{"id":2257,"date":"2026-09-23T17:21:55","date_gmt":"2026-09-23T15:21:55","guid":{"rendered":"https:\/\/www.geoleg.cat\/?page_id=2257"},"modified":"2026-09-23T17:21:55","modified_gmt":"2026-09-23T15:21:55","slug":"calculadora-dexplosivitat-volcanica","status":"publish","type":"page","link":"https:\/\/www.geoleg.cat\/index.php\/que-oferim\/recursos-didactics\/recursos-geologia\/calculadora-dexplosivitat-volcanica\/","title":{"rendered":"Calculadora d&#8217;explosivitat volc\u00e0nica"},"content":{"rendered":"\t\t\t<section class=\"giv-calculator\" id=\"giv-1\" data-giv data-watermark-primary=\"ge\u00f2leg.cat\" data-watermark-secondary=\"geologia365.com\" aria-labelledby=\"giv-1-title\">\n\t\t\t\t<header class=\"giv-header\">\n\t\t\t\t\t<div class=\"giv-brand-row\">\n\t\t\t\t\t\t<a class=\"giv-brand giv-brand--geoleg\" href=\"https:\/\/www.geoleg.cat\/\" target=\"_blank\" rel=\"noopener noreferrer\" aria-label=\"Visita Ge\u00f2leg.cat\">\n\t\t\t\t\t\t\t<img decoding=\"async\" data-src=\"https:\/\/www.geoleg.cat\/wp-content\/plugins\/geoleg-calculadora-explosivitat-volcanica\/assets\/img\/geoleg-logo.png\" alt=\"Ge\u00f2leg.cat\" src=\"data:image\/svg+xml;base64,PHN2ZyB3aWR0aD0iMSIgaGVpZ2h0PSIxIiB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciPjwvc3ZnPg==\" class=\"lazyload\" style=\"--smush-placeholder-width: 600px; --smush-placeholder-aspect-ratio: 600\/128;\">\n\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t<span class=\"giv-brand-separator\" aria-hidden=\"true\"><\/span>\n\t\t\t\t\t\t<a class=\"giv-brand giv-brand--365\" href=\"https:\/\/geologia365.com\/\" target=\"_blank\" rel=\"noopener noreferrer\" aria-label=\"Visita Geologia365.com\">\n\t\t\t\t\t\t\t<img decoding=\"async\" data-src=\"https:\/\/www.geoleg.cat\/wp-content\/plugins\/geoleg-calculadora-explosivitat-volcanica\/assets\/img\/geologia365-logo.jpg\" alt=\"Geologia365.com\" src=\"data:image\/svg+xml;base64,PHN2ZyB3aWR0aD0iMSIgaGVpZ2h0PSIxIiB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciPjwvc3ZnPg==\" class=\"lazyload\" style=\"--smush-placeholder-width: 1400px; --smush-placeholder-aspect-ratio: 1400\/373;\">\n\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t<button class=\"giv-text-size\" type=\"button\" data-action=\"text-size\" aria-label=\"Augmenta la mida del text\" title=\"Mida del text\">A+<\/button>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<p class=\"giv-kicker\">Laboratori virtual \u00b7 Vulcanologia<\/p>\n\t\t\t\t\t<h2 id=\"giv-1-title\">\u00cdndex d\u2019explosivitat volc\u00e0nica<\/h2>\n\t\t\t\t\t<p>L\u2019\u00edndex d\u2019explosivitat volc\u00e0nica (IEV; VEI en angl\u00e8s) classifica la mida d\u2019una erupci\u00f3 explosiva a partir del volum de productes pirocl\u00e0stics. Aqu\u00ed tamb\u00e9 pots comprovar si l\u2019al\u00e7ada de la columna eruptiva \u00e9s coherent.<\/p>\n\t\t\t\t\t<div class=\"giv-header-tags\" aria-label=\"Caracter\u00edstiques de l'eina\">\n\t\t\t\t\t\t<span>IEV 0\u20138<\/span><span>volum de tefra<\/span><span>columna opcional<\/span><span>sense predicci\u00f3 de risc<\/span>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/header>\n\n\t\t\t\t<div class=\"giv-key-message\" role=\"note\">\n\t\t\t\t\t<span class=\"giv-key-icon\" aria-hidden=\"true\">!<\/span>\n\t\t\t\t\t<div><strong>L\u2019IEV classifica la mida de la part explosiva d\u2019una erupci\u00f3, no el perill ni el risc.<\/strong> En aquesta calculadora, el volum assigna la classe; l\u2019al\u00e7ada de la columna nom\u00e9s serveix com a comprovaci\u00f3 orientativa.