Renowned for its geothermal activity (here, the Larderello power plant, the oldest in the world), Tuscany also hides vast magma reservoirs beneath its landscapes, similar to those found at Yellowstone in the United States.
Photo Credit: © Matteo Lupi
Scientific Frontline: Extended "At a Glance" Summary: Super Magma Reservoirs Beneath Tuscany
The Core Concept: A vast, previously undetected reservoir containing approximately 6,000 cubic kilometers of magma has been discovered beneath the region of Tuscany. This subterranean body of volcanic fluid is situated at depths ranging from 8 to 15 kilometers within the continental crust.
Key Distinction/Mechanism: Unlike typical volcanic systems that present obvious surface indicators such as craters, gas emissions, or ground deformation, this massive magma body remained completely hidden. Researchers detected it utilizing ambient noise tomography, an imaging technique that acts as an "X-ray" for the deep subsurface by analyzing natural environmental vibrations from oceans, wind, and human activity. As these vibrations travel through the ground, exceptionally low seismic wave velocities indicate the presence of molten material.
Major Frameworks/Components:
- Ambient Noise Tomography: The primary observational framework that utilizes high-resolution surface sensors to harness background environmental vibrations for three-dimensional crustal mapping.
- Seismic Wave Velocity Analysis: The underlying principle that seismic waves slow down significantly when propagating through liquids and molten rock, allowing scientists to differentiate magma from solid crust.
- Volumetric Analogs: The theoretical comparison of the Tuscan reservoir's massive volume (6,000 km³) to established supervolcanic systems like Yellowstone, Lake Toba, and Lake Taupo, though the Tuscan reservoir currently poses no eruptive threat.
Branch of Science: Seismology, Volcanology, and Geophysics.
Future Application: The successful use of ambient noise tomography to identify deep magmatic systems paves the way for faster and more cost-effective subsurface exploration. This will directly aid in locating viable geothermal energy reservoirs and critical mineral deposits—such as lithium and rare earth elements—that are intrinsically linked to deep magmatic activity and essential for electric vehicle batteries.
Why It Matters: The ability to map immense, hidden magmatic systems revolutionizes subsurface resource exploration. By providing a highly precise, low-cost method to locate deep reservoirs, this breakthrough significantly advances our capacity to secure sustainable energy resources and critical materials required for the global energy transition.
How can magma buried 5, 10, or even 15 km underground be detected without any surface indicators? The answer lies in ambient noise tomography, a technique that analyzes natural ground vibrations with high precision. A team from the University of Geneva (UNIGE), the Institute of Geosciences and Earth Resources (CNR-IGG), and the National Institute of Geophysics and Volcanology (INGV) has identified a vast reservoir containing approximately 6,000 km3 of magma beneath Tuscany. Beyond its scientific significance, this breakthrough paves the way for faster and more cost-effective exploration methods to locate resources such as geothermal reservoirs, lithium, and rare earth elements, whose formation is closely linked to deep magmatic systems. The study was published in the journal Communications Earth & Environment.
Yellowstone National Park in the United States, Lake Toba in Indonesia, or Lake Taupo in New Zealand: these iconic volcanic sites harbor immense magma reservoirs measuring several thousand km3 beneath their surfaces. Their presence has been revealed through surface evidence such as eruptive deposits, craters, ground deformation, and gas emissions. However, in the absence of such signals, large volumes of magma can remain hidden and unsuspected deep within the Earth’s crust.
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.
This was precisely the case in Tuscany, where reservoirs containing approximately 6,000 km³ of volcanic fluids at depths of 8–15 km within the continental crust were discovered by a team from the UNIGE, with contributions from researchers at the Institute of Geosciences and Earth Resources (IGG-CNR) and the National Institute of Geophysics and Volcanology (INGV).
Although this magma body could, in theory, contribute to the formation of a supervolcano over geological timescales, it currently poses no threat. “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, who led the study.
An X-ray of the deep subsurface
This molten rock was detected using ambient noise tomography, a subsurface imaging technique widely used in seismology. It makes it possible to “X-ray” the Earth’s crust by harnessing natural environmental vibrations generated by ocean waves, wind, or human activity. As these signals travel through the ground, they are recorded by high-resolution seismic sensors deployed at the surface — around 60 instruments were used in this study. When seismic waves propagate at unusually low velocities, this can indicate the presence of molten material such as magma.
Combined analysis of the recordings made it possible to reconstruct a three-dimensional image of the internal structure of the covered area. "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.
Published in journal: Communications Earth & Environment
Authors: Matteo Lupi, Douglas Stumpp, Iván Cabrera-Pérez, Konstantinos Michailos, Gilberto Saccorotti, Marco Bonini, Federico Farina, Elliot Amir Jiwani-Brown, Riccardo Lanari, Samuele Papeschi, Geneviève Savard, Juan Porras, Julien Sfalcin, Francisco Muñoz-Burbano, Riccardo Minetto, Chiara Del Ventisette, Davide Piccinini, and Domenico Montanari
Source/Credit: Université de Genève
Reference Number: es041426_01
