The research, published in Nature Communications, was based on the study of a failed eruption on the island of São Jorge, in the Azores. The results indicate that large faults in the Earth's crust not only facilitate magma movement but can also act as a containment mechanism, preventing it from reaching the surface and causing an eruption.
This finding is highly relevant for active volcanic areas, including the Canary Islands. The study demonstrates that magma can ascend extremely rapidly and with minimal seismic signals, stopping a short distance from the surface due to the influence of tectonic structures.
During the seismic crisis in São Jorge in March, thousands of earthquakes were recorded, but the eruption never materialized. Thanks to advanced technology such as radar satellites (InSAR), GPS stations, and ocean-bottom seismometers, researchers were able to reconstruct the underground process. Magma ascended vertically from more than 20 kilometers deep, stopping just 1.6 kilometers from the surface, much of this journey occurring “silently.”
“"The fault acted both as a highway and a leak; it helped the magma ascend, but it may also have prevented the eruption."
The key to this phenomenon was found in the Pico do Carvão fault. This structure not only guided the magma upwards but also allowed the lateral release of gases and volatile fluids. This pressure loss was crucial in halting the ascent, resulting in what is known as a failed eruption.
Although the study focused on the Azores, its conclusions are applicable to other volcanoes, including those in the Canary archipelago. This discovery necessitates a reevaluation of monitoring protocols, as magmatic intrusions can occur with minimal precursor signals before reaching critical levels. Modeling carried out by the CSIC showed an island surface uplift of 6 centimeters, confirming magma entry into the upper crust.