<\/div>\n\t\t\t\t<\/div>\n\n\t\t\t\t<form class=\"giv-form\" data-form novalidate>\n\t\t\t\t\t<div class=\"giv-section-heading\">\n\t\t\t\t\t\t<div><span class=\"giv-step\">1<\/span><h3>Dades de l\u2019erupci\u00f3<\/h3><\/div>\n\t\t\t\t\t\t<button type=\"button\" class=\"giv-link-button\" data-action=\"example\">Carrega un exemple aleatori (dades inventades)<\/button>\n\t\t\t\t\t<\/div>\n\n\t\t\t\t\t<div class=\"giv-fields\">\n\t\t\t\t\t\t<div class=\"giv-field\">\n\t\t\t\t\t\t\t<label for=\"giv-1-volume\">Volum total dels productes pirocl\u00e0stics<\/label>\n\t\t\t\t\t\t\t<div class=\"giv-input-unit\">\n\t\t\t\t\t\t\t\t<input id=\"giv-1-volume\" data-field=\"volume\" type=\"text\" inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" placeholder=\"p. ex. 0,12\" aria-describedby=\"giv-1-volume-help\">\n\t\t\t\t\t\t\t\t<select data-field=\"volume-unit\" aria-label=\"Unitat del volum\">\n\t\t\t\t\t\t\t\t\t<option value=\"km3\">km\u00b3<\/option>\n\t\t\t\t\t\t\t\t\t<option value=\"m3\">m\u00b3<\/option>\n\t\t\t\t\t\t\t\t<\/select>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<p class=\"giv-help\" id=\"giv-1-volume-help\">Inclou cendra, lapil\u00b7li, esc\u00f2ries, bombes, blocs i altres materials expulsats explosivament. <strong>No hi sumis les colades de lava.<\/strong> Si l\u2019erupci\u00f3 \u00e9s purament efusiva i no disposes d\u2019un volum de tefra, aquesta calculadora no \u00e9s l\u2019eina adequada.<\/p>\n\t\t\t\t\t\t<\/div>\n\n\t\t\t\t\t\t<div class=\"giv-field\">\n\t\t\t\t\t\t\t<label for=\"giv-1-height\">Al\u00e7ada m\u00e0xima de la columna eruptiva <span class=\"giv-optional\">opcional<\/span><\/label>\n\t\t\t\t\t\t\t<div class=\"giv-input-unit\">\n\t\t\t\t\t\t\t\t<input id=\"giv-1-height\" data-field=\"height\" type=\"text\" inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" placeholder=\"p. ex. 18\" aria-describedby=\"giv-1-height-help\">\n\t\t\t\t\t\t\t\t<select data-field=\"height-unit\" aria-label=\"Unitat de l'al\u00e7ada\">\n\t\t\t\t\t\t\t\t\t<option value=\"km\">km<\/option>\n\t\t\t\t\t\t\t\t\t<option value=\"m\">m<\/option>\n\t\t\t\t\t\t\t\t<\/select>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t\t<p class=\"giv-help\" id=\"giv-1-height-help\">Mesura-la sobre la boca d\u2019emissi\u00f3, no sobre el nivell del mar. No canvia l\u2019IEV calculat pel volum.<\/p>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\n\t\t\t\t\t<p class=\"giv-input-note\">Pots escriure decimals amb coma o punt, i notaci\u00f3 cient\u00edfica com <strong>1e8<\/strong>. Per evitar ambig\u00fcitats, no facis servir separadors de milers.<\/p>\n\t\t\t\t\t<div class=\"giv-actions\">\n\t\t\t\t\t\t<button class=\"giv-primary\" type=\"submit\">Calcula l\u2019IEV<\/button>\n\t\t\t\t\t\t<button class=\"giv-secondary\" type=\"button\" data-action=\"reset\">Reinicia<\/button>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/form>\n\n\t\t\t\t<div class=\"giv-errors\" data-errors role=\"alert\" aria-live=\"assertive\" hidden><\/div>\n\n\t\t\t\t<section class=\"giv-results\" data-results aria-live=\"polite\" hidden>\n\t\t\t\t\t<img decoding=\"async\" class=\"giv-watermark lazyload\" data-src=\"https:\/\/www.geoleg.cat\/wp-content\/plugins\/geoleg-calculadora-explosivitat-volcanica\/assets\/img\/geologia365-logo.jpg\" alt=\"\" aria-hidden=\"true\" src=\"data:image\/svg+xml;base64,PHN2ZyB3aWR0aD0iMSIgaGVpZ2h0PSIxIiB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciPjwvc3ZnPg==\" style=\"--smush-placeholder-width: 1400px; --smush-placeholder-aspect-ratio: 1400\/373;\">\n\t\t\t\t\t<div class=\"giv-section-heading giv-results-heading\">\n\t\t\t\t\t\t<div><span