Recent research indicates that so-called extinct volcanoes may be silently accumulating significant amounts of magma. This finding comes from a study conducted by volcanologists at ETH Zurich, focusing on the Methana volcano near Athens, Greece. The research spans 700,000 years of geological history.
Dormant Volcanoes and Magma Accumulation
ETH Zurich researchers found a notable increase in tiny zircon crystals during Methana’s period of dormancy, which lasted over 100,000 years. This suggests that large reservoirs of magma were still accumulating during a time when the volcano appeared inactive.
- Research Duration: 700,000 years
- Longest Dormant Period: Over 100,000 years
- Zircon Analysis: More than 1,250 crystals studied
Volcanic Activity and Historical Context
The Methana volcano is part of the South Aegean Volcanic Arc, a region characterized by active volcanic hotspots formed by plate tectonics. It notably includes the Thera volcano, which was responsible for the catastrophic eruption that affected the Minoan civilization approximately 3,600 years ago.
Over the past several hundred thousand years, Methana has experienced more than 31 eruptions, including three significant explosive events. According to historical records, the latest eruption occurred around 2,250 years ago, documented by the ancient Greek historian Strabo.
Geological Insights from Zircon Crystals
Zircon crystals serve as valuable geological time capsules, revealing essential information about the conditions under which they were formed. By analyzing these crystals, researchers can trace the volcano’s activity over millennia.
Interestingly, the peak formation of zircons coincided with an extended quiet period between 280,000 and 170,000 years ago, suggesting that magma production can occur without surface activity. This phenomenon is attributed to subduction, where one tectonic plate slides beneath another, carrying water and sediments into the Earth’s interior.
Implications for Volcanic Hazard Assessment
This study raises significant concerns about how volcanic hazard assessments are conducted. The traditional view that volcanoes may be considered extinct after 10,000 years of inactivity has been challenged. The accumulation of magma during prolonged dormancy may increase the risk of future eruptions.
Volcanologist Răzvan-Gabriel Popa emphasizes that many volcanoes could be actively fed by wet magma, a concept not widely acknowledged in the scientific community. This finding suggests that monitoring dormant volcanoes, even when they show no recent activity, is crucial for hazard assessments.
Monitoring Approaches
- Gas emissions analysis
- Ground deformation tracking
- Monitoring of volcano-tectonic earthquakes
- Gravity anomaly assessments
In conclusion, ongoing research into dormant volcanoes like Methana provides new insights into the potential risks they pose. Authorities may need to reevaluate their classifications of ‘extinct’ volcanoes based on these findings, emphasizing the importance of continuous monitoring.
This research was published in the journal Science Advances.
