{"id":12632,"date":"2021-08-21T19:42:27","date_gmt":"2021-08-21T17:42:27","guid":{"rendered":"http:\/\/volcanx.cluster031.hosting.ovh.net\/?page_id=12632"},"modified":"2021-10-04T19:42:19","modified_gmt":"2021-10-04T17:42:19","slug":"lahars","status":"publish","type":"page","link":"https:\/\/volcanofoundation.org\/fr\/renforcer-la-connaissance-des-risques\/dangers\/lahars\/","title":{"rendered":"LAHARS"},"content":{"rendered":"<div id=\"av_section_1\" class=\"avia-section av-85tvrm-3e95231a7b3e6eb192907f404f41a286 main_color avia-section-default avia-no-border-styling  avia-builder-el-0  el_before_av_section  avia-builder-el-first  avia-full-stretch av-parallax-section avia-bg-style-parallax av-minimum-height av-minimum-height-25 av-height-25  container_wrap fullsize\" data-section-bg-repeat=\"stretch\" data-av_minimum_height_pc=\"25\" data-av_min_height_opt=\"25\"><div class=\"av-parallax\" data-avia-parallax-ratio=\"0.3\"><div class=\"av-parallax-inner main_color avia-full-stretch\"><\/div><\/div><div class=\"container av-section-cont-open\"><main role=\"main\" itemprop=\"mainContentOfPage\" class=\"template-page content  av-content-full alpha units\"><div class=\"post-entry post-entry-type-page post-entry-12632\"><div class=\"entry-content-wrapper clearfix\">\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-377mki-891bdcf97286948f143384db57d78c91\">\n.flex_column.av-377mki-891bdcf97286948f143384db57d78c91{\nborder-radius:0px 0px 0px 0px;\npadding:0px 0px 0px 0px;\n}\n<\/style>\n<div class=\"flex_column av-377mki-891bdcf97286948f143384db57d78c91 av_one_fifth  avia-builder-el-1  el_before_av_three_fifth  avia-builder-el-first  first flex_column_div av-zero-column-padding  \"><\/div>\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-44v1oi-4270c45783cf4dfabc2e0046b5bfca7a\">\n.flex_column.av-44v1oi-4270c45783cf4dfabc2e0046b5bfca7a{\nborder-radius:0px 0px 0px 0px;\npadding:0px 0px 0px 0px;\n}\n<\/style>\n<div class=\"flex_column av-44v1oi-4270c45783cf4dfabc2e0046b5bfca7a av_three_fifth  avia-builder-el-2  el_after_av_one_fifth  el_before_av_one_fifth  flex_column_div av-zero-column-padding  \"><style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-2wneaq-c7141c0f93804d3dc6134a419c02967d\">\n#top .av_textblock_section.av-2wneaq-c7141c0f93804d3dc6134a419c02967d .avia_textblock{\ncolor:#ffffff;\n}\n<\/style>\n<section class=\"av_textblock_section av-2wneaq-c7141c0f93804d3dc6134a419c02967d \" itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/CreativeWork\"><div class=\"avia_textblock av_inherit_color\" itemprop=\"text\"><div class=\"h2-cinta-programas\">\n<h1 style=\"text-align: center; font-size: 2.5em;\">RENFORCER LA CONNAISSANCE DES RISQUES<\/h1>\n<\/div>\n<\/div><\/section><br>\n<section class=\"av_textblock_section av-2wneaq-34462baf835e0e88628f9f1fcf41a06e \" itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/CreativeWork\"><div class=\"avia_textblock\" itemprop=\"text\"><p class=\"p-cinta-programas\" style=\"text-align: center; background: #f5312a !important;\">POURQUOI LA FONDATION EST N&Eacute;E ?<span class=\"flecha-donativo\" style=\"vertical-align: inherit;\"> &gt;<\/span><\/p>\n<\/div><\/section><\/div>\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-377mki-fc3240a24cacc3f72868647236f26abd\">\n.flex_column.av-377mki-fc3240a24cacc3f72868647236f26abd{\nborder-radius:0px 0px 0px 0px;\npadding:0px 0px 0px 0px;\n}\n<\/style>\n<div class=\"flex_column av-377mki-fc3240a24cacc3f72868647236f26abd av_one_fifth  avia-builder-el-5  el_after_av_three_fifth  avia-builder-el-last  flex_column_div av-zero-column-padding  \"><\/div><\/div><\/div><\/main><!-- close content main element --><\/div><\/div>\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-k3yaxsym-b831a12c8acddceb21a18cbb360fd41d\">\n.avia-section.av-k3yaxsym-b831a12c8acddceb21a18cbb360fd41d{\nbackground-color:#000000;\nbackground-image:unset;\n}\n.avia-section.av-k3yaxsym-b831a12c8acddceb21a18cbb360fd41d .av-section-color-overlay{\nopacity:0.9;\nbackground-color:#000000;\n}\n<\/style>\n<div id=\"av_section_2\" class=\"avia-section av-k3yaxsym-b831a12c8acddceb21a18cbb360fd41d main_color avia-section-default avia-no-border-styling  avia-builder-el-6  el_after_av_section  el_before_av_textblock  avia-bg-style-fixed av-section-color-overlay-active container_wrap fullsize\"><div class=\"av-section-color-overlay-wrap\"><div class=\"av-section-color-overlay\"><\/div><div class=\"container av-section-cont-open\"><div class=\"template-page content  av-content-full alpha units\"><div class=\"post-entry post-entry-type-page post-entry-12632\"><div class=\"entry-content-wrapper clearfix\">\n<div class=\"flex_column_table av-a5p0bb-0286912bb6bfb93801b9fa33860921b2 sc-av_one_full av-equal-height-column-flextable\">\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-a5p0bb-0286912bb6bfb93801b9fa33860921b2\">\n.flex_column.av-a5p0bb-0286912bb6bfb93801b9fa33860921b2{\nborder-radius:0px 0px 0px 0px;\npadding:0px 0px 0px 0px;\n}\n<\/style>\n<div class=\"flex_column av-a5p0bb-0286912bb6bfb93801b9fa33860921b2 av_one_full  avia-builder-el-7  avia-builder-el-no-sibling  first flex_column_table_cell av-equal-height-column av-align-middle av-zero-column-padding  \"><style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-joihkone-69e81b3ac324ed7c1268b0d71e700013\">\n#top .av_textblock_section.av-joihkone-69e81b3ac324ed7c1268b0d71e700013 .avia_textblock{\nfont-size:18px;\ncolor:#ffffff;\n}\n\n@media only screen and (min-width: 768px) and (max-width: 989px){ \n#top .av_textblock_section.av-joihkone-69e81b3ac324ed7c1268b0d71e700013 .avia_textblock{\nfont-size:16px;\n}\n}\n\n@media only screen and (min-width: 480px) and (max-width: 767px){ \n#top .av_textblock_section.av-joihkone-69e81b3ac324ed7c1268b0d71e700013 .avia_textblock{\nfont-size:16px;\n}\n}\n\n@media only screen and (max-width: 479px){ \n#top .av_textblock_section.av-joihkone-69e81b3ac324ed7c1268b0d71e700013 .avia_textblock{\nfont-size:16px;\n}\n}\n<\/style>\n<section class=\"av_textblock_section av-joihkone-69e81b3ac324ed7c1268b0d71e700013 \" itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/CreativeWork\"><div class=\"avia_textblock av_inherit_color\" itemprop=\"text\"><blockquote>\n<p><a href=\"http:\/\/www.undrr.org\"><strong>LES DISASTERS NE SONT PAS NATURELS<\/strong><\/a>, ils sont construits socialement, par manque de pr&eacute;paration, de pr&eacute;vention, de travail d&rsquo;att&eacute;nuation, d&rsquo;&eacute;ducation et de suivi. <a class=\"glossaryLink\"  aria-describedby=\"tt\"  data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;CE&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;Abr&eacute;viation de &amp;quot;l&amp;#039;&egrave;re commune&amp;quot; ou &amp;quot;l&amp;#039;&egrave;re actuelle&amp;quot;. CE se r&eacute;f&egrave;re &agrave; l&amp;#039;ann&eacute;e &eacute;coul&eacute;e depuis le d&eacute;but de l&amp;#039;&egrave;re actuelle dans le calendrier julien ou gr&eacute;gorien, par exemple l&amp;#039;ann&eacute;e civile. L&amp;#039;&egrave;re pr&eacute;c&eacute;dente est appel&eacute;e &amp;quot;Avant l&amp;#039;&egrave;re actuelle&amp;quot; ou BCE.