class=\"giv-step\">2<\/span><h3>Resultats<\/h3><\/div>\n\t\t\t\t\t\t<div class=\"giv-result-tools\">\n\t\t\t\t\t\t\t<time class=\"giv-timestamp\" data-result=\"timestamp\"><\/time>\n\t\t\t\t\t\t\t<span class=\"giv-status\" data-result=\"status\">Estimaci\u00f3 per volum<\/span>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\n\t\t\t\t\t<div class=\"giv-result-hero\">\n\t\t\t\t\t\t<article class=\"giv-big-result giv-big-result--iev\">\n\t\t\t\t\t\t\t<span class=\"giv-result-label\">IEV estimat segons el volum<\/span>\n\t\t\t\t\t\t\t<strong data-result=\"iev\">\u2014<\/strong>\n\t\t\t\t\t\t\t<span data-result=\"range\">\u2014<\/span>\n\t\t\t\t\t\t<\/article>\n\t\t\t\t\t\t<article class=\"giv-big-result\">\n\t\t\t\t\t\t\t<span class=\"giv-result-label\">Volum introdu\u00eft<\/span>\n\t\t\t\t\t\t\t<strong data-result=\"volume-primary\">\u2014<\/strong>\n\t\t\t\t\t\t\t<span data-result=\"volume-secondary\">\u2014<\/span>\n\t\t\t\t\t\t<\/article>\n\t\t\t\t\t\t<article class=\"giv-big-result\">\n\t\t\t\t\t\t\t<span class=\"giv-result-label\">Equivalent geom\u00e8tric<\/span>\n\t\t\t\t\t\t\t<strong data-result=\"cube-side\">\u2014<\/strong>\n\t\t\t\t\t\t\t<span>costat d\u2019un cub amb el mateix volum<\/span>\n\t\t\t\t\t\t<\/article>\n\t\t\t\t\t<\/div>\n\n\t\t\t\t\t<article class=\"giv-scale-card\">\n\t\t\t\t\t\t<div class=\"giv-card-heading\">\n\t\t\t\t\t\t\t<div><h4>Escala de l\u2019IEV<\/h4><p>Cada casella \u00e9s una classe de volum, no un valor continu d\u2019energia.<\/p><\/div>\n\t\t\t\t\t\t\t<span class=\"giv-scale-badge\" data-result=\"scale-badge\">IEV \u2014<\/span>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<div class=\"giv-scale-scroll\" role=\"group\" aria-label=\"Escala de l'\u00edndex d'explosivitat volc\u00e0nica\">\n\t\t\t\t\t\t\t<ol class=\"giv-scale\">\n\t\t\t\t\t\t\t\t<li data-iev=\"0\"><strong>0<\/strong><span>&lt;10<sup>4<\/sup> m\u00b3<\/span><em data-current-label hidden>Resultat<\/em><\/li>\n\t\t\t\t\t\t\t\t<li data-iev=\"1\"><strong>1<\/strong><span>10<sup>4<\/sup>\u2013&lt;10<sup>6<\/sup> m\u00b3<\/span><em data-current-label hidden>Resultat<\/em><\/li>\n\t\t\t\t\t\t\t\t<li data-iev=\"2\"><strong>2<\/strong><span>10<sup>6<\/sup>\u2013&lt;10<sup>7<\/sup> m\u00b3<\/span><em data-current-label hidden>Resultat<\/em><\/li>\n\t\t\t\t\t\t\t\t<li data-iev=\"3\"><strong>3<\/strong><span>10<sup>7<\/sup>\u2013&lt;10<sup>8<\/sup> m\u00b3<\/span><em data-current-label hidden>Resultat<\/em><\/li>\n\t\t\t\t\t\t\t\t<li data-iev=\"4\"><strong>4<\/strong><span>10<sup>8<\/sup>\u2013&lt;10<sup>9<\/sup> m\u00b3<\/span><em data-current-label hidden>Resultat<\/em><\/li>\n\t\t\t\t\t\t\t\t<li data-iev=\"5\"><strong>5<\/strong><span>10<sup>9<\/sup>\u2013&lt;10<sup>10<\/sup> m\u00b3<\/span><em data-current-label hidden>Resultat<\/em><\/li>\n\t\t\t\t\t\t\t\t<li data-iev=\"6\"><strong>6<\/strong><span>10<sup>10<\/sup>\u2013&lt;10<sup>11<\/sup> m\u00b3<\/span><em data-current-label hidden>Resultat<\/em><\/li>\n\t\t\t\t\t\t\t\t<li data-iev=\"7\"><strong>7<\/strong><span>10<sup>11<\/sup>\u2013&lt;10<sup>12<\/sup> m\u00b3<\/span><em data-current-label hidden>Resultat<\/em><\/li>\n\t\t\t\t\t\t\t\t<li data-iev=\"8\"><strong>8<\/strong><span>\u226510<sup>12<\/sup> m\u00b3<\/span><em data-current-label hidden>Resultat<\/em><\/li>\n\t\t\t\t\t\t\t<\/ol>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<p class=\"giv-scale-note\"><strong>Canvi d\u2019escala:<\/strong> a partir de l\u2019IEV 2, cada pas correspon a un llindar de volum 10 vegades m\u00e9s gran. El salt del llindar d\u2019IEV 1 al d\u2019IEV 2 \u00e9s de 100 vegades.