Scientists have discovered that the Methana volcano in Greece, thought to be dormant for more than 100,000 years, has been steadily accumulating vast amounts of magma deep within its chambers. The volcano, located approximately 50 kilometres southwest of Athens, has shown no signs of eruption in that time, but new research suggests it is far from extinct.
Researchers analysed over 1,250 zircon crystals from the volcano's magma reservoirs. These tiny crystals act as natural time capsules, preserving information about when and under what conditions they grew. The study, published in Science Advances, reveals that magma production has been almost continuous beneath Methana, with peak zircon growth indicating intense magma activity during the long quiet period.
The magma supplying Methana's upper chamber was found to be exceptionally water-rich, far more so than expected. Scientists believe this is due to the mantle beneath the volcano being strongly influenced by ocean-floor sediments and substantial amounts of water. This process “hydrates” the mantle, triggers crystallisation, and makes magma production more efficient.
Volcanologist Olivier Bachmann from ETH Zurich said the findings show that volcanoes can “breathe” underground for millennia without ever breaking the surface. Co-author Răzvan-Gabriel Popa added that many subduction zone volcanoes might be periodically fed by particularly wet primitive magma, a phenomenon not yet fully recognised by the scientific community.
The study highlights the need for authorities in volcanically active regions such as Greece, Italy, Indonesia, the Philippines, and the Americas to re-evaluate the threat level of volcanoes that have been quiet for tens of thousands of years but show signs of magmatic unrest. A prolonged period of silence could signal the buildup of a large and potentially more dangerous magma system.
