Earth's crust is 'unzipping' beneath Italy — and that could explain most of the earthquakes in the region

Research shows Italy's crust is unzipping, causing much of the seismic activity in the Apennine Mountains. This late-stage subduction process, led by geoscientist Stefano Tavani of the University of Florence, marks the swan song of the subduction. The Mediterranean region, a patchwork of tectonic microplates, is being shaped by the African plate pushing northward, squeezing the crust and driving the sinking of the ancient Tethys ocean into the mantle beneath the Apennines.

Over the past 50 million years, this process has built the Apennines and led to the formation of two basins in the Mediterranean, east and west of Corsica and Sardinia. Until now, the forces behind the extension creating these basins and the compression building the Apennines remained unclear. Through a combination of earthquake data, GPS measurements, and tectonic models, Tavani and colleagues discovered that the lower crust is peeling away and dropping into the mantle, a process called delamination.

This delamination, rather than subduction, is responsible for most of the seismic activity in the Apennines. As the lower crust continues to drop away over the next few million years, the two plates will eventually fuse together. Similar processes are occurring elsewhere, such as in Greece's Hellenic trench. This late-stage tectonic movement could help explain similar geological phenomena around the world.