For years, Maisana volcano in Greece has been classified as a dormant volcano because it appears calm and inactive due to its proximity to the Saronic Gulf near Athens. It was thought that it showed no signs of volcanic activity for hundreds of years, but scientists’ current findings prove this was just a misunderstanding. Geological studies show that the volcano maintained a calm surface for decades, during which time magma accumulated below the surface.
Greece’s Maisana volcano reawakens after hiding magma activity for 100,000 years
The last recorded eruption of Maisana occurred around 250 BC. This is documented in some ancient Greek texts, and since then there has been no surface activity at Maisana volcano. Therefore, its relative peace has led to the perception that it poses no threat to humanity.According to research published in Science Advances, titled “A volcano reawakens after more than 100,000 years of growth in a ‘silent’ magma chamber,” Modern scientists claim this belief is wrong. Scientists at ETH Zurich conducted a thorough study of Maisana’s geology and discovered something unexpected. Over the past 700,000 years, Maisana volcano has experienced multiple phases of volcanic activity, each separated by long periods of quiet.One of the most interesting findings is that for about a hundred thousand years, Maisana showed no activity on the surface, but was anything but quiet inside the planet.
Zircon crystals reveal Maisana’s hidden underground activities
To understand Methana’s history, more than 1,250 zircon crystals obtained from ancient volcanic flows were studied. Such crystals form in magma and can preserve information about geological processes over time. Studies of radioactive uranium degradation processes can estimate the timing of volcanic eruptions.It turns out that zircon formation was active even during periods when the volcano was not erupting. This indicates that there was magma movement beneath the volcano. Scientists speculate that Maisana was not in a dormant state during this period, but entered a state where magma accumulated underground, but did not come to the surface.
Why is magma trapped underground?
Maisana sits atop a subduction zone, where one plate moves beneath another. The melting of certain parts of the ocean floor creates magma, which then moves upward to the surface. Unlike other magmas, this particular one is unusually rich in water.As magma with a high water content moves upward, gases begin to form due to a decrease in pressure. In many ways, magma is similar to soda in that the gas creates bubbles, causing it to become very viscous. Magma does not rise to the Earth’s surface; Instead, it’s trapped within the Earth. As a result, magma chambers formed deep within the volcano.
Maisana study suggests some ‘extinct volcanoes’ may still be active underground
Typically, an extinct volcano is defined as one that has not erupted in the past 10,000 years. The history of Methana challenges this definition. Volcanoes can take up to 100,000 years to enter a dormant phase, suggesting that dormancy does not mean the volcano is extinct.It has been speculated that volcanoes that are defined as extinct may actually have active magma chambers beneath their surface. Such magma chambers may simply be dormant and require specific conditions to erupt.