<\/p>\n\t\t\t\t\t<\/article>\n\n\t\t\t\t\t<div class=\"giv-result-grid\">\n\t\t\t\t\t\t<article class=\"giv-result-card giv-column-card\" data-column-card>\n\t\t\t\t\t\t\t<div class=\"giv-card-icon\" data-result=\"column-icon\" aria-hidden=\"true\">?<\/div>\n\t\t\t\t\t\t\t<div>\n\t\t\t\t\t\t\t\t<h4>Comprovaci\u00f3 de la columna eruptiva<\/h4>\n\t\t\t\t\t\t\t\t<strong data-result=\"column-title\">Dada no introdu\u00efda<\/strong>\n\t\t\t\t\t\t\t\t<p data-result=\"column-message\">Pots afegir-ne l\u2019al\u00e7ada per comparar-la amb els intervals orientatius de l\u2019escala.<\/p>\n\t\t\t\t\t\t\t\t<dl class=\"giv-mini-data\">\n\t\t\t\t\t\t\t\t\t<div><dt>Al\u00e7ada indicada<\/dt><dd data-result=\"column-entered\">\u2014<\/dd><\/div>\n\t\t\t\t\t\t\t\t\t<div><dt>Interval orientatiu<\/dt><dd data-result=\"column-typical\">\u2014<\/dd><\/div>\n\t\t\t\t\t\t\t\t<\/dl>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/article>\n\n\t\t\t\t\t\t<article class=\"giv-result-card\">\n\t\t\t\t\t\t\t<div class=\"giv-card-icon giv-card-icon--info\" aria-hidden=\"true\">i<\/div>\n\t\t\t\t\t\t\t<div>\n\t\t\t\t\t\t\t\t<h4>Com s\u2019ha d\u2019interpretar?<\/h4>\n\t\t\t\t\t\t\t\t<p data-result=\"interpretation\">\u2014<\/p>\n\t\t\t\t\t\t\t\t<p>Una columna m\u00e9s alta o m\u00e9s baixa del que \u00e9s habitual <strong>no reclassifica<\/strong> el resultat. L\u2019aigua externa, la din\u00e0mica del vent, l\u2019atmosfera i la incertesa de les mesures poden alterar la relaci\u00f3.<\/p>\n\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/article>\n\t\t\t\t\t<\/div>\n\n\t\t\t\t\t<div class=\"giv-warnings\" data-warnings hidden><\/div>\n\n\t\t\t\t\t<details class=\"giv-details\">\n\t\t\t\t\t\t<summary>Veure el c\u00e0lcul pas a pas<\/summary>\n\t\t\t\t\t\t<div class=\"giv-details-body\">\n\t\t\t\t\t\t\t<table>\n\t\t\t\t\t\t\t\t<tbody>\n\t\t\t\t\t\t\t\t\t<tr><th>Volum introdu\u00eft<\/th><td data-result=\"input-volume\">\u2014<\/td><\/tr>\n\t\t\t\t\t\t\t\t\t<tr><th>Conversi\u00f3 aplicada<\/th><td data-result=\"conversion\">\u2014<\/td><\/tr>\n\t\t\t\t\t\t\t\t\t<tr><th>Interval que cont\u00e9 el volum<\/th><td data-result=\"threshold-check\">\u2014<\/td><\/tr>\n\t\t\t\t\t\t\t\t\t<tr><th>Assignaci\u00f3 final<\/th><td data-result=\"assignment\">\u2014<\/td><\/tr>\n\t\t\t\t\t\t\t\t<\/tbody>\n\t\t\t\t\t\t\t<\/table>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/details>\n\t\t\t\t<\/section>\n\n\t\t\t\t<section class=\"giv-explainer\" aria-labelledby=\"giv-1-explainer-title\">\n\t\t\t\t\t<div class=\"giv-section-heading\">\n\t\t\t\t\t\t<div><span class=\"giv-step\">3<\/span><h3 id=\"giv-1-explainer-title\">Qu\u00e8 fa que una erupci\u00f3 sigui explosiva?<\/h3><\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<p class=\"giv-section-intro\">S\u00f3n factors relacionats, per\u00f2 cap d\u2019ells permet calcular tot sol un IEV. Per aix\u00f2 els expliquem sense convertir-los en falsos controls num\u00e8rics.<\/p>\n\t\t\t\t\t<div class=\"giv-factor-grid\">\n\t\t\t\t\t\t<article>\n\t\t\t\t\t\t\t<span class=\"giv-factor-icon\" aria-hidden=\"true\">\u2248<\/span>\n\t\t\t\t\t\t\t<h4>Viscositat<\/h4>\n\t\t\t\t\t\t\t<p>Un magma m\u00e9s visc\u00f3s dificulta que els gasos escapin i pot afavorir l\u2019acumulaci\u00f3 de pressi\u00f3.<\/p>\n\t\t\t\t\t\t<\/article>\n\t\t\t\t\t\t<article>\n\t\t\t\t\t\t\t<span class=\"giv-factor-icon\" aria-hidden=\"true\">\u25cb<\/span>\n\t\t\t\t\t\t\t<h4>Gasos dissolts<\/h4>\n\t\t\t\t\t\t\t<p>En disminuir la pressi\u00f3, els vol\u00e0tils formen bombolles i s\u2019expandeixen. La quantitat de gas disponible \u00e9s important.