&lt;\/div&gt;\"  href=\"https:\/\/volcanofoundation.org\/fr\/glossary\/ce-fr\/\"  data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'  tabindex='0' role='link'>Ce<\/a> sont des risques ou des dangers naturels qui ont un impact sur les soci&eacute;t&eacute;s vuln&eacute;rables. Les connaissances aident &agrave; <strong>r&eacute;duire la vuln&eacute;rabilit&eacute; sociale<\/strong> et <strong>structurale<\/strong> afin d&rsquo;avoir des soci&eacute;t&eacute;s plus <strong>r&eacute;silientes<\/strong>!<\/p>\n<\/blockquote>\n<\/div><\/section><\/div><\/div><!--close column table wrapper. Autoclose: 1 --><\/div><\/div><\/div><!-- close content main div --><\/div><\/div><\/div><div id=\"after_section_2\" class=\"main_color av_default_container_wrap container_wrap fullsize\"><div class=\"container av-section-cont-open\"><div class=\"template-page content  av-content-full alpha units\"><div class=\"post-entry post-entry-type-page post-entry-12632\"><div class=\"entry-content-wrapper clearfix\"><section class=\"av_textblock_section av-kqt9jd5e-cd33964ef4e3b772df7fef522b816d29 \" itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/CreativeWork\"><div class=\"avia_textblock\" itemprop=\"text\"><h2>Les lahars descendent rapidement les vall&eacute;es comme des rivi&egrave;res de b&eacute;ton<\/h2>\n<\/div><\/section>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-kqt9ln1w-f6affe7cdeee6be02fc225bbc4bc5689\">\n#top .hr.av-kqt9ln1w-f6affe7cdeee6be02fc225bbc4bc5689{\nmargin-top:15px;\nmargin-bottom:15px;\n}\n.hr.av-kqt9ln1w-f6affe7cdeee6be02fc225bbc4bc5689 .hr-inner{\nwidth:100%;\nborder-color:#d8d8d8;\n}\n<\/style>\n<div class=\"hr av-kqt9ln1w-f6affe7cdeee6be02fc225bbc4bc5689 hr-custom  avia-builder-el-10  el_after_av_textblock  el_before_av_one_half  hr-center hr-icon-no\"><span class=\"hr-inner inner-border-av-border-thin\"><span class=\"hr-inner-style\"><\/span><\/span><\/div>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-1wlhzr6-8cc129343b9618e21784b665a1361b31\">\n.flex_column.av-1wlhzr6-8cc129343b9618e21784b665a1361b31{\nborder-radius:0px 0px 0px 0px;\npadding:0px 0px 0px 0px;\n}\n<\/style>\n<div class=\"flex_column av-1wlhzr6-8cc129343b9618e21784b665a1361b31 av_one_half  avia-builder-el-11  el_after_av_hr  el_before_av_one_half  first flex_column_div av-zero-column-padding  \"><p><section class=\"av_textblock_section av-kqt9tgn4-955ae44a3b12f5f76d41e08b4c147261 \" itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/CreativeWork\"><div class=\"avia_textblock\" itemprop=\"text\"><p>Le <a class=\"glossaryLink\"  aria-describedby=\"tt\"  data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;LAHAR&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;Le lahar est un mot indon&eacute;sien d&eacute;signant un m&eacute;lange de d&eacute;bris rocheux et d&amp;#039;eau qui s&amp;#039;&eacute;coule rapidement et qui prend naissance sur les pentes d&amp;#039;un volcan. Les lahars sont &eacute;galement appel&eacute;s coul&eacute;es de boue volcanique ou coul&eacute;es de d&eacute;bris.&lt;\/div&gt;\"  href=\"https:\/\/volcanofoundation.org\/fr\/glossary\/lahar-fr\/\"  data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'  tabindex='0' role='link'>lahar<\/a> est un terme indon&eacute;sien qui d&eacute;crit un m&eacute;lange chaud ou froid d&rsquo;eau et de fragments de roche qui s&rsquo;&eacute;coule le long des pentes d&rsquo;un volcan et p&eacute;n&egrave;tre g&eacute;n&eacute;ralement dans la vall&eacute;e d&rsquo;une rivi&egrave;re. Les petits &eacute;v&eacute;nements saisonniers sont parfois appel&eacute;s &laquo;&nbsp;coul&eacute;es de d&eacute;bris&nbsp;&raquo;, notamment dans les Cascades. Les lahars se produisent g&eacute;n&eacute;ralement sur ou pr&egrave;s des stratovolcans, comme ceux de l&rsquo;arc volcanique des Al&eacute;outiennes en Alaska et de la cha&icirc;ne des Cascades dans l&rsquo;ouest des &Eacute;tats-Unis.<\/p>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-94w3ety-24922f5374585901c3d11c77bdd31d48\">\n#top .hr.hr-invisible.av-94w3ety-24922f5374585901c3d11c77bdd31d48{\nheight:20px;\n}\n<\/style>\n<div class=\"hr av-94w3ety-24922f5374585901c3d11c77bdd31d48 hr-invisible  avia-builder-el-13  avia-builder-el-no-sibling \"><span class=\"hr-inner \"><span class=\"hr-inner-style\"><\/span><\/span><\/div>\n<p>Un <a class=\"glossaryLink\"  aria-describedby=\"tt\"  data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;LAHAR&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;Le lahar est un mot indon&eacute;sien d&eacute;signant un m&eacute;lange de d&eacute;bris rocheux et d&amp;#039;eau qui s&amp;#039;&eacute;coule rapidement et qui prend naissance sur les pentes d&amp;#039;un volcan. Les lahars sont &eacute;galement appel&eacute;s coul&eacute;es de boue volcanique ou coul&eacute;es de d&eacute;bris.&lt;\/div&gt;\"  href=\"https:\/\/volcanofoundation.org\/fr\/glossary\/lahar-fr\/\"  data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'  tabindex='0' role='link'>lahar<\/a> en mouvement ressemble &agrave; une boue de b&eacute;ton humide et, &agrave; mesure qu&rsquo;il se pr&eacute;cipite vers l&rsquo;aval, la taille, la vitesse et la quantit&eacute; de mat&eacute;riau transport&eacute; peuvent changer constamment. Le flux initial peut &ecirc;tre relativement faible, mais un <a class=\"glossaryLink\"  aria-describedby=\"tt\"  data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;LAHAR&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;Le lahar est un mot indon&eacute;sien d&eacute;signant un m&eacute;lange de d&eacute;bris rocheux et d&amp;#039;eau qui s&amp;#039;&eacute;coule rapidement et qui prend naissance sur les pentes d&amp;#039;un volcan. Les lahars sont &eacute;galement appel&eacute;s coul&eacute;es de boue volcanique ou coul&eacute;es de d&eacute;bris.