Recent research has revealed that the fragile layers deep within the crust beneath Campi Flegrei in Italy are responsible for the caldera’s periods of geological unrest.
This study was published in a journal on April 5th and notes that these layers lie at a depth of 1.8-2.5 miles (3-4 km). They consist of a type of rock known as tuff, which has been compromised by numerous magmatic incursions spanning tens of thousands of years.
This tuff, a lightweight rock formed from compressed volcanic ash, functions much like a sponge, absorbing volcanic gases from a magma chamber located at least 7.5 miles (12 km) deep. When these gases saturate the tuff’s pores, the rocks can distort and fracture, leading to earthquakes. The findings suggest that this may account for the ongoing restless activity at Campi Flegrei, according to Lucia Paparardo, a senior researcher at the National Institute of Geophysics (INGV) in Italy.
Paparardo mentioned to Live Science, “Other calderas across the globe exhibit similar behaviors. We believe our model could be applicable to these other calderas as well.”
This research is part of a broader initiative aimed at enhancing eruption prediction capabilities for Campi Flegrei. In Italy, roughly 500,000 residents inhabit areas susceptible to caldera eruptions that could unleash torrents of searing ash and gaseous debris, as highlighted by the Civil Protection Division.
Campi Flegrei has erupted for at least 47,000 years, with its last major eruption occurring in 1538. The caldera has been experiencing heightened activity since 2005, characterized by frequent minor quakes. One such quake caused a wall to collapse at a historical site in Pompeii on June 5. News Report.
Paparardo and her colleagues aimed to uncover how the composition and strength of the rocks beneath the caldera influence volcanic activity. They analyzed rock samples excavated from significant depths within the caldera decades prior.
They examined the minerals and elements within the samples, utilizing a technique known as “4D computer X-ray microtomography” to visualize the rock’s internal structure and any fractures. This provided insights into rock strength and mechanical properties, as explained by research co-author Gianmarco Buono, who spoke to Live Science.
Through these tests on samples from different rock layers, researchers identified weak tuff formations, a finding that took them by surprise. Paparardo noted that computer modeling indicated this layer likely trapped various magmatic incursions over centuries, which heated and deformed the rock, compromising its strength.
Currently, researchers are investigating how materials from the caldera’s deep magma chambers ascend to the surface, potentially triggering eruptions. Nonetheless, Paparardo reassured that there are no signs indicating an imminent major eruption, stating, “At this moment, our monitoring system is not detecting any parameters suggesting magma movement. Therefore, an eruption is not likely to occur in the near future.”
Source: www.livescience.com