Beneath Portugal’s São Jorge Island, a huge body of magma rose quietly from over 20 kilometers deep in March 2022, causing thousands of earthquakes before halting just beneath the surface and avoiding an eruption. This ‘failed eruption’ offers new insights into volcanic activity and fault dynamics.
- Magma rose rapidly and silently from 20+ km deep in March 2022
- Thousands of quakes clustered along a major fault system
- Eruption was prevented as magma stalled just below surface
What happened
In early 2022, a giant surge of molten rock pushed upward beneath São Jorge Island in Portugal’s Azores. This magma, originating from more than 20 kilometers beneath the Earth’s surface, traveled swiftly upward through a significant fault known as the Pico do Carvão Fault Zone. As it moved, the magma caused thousands of earthquakes, though most seismic activity occurred after the magma ceased climbing, just 1.6 kilometers below the island’s surface.
Scientists observed the ground rising by about six centimeters using satellite data, confirming the magma intrusion. Despite the scale and speed of the magma’s movement—enough to fill around 32,000 Olympic-sized swimming pools—it never reached the surface, resulting in a ‘failed eruption.’ This discovered sequence of events unfolded over just a few days, offering a rare glimpse into rapid underground magma dynamics.
Why it feels good
This event highlights nature’s tendency to keep us safe through subtle underground mechanisms. The fault zone acted both as a pipeline guiding the magma upwards and a relief valve allowing gases and fluids to escape sideways. This dual role likely reduced the pressure within the magma chamber, preventing an eruption that could have posed a risk to the local community.
The findings also demonstrate the effectiveness of combining multiple monitoring techniques—including seismic sensors on land and sea, plus satellite ground deformation measurements—to understand complex volcanic processes. Such insights are invaluable to local authorities and scientists aiming to predict volcanic hazards more accurately, helping communities prepare better for future geological events.
What to enjoy or watch next
Researchers plan to continue refining their understanding of how magma intrusions occur and evolve, especially the influence of geological faults on whether magma reaches the surface or stalls underground. Advances in monitoring technology and international cooperation, as seen in this study involving teams from Portugal, the UK, and Spain, will enhance early-warning systems for volcanic activity in the Azores and similar regions worldwide.
For volcano enthusiasts and curious readers, this study serves as a reminder of the dynamic nature of our planet beneath its calm surface. Future scientific updates may reveal more ‘hidden’ magma movements and better explain the subtle signals that precede eruptions, offering a deeper appreciation for Earth's powerful but often unseen forces.