Methana: A “dormant” volcano with hidden activity for 100,000 years revealed by a new study

For much than 100,000 years, the Methana volcano—part of the South Aegean volcanic arc—appeared inactive. An planetary probe squad led by ETH Zurich reconstructed successful item implicit 700,000 years of its volcanic enactment and recovered that during this quiescent period, the volcano continued to person underground activity. “Greek volcanoes person overmuch much to reveal,” notes Popa.

The team’s analyses screen 31 eruptions implicit astir 700,000 years. To recognize the volcano’s history, researchers conducted tract sampling, collecting worldly from lava flows, volcanic domes, and ash deposits. They besides studied much than 1,250 tiny magma crystals called zircon, which, arsenic Popa explains, enactment similar “microscopic clip capsules”: they turn successful magma astatine antithetic times and grounds the conditions and timing of their formation.

The reconstruction showed that the volcano erstwhile remained inactive for astir 110,000 years earlier reawakening and restarting its existent enactment cycle. Until now, specified a agelong dormant play was considered grounds that a volcano had permanently gone extinct. However, the caller study—published successful the diary Science Advances—overturns this assumption, astonishing adjacent the researchers. “Our survey challenges this thought and shows the other whitethorn beryllium true. It overturns however we specify extinct volcanoes, arsenic a agelong dormancy does not needfully mean a strategy has stopped,” the pb researcher emphasizes.

Researchers besides recovered thing adjacent much striking: during the dormant period, magma accumulation did not decrease. Instead, magma continuously accumulated astatine depth, and the magma enclosure really grew successful size. During this time, zircon crystal maturation peaked, showing wide signs of aggravated magmatic activity.

According to Popa, the “secret” lies successful the magma’s precocious h2o content, which slowed its ascent to the aboveground done crystallization, preventing eruptions. “Thus, it accumulates successful the magma enclosure for immense periods without erupting. However, erstwhile deeper magmas go drier, eruptions tin resume unexpectedly, and determination is present a larger magma enclosure to provender them,” helium explains.

These findings fundamentally alteration however volcanologists recognize dormant and extinct volcanoes. “Many volcanoes we see extinct contiguous whitethorn really beryllium successful this state,” Popa explains, adding a warning: “These results amusement we should commencement reassessing our ‘dead’ volcanoes, arsenic they whitethorn simply beryllium gathering strength. During agelong dormant periods, specified systems tin sometimes germinate into overmuch larger igneous bodies susceptible of much energetic eruptions. In different words, volcanoes successful semipermanent dormancy bash not needfully weaken oregon go safer; successful immoderate cases, the other whitethorn beryllium true—they whitethorn go much unsafe and necessitate attention.” Methana, helium clarifies, “is not presently a unsafe volcano, but if it undergoes different agelong ‘sleeping beauty’ period, it could go one.”

Methana is not an exception. Popa notes that akin behaviour is observed astatine the Ciomadul Volcano, which past erupted astir 30,000 years agone but remains intelligibly active, with geophysical measurements indicating an progressive magma enclosure forming beneath it.

Popa stresses the value of monitoring volcanic regions, arsenic “magma chambers whitethorn beryllium forming beneath our feet without america knowing it.”