00e0 la fois dans les ann\u00e9es 1990 et encore r\u00e9cemment en 2013 et 2014. Les tremblements de terre laissent tout simplement la montagne de se rel\u00e2cher efficacement (ce qui correspond \u00e0 cette pression sismique) avant qu&rsquo;elle ne puisse s\u00e9rieusement entrer en \u00e9ruption. Johnston affirme que le Mt. St. Helens n&rsquo;a tout simplement pas assez de jus pour exploser.<\/p><div class=\"1665f18d14f35dd9e7566e1a8ac9a3e9\" data-index=\"2\" style=\"float: none; margin:10px 0 10px 0; text-align:center;\">\n<script async src=\"https:\/\/pagead2.googlesyndication.com\/pagead\/js\/adsbygoogle.js\"><\/script>\r\n<ins class=\"adsbygoogle\"\r\n     style=\"display:block; text-align:center;\"\r\n     data-ad-layout=\"in-article\"\r\n     data-ad-format=\"fluid\"\r\n     data-ad-client=\"ca-pub-2860849627502538\"\r\n     data-ad-slot=\"3019501113\"><\/ins>\r\n<script>\r\n     (adsbygoogle = window.adsbygoogle || []).push({});\r\n<\/script>\n<\/div>\n\n<p style=\"text-align: justify;\">L&rsquo;USGS lui-m\u00eame est sceptique sur le fait que le Mt. St. Helens exploserait de la m\u00eame mani\u00e8re qu&rsquo;en 1980, quand il est devenu l&rsquo;\u00e9ruption volcanique la plus \u00e9tudi\u00e9e aux \u00c9tats-Unis au 20e si\u00e8cle. L&rsquo;\u00e9ruption volcanique de cette ann\u00e9e 1980 tua 57 personnes et a \u00e9t\u00e9 consid\u00e9r\u00e9 comme l&rsquo;une des pires catastrophes naturelles qui a jamais frapp\u00e9 les \u00c9tats-Unis. L&rsquo;explosion initiale a aplati 150.000 acres d&rsquo;arbres, a d\u00e9clench\u00e9 l&rsquo;un des plus grands glissements de terrain jamais vu, et de cendres qui ont vol\u00e9 aussi loin que le centre du Montana.<\/p>\n<p style=\"text-align: justify;\">Pourtant, l&rsquo;USGS appelle \u00e0 la prudence. \u00ab\u00a0&#8230; Il n&rsquo;y a absolument aucun signe que le\u00a0Mt. St. Helens va exploser\u00a0de sit\u00f4t, mais les donn\u00e9es que nous collectons nous disent que le volcan est toujours tr\u00e8s vivant,\u00a0\u00bb ont indiqu\u00e9 des responsables, selon CNN cette semaine (d\u00e9but mai 2016). Dans une d\u00e9claration sur le site Web de l&rsquo; USGS, un porte &#8211; parole a d\u00e9clar\u00e9 qu&rsquo;\u00ab aucun gaz anormal, qu&rsquo;aucune augmentation de l&rsquo;inflation du\u00a0sol ou sismicit\u00e9 anormale\u00a0ont \u00e9t\u00e9 d\u00e9tect\u00e9s avec cet essaim, et il n&rsquo;y a aucun signe d&rsquo;une \u00e9ruption imminente.\u00a0\u00bb<\/p>\n<p style=\"text-align: justify;\">Bien que personnellement, je ne crois pas que le Mt. <span class=\"goog-text-highlight\">St. Helens puisse exploser \u00e0\u00a0nouveau et\u00a0de sit\u00f4t, je sais que je\u00a0dois garder\u00a0un \u0153il tr\u00e8s attentif sur\u00a0les param\u00e8tres que\u00a0nous surveillons.<\/span><\/p>\n<p>Adaptation et traduction de <a href=\"http:\/\/www.laterredufutur.com\/accueil\/\">la Terre du Futur<\/a><\/p>\n<p>sources : <a href=\"http:\/\/www.futura-sciences.com\/magazines\/terre\/infos\/actu\/d\/geologie-il-y-30-ans-mont-st-helens-explosait-23788\/\" target=\"_blank\">http:\/\/www.futura-sciences.com\/<\/a> \/ <a href=\"https:\/\/www.romper.com\/p\/will-mt-st-helens-erupt-recent-earthquakes-give-us-a-clue-10249\" target=\"_blank\">https:\/\/www.romper.com<\/a><\/p>\n<p class=\"bawpvc-ajax-counter\" data-id=\"12152\">(2831)<\/p>\n<!--CusAds0-->\n<div style=\"font-size: 0px; height: 0px; line-height: 0px; margin: 0; padding: 0; clear: both;\"><\/div>","protected":false},"excerpt":{"rendered":"<p>En 1980, survenait dans l\u2019ouest des Etats-Unis l\u2019une des \u00e9ruptions les plus violentes de ces derniers mill\u00e9naires. Le Mont St&#8230;<\/p>\n","protected":false},"author":1,"featured_media":12154,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_exactmetrics_skip_tracking":false,"_exactmetrics_sitenote_active":false,"_exactmetrics_sitenote_note":"","_exactmetrics_sitenote_category":0,"ngg_post_thumbnail":0,"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"Il y a 36 ans, le Mont #St Helens explosait et aujourd'hui que se passe t-il ? @laterredufutur","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[19],"tags":[374,742,671,5024,347,1666,48],"class_list":["post-12152","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-seismes-et-volcans","tag-eruption","tag-eruption-volcanique","tag-explosion","tag-mont-saint-helens","tag-seisme","tag-usgs","tag-volcan","wpcat-19-id"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2016\/05\/mt_st_Helens.jpg?fit=973%2C608&ssl=1","jetpack_shortlink":"https:\/\/wp.me\/p631RN-3a0","jetpack-related-posts":[{"id":18127,"url":"https:\/\/www.laterredufutur.com\/accueil\/le-dome-du-mont-st-helens-seleve-de-5-metres-par-jour\/","url_meta":{"origin":12152,"position":0},"title":"Le d\u00f4me du mont St Helens s&rsquo;\u00e9l\u00e8ve de 5 m\u00e8tres par jour","author":"Admin","date":"28 janvier 2019","format":false,"excerpt":"Le Mont Saint Helens pourrait \u00e0 nouveau entrer en \u00e9ruption alors que les scientifiques surveillent de pr\u00e8s un d\u00f4me de lave s'\u00e9levant de cinq m\u00e8tres par jour. Un scientifique de l'USGS ajoute: \u00ab Ce qui est vraiment ph\u00e9nom\u00e9nal, c'est la quantit\u00e9 de roche qui sort encore du sol. Il est\u2026","rel":"","context":"Dans &quot;Seismes\/Volcans&quot;","block_context":{"text":"Seismes\/Volcans","link":"https:\/\/www.laterredufutur.com\/accueil\/sujets\/seismes-et-volcans\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2019\/01\/mont-st-helens.jpg?fit=1024%2C576&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2019\/01\/mont-st-helens.jpg?fit=1024%2C576&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2019\/01\/mont-st-helens.jpg?fit=1024%2C576&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2019\/01\/mont-st-helens.jpg?fit=1024%2C576&ssl=1&resize=700%2C400 2x"},"classes":[]},{"id":6696,"url":"https:\/\/www.laterredufutur.com\/accueil\/eruption-du-mont-st-helens-le-18-mai-1980\/","url_meta":{"origin":12152,"position":1},"title":"Eruption du Mont St. Helens, le 18 mai 1980","author":"Admin","date":"19 mai 2015","format":false,"excerpt":"A 15h45, le 18 mai 1980, GOES-3 a pris cette image visible du Pacifique Nord-Ouest montrant l'\u00e9ruption massive du mont St. Helens dans la partie ouest de la cha\u00eene des Cascades. Un grand panache pyroclastique de fum\u00e9es et de cendres peut \u00eatre vu dans le centre de l'image qui a\u2026","rel":"","context":"Dans &quot;Seismes\/Volcans&quot;","block_context":{"text":"Seismes\/Volcans","link":"https:\/\/www.laterredufutur.com\/accueil\/sujets\/seismes-et-volcans\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2015\/05\/mont-st-helen-18-mai-1980.jpg?fit=1200%2C675&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2015\/05\/mont-st-helen-18-mai-1980.jpg?fit=1200%2C675&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2015\/05\/mont-st-helen-18-mai-1980.jpg?fit=1200%2C675&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2015\/05\/mont-st-helen-18-mai-1980.jpg?fit=1200%2C675&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2015\/05\/mont-st-helen-18-mai-1980.jpg?fit=1200%2C675&ssl=1&resize=1050%2C600 3x"},"classes":[]},{"id":1926,"url":"https:\/\/www.laterredufutur.com\/accueil\/que-se-passe-t-il-au-yellowstone\/","url_meta":{"origin":12152,"position":2},"title":"Que se passe t-il au Yellowstone ?","author":"Admin","date":"3 avril 2014","format":false,"excerpt":"Que se passe t-il au Yellowstone ? Suite au tremblement de terre de 4.8, C'est le plus important au Yellowstone depuis 1980, selon le US Geological Survey. Depuis plusieurs semaines, des bloggeurs ont pu filmer des troupeaux de bisons fuyant le parc naturel de Yellowstone secou\u00e9 par des petits tremblements\u2026","rel":"","context":"Dans &quot;Seismes\/Volcans&quot;","block_context":{"text":"Seismes\/Volcans","link":"https:\/\/www.laterredufutur.com\/accueil\/sujets\/seismes-et-volcans\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2014\/04\/.._spaw_images_img94.gif?fit=410%2C281&ssl=1&resize=350%2C200","width":350,"height":200},"classes":[]},{"id":9210,"url":"https:\/\/www.laterredufutur.com\/accueil\/decouverte-de-2-chambres-magmatiques-sur-le-mont-saint-helens\/","url_meta":{"origin":12152,"position":3},"title":"D\u00e9couverte de 2 chambres magmatiques sur le mont Saint Helens","author":"Admin","date":"18 novembre 2015","format":false,"excerpt":"Lentement mais s\u00fbrement, les volcans livrent leurs secrets. On vient ainsi de r\u00e9aliser une tomographie sismique sous le c\u00e9l\u00e8bre mont Saint Helens. Elle a r\u00e9v\u00e9l\u00e9 l\u2019existence de deux chambres magmatiques et sugg\u00e9r\u00e9 l\u2019existence d\u2019une connexion entre elles qui serait peut-\u00eatre \u00e0 l\u2019origine de la fameuse \u00e9ruption du 18 mai 1980.