&lt;\/div&gt;\"  href=\"https:\/\/volcanofoundation.org\/fr\/glossary\/lahar-fr\/\"  data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'  tabindex='0' role='link'>lahar<\/a> peut augmenter de volume &agrave; mesure qu&rsquo;il entra&icirc;ne et incorpore tout <a class=\"glossaryLink\"  aria-describedby=\"tt\"  data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;CE&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;Abr&eacute;viation de &amp;quot;l&amp;#039;&egrave;re commune&amp;quot; ou &amp;quot;l&amp;#039;&egrave;re actuelle&amp;quot;. CE se r&eacute;f&egrave;re &agrave; l&amp;#039;ann&eacute;e &eacute;coul&eacute;e depuis le d&eacute;but de l&amp;#039;&egrave;re actuelle dans le calendrier julien ou gr&eacute;gorien, par exemple l&amp;#039;ann&eacute;e civile. L&amp;#039;&egrave;re pr&eacute;c&eacute;dente est appel&eacute;e &amp;quot;Avant l&amp;#039;&egrave;re actuelle&amp;quot; ou BCE.&lt;\/div&gt;\"  href=\"https:\/\/volcanofoundation.org\/fr\/glossary\/ce-fr\/\"  data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'  tabindex='0' role='link'>ce<\/a> qui se trouve sur son chemin &ndash; roches, terre, v&eacute;g&eacute;tation, et m&ecirc;me b&acirc;timents et ponts. La boue qui s&rsquo;&eacute;coule peut consommer de l&rsquo;eau suppl&eacute;mentaire par la fonte de la neige et de la glace ou en engloutissant l&rsquo;eau d&rsquo;une rivi&egrave;re ou d&rsquo;un lac. Les lahars volumineux atteignent g&eacute;n&eacute;ralement plus de dix fois leur taille initiale lorsqu&rsquo;ils descendent la pente. Dans les zones escarp&eacute;es, les lahars peuvent d&eacute;passer des vitesses de 200 km\/h (120 mi\/h), mais &agrave; mesure qu&rsquo;ils s&rsquo;&eacute;loignent du volcan et qu&rsquo;ils ralentissent dans les plaines, ils commencent &agrave; d&eacute;poser une partie de leur charge et diminuent en taille.<\/p>\n<\/div><\/section><br>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-kqta1i5b-107d1a9c40127944f7fe3b907c4f1f41\">\n#top .hr.hr-invisible.av-kqta1i5b-107d1a9c40127944f7fe3b907c4f1f41{\nheight:30px;\n}\n<\/style>\n<\/p><div class=\"hr av-kqta1i5b-107d1a9c40127944f7fe3b907c4f1f41 hr-invisible  avia-builder-el-14  el_after_av_textblock  avia-builder-el-last \"><span class=\"hr-inner \"><span class=\"hr-inner-style\"><\/span><\/span><\/div><\/div>\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-4syb7u1-2e782103a5a11106f5050bb03ca2c081\">\n.flex_column.av-4syb7u1-2e782103a5a11106f5050bb03ca2c081{\nborder-radius:0px 0px 0px 0px;\npadding:0px 0px 0px 0px;\n}\n<\/style>\n<div class=\"flex_column av-4syb7u1-2e782103a5a11106f5050bb03ca2c081 av_one_half  avia-builder-el-15  el_after_av_one_half  el_before_av_one_half  flex_column_div av-zero-column-padding  \"><p>\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-kr6ib1mz-756d18989165d234eb5051fb0f451aad\">\n.avia-image-container.av-kr6ib1mz-756d18989165d234eb5051fb0f451aad img.avia_image{\nbox-shadow:none;\n}\n.avia-image-container.av-kr6ib1mz-756d18989165d234eb5051fb0f451aad .av-image-caption-overlay-center{\ncolor:#ffffff;\n}\n<\/style>\n<\/p><div class=\"avia-image-container av-kr6ib1mz-756d18989165d234eb5051fb0f451aad av-styling- avia-align-center  avia-builder-el-16  el_before_av_textblock  avia-builder-el-first \" itemprop=\"image\" itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/ImageObject\"><div class=\"avia-image-container-inner\"><div class=\"avia-image-overlay-wrap\"><img decoding=\"async\" fetchpriority=\"high\" class=\"wp-image-12636 avia-img-lazy-loading-not-12636 avia_image \" src=\"https:\/\/volcanofoundation.org\/wp-content\/uploads\/2021\/07\/lhar-devastation-eruption-mount-pinatubo-philippines.jpg\" alt=\"\" title=\"lhar-devastation-eruption-mount-pinatubo-philippines\" height=\"1469\" width=\"1140\" itemprop=\"thumbnailUrl\" srcset=\"https:\/\/volcanofoundation.org\/wp-content\/uploads\/2021\/07\/lhar-devastation-eruption-mount-pinatubo-philippines.jpg 1140w, https:\/\/volcanofoundation.org\/wp-content\/uploads\/2021\/07\/lhar-devastation-eruption-mount-pinatubo-philippines-233x300.jpg 233w, https:\/\/volcanofoundation.org\/wp-content\/uploads\/2021\/07\/lhar-devastation-eruption-mount-pinatubo-philippines-799x1030.jpg 799w, https:\/\/volcanofoundation.org\/wp-content\/uploads\/2021\/07\/lhar-devastation-eruption-mount-pinatubo-philippines-768x990.jpg 768w, https:\/\/volcanofoundation.org\/wp-content\/uploads\/2021\/07\/lhar-devastation-eruption-mount-pinatubo-philippines-547x705.jpg 547w\" sizes=\"(max-width: 1140px) 100vw, 1140px\"\/><\/div><\/div><\/div><br>\n<section class=\"av_textblock_section av-kr6i76jb-4d99ac4ff95732f9d5a32379964de404 \" itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/CreativeWork\"><div class=\"avia_textblock\" itemprop=\"text\"><p style=\"text-align: right;\"><em>D&eacute;vastation par le <a class=\"glossaryLink\"  aria-describedby=\"tt\"  data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;LAHAR&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;Le lahar est un mot indon&eacute;sien d&eacute;signant un m&eacute;lange de d&eacute;bris rocheux et d&amp;#039;eau qui s&amp;#039;&eacute;coule rapidement et qui prend naissance sur les pentes d&amp;#039;un volcan. Les lahars sont &eacute;galement appel&eacute;s coul&eacute;es de boue volcanique ou coul&eacute;es de d&eacute;bris.&lt;\/div&gt;\"  href=\"https:\/\/volcanofoundation.org\/fr\/glossary\/lahar-fr\/\"  data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'  tabindex='0' role='link'>lahar<\/a> apr&egrave;s l&rsquo;&eacute;ruption du mont Pinatubo, aux Philippines.<\/em><\/p>\n<\/div><\/section><br>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-4b7podl-d558ccf1b9e3dec760b5573ff0ebb60d\">\n#top .hr.hr-invisible.av-4b7podl-d558ccf1b9e3dec760b5573ff0ebb60d{\nheight:30px;\n}\n<\/style>\n<div class=\"hr av-4b7podl-d558ccf1b9e3dec760b5573ff0ebb60d hr-invisible  avia-builder-el-18  el_after_av_textblock  avia-builder-el-last \"><span class=\"hr-inner \"><span class=\"hr-inner-style\"><\/span><\/span><\/div><\/div>\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-40ljj61-7d15744f81def97a37c1d330a5cbf253\">\n.flex_column.av-40ljj61-7d15744f81def97a37c1d330a5cbf253{\nborder-radius:0px 0px 0px 0px;\npadding:0px 0px 0px 0px;\n}\n<\/style>\n<div class=\"flex_column av-40ljj61-7d15744f81def97a37c1d330a5cbf253 av_one_half  avia-builder-el-19  el_after_av_one_half  el_before_av_one_half  first flex_column_div av-zero-column-padding  column-top-margin\"><section class=\"av_textblock_section av-kr6idive-07796dbcb0509cd18991f12f1974244e \" itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/CreativeWork\"><div class=\"avia_textblock\" itemprop=\"text\"><h2>Les lahars peuvent se produire avec ou sans &eacute;ruption volcanique<\/h2>\n<p>Les &eacute;ruptions peuvent d&eacute;clencher des