Scientists have discovered a vast underground magma system beneath Tuscany, Italy, despite the region showing few of the surface signs usually linked to volcanic activity. Using a seismic imaging technique called ambient noise tomography, researchers identified around 6,000 km3 of hot volcanic fluids located 8 to 15 kilometers below the surface. That volume is equivalent to approximately 2.4 billion standard Olympic-size swimming pools.
The international research team included scientists from the University of Geneva (UNIGE), the Institute of Geosciences and Earth Resources (CNR-IGG), and the National Institute of Geophysics and Volcanology (INGV). Their findings, published in Communications Earth & Environment, could improve scientists’ understanding of Tuscany’s hidden geology while helping identify geothermal reservoirs, lithium deposits, and rare earth elements associated with deep magmatic systems.
Massive Magma Reservoir Hidden Beneath Tuscany
Some of the world’s most famous volcanic regions—including Yellowstone in the United States, Lake Toba in Indonesia, and Lake Taupo in New Zealand—are located above magma reservoirs containing thousands of cubic kilometers of molten or partially molten material.
Scientists typically detect these underground systems through surface evidence such as ancient eruption deposits, volcanic craters, ground deformation, and gases escaping from the Earth. However, when those warning signs are missing, even extremely large magma bodies can remain concealed deep within the continental crust.
That appears to be the case in Tuscany. Researchers from UNIGE, together with experts from the Institute of Geosciences and Earth Resources (IGG-CNR) and the National Institute of Geophysics and Volcanology (INGV), mapped an estimated 6,000 km3 of volcanic fluids beneath the region.
The newly identified underground system stretches across Tuscany at depths of approximately 8 to 15 kilometers.
Researchers Say the Magma System Is Not an Immediate Threat
Although a magma body of this size could, over geological timescales, contribute to the formation of a supervolcano, researchers stress that the discovery does not indicate an imminent volcanic threat to Tuscany.
“We knew that this region, which extends from north to south across Tuscany, is geothermally active, but we did not realize it contained such a large volume of magma, comparable to that of supervolcanic systems such as Yellowstone,” explains Matteo Lupi, associate professor in the Department of Earth Sciences at UNIGE’s Faculty of Science and lead author of the study.
Ambient Noise Tomography Reveals Hidden Magma
The research team used ambient noise tomography to map the magma system beneath Tuscany. This seismic imaging method acts like an underground “X-ray” by analyzing continuous vibrations generated by ocean waves, wind, traffic, and other human activities.
As these vibrations travel through the Earth, seismic instruments on the surface measure how quickly the waves move through different underground materials. For the study, researchers installed approximately 60 high-resolution seismic sensors across the region.
Seismic waves generally travel more slowly through exceptionally hot or partially molten rock. By identifying areas where seismic velocities were lower than expected, scientists were able to locate the likely distribution of the deep volcanic fluids.
The researchers combined the seismic measurements to produce a three-dimensional model of the underground structures beneath Tuscany, revealing the scale and depth of the previously hidden magma system.
Discovery Could Support Geothermal Energy and Critical Mineral Exploration
The discovery has implications beyond the study of Tuscany’s volcanic history. Because ambient noise tomography can examine large areas of the subsurface quickly and at relatively low cost, the technique could become a valuable tool for exploring geothermal energy resources and mineral deposits.
Deep magmatic systems are often linked to concentrations of lithium and rare earth elements. These critical minerals are essential for technologies including electric vehicle batteries, renewable energy systems, and other components of the global energy transition.
“These results are important both for fundamental research and for practical applications, such as locating geothermal reservoirs or deposits rich in lithium and rare earth elements, which are used, for example, in electric vehicle batteries. In addition to their great scientific interest, these studies show that tomography, by exploring the subsoil quickly and at low cost, can be a useful tool for the energy transition,” concludes Matteo Lupi.
Source: www.sciencedaily.com