<\/p>\n\t\t\t\t\t\t<\/article>\n\t\t\t\t\t\t<article>\n\t\t\t\t\t\t\t<span class=\"giv-factor-icon\" aria-hidden=\"true\">\u21e1<\/span>\n\t\t\t\t\t\t\t<h4>Escapament dels gasos<\/h4>\n\t\t\t\t\t\t\t<p>Si les bombolles poden connectar-se i sortir amb facilitat, disminueix la sobrepressi\u00f3 dins del magma.<\/p>\n\t\t\t\t\t\t<\/article>\n\t\t\t\t\t\t<article>\n\t\t\t\t\t\t\t<span class=\"giv-factor-icon\" aria-hidden=\"true\">\u2248\u25cb<\/span>\n\t\t\t\t\t\t\t<h4>Interacci\u00f3 magma\u2013aigua<\/h4>\n\t\t\t\t\t\t\t<p>Una interacci\u00f3 eficient amb aigua externa pot fragmentar el magma i originar activitat freatomagm\u00e0tica.<\/p>\n\t\t\t\t\t\t<\/article>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/section>\n\n\t\t\t\t<section class=\"giv-outside\" aria-labelledby=\"giv-1-outside-title\">\n\t\t\t\t\t<h3 id=\"giv-1-outside-title\">Qu\u00e8 no calcula aquesta eina?<\/h3>\n\t\t\t\t\t<div class=\"giv-outside-grid\">\n\t\t\t\t\t\t<article>\n\t\t\t\t\t\t\t<h4>Tipus de magma i composici\u00f3<\/h4>\n\t\t\t\t\t\t\t<p>La composici\u00f3 influeix en la viscositat, per\u00f2 tamb\u00e9 ho fan la temperatura, els cristalls i els gasos. No hi ha una conversi\u00f3 \u00fanica de composici\u00f3 a IEV.<\/p>\n\t\t\t\t\t\t<\/article>\n\t\t\t\t\t\t<article>\n\t\t\t\t\t\t\t<h4>Edifici volc\u00e0nic i col\u00b7lapses<\/h4>\n\t\t\t\t\t\t\t<p>L\u2019IEV no dona la probabilitat de col\u00b7lapse de l\u2019edifici ni de la columna. S\u00f3n processos diferents: poden generar, respectivament, allaus de detritus o corrents de densitat pirocl\u00e0stica.<\/p>\n\t\t\t\t\t\t<\/article>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/section>\n\n\t\t\t\t<details class=\"giv-sources\">\n\t\t\t\t\t<summary>Fonts, criteris i l\u00edmits cient\u00edfics<\/summary>\n\t\t\t\t\t<div>\n\t\t\t\t\t\t<ul>\n\t\t\t\t\t\t\t<li><a href=\"https:\/\/doi.org\/10.1029\/JC087iC02p01231\" target=\"_blank\" rel=\"noopener noreferrer\">Newhall i Self (1982)<\/a>: proposta original de l\u2019\u00edndex d\u2019explosivitat volc\u00e0nica.<\/li>\n\t\t\t\t\t\t\t<li><a href=\"https:\/\/www.usgs.gov\/observatories\/yvo\/news\/volcanic-explosivity-index-a-tool-comparing-sizes-explosive-volcanic\" target=\"_blank\" rel=\"noopener noreferrer\">USGS \u2014 The Volcanic Explosivity Index<\/a>: \u00fas del volum, l\u2019al\u00e7ada i les limitacions de l\u2019escala.<\/li>\n\t\t\t\t\t\t\t<li><a href=\"https:\/\/www.usgs.gov\/publications\/did-steam-boost-height-and-growth-rate-giant-hunga-eruption-plume\" target=\"_blank\" rel=\"noopener noreferrer\">USGS \u2014 Hunga Tonga i el paper del vapor<\/a>: exemple d\u2019una columna excepcionalment alta per la interacci\u00f3 amb aigua.<\/li>\n\t\t\t\t\t\t\t<li><a href=\"https:\/\/volcano.si.edu\/\" target=\"_blank\" rel=\"noopener noreferrer\">Smithsonian Global Volcanism Program<\/a>: cat\u00e0leg i documentaci\u00f3 d\u2019erupcions volc\u00e0niques.<\/li>\n\t\t\t\t\t\t<\/ul>\n\t\t\t\t\t\t<p>La classificaci\u00f3 principal d\u2019aquesta eina usa exclusivament el volum estimat de productes pirocl\u00e0stics. Els intervals de columna s\u00f3n orientatius, se solapen i no separen els IEV 5\u20138. Una estimaci\u00f3 cient\u00edfica pot canviar quan millora la cartografia dels dip\u00f2sits o el m\u00e8tode de conversi\u00f3 de volums.