lahars en faisant fondre la neige et la glace ou en &eacute;jectant l&rsquo;eau d&rsquo;un lac de crat&egrave;re. Les coul&eacute;es pyroclastiques peuvent g&eacute;n&eacute;rer des lahars lorsque des d&eacute;bris rocheux extr&ecirc;mement chauds et coulants &eacute;rodent, se m&eacute;langent et font fondre la neige et la glace en d&eacute;valant rapidement des pentes raides. \n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-8hh1m8m-dc3e6ccc26117b98eade23db95a2f52c\">\n#top .hr.hr-invisible.av-8hh1m8m-dc3e6ccc26117b98eade23db95a2f52c{\nheight:20px;\n}\n<\/style>\n<\/p><div class=\"hr av-8hh1m8m-dc3e6ccc26117b98eade23db95a2f52c hr-invisible  avia-builder-el-21  el_before_av_hr  avia-builder-el-first \"><span class=\"hr-inner \"><span class=\"hr-inner-style\"><\/span><\/span><\/div> Les lahars peuvent &eacute;galement se former lorsque des pr&eacute;cipitations de grand volume ou de longue dur&eacute;e se produisent pendant ou apr&egrave;s une &eacute;ruption. Sur des pentes raides, l&rsquo;eau de pluie peut facilement &eacute;roder et transporter des s&eacute;diments volcaniques meubles &agrave; grain fin et former une boue, en particulier si la v&eacute;g&eacute;tation n&rsquo;a pas eu le temps de repousser sur les d&eacute;p&ocirc;ts volcaniques r&eacute;cents. \n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-85v16eu-0eed8e48f4c59024e6c25f7d00b069ea\">\n#top .hr.hr-invisible.av-85v16eu-0eed8e48f4c59024e6c25f7d00b069ea{\nheight:20px;\n}\n<\/style>\n<div class=\"hr av-85v16eu-0eed8e48f4c59024e6c25f7d00b069ea hr-invisible  avia-builder-el-22  el_after_av_hr  el_before_av_hr \"><span class=\"hr-inner \"><span class=\"hr-inner-style\"><\/span><\/span><\/div> Certains des plus grands lahars commencent par des glissements de terrain de roches humides et hydrothermales sur les flancs abrupts des volcans. Ces types d&rsquo;effondrement et les lahars qui en r&eacute;sultent sont des &eacute;v&eacute;nements naturels au cours de la vie d&rsquo;un <a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;STRATOVOLCAN&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;Les volcans coniques abrupts construits par l&amp;#039;&eacute;ruption de coul&eacute;es de lave visqueuses, de t&eacute;phra et de coul&eacute;es pyroclastes sont appel&eacute;s stratovolcans. Habituellement construits sur une p&eacute;riode de dizaines &agrave; des centaines de milliers d&amp;#039;ann&eacute;es, les stratovolcans peuvent faire &eacute;ruption d&amp;#039;une vari&eacute;t&eacute; de types de magmatiques, y compris le basalte, l&amp;#039;and&eacute;site, la dacite et la rhyolite. Tous, sauf le basalte, g&eacute;n&egrave;rent g&eacute;n&eacute;ralement des &eacute;ruptions tr&egrave;s explosives. Un stratovolcan se compose g&eacute;n&eacute;ralement de nombreux &eacute;vents distincts, dont certains peuvent avoir &eacute;clat&eacute; de c&ocirc;nes de cendres et de d&ocirc;mes sur les flancs du volcan. Un synonyme est volcan composite.&lt;\/div&gt;\" href=\"https:\/\/volcanofoundation.org\/fr\/glossary\/stratovolcan-fr\/\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">stratovolcan<\/a> et peuvent se produire longtemps apr&egrave;s l&rsquo;arr&ecirc;t des &eacute;ruptions. \n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-7jcysqe-3b2bf3948bafe19df72c25fc9a817272\">\n#top .hr.hr-invisible.av-7jcysqe-3b2bf3948bafe19df72c25fc9a817272{\nheight:20px;\n}\n<\/style>\n<div class=\"hr av-7jcysqe-3b2bf3948bafe19df72c25fc9a817272 hr-invisible  avia-builder-el-23  el_after_av_hr  avia-builder-el-last \"><span class=\"hr-inner \"><span class=\"hr-inner-style\"><\/span><\/span><\/div>\n<\/div><\/section><br>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-9fscnd-a86860623a94a2f3d04ab0394bde8832\">\n#top .hr.hr-invisible.av-9fscnd-a86860623a94a2f3d04ab0394bde8832{\nheight:30px;\n}\n<\/style>\n<div class=\"hr av-9fscnd-a86860623a94a2f3d04ab0394bde8832 hr-invisible  avia-builder-el-24  el_after_av_textblock  avia-builder-el-last \"><span class=\"hr-inner \"><span class=\"hr-inner-style\"><\/span><\/span><\/div><\/div>\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-28ffiuh-89c023858b6774d5b410d384c2eb13fe\">\n.flex_column.av-28ffiuh-89c023858b6774d5b410d384c2eb13fe{\nborder-radius:0px 0px 0px 0px;\npadding:0px 0px 0px 0px;\n}\n<\/style>\n<div class=\"flex_column av-28ffiuh-89c023858b6774d5b410d384c2eb13fe av_one_half  avia-builder-el-25  el_after_av_one_half  el_before_av_one_full  flex_column_div av-zero-column-padding  column-top-margin\"><p>\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-1rki8rt-36657b52c8a83f0b999dd67d2cbe1528\">\n.avia-image-container.av-1rki8rt-36657b52c8a83f0b999dd67d2cbe1528 img.avia_image{\nbox-shadow:none;\n}\n.avia-image-container.av-1rki8rt-36657b52c8a83f0b999dd67d2cbe1528 .av-image-caption-overlay-center{\ncolor:#ffffff;\n}\n<\/style>\n<\/p><div class=\"avia-image-container av-1rki8rt-36657b52c8a83f0b999dd67d2cbe1528 av-styling- avia-align-center  avia-builder-el-26  el_before_av_textblock  avia-builder-el-first \" itemprop=\"image\" itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/ImageObject\"><div class=\"avia-image-container-inner\"><div class=\"avia-image-overlay-wrap\"><img decoding=\"async\" fetchpriority=\"high\" class=\"wp-image-12639 avia-img-lazy-loading-not-12639 avia_image \" src=\"https:\/\/volcanofoundation.org\/wp-content\/uploads\/2021\/07\/volcanic-mudflows-lahars.jpg\" alt=\"\" title=\"IMG0021.PCD\" height=\"773\" width=\"1140\" itemprop=\"thumbnailUrl\" srcset=\"https:\/\/volcanofoundation.org\/wp-content\/uploads\/2021\/07\/volcanic-mudflows-lahars.jpg 1140w, https:\/\/volcanofoundation.org\/wp-content\/uploads\/2021\/07\/volcanic-mudflows-lahars-300x203.jpg 300w, https:\/\/volcanofoundation.org\/wp-content\/uploads\/2021\/07\/volcanic-mudflows-lahars-1030x698.jpg 1030w, https:\/\/volcanofoundation.org\/wp-content\/uploads\/2021\/07\/volcanic-mudflows-lahars-768x521.jpg 768w, https:\/\/volcanofoundation.org\/wp-content\/uploads\/2021\/07\/volcanic-mudflows-lahars-705x478.jpg 705w\" sizes=\"(max-width: 1140px) 100vw, 1140px\"\/><\/div><\/div><\/div><br>\n<section class=\"av_textblock_section av-ktrft5-5d6deb4918e757b5f22b7d75fb4dc8ec \" itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/CreativeWork\"><div class=\"avia_textblock\" itemprop=\"text\"><p style=\"text-align: right;\"><em>Les coul&eacute;es de boue volcaniques (lahars et coul&eacute;es de d&eacute;bris) se produisent plus fr&eacute;quemment apr&egrave;s qu&rsquo;un paysage a &eacute;t&eacute; recouvert de mat&eacute;riaux volcaniques meubles. Panneau de signalisation sur les pentes de Rabaul, en Papouasie-Nouvelle-Guin&eacute;e.