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New research suggests the lower crust beneath Italy is peeling away and sinking into the mantle — a process that helps explain much of the earthquakes along the Apennine mountain chain. The finding, from a team led by Stefano Tavani of the University of Florence, reframes how geologists view the region’s late-stage tectonics.
Peeling crust, not just plate collision
Using a combination of earthquake records, GPS and satellite measurements, and tectonic models, the researchers found that chunks of the lower crust beneath the Apennine Mountains are detaching and dropping into the mantle. The team describes this process as delamination, or an “unzipping” of the crust, rather than ongoing subduction alone.
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“We are experiencing the very, very late-stage to the subduction, and the tectonics is driven by a different engine, which is this unzipping,” Tavani said in an interview with Live Science. The study appears this month in Communications Earth & Environment.
Why the Apennines are seismically active
The Apennines run like a spine down Italy, where seismic activity has long puzzled geologists because the region combines both compressional and extensional forces. The new analysis indicates that much of the seismicity comes from the lower crust peeling away, rather than from the classic picture of one plate thrusting beneath another.
That detachment causes stretching and instability in the overlying crust, producing the earthquakes that have been observed across the mountain range. According to the authors, this mechanism better matches the pattern of ground motion and seismicity recorded across the peninsula.
Long-term tectonic context
The Mediterranean between Africa and Eurasia is made of numerous microplates and complex margins. For about 50 million years, northward motion of the African plate has driven the sinking of the ancient Tethys oceanic lithosphere beneath Eurasia. That long-run history produced both the fold-and-thrust structures of the Apennines and two large basins east and west of Corsica and Sardinia.
One of those basins, the Tyrrhenian Sea, formed roughly 10 million years ago. Previous explanations for why the area simultaneously experienced basin-forming extension and mountain-building compression were incomplete. The new work argues that late-stage lower-crust detachment provides the missing piece of that puzzle.
What the study used and what it means
The authors combined seismic catalogs with measurements of surface displacement from GPS and satellites, and then tested models of plate motion and crustal dynamics. That multi-data approach led them to conclude that delamination — the progressive loss of lower crustal material into the mantle — is responsible for the dominant tectonic signal in the Apennines.
Researchers suggest the process is transient. Tavani and colleagues estimate that in a few million years the detaching lower crust will have largely dropped away and the two plates could “weld” together at depth, shifting the region into a different tectonic regime.
Broader relevance
The paper notes similar late-stage processes elsewhere, such as beneath the Hellenic trench south of Greece. The authors say their results may apply to other tectonic settings undergoing the final phases of subduction, offering a framework to interpret seismicity in comparable margins.
By tying observed earthquakes and ground motion to a specific deep-crustal process, the study provides a fresh perspective on the forces shaping Italy’s mountains and the hazards those forces produce. The full study citation is Tavani et al., 2026, Communications Earth & Environment (DOI: 10.1038/s43247-026-04021-w).