<\/p>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/details>\n\n\t\t\t\t<footer class=\"giv-footer\">\n\t\t\t\t\t<div class=\"giv-counter\" aria-live=\"polite\"><span data-count>8<\/span> c\u00e0lculs efectuats<\/div>\n\t\t\t\t\t<div class=\"giv-footer-brand\"><img decoding=\"async\" data-src=\"https:\/\/www.geoleg.cat\/wp-content\/plugins\/geoleg-calculadora-explosivitat-volcanica\/assets\/img\/geologia365-logo.jpg\" alt=\"Geologia365.com\" src=\"data:image\/svg+xml;base64,PHN2ZyB3aWR0aD0iMSIgaGVpZ2h0PSIxIiB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciPjwvc3ZnPg==\" class=\"lazyload\" style=\"--smush-placeholder-width: 1400px; --smush-placeholder-aspect-ratio: 1400\/373;\"><span>Amb el suport de Geologia365.com<\/span><\/div>\n\t\t\t\t\t<p><strong>\u00a9 2026 Ge\u00f2leg.cat. Eina creada per Ge\u00f2leg.cat.<\/strong> Tots els drets reservats sobre el codi, el disseny i els continguts originals.<\/p>\n\t\t\t\t\t<p>Eina did\u00e0ctica. El resultat \u00e9s una classificaci\u00f3 aproximada basada en dades introdu\u00efdes per l\u2019usuari; no prediu una erupci\u00f3 ni substitueix una avaluaci\u00f3 volcanol\u00f2gica o de risc.<\/p>\n\t\t\t\t<\/footer>\n\t\t\t\t<noscript><p class=\"giv-errors\">Cal activar JavaScript per utilitzar aquesta calculadora.<\/p><\/noscript>\n\t\t\t<\/section>\n\t\t\t\n<p>&nbsp;<\/p>\n<ul>\n<li>\n<h1>Laboratori virtual \u2013 \u00cdndex d\u2019explosivitat volc\u00e0nica<\/h1>\n<p>Quina mida pot tenir una erupci\u00f3 explosiva? Aquesta calculadora estima l\u2019<strong>\u00edndex d\u2019explosivitat volc\u00e0nica<\/strong> \u2014IEV, o VEI en angl\u00e8s\u2014 a partir del volum total de materials expulsats durant l\u2019erupci\u00f3.<\/p>\n<p>Cal introduir el volum dels <strong>productes pirocl\u00e0stics o tefra<\/strong>, com ara cendra, lapil\u00b7li, esc\u00f2ries, bombes i blocs. Les colades de lava no s\u2019hi han de sumar, perqu\u00e8 l\u2019IEV descriu principalment la part explosiva de l\u2019erupci\u00f3.<\/p>\n<h2>Com funciona?<\/h2>\n<ol>\n<li>Introdueix el volum estimat dels productes pirocl\u00e0stics en metres c\u00fabics o quil\u00f2metres c\u00fabics.<\/li>\n<li>Opcionalment, indica l\u2019al\u00e7ada m\u00e0xima de la columna eruptiva, mesurada des de la boca d\u2019emissi\u00f3.<\/li>\n<li>La calculadora assignar\u00e0 un valor entre <strong>IEV 0 i IEV 8<\/strong> i mostrar\u00e0 l\u2019interval de volum corresponent.<\/li>\n<\/ol>\n<p>L\u2019al\u00e7ada de la columna nom\u00e9s s\u2019utilitza com a comprovaci\u00f3 orientativa. Si \u00e9s m\u00e9s alta o m\u00e9s baixa del que seria habitual, el resultat calculat a partir del volum no canvia.<\/p>\n<h2>Com s\u2019interpreta l\u2019escala?<\/h2>\n<p>L\u2019IEV \u00e9s una escala discreta i, a partir de l\u2019IEV 2, aproximadament logar\u00edtmica respecte del volum. Aix\u00f2 significa que cada classe comen\u00e7a amb un volum deu vegades m\u00e9s gran que l\u2019anterior:<\/p>\n<ul>\n<li><strong>IEV 4:<\/strong> a partir de 0,1 km\u00b3 de productes pirocl\u00e0stics.<\/li>\n<li><strong>IEV 5:<\/strong> a partir d\u20191 km\u00b3.<\/li>\n<li><strong>IEV 6:<\/strong> a partir de 10 km\u00b3.<\/li>\n<li><strong>IEV 7:<\/strong> a partir de 100 km\u00b3.<\/li>\n<li><strong>IEV 8:<\/strong> a partir de 1.000 km\u00b3.<\/li>\n<\/ul>\n<p>La calculadora tamb\u00e9 mostra el volum en diferents unitats i el representa com el costat d\u2019un cub equivalent, per ajudar a visualitzar-ne la magnitud.<\/p>\n<h2>Qu\u00e8 fa que una erupci\u00f3 sigui explosiva?<\/h2>\n<p>L\u2019explosivitat dep\u00e8n de la interacci\u00f3 de diversos factors: la viscositat del magma, la quantitat de gasos dissolts, la facilitat amb qu\u00e8 aquests gasos poden escapar i, en alguns casos, el contacte del magma amb aigua externa.<\/p>\n<p>La composici\u00f3 del magma hi influeix, per\u00f2 no permet determinar per si sola un IEV. Tampoc no es pot convertir directament la pres\u00e8ncia d\u2019aigua o el tipus d\u2019edifici volc\u00e0nic en un valor num\u00e8ric fiable.