<\/em><\/p>\n<p><strong><\/strong><\/p>\n<\/div><\/section>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-17kvlvt-8bad000a6fd4326ecf00bb90657344d8\">\n#top .hr.hr-invisible.av-17kvlvt-8bad000a6fd4326ecf00bb90657344d8{\nheight:30px;\n}\n<\/style>\n<div class=\"hr av-17kvlvt-8bad000a6fd4326ecf00bb90657344d8 hr-invisible  avia-builder-el-28  el_after_av_textblock  avia-builder-el-last \"><span class=\"hr-inner \"><span class=\"hr-inner-style\"><\/span><\/span><\/div><\/div>\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-av_one_full-53b0b300fb3685750664fb085c5ad19d\">\n.flex_column.av-av_one_full-53b0b300fb3685750664fb085c5ad19d{\nborder-radius:0px 0px 0px 0px;\npadding:0px 0px 0px 0px;\n}\n<\/style>\n<div class=\"flex_column av-av_one_full-53b0b300fb3685750664fb085c5ad19d av_one_full  avia-builder-el-29  el_after_av_one_half  el_before_av_one_half  first flex_column_div av-zero-column-padding  column-top-margin\"><section class=\"av_textblock_section av-kr6k8d7x-867f0b4b8138ac57d339c0fd468344b9 \" itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/CreativeWork\"><div class=\"avia_textblock\" itemprop=\"text\"><p>Les crues de d&eacute;bordement qui se produisent sans &eacute;ruption peuvent &eacute;galement conduire &agrave; des lahars. Elles se produisent g&eacute;n&eacute;ralement apr&egrave;s qu&rsquo;un cours d&rsquo;eau ait &eacute;t&eacute; bloqu&eacute; par un glissement de terrain volcanique ou une <a class=\"glossaryLink\"  aria-describedby=\"tt\"  data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;COUL&Eacute;E&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;Un d&ocirc;me de lave allong&eacute; qui se forme g&eacute;n&eacute;ralement sous la forme d&amp;#039;une lave &agrave; haute silice &eacute;clate sur le flanc abrupt d&amp;#039;un volcan. L&amp;#039;axe du d&ocirc;me perpendiculaire &agrave; la pente du volcan est plus court que l&amp;#039;axe parall&egrave;le &agrave; la pente, cr&eacute;ant une forme elliptique. Le bord d&amp;#039;attaque de la coul&eacute;e est souvent bloc et escarp&eacute;.&lt;\/div&gt;\"  href=\"https:\/\/volcanofoundation.org\/fr\/glossary\/coulee-fr\/\"  data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'  tabindex='0' role='link'>coul&eacute;e<\/a> pyroclastique formant un barrage naturel. La cause la plus fr&eacute;quente d&rsquo;un lahars est le d&eacute;bordement d&rsquo;eau &agrave; travers un barrage naturel nouvellement form&eacute;, suivi d&rsquo;une &eacute;rosion rapide des d&eacute;bris rocheux d&eacute;tach&eacute;s. En raison de l&rsquo;&eacute;rosion et de l&rsquo;entra&icirc;nement des s&eacute;diments et de l&rsquo;eau, la crue initiale peut se transformer en une boue et augmenter de volume en descendant la vall&eacute;e.<\/p>\n<\/div><\/section><\/div>\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-73swbyu-564a18d44832327c95bddf9751c2d927\">\n.flex_column.av-73swbyu-564a18d44832327c95bddf9751c2d927{\nborder-radius:0px 0px 0px 0px;\npadding:0px 0px 0px 0px;\n}\n<\/style>\n<div class=\"flex_column av-73swbyu-564a18d44832327c95bddf9751c2d927 av_one_half  avia-builder-el-31  el_after_av_one_full  el_before_av_one_half  first flex_column_div av-zero-column-padding  column-top-margin\"><section class=\"av_textblock_section av-kr6jiu2y-45a206165ab9fee20b694886f498f267 \" itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/CreativeWork\"><div class=\"avia_textblock\" itemprop=\"text\"><h3>Les lahars et l&rsquo;exc&egrave;s de s&eacute;diments causent de graves dommages &eacute;conomiques et environnementaux aux vall&eacute;es fluviales et aux plaines inondables<\/h3>\n<p>Les grands lahars peuvent &eacute;craser, abraser, enterrer ou emporter presque tout <a class=\"glossaryLink\"  aria-describedby=\"tt\"  data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;CE&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;Abr&eacute;viation de &amp;quot;l&amp;#039;&egrave;re commune&amp;quot; ou &amp;quot;l&amp;#039;&egrave;re actuelle&amp;quot;. CE se r&eacute;f&egrave;re &agrave; l&amp;#039;ann&eacute;e &eacute;coul&eacute;e depuis le d&eacute;but de l&amp;#039;&egrave;re actuelle dans le calendrier julien ou gr&eacute;gorien, par exemple l&amp;#039;ann&eacute;e civile. L&amp;#039;&egrave;re pr&eacute;c&eacute;dente est appel&eacute;e &amp;quot;Avant l&amp;#039;&egrave;re actuelle&amp;quot; ou BCE.&lt;\/div&gt;\"  href=\"https:\/\/volcanofoundation.org\/fr\/glossary\/ce-fr\/\"  data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'  tabindex='0' role='link'>ce<\/a> qui se trouve sur leur passage. Les b&acirc;timents et les terrains de valeur peuvent &ecirc;tre partiellement ou compl&egrave;tement enterr&eacute;s. En d&eacute;truisant les ponts et les routes, les lahars peuvent &eacute;galement pi&eacute;ger les gens dans des zones vuln&eacute;rables &agrave; d&rsquo;autres activit&eacute;s volcaniques dangereuses, en particulier si les lahars laissent des d&eacute;p&ocirc;ts frais trop profonds, trop mous ou trop chauds pour &ecirc;tre travers&eacute;s.<\/p>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-6vot2l2-c439741a48cc90320d00e5e92c2d0041\">\n#top .hr.hr-invisible.av-6vot2l2-c439741a48cc90320d00e5e92c2d0041{\nheight:20px;\n}\n<\/style>\n<div class=\"hr av-6vot2l2-c439741a48cc90320d00e5e92c2d0041 hr-invisible  avia-builder-el-33  avia-builder-el-no-sibling \"><span class=\"hr-inner \"><span class=\"hr-inner-style\"><\/span><\/span><\/div>\n<\/div><\/section><br>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-69f2rdi-22c817fadee504346f2d889d95eb5896\">\n#top .hr.hr-invisible.av-69f2rdi-22c817fadee504346f2d889d95eb5896{\nheight:30px;\n}\n<\/style>\n<div class=\"hr av-69f2rdi-22c817fadee504346f2d889d95eb5896 hr-invisible  avia-builder-el-34  el_after_av_textblock  avia-builder-el-last \"><span class=\"hr-inner \"><span class=\"hr-inner-style\"><\/span><\/span><\/div><\/div>\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-5k7wkxi-02eba14496379936ec05700e15d49dac\">\n.flex_column.av-5k7wkxi-02eba14496379936ec05700e15d49dac{\nborder-radius:0px 0px 0px 0px;\npadding:0px 0px 0px 0px;\n}\n<\/style>\n<div class=\"flex_column av-5k7wkxi-02eba14496379936ec05700e15d49dac av_one_half  avia-builder-el-35  el_after_av_one_half  el_before_av_one_full  flex_column_div av-zero-column-padding  column-top-margin\"><p>\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-5emlxau-286ea65949240b7d43a5934cc74c5811\">\n.avia-image-container.av-5emlxau-286ea65949240b7d43a5934cc74c5811 