\u2026","rel":"","context":"Dans &quot;Seismes\/Volcans&quot;","block_context":{"text":"Seismes\/Volcans","link":"https:\/\/www.laterredufutur.com\/accueil\/sujets\/seismes-et-volcans\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2015\/11\/Mount_St_Helens.jpg?fit=624%2C352&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2015\/11\/Mount_St_Helens.jpg?fit=624%2C352&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2015\/11\/Mount_St_Helens.jpg?fit=624%2C352&ssl=1&resize=525%2C300 1.5x"},"classes":[]},{"id":2735,"url":"https:\/\/www.laterredufutur.com\/accueil\/periodicite-surprenante\/","url_meta":{"origin":12152,"position":4},"title":"P\u00e9riodicit\u00e9 surprenante","author":"Admin","date":"10 mars 2005","format":false,"excerpt":"Une \u00e9ruption volcanique de forte ampleur peut influencer le climat d'une fa\u00e7on importante pour plusieurs ann\u00e9es. Bien que les \u00e9ruptions elles-m\u00eames ne soient cependant pas pr\u00e9visibles, on peut avoir une id\u00e9e sur l'effet sur le climat. Benjamin Franklin (1706-1790) a \u00e9t\u00e9 le premier \u00e0 voir que les \u00e9ruptions volcaniques ont\u2026","rel":"","context":"Dans &quot;Seismes\/Volcans&quot;","block_context":{"text":"Seismes\/Volcans","link":"https:\/\/www.laterredufutur.com\/accueil\/sujets\/seismes-et-volcans\/"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":5498,"url":"https:\/\/www.laterredufutur.com\/accueil\/le-supervolcan-de-toba\/","url_meta":{"origin":12152,"position":5},"title":"Le Supervolcan De Toba","author":"Admin","date":"20 ao\u00fbt 2010","format":false,"excerpt":"Il y a 75000 ans, en Indon\u00e9sie, une \u00e9ruption g\u00e9ante faillit d\u00e9truire la Terre. Le supervolcan s'est-il endormi \u00e0 jamais ? L'hypoth\u00e8se d'une gigantesque \u00e9ruption volcanique survenue entre -75000 et -70000 ans, d'une puissance peut-\u00eatre 1000 fois sup\u00e9rieure \u00e0 toutes celles que l'humanit\u00e9 \u00e0 connu jusque-l\u00e0, date de 1994. Le\u2026","rel":"","context":"Dans &quot;Seismes\/Volcans&quot;","block_context":{"text":"Seismes\/Volcans","link":"https:\/\/www.laterredufutur.com\/accueil\/sujets\/seismes-et-volcans\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2015\/06\/toba_caldeira1.jpg?fit=1024%2C768&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2015\/06\/toba_caldeira1.jpg?fit=1024%2C768&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2015\/06\/toba_caldeira1.jpg?fit=1024%2C768&ssl=1&resize=525%2C300 1.5x, https:\/\/i0.wp.com\/www.laterredufutur.com\/accueil\/wp-content\/uploads\/2015\/06\/toba_caldeira1.jpg?fit=1024%2C768&ssl=1&resize=700%2C400 2x"},"classes":[]}],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.laterredufutur.com\/accueil\/wp-json\/wp\/v2\/posts\/12152","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.laterredufutur.com\/accueil\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.laterredufutur.com\/accueil\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.laterredufutur.com\/accueil\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.laterredufutur.com\/accueil\/wp-json\/wp\/v2\/comments?post=12152"}],"version-history":[{"count":1,"href":"https:\/\/www.laterredufutur.com\/accueil\/wp-json\/wp\/v2\/posts\/12152\/revisions"}],"predecessor-version":[{"id":12155,"href":"https:\/\/www.laterredufutur.com\/accueil\/wp-json\/wp\/v2\/posts\/12152\/revisions\/12155"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.laterredufutur.com\/accueil\/wp-json\/wp\/v2\/media\/12154"}],"wp:attachment":[{"href":"https:\/\/www.laterredufutur.com\/accueil\/wp-json\/wp\/v2\/media?parent=12152"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.laterredufutur.com\/accueil\/wp-json\/wp\/v2\/categories?post=12152"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.laterredufutur.com\/accueil\/wp-json\/wp\/v2\/tags?post=12152"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}