<\/p>\n<h2>Qu\u00e8 no calcula aquesta eina?<\/h2>\n<p>L\u2019IEV expressa la <strong>mida de la part explosiva d\u2019una erupci\u00f3<\/strong>, per\u00f2 no indica directament:<\/p>\n<ul>\n<li>l\u2019energia total alliberada;<\/li>\n<li>la probabilitat que es produeixi una erupci\u00f3;<\/li>\n<li>el perill o el risc per a la poblaci\u00f3;<\/li>\n<li>la possibilitat de col\u00b7lapse de l\u2019edifici volc\u00e0nic;<\/li>\n<li>la probabilitat de col\u00b7lapse de la columna eruptiva;<\/li>\n<li>els danys o les v\u00edctimes que podria causar.<\/li>\n<\/ul>\n<p>Una erupci\u00f3 amb un IEV baix pot ser molt perillosa si es produeix a prop d\u2019una zona habitada. El risc dep\u00e8n tamb\u00e9 del tipus de fenomen volc\u00e0nic, la dist\u00e0ncia, l\u2019exposici\u00f3 i la vulnerabilitat del territori.<\/p>\n<p>Aquesta \u00e9s una <strong>eina did\u00e0ctica<\/strong>. Els volums eruptius s\u00f3n estimacions que poden canviar quan es cartografien millor els dip\u00f2sits. En erupcions purament efusives, sense un volum conegut de tefra, aquesta calculadora no \u00e9s adequada.<\/p>\n<p>Introdueix les dades, compara els resultats i descobreix com varia la magnitud de les erupcions explosives.<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>&nbsp; Laboratori virtual \u2013 \u00cdndex d\u2019explosivitat volc\u00e0nica Quina mida pot tenir una erupci\u00f3 explosiva? Aquesta calculadora estima l\u2019\u00edndex d\u2019explosivitat volc\u00e0nica \u2014IEV, o VEI en angl\u00e8s\u2014 a partir del volum total [&hellip;]<\/p>\n","protected":false},"author":3,"featured_media":0,"parent":1204,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_monsterinsights_skip_tracking":false,"footnotes":""},"wf_page_folders":[],"class_list":["post-2257","page","type-page","status-publish","hentry"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v28.5 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Calculadora d&#039;explosivitat volc\u00e0nica - Formaci\u00f3 i Divulgaci\u00f3 en Geologia #Geoturisme<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.geoleg.cat\/index.php\/que-oferim\/recursos-didactics\/recursos-geologia\/calculadora-dexplosivitat-volcanica\/\" \/>\n<meta property=\"og:locale\" content=\"ca_ES\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Calculadora d&#039;explosivitat volc\u00e0nica - Formaci\u00f3 i Divulgaci\u00f3 en Geologia #Geoturisme\" \/>\n<meta property=\"og:description\" content=\"&nbsp; Laboratori virtual \u2013 \u00cdndex d\u2019explosivitat volc\u00e0nica Quina mida pot tenir una erupci\u00f3 explosiva? Aquesta calculadora estima l\u2019\u00edndex d\u2019explosivitat volc\u00e0nica \u2014IEV, o VEI en angl\u00e8s\u2014 a partir del volum total [&hellip;]\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.geoleg.cat\/index.php\/que-oferim\/recursos-didactics\/recursos-geologia\/calculadora-dexplosivitat-volcanica\/\" \/>\n<meta property=\"og:site_name\" content=\"Formaci\u00f3 i Divulgaci\u00f3 en Geologia #Geoturisme\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:site\" content=\"@geolegCAT\" \/>\n<meta name=\"twitter:label1\" content=\"Temps estimat de lectura\" \/>\n\t<meta name=\"twitter:data1\" content=\"3 minuts\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/www.geoleg.cat\\\/index.php\\\/que-oferim\\\/recursos-didactics\\\/recursos-geologia\\\/calculadora-dexplosivitat-volcanica\\\/\",\"url\":\"https:\\\/\\\/www.geoleg.cat\\\/index.php\\\/que-oferim\\\/recursos-didactics\\\/recursos-geologia\\\/calculadora-dexplosivitat-volcanica\\\/\",\"name\":\"Calculadora