img.avia_image{\nbox-shadow:none;\n}\n.avia-image-container.av-5emlxau-286ea65949240b7d43a5934cc74c5811 .av-image-caption-overlay-center{\ncolor:#ffffff;\n}\n<\/style>\n<\/p><div class=\"avia-image-container av-5emlxau-286ea65949240b7d43a5934cc74c5811 av-styling- avia-align-center  avia-builder-el-36  el_before_av_textblock  avia-builder-el-first \" itemprop=\"image\" itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/ImageObject\"><div class=\"avia-image-container-inner\"><div class=\"avia-image-overlay-wrap\"><img decoding=\"async\" fetchpriority=\"high\" class=\"wp-image-12642 avia-img-lazy-loading-not-12642 avia_image \" src=\"https:\/\/volcanofoundation.org\/wp-content\/uploads\/2021\/07\/lahars-material-pinatubo-philippines.jpg\" alt=\"\" title=\"lahars-material-pinatubo-philippines\" height=\"756\" width=\"1140\" itemprop=\"thumbnailUrl\" srcset=\"https:\/\/volcanofoundation.org\/wp-content\/uploads\/2021\/07\/lahars-material-pinatubo-philippines.jpg 1140w, https:\/\/volcanofoundation.org\/wp-content\/uploads\/2021\/07\/lahars-material-pinatubo-philippines-300x199.jpg 300w, https:\/\/volcanofoundation.org\/wp-content\/uploads\/2021\/07\/lahars-material-pinatubo-philippines-1030x683.jpg 1030w, https:\/\/volcanofoundation.org\/wp-content\/uploads\/2021\/07\/lahars-material-pinatubo-philippines-768x509.jpg 768w, https:\/\/volcanofoundation.org\/wp-content\/uploads\/2021\/07\/lahars-material-pinatubo-philippines-705x468.jpg 705w\" sizes=\"(max-width: 1140px) 100vw, 1140px\"\/><\/div><\/div><\/div><br>\n<section class=\"av_textblock_section av-4wwwj92-a32a9a35037c8a9ff46488b9d9bb640a \" itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/CreativeWork\"><div class=\"avia_textblock\" itemprop=\"text\"><p style=\"text-align: right;\"><em>Les lahars ramassent des mat&eacute;riaux lors de leur d&eacute;placement, <a class=\"glossaryLink\"  aria-describedby=\"tt\"  data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;CE&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;Abr&eacute;viation de &amp;quot;l&amp;#039;&egrave;re commune&amp;quot; ou &amp;quot;l&amp;#039;&egrave;re actuelle&amp;quot;. CE se r&eacute;f&egrave;re &agrave; l&amp;#039;ann&eacute;e &eacute;coul&eacute;e depuis le d&eacute;but de l&amp;#039;&egrave;re actuelle dans le calendrier julien ou gr&eacute;gorien, par exemple l&amp;#039;ann&eacute;e civile. L&amp;#039;&egrave;re pr&eacute;c&eacute;dente est appel&eacute;e &amp;quot;Avant l&amp;#039;&egrave;re actuelle&amp;quot; ou BCE.&lt;\/div&gt;\"  href=\"https:\/\/volcanofoundation.org\/fr\/glossary\/ce-fr\/\"  data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'  tabindex='0' role='link'>ce<\/a> qui peut causer des dommages aux structures sur leur passage. Ici, les dommages caus&eacute;s par le mont Pinatubo, aux Philippines.<\/em>Les dommages caus&eacute;s par le mont Pinatubo, aux Philippines.<\/p>\n<\/div><\/section><br>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-4gl5euu-beac8021a7125d6aba776f52834817a1\">\n#top .hr.hr-invisible.av-4gl5euu-beac8021a7125d6aba776f52834817a1{\nheight:30px;\n}\n<\/style>\n<div class=\"hr av-4gl5euu-beac8021a7125d6aba776f52834817a1 hr-invisible  avia-builder-el-38  el_after_av_textblock  avia-builder-el-last \"><span class=\"hr-inner \"><span class=\"hr-inner-style\"><\/span><\/span><\/div><\/div>\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-oi1ygm-9e41d58b6bf01a56ce5d525adfa3cf69\">\n.flex_column.av-oi1ygm-9e41d58b6bf01a56ce5d525adfa3cf69{\nborder-radius:0px 0px 0px 0px;\npadding:0px 0px 0px 0px;\n}\n<\/style>\n<div class=\"flex_column av-oi1ygm-9e41d58b6bf01a56ce5d525adfa3cf69 av_one_full  avia-builder-el-39  el_after_av_one_half  el_before_av_one_half  first flex_column_div av-zero-column-padding  column-top-margin\"><section class=\"av_textblock_section av-kr6k4joo-ec2c434695602eb00ad56865a3135e1e \" itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/CreativeWork\"><div class=\"avia_textblock\" itemprop=\"text\"><p>Sur une p&eacute;riode allant de quelques semaines &agrave; plusieurs ann&eacute;es apr&egrave;s une &eacute;ruption volcanique, l&rsquo;&eacute;rosion et le transport de d&eacute;p&ocirc;ts volcaniques meubles peuvent entra&icirc;ner de graves inondations dans des zones situ&eacute;es loin en aval d&rsquo;un volcan. Les pluies intenses &eacute;rodent facilement les s&eacute;diments meubles sur les pentes raides pour produire des lahars qui se d&eacute;placent dans les plaines d&rsquo;inondation et ensevelissent des villes enti&egrave;res et de pr&eacute;cieuses terres agricoles. Ces lahars provoqu&eacute;s par les pluies peuvent causer des ravages sur les rivi&egrave;res et les ruisseaux, d&eacute;posant parfois tellement de s&eacute;diments que les inondations chroniques deviennent &eacute;galement un probl&egrave;me.<\/p>\n<\/div><\/section><\/div>\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-4068oye-5af03477b8c41ab0d91b7491aac9a47c\">\n.flex_column.av-4068oye-5af03477b8c41ab0d91b7491aac9a47c{\nborder-radius:0px 0px 0px 0px;\npadding:0px 0px 0px 0px;\n}\n<\/style>\n<div class=\"flex_column av-4068oye-5af03477b8c41ab0d91b7491aac9a47c av_one_half  avia-builder-el-41  el_after_av_one_full  el_before_av_one_half  first flex_column_div av-zero-column-padding  column-top-margin\"><section class=\"av_textblock_section av-kr6jkkfw-70de922c61b017ecf3d3475cfad5ed5d \" itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/CreativeWork\"><div class=\"avia_textblock\" itemprop=\"text\"><h4>Les coul&eacute;es de d&eacute;bris saisonni&egrave;res se produisent couramment sur les volcans recouverts de glaciers<\/h4>\n<p>Les volcans recouverts de glace sont des endroits courants pour le d&eacute;clenchement de petites coul&eacute;es de d&eacute;bris, en raison de leurs pentes raides, de l&rsquo;abondance de roches meubles et d&rsquo;eau de surface, et de la variabilit&eacute; diurne, saisonni&egrave;re et &agrave; long terme du d&eacute;bit d&rsquo;eau de surface. Ces &eacute;v&eacute;nements ont une certaine saisonnalit&eacute; : une population d&rsquo;&eacute;v&eacute;nements se produit apr&egrave;s la diminution du <a class=\"glossaryLink\"  aria-describedby=\"tt\"  data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;MANTEAU&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;Le manteau est la partie de l&amp;#039;int&eacute;rieur de la terre entre le noyau ext&eacute;rieur m&eacute;tallique (sous le manteau) et la cro&ucirc;te (au-dessus du manteau).