A volcano near Methana, Greece, once thought to be inactive might not be as quiet as it seems. A recent study in Science Advances spans 700,000 years of volcanic history, suggesting that magma can build up quietly underground for tens of thousands of years before an eruption happens. This changes how scientists assess volcanic risk.
The Methana volcano, located in the Saronic Gulf near Athens, last erupted around 250 B.C.E., according to ancient historian Strabo. For a long time, it seemed dormant, blending into its surroundings. Yet this study reveals a much more complex picture, challenging how scientists understand volcanic activity.
Led by Razvan-Gabriel Popa from ETH Zurich, researchers found at least 31 eruptions throughout Methana’s history. Notably, a dormant period of nearly 100,000 years showed no surface activity. By standard measures, this volcano would be considered extinct. But the findings uncovered a different story—one of ongoing activity beneath the surface, where magma was slowly accumulating.
Using zircon crystals from more than 1,250 ancient lava samples, scientists created a precise timeline of Methana’s volcanic activity. These tiny minerals, which form as magma cools, helped identify when magma was being produced, even during dormant periods.
“We chose Methana because its lava flows are well spread out,” Popa explained to Nautilus. This unique layout made it easier for scientists to study different eruptive phases without interference from later flows. Their analysis found that the most zircon formation occurred during Methana’s long quiet period, suggesting that while the volcano was silent, magma production was ramping up below.
The reason for this hidden activity lies in Methana’s tectonic setting. The volcano sits above a subduction zone, where one tectonic plate dives beneath another. This process creates “superhydrous magma,” which can trap water and cause pressure to build. As the magma rises, gas bubbles form, thickening the magma and slowing its ascent. This means that instead of erupting, magma accumulates underground, leading to potential future eruptions that could be more powerful due to increased pressure.
The implications of this study extend beyond Methana. Many volcanoes around the world, especially those in subduction zones like the Pacific Ring of Fire, may also hold hidden magma systems. As Popa noted, “Quiet doesn’t always mean safe.” This insight calls for a deeper understanding of volcanic hazards, especially in urban areas like Athens.
Recent statistics show that many regions worldwide are home to dormant volcanoes, yet our understanding of risk here may need an urgent update. It’s vital to reevaluate how we monitor volcanic activity—to look beyond what’s visible on the surface and consider the geological processes at play beneath.
With continued research, better monitoring might help us prepare for these hidden threats, ensuring communities stay informed about potential risks from seemingly inactive volcanoes.