d'explosivitat volc\u00e0nica - Formaci\u00f3 i Divulgaci\u00f3 en Geologia #Geoturisme\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/www.geoleg.cat\\\/#website\"},\"datePublished\":\"2026-09-23T15:21:55+00:00\",\"breadcrumb\":{\"@id\":\"https:\\\/\\\/www.geoleg.cat\\\/index.php\\\/que-oferim\\\/recursos-didactics\\\/recursos-geologia\\\/calculadora-dexplosivitat-volcanica\\\/#breadcrumb\"},\"inLanguage\":\"ca\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\\\/\\\/www.geoleg.cat\\\/index.php\\\/que-oferim\\\/recursos-didactics\\\/recursos-geologia\\\/calculadora-dexplosivitat-volcanica\\\/\"]}]},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\\\/\\\/www.geoleg.cat\\\/index.php\\\/que-oferim\\\/recursos-didactics\\\/recursos-geologia\\\/calculadora-dexplosivitat-volcanica\\\/#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Inici\",\"item\":\"https:\\\/\\\/www.geoleg.cat\\\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Qu\u00e8 oferim\",\"item\":\"https:\\\/\\\/www.geoleg.cat\\\/index.php\\\/que-oferim\\\/\"},{\"@type\":\"ListItem\",\"position\":3,\"name\":\"Recursos did\u00e0ctics\",\"item\":\"https:\\\/\\\/www.geoleg.cat\\\/index.php\\\/que-oferim\\\/recursos-didactics\\\/\"},{\"@type\":\"ListItem\",\"position\":4,\"name\":\"Recursos geologia\",\"item\":\"https:\\\/\\\/www.geoleg.cat\\\/index.php\\\/que-oferim\\\/recursos-didactics\\\/recursos-geologia\\\/\"},{\"@type\":\"ListItem\",\"position\":5,\"name\":\"Calculadora d&#8217;explosivitat volc\u00e0nica\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\\\/\\\/www.geoleg.cat\\\/#website\",\"url\":\"https:\\\/\\\/www.geoleg.cat\\\/\",\"name\":\"Formaci\u00f3 i Divulgaci\u00f3 en Geologia #Geoturisme\",\"description\":\"Formaci\u00f3 i Divulgaci\u00f3 en Geologia #Geoturisme\",\"publisher\":{\"@id\":\"https:\\\/\\\/www.geoleg.cat\\\/#organization\"},\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\\\/\\\/www.geoleg.cat\\\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"ca\"},{\"@type\":\"Organization\",\"@id\":\"https:\\\/\\\/www.geoleg.cat\\\/#organization\",\"name\":\"Ge\u00f2leg.cat\",\"url\":\"https:\\\/\\\/www.geoleg.cat\\\/\",\"logo\":{\"@type\":\"ImageObject\",\"inLanguage\":\"ca\",\"@id\":\"https:\\\/\\\/www.geoleg.cat\\\/#\\\/schema\\\/logo\\\/image\\\/\",\"url\":\"https:\\\/\\\/i0.wp.com\\\/www.geoleg.cat\\\/wp-content\\\/uploads\\\/2019\\\/09\\\/Logo-petit.png?fit=600%2C128&ssl=1\",\"contentUrl\":\"https:\\\/\\\/i0.wp.com\\\/www.geoleg.cat\\\/wp-content\\\/uploads\\\/2019\\\/09\\\/Logo-petit.png?fit=600%2C128&ssl=1\",\"width\":600,\"height\":128,\"caption\":\"Ge\u00f2leg.cat\"},\"image\":{\"@id\":\"https:\\\/\\\/www.geoleg.cat\\\/#\\\/schema\\\/logo\\\/image\\\/\"},\"sameAs\":[\"https:\\\/\\\/x.com\\\/geolegCAT\",\"https:\\\/\\\/www.instagram.com\\\/geoleg.cat\\\/\"]}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Calculadora d'explosivitat volc\u00e0nica - Formaci\u00f3 i Divulgaci\u00f3 en Geologia #Geoturisme","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/www.geoleg.cat\/index.php\/que-oferim\/recursos-didactics\/recursos-geologia\/calculadora-dexplosivitat-volcanica\/","og_locale":"ca_ES","og_type":"article","og_title":"Calculadora d'explosivitat volc\u00e0nica - Formaci\u00f3 i Divulgaci\u00f3 en Geologia #Geoturisme","og_description":"&nbsp; Laboratori virtual \u2013 \u00cdndex d\u2019explosivitat volc\u00e0nica Quina mida pot tenir una erupci\u00f3 explosiva? 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