&lt;\/div&gt;\"  href=\"https:\/\/volcanofoundation.org\/fr\/glossary\/manteau-fr\/\"  data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'  tabindex='0' role='link'>manteau<\/a> neigeux au milieu ou &agrave; la fin de l&rsquo;&eacute;t&eacute;, et l&rsquo;autre est d&eacute;clench&eacute;e par les pluies intenses du d&eacute;but de l&rsquo;hiver, avant que le <a class=\"glossaryLink\"  aria-describedby=\"tt\"  data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;MANTEAU&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;Le manteau est la partie de l&amp;#039;int&eacute;rieur de la terre entre le noyau ext&eacute;rieur m&eacute;tallique (sous le manteau) et la cro&ucirc;te (au-dessus du manteau).&lt;\/div&gt;\"  href=\"https:\/\/volcanofoundation.org\/fr\/glossary\/manteau-fr\/\"  data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'  tabindex='0' role='link'>manteau<\/a> neigeux ne se soit accumul&eacute;. L&rsquo;Observatoire volcanique des Cascades propose des informations suppl&eacute;mentaires sur ces &eacute;v&eacute;nements.<\/p>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-3bgoy0m-9c4719a68ca7a28bb0fd38d056b1e417\">\n#top .hr.hr-invisible.av-3bgoy0m-9c4719a68ca7a28bb0fd38d056b1e417{\nheight:20px;\n}\n<\/style>\n<div class=\"hr av-3bgoy0m-9c4719a68ca7a28bb0fd38d056b1e417 hr-invisible  avia-builder-el-43  el_before_av_hr  avia-builder-el-first \"><span class=\"hr-inner \"><span class=\"hr-inner-style\"><\/span><\/span><\/div>\n<h3>La recherche porte sur les m&eacute;canismes de d&eacute;clenchement des lahars, la dynamique de l&rsquo;&eacute;coulement, les pr&eacute;visions et l&rsquo;am&eacute;lioration des syst&egrave;mes d&rsquo;alerte<\/h3>\n<p>Pour comprendre les lahars, les scientifiques observent et quantifient <a class=\"glossaryLink\"  aria-describedby=\"tt\"  data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;CE&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;Abr&eacute;viation de &amp;quot;l&amp;#039;&egrave;re commune&amp;quot; ou &amp;quot;l&amp;#039;&egrave;re actuelle&amp;quot;. CE se r&eacute;f&egrave;re &agrave; l&amp;#039;ann&eacute;e &eacute;coul&eacute;e depuis le d&eacute;but de l&amp;#039;&egrave;re actuelle dans le calendrier julien ou gr&eacute;gorien, par exemple l&amp;#039;ann&eacute;e civile. L&amp;#039;&egrave;re pr&eacute;c&eacute;dente est appel&eacute;e &amp;quot;Avant l&amp;#039;&egrave;re actuelle&amp;quot; ou BCE.&lt;\/div&gt;\"  href=\"https:\/\/volcanofoundation.org\/fr\/glossary\/ce-fr\/\"  data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'  tabindex='0' role='link'>ce<\/a> qui se passe lorsque ces &eacute;v&eacute;nements se produisent naturellement, d&eacute;rivent des &eacute;quations pour d&eacute;crire le comportement des lahars et r&eacute;alisent des exp&eacute;riences contr&ocirc;l&eacute;es dans un canal de <a class=\"glossaryLink\"  aria-describedby=\"tt\"  data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;COUL&Eacute;E&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;Un d&ocirc;me de lave allong&eacute; qui se forme g&eacute;n&eacute;ralement sous la forme d&amp;#039;une lave &agrave; haute silice &eacute;clate sur le flanc abrupt d&amp;#039;un volcan. L&amp;#039;axe du d&ocirc;me perpendiculaire &agrave; la pente du volcan est plus court que l&amp;#039;axe parall&egrave;le &agrave; la pente, cr&eacute;ant une forme elliptique. Le bord d&amp;#039;attaque de la coul&eacute;e est souvent bloc et escarp&eacute;.&lt;\/div&gt;\"  href=\"https:\/\/volcanofoundation.org\/fr\/glossary\/coulee-fr\/\"  data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'  tabindex='0' role='link'>coul&eacute;e<\/a> de d&eacute;bris de 310 pieds (95 m) de long. Les r&eacute;sultats nous aident &agrave; comprendre la dynamique des flux et &agrave; d&eacute;velopper des technologies am&eacute;lior&eacute;es pour att&eacute;nuer les effets destructeurs des lahars et autres coul&eacute;es de d&eacute;bris.<\/p>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-35bzk2e-ecccb8922654fcf3946305145dce79af\">\n#top .hr.hr-invisible.av-35bzk2e-ecccb8922654fcf3946305145dce79af{\nheight:20px;\n}\n<\/style>\n<div class=\"hr av-35bzk2e-ecccb8922654fcf3946305145dce79af hr-invisible  avia-builder-el-44  el_after_av_hr  avia-builder-el-last \"><span class=\"hr-inner \"><span class=\"hr-inner-style\"><\/span><\/span><\/div>\n<p>En raison du danger que repr&eacute;sentent les lahars, les scientifiques sont pr&ecirc;ts &agrave; d&eacute;ployer des syst&egrave;mes de d&eacute;tection des lahars lorsque les &eacute;ruptions sont imminentes. Les responsables du Mont Rainier, dans l&rsquo;&Eacute;tat de Washington, disposent d&rsquo;un syst&egrave;me permanent de d&eacute;tection des lahars et d&rsquo;un syst&egrave;me d&rsquo;information du public.<\/p>\n<\/div><\/section><br>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-8wsmhi-204a22d983c77d57ca54fed77947bd19\">\n#top .hr.hr-invisible.av-8wsmhi-204a22d983c77d57ca54fed77947bd19{\nheight:30px;\n}\n<\/style>\n<div class=\"hr av-8wsmhi-204a22d983c77d57ca54fed77947bd19 hr-invisible  avia-builder-el-45  el_after_av_textblock  avia-builder-el-last \"><span class=\"hr-inner \"><span class=\"hr-inner-style\"><\/span><\/span><\/div><\/div>\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-25m1ek6-854521d57f019f80a51efe13fc49dc31\">\n.flex_column.av-25m1ek6-854521d57f019f80a51efe13fc49dc31{\nborder-radius:0px 0px 0px 0px;\npadding:0px 0px 0px 0px;\n}\n<\/style>\n<div class=\"flex_column av-25m1ek6-854521d57f019f80a51efe13fc49dc31 av_one_half  avia-builder-el-46  el_after_av_one_half  avia-builder-el-last  flex_column_div av-zero-column-padding  column-top-margin\"><p>\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-1j5kw7q-c174dce36a6802d0b01deee088bf61c5\">\n.avia-image-container.av-1j5kw7q-c174dce36a6802d0b01deee088bf61c5 img.avia_image{\nbox-shadow:none;\n}\n.avia-image-container.av-1j5kw7q-c174dce36a6802d0b01deee088bf61c5 .av-image-caption-overlay-center{\ncolor:#ffffff;\n}\n<\/style>\n<\/p><div class=\"avia-image-container av-1j5kw7q-c174dce36a6802d0b01deee088bf61c5 av-styling- avia-align-center  avia-builder-el-47  el_before_av_textblock  avia-builder-el-first \" itemprop=\"image\" itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/ImageObject\"><div class=\"avia-image-container-inner\"><div class=\"avia-image-overlay-wrap\"><img decoding=\"async\" fetchpriority=\"high\" class=\"wp-image-12645 avia-img-lazy-loading-not-12645 avia_image \" src=\"https:\/\/volcanofoundation.org\/wp-content\/uploads\/2021\/07\/bridge-lahar-north.fork-toutle-river.jpg\" alt=\"\" title=\"bridge-lahar-north.fork-toutle-river\" height=\"610\" width=\"900\" itemprop=\"thumbnailUrl\" srcset=\"https:\/\/volcanofoundation.org\/wp-content\/uploads\/2021\/07\/bridge-lahar-north.fork-toutle-river.jpg 