Crustal 'unzipping' under Italy drives Apennine quakes, study finds
New research suggests that the peeling away of Earth's crust beneath Italy is a major driver of seismic activity in the Apennine Mountains. This process represents the final stage of subduction, with the crust sinking into the mantle. The study, led by Stefano Tavani of the University of Florence, offers a fresh explanation for the region's frequent earthquakes.
The Apennine Mountains formed over roughly 50 million years as the African plate pushed northward, forcing the ancient Tethys ocean floor beneath the Eurasian crust. This long-running subduction has now reached its final phase, with the lower crust peeling away and sinking into the mantle—a process known as delamination.
Researchers combined earthquake records, GPS ground-movement data, and satellite measurements with plate-tectonic models to reach this conclusion. The unzipping explains both the stretching that created the Tyrrhenian Sea basin about 10 million years ago and the compressional forces still building the Apennines today. Tavani's team found delamination, rather than ongoing plate-on-plate subduction, drives most regional quakes.
This research could reshape how seismologists assess earthquake risk across central Italy, where millions of people live in towns and cities along the Apennine chain. A clearer understanding of the crustal processes driving these quakes may improve hazard models and inform building codes and emergency planning. Communities in the region—already familiar with destructive seismic events—could benefit from more accurate forecasting of where future tremors are likely to concentrate.