A new study revealed that the Methana volcano remained active beneath the surface despite appearing dormant for more than 100,000 years, according to research led by ETH Zurich.
The international research team reconstructed over 700,000 years of volcanic activity, analysing 31 eruptions to better understand the volcano’s history. Lead author Razvan-Gabriel Popa stated that Greek volcanoes still held significant undiscovered insights.
Researchers collected samples from lava flows, volcanic domes and ash deposits, while also examining more than 1,250 zircon crystals—described as “microscopic time capsules”—which recorded the timing and conditions of magma formation.
The findings, published in Science Advances, showed that the volcano remained inactive for around 110,000 years before reawakening and entering its current cycle. Scientists had previously believed such long dormancy indicated permanent extinction, but the study challenged that assumption.
During this inactive period, magma production did not decline. Instead, magma continued to accumulate underground, causing the magma chamber to expand. Zircon crystal growth peaked during this time, indicating intense subsurface activity.
Popa explained that the key factor was the magma’s high water content, which slowed its ascent to the surface through crystallisation and prevented eruptions. When deeper magma became drier, eruptions resumed unexpectedly, often fuelled by a larger magma reservoir.
The findings reshaped how scientists understood dormant and extinct volcanoes. Popa warned that many volcanoes considered inactive might still be accumulating energy beneath the surface. He noted that long dormant periods did not necessarily make volcanoes safer and, in some cases, could increase the risk of more powerful eruptions.
Although Methana did not currently pose a significant खत, he cautioned that extended dormancy could eventually make it more dangerous.
The study also highlighted similar behaviour at the Ciomadul volcano in Romania’s Carpathian Mountains, which last erupted around 30,000 years ago but still showed evidence of an active magma chamber forming below.
Researchers stressed the importance of monitoring volcanic regions, warning that magma chambers could develop undetected beneath the surface, potentially increasing future risks.