900w, https:\/\/volcanofoundation.org\/wp-content\/uploads\/2021\/07\/bridge-lahar-north.fork-toutle-river-300x203.jpg 300w, https:\/\/volcanofoundation.org\/wp-content\/uploads\/2021\/07\/bridge-lahar-north.fork-toutle-river-768x521.jpg 768w, https:\/\/volcanofoundation.org\/wp-content\/uploads\/2021\/07\/bridge-lahar-north.fork-toutle-river-705x478.jpg 705w\" sizes=\"(max-width: 900px) 100vw, 900px\"\/><\/div><\/div><\/div><br>\n<section class=\"av_textblock_section av-3uju7q-77c96b519e89ee38b506d8dbfe5c5a00 \" itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/CreativeWork\"><div class=\"avia_textblock\" itemprop=\"text\"><p style=\"text-align: right;\"><em>Pont d&eacute;truit par un <a class=\"glossaryLink\"  aria-describedby=\"tt\"  data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;LAHAR&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;Le lahar est un mot indon&eacute;sien d&eacute;signant un m&eacute;lange de d&eacute;bris rocheux et d&amp;#039;eau qui s&amp;#039;&eacute;coule rapidement et qui prend naissance sur les pentes d&amp;#039;un volcan. Les lahars sont &eacute;galement appel&eacute;s coul&eacute;es de boue volcanique ou coul&eacute;es de d&eacute;bris.&lt;\/div&gt;\"  href=\"https:\/\/volcanofoundation.org\/fr\/glossary\/lahar-fr\/\"  data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]'  tabindex='0' role='link'>lahar<\/a> dans la rivi&egrave;re Toutle de North Fork lors de l&rsquo;&eacute;ruption du mont St. Helens, le 18 mai 1980.<\/em><\/p>\n<\/div><\/section><br>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-ijawk6-8937441572ccb2178a7222912c9ab3d8\">\n#top .hr.hr-invisible.av-ijawk6-8937441572ccb2178a7222912c9ab3d8{\nheight:30px;\n}\n<\/style>\n<div class=\"hr av-ijawk6-8937441572ccb2178a7222912c9ab3d8 hr-invisible  avia-builder-el-49  el_after_av_textblock  el_before_av_image \"><span class=\"hr-inner \"><span class=\"hr-inner-style\"><\/span><\/span><\/div><br>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-kr6k1zs0-89cdab03f0627860c66527a736fc4acc\">\n.avia-image-container.av-kr6k1zs0-89cdab03f0627860c66527a736fc4acc img.avia_image{\nbox-shadow:none;\n}\n.avia-image-container.av-kr6k1zs0-89cdab03f0627860c66527a736fc4acc .av-image-caption-overlay-center{\ncolor:#ffffff;\n}\n<\/style>\n<div class=\"avia-image-container av-kr6k1zs0-89cdab03f0627860c66527a736fc4acc av-styling- avia-align-center  avia-builder-el-50  el_after_av_hr  el_before_av_textblock \" itemprop=\"image\" itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/ImageObject\"><div class=\"avia-image-container-inner\"><div class=\"avia-image-overlay-wrap\"><img decoding=\"async\" fetchpriority=\"high\" class=\"wp-image-12648 avia-img-lazy-loading-not-12648 avia_image \" src=\"https:\/\/volcanofoundation.org\/wp-content\/uploads\/2021\/07\/rock-ice-debris-1997-mount-adams.jpg\" alt=\"\" title=\"rock-ice-debris-1997-mount-adams\" height=\"762\" width=\"1140\" itemprop=\"thumbnailUrl\" srcset=\"https:\/\/volcanofoundation.org\/wp-content\/uploads\/2021\/07\/rock-ice-debris-1997-mount-adams.jpg 1140w, https:\/\/volcanofoundation.org\/wp-content\/uploads\/2021\/07\/rock-ice-debris-1997-mount-adams-300x201.jpg 300w, https:\/\/volcanofoundation.org\/wp-content\/uploads\/2021\/07\/rock-ice-debris-1997-mount-adams-1030x688.jpg 1030w, https:\/\/volcanofoundation.org\/wp-content\/uploads\/2021\/07\/rock-ice-debris-1997-mount-adams-768x513.jpg 768w, https:\/\/volcanofoundation.org\/wp-content\/uploads\/2021\/07\/rock-ice-debris-1997-mount-adams-705x471.jpg 705w\" sizes=\"(max-width: 1140px) 100vw, 1140px\"\/><\/div><\/div><\/div><br>\n<section class=\"av_textblock_section av-kr6k2eb0-ab93fcb24830832cdb9738640e98a57b \" itemscope=\"itemscope\" itemtype=\"https:\/\/schema.org\/CreativeWork\"><div class=\"avia_textblock\" itemprop=\"text\"><p style=\"text-align: right;\"><em><a class=\"glossaryLink\" aria-describedby=\"tt\" data-cmtooltip=\"&lt;div class=glossaryItemTitle&gt;AVALANCHE DE D&Eacute;BRIS&lt;\/div&gt;&lt;div class=glossaryItemBody&gt;Les masses mobiles de roches, de terre et de neige qui se produisent lorsque le flanc d&amp;#039;une montagne ou d&amp;#039;un volcan s&amp;#039;effondre et glisse vers le bas de la pente.&lt;\/div&gt;\" href=\"https:\/\/volcanofoundation.org\/fr\/glossary\/avalanche-debris-fr\/\" data-gt-translate-attributes='[{\"attribute\":\"data-cmtooltip\", \"format\":\"html\"}]' tabindex=\"0\" role=\"link\">Avalanche de d&eacute;bris<\/a> de roche et de glace (20 octobre 1997) sur le versant est du mont Adams.<\/em><\/p>\n<\/div><\/section><br>\n\n<style type=\"text\/css\" data-created_by=\"avia_inline_auto\" id=\"style-css-av-j0g6s6-994d5b4e32f8d86ab5a77dc24e629f9f\">\n#top .hr.hr-invisible.av-j0g6s6-994d5b4e32f8d86ab5a77dc24e629f9f{\nheight:30px;\n}\n<\/style>\n<div class=\"hr av-j0g6s6-994d5b4e32f8d86ab5a77dc24e629f9f hr-invisible  avia-builder-el-52  el_after_av_textblock  avia-builder-el-last \"><span class=\"hr-inner \"><span class=\"hr-inner-style\"><\/span><\/span><\/div><\/div>\n<\/div><\/div><\/div><\/div><\/div>","protected":false},"excerpt":{"rendered":"<p>LES CATASTROPHES NE SONT PAS NATURELLES, elles sont construites par la soci&eacute;t&eacute;, en raison du manque de pr&eacute;paration, de pr&eacute;vention, de travail d&rsquo;att&eacute;nuation, d&rsquo;&eacute;ducation et de suivi.<\/p>\n","protected":false},"author":8,"featured_media":11142,"parent":12582,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-12632","page","type-page","status-publish","has-post-thumbnail","hentry"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/volcanofoundation.org\/fr\/wp-json\/wp\/v2\/pages\/12632","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/volcanofoundation.org\/fr\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/volcanofoundation.org\/fr\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/volcanofoundation.org\/fr\/wp-json\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"https:\/\/volcanofoundation.org\/fr\/wp-json\/wp\/v2\/comments?post=12632"}],"version-history":[{"count":0,"href":"https:\/\/volcanofoundation.org\/fr\/wp-json\/wp\/v2\/pages\/12632\/revisions"}],"up":[{"embeddable":true,"href":"https:\/\/volcanofoundation.org\/fr\/wp-json\/wp\/v2\/pages\/12582"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/volcanofoundation.org\/fr\/wp-json\/wp\/v2\/media\/11142"}],"wp:attachment":[{"href":"https:\/\/volcanofoundation.org\/fr\/wp-json\/wp\/v2\/media?parent=12632"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}