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Across layers of lava built up over roughly 500,000 years on Mount Etna, the same deep source continues to feed the volcano\u2019s eruptions.<\/p>\n
By tracing those deposits, Sebastien Pilet at the University of Lausanne (UNIL<\/a>) showed that the magma originates from a stable reservoir already present far below the surface.<\/p>\n Even as the volcano expanded into a 9,800-foot stratovolcano, that underlying source remained remarkably consistent over time.<\/p>\n This persistence suggests that Etna\u2019s eruptions depend less on newly generated magma and more on how tectonic forces release what is already stored deep below.<\/p>\n Why Etna stands apart<\/p>\n Most volcanoes fall into three familiar families, but Etna has long refused to sit neatly in any one.<\/p>\n Some grow where plates pull apart, others where one plate sinks, and others over hot plumes such as Hawaii.<\/p>\n Etna stands near a subduction zone, where one tectonic plate dives under another, yet its lava chemistry resembles eruptions far away.<\/p>\n That mismatch is why researchers started asking whether Etna belongs to a fourth volcanic class rather than a strange exception.<\/p>\n A hidden reservoir<\/p>\n About 50 miles (80 kilometers) beneath the volcano, the team places the source in the Low Velocity Zone, a weak layer atop the mantle.<\/p>\n Similar melt-rich layers have turned up beneath other subducting plates in geophysical studies<\/a>, strengthening the idea that such storage zones are real.<\/p>\n Instead of forming right before an eruption, Etna\u2019s magma may wait deep underground until plate motion helps it escape.<\/p>\n \u201cEtna may have formed through a mechanism similar to the one that generates petit-spot submarine volcanoes,\u201d said Pilet.<\/p>\n Bending frees magma<\/p>\n What frees that deep melt is not a column of rising hot mantle but the bending of Earth\u2019s crust as the African plate pushes beneath the Eurasian plate.<\/p>\n As the slab flexes near Sicily, fractures open and pressure changes, giving stored magma a path toward the surface.<\/p>\n That process resembles petit-spot volcanoes<\/a>, small eruptions above bending ocean plates, although Etna is vastly larger than those seafloor examples.<\/p>\n The comparison matters because it ties Etna\u2019s growth to crustal stress and plate shape, not only to unusually hot mantle.<\/p>\n How magma evolved<\/p>\n Early in Etna\u2019s history, smaller eruptions gave way to alkaline lava \u2013 magma unusually rich in sodium and potassium \u2013 that later dominated the volcano.<\/p>\n During a melt-rock reaction, magma<\/a> chemically changes the surrounding mantle as it rises, and the lava can take on Etna\u2019s earliest chemistry.<\/p>\n Those interactions likely helped carve more porous pathways, so later batches of deeper magma could move upward with less chemical scrambling.<\/p>\n The result fits a volcano that started with modest output and then ramped up without needing a brand-new magma source.<\/p>\n What stayed steady<\/p>\n Across 85 rock samples from East Sicily, the chemistry after Etna\u2019s early phase remained steady for most of its life.<\/p>\n That pattern suggests plate<\/a> movement mainly controlled how much magma escaped, while the source itself changed very little.<\/p>\n Over roughly 60,000 years, Etna produced about 83 cubic miles (346 cubic kilometers) of alkaline lava without a matching overhaul in composition.<\/p>\n Explaining that combination is hard if each increase came from fresh melting deep below the volcano.<\/p>\n Older Sicilian clues<\/p>\n South of Etna, older lavas from the Hyblean Plateau, a volcanic region in southeastern Sicily, hint that this deep process may have been working earlier.<\/p>\n Those scattered eruptions were much smaller, but their chemistry links them to the same deep<\/a> store of low-degree melt.<\/p>\n Some of that older magma seems to have stalled, cooled, and altered the surrounding mantle before later eruptions remobilized related material.<\/p>\n Linking both volcanic episodes into one longer story makes Etna look less like an outlier and more like an exposed process.<\/p>\n Risk on Etna slopes<\/p>\n That deeper model could sharpen monitoring on Europe\u2019s most active volcano, a mountain that erupts several times a year near towns.<\/p>\n Since 1986, the summit craters have produced more than 240 paroxysmal episodes<\/a>, sudden bursts of lava fountaining and ash.<\/p>\n If tectonic stress helps decide when melt escapes, tracking faults and ground movement could become even more important.<\/p>\n Such work would not predict exact eruptions, but it could improve where scientists focus the most urgent warning signs.<\/p>\n Why Etna differs<\/p>\n No known volcano of Etna\u2019s size has been convincingly tied to this mechanism before, which is why the claim stands out.<\/p>\n Earlier examples involved tiny submarine cones only a few hundred feet tall, not a giant cone volcano above sea level.<\/p>\n The case still rests on chemistry, tectonic history, and geophysical clues rather than a direct view of molten pockets 50 miles (80 kilometers) down.<\/p>\n Even with that limit, the model offers a clean answer to why Etna looks ordinary on the surface and odd at depth.<\/p>\n Rethinking volcano systems<\/p>\n Etna now looks like a place where stored, gas-rich melt at the base of a plate can reach the surface at an unusual scale.<\/p>\n If that picture holds, scientists may use Sicily to test how deep melt lubricates plate motion and feeds volcanoes elsewhere.<\/p>\n The study is published in the Journal of Geophysical Research: Solid Earth<\/a>.<\/p>\n \u2014\u2013<\/p>\n Like what you read?\u00a0Subscribe to our newsletter<\/a>\u00a0for engaging articles, exclusive content, and the latest updates.<\/p>\n Check us out on\u00a0EarthSnap<\/a>, a free app brought to you by\u00a0Eric Ralls<\/a>\u00a0and Earth.com.<\/p>\n \u2014\u2013<\/p>\n","protected":false},"excerpt":{"rendered":"Researchers have found that Mount Etna, a volcano on the Italian island of Sicily, draws magma from a…\n","protected":false},"author":2,"featured_media":389462,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[111,139,69,147],"class_list":{"0":"post-389461","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-science","8":"tag-new-zealand","9":"tag-newzealand","10":"tag-nz","11":"tag-science"},"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/389461","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/comments?post=389461"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/389461\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media\/389462"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media?parent=389461"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/categories?post=389461"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/tags?post=389461"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}