Giant Magma Reservoir Found Under Tuscany, Its Size Is Said to Be Equivalent to Yellowstone

Illustration of magma. (Wikiemdia Commons - Hawaii Volcano Observatory - DAS)

JAKARTA - A giant magma reservoir, a large pocket containing hot molten rock under the earth's surface, has been found deep beneath Tuscany, Italy. Citing a report by The Independent, Monday, April 20, its volume is estimated to reach 6,000 cubic kilometers.

In the report, the size was said to be comparable to the magma system under Yellowstone in the United States and Lake Taupo in New Zealand, two areas known to have very large volcanic systems.

The findings, published in the journal Nature, surprised researchers. Because Tuscany shows almost no signs on the surface that usually indicate the presence of a large magma body underground. There are no large craters, no significant eruptions in hundreds of thousands of years, and no noticeable changes in the shape of the land.

The last eruption in the area came from Mount Amiata about 300,000 years ago, and its scale was relatively small.

The reservoir was discovered by a team from the University of Geneva, the Institute of Geosciences and Earth Resources of Italy, and the National Institute of Geophysics and Volcanology. In a report quoted by The Independent, they found it with the ambient noise tomography technique, a method that maps the earth's interior by recording natural vibrations from ocean waves, wind, and human activity.

With the help of about 60 high-resolution seismic sensors, the research team compiled a three-dimensional image of the earth's crust to a depth of 15 kilometers. If the vibrations move more slowly in certain zones, it is an indication of liquid or semi-liquid rocks below the surface.

"We knew this area was geothermally active, but we didn't realize that this area contained such a large volume of magma, comparable to supervolcanic systems like Yellowstone," said Matteo Lupi, associate professor at the University of Geneva's Department of Earth Sciences who led the study.

The magma is at a depth of 8 to 15 kilometers. Researchers estimate that there are about 3,000 cubic kilometers of liquid melt in the center, surrounded by about 5,000 cubic kilometers of semi-liquid rock rich in crystals. Under Mount Amiata, the volume is suspected to be even larger, although further analysis is still needed.

Despite its huge size, researchers assess that this reservoir does not pose a threat of eruption in the near future. The reason is that the magma in Tuscany is very viscous. In simple terms, magma like this tends to accumulate slowly underground, not quickly rise and then erupt.

This finding also answers a long-standing puzzle in Tuscany: why the region has such a high geothermal activity, even though it has no obvious volcanic sources on the surface.

The Larderello area in Tuscany, once known as the Valley of the Devil because of its hot steam eruption activity, is one of the most productive geothermal fields in the world and has been producing electricity since the early 20th century. According to the findings, it is this magma reservoir that is the source of geothermal energy in the region.

Lupi said that this finding is not only important for basic research, but also for practical needs. "These results are important for both basic research and practical applications, such as finding geothermal reservoirs or deposits rich in lithium and rare earth elements," he said, quoted by The Independent.