Italy's Mount Etna Is Preparing for a 'Catastrophic' Collapse That May Cause a Tsunami

Thursday, 11 October 2018 - 12:29PM
Earth
Thursday, 11 October 2018 - 12:29PM
Italy's Mount Etna Is Preparing for a 'Catastrophic' Collapse That May Cause a Tsunami
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Mount Etna may not spew out as much lava as Hawaii's Kilauea volcano (which has been erupting for months), but it's not an eruption that geologists are afraid of—it's a fast-moving landslide into the ocean, where the mass of Etna's southeastern slope could trigger a tsunami.

Etna, which has a max elevation of 10,900 feet, sits on the east coast of Sicily, in the province of Catania. Its slopes stretch to the Mediterranean, and it's been going through periods of eruption and dormancy for about 8,000 years, with its most recent cycle starting in 2013. The southeastern slope has been inching toward the sea for the past 30 years, but the key question is whether this is a result of magma moving within the volcano itself, or if gravity is pushing the slope downwards. It turns out the key to that question lay beneath the ocean.

A research team led by Morelia Urlaub, an expert in marine geodynamics from the GEOMAR Helmholtz Centre for Ocean Research, set up transponders on the seafloor near Etna to monitor any movement. They found that a large fault in the ocean floor moved 1.6 inches over the course of eight days, which is pretty significant considering that Etna's southeastern slope usually moves at a rate of a half-inch per year. What's more, this region of seafloor isn't even remotely close to Etna's subterranean magma chambers, meaning that magma can't be behind the movement. That leaves gravity as the culprit...and raises the threat of a sudden collapse.

According to Uralaub: "We know from other volcanoes in the geological record that these have collapsed catastrophically and caused really, really big, fast landslides, and if these landslides enter the sea, they can cause a tsunami." Some of the most powerful tsunamis in history were caused by volcanic eruptions or collapses, including the one caused by Krakatoa in 1883 and the hypothesized tsunami that wiped out the Minoan Civilization in 1490 B.C. Uralaub doesn't know how imminent a collapse may be, but advises researchers to continue monitoring the volcano.

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