University of Oregon geologist Becky Dorsey found that marine terraces in southern Italy are rising much faster than expected. In 2025, her team collected samples from high elevations, showing the land moves five to 10 times quicker. These findings, published Nov. 6, suggest a tectonic slab is tearing beneath Calabria.
University of Oregon geologist Becky Dorsey's latest research sheds light on the Siculo-Calabrian rift zone, a belt of faults spanning more than 100 miles (160 kilometers) in southern Italy. The new data could help improve earthquake hazard assessment in this seismically active region.
In 2025, a UO-led research team collected sand samples from marine terraces up to approximately 1,000 meters (3,300 feet) above sea level in southern Calabria. That bold experiment revealed evidence these step-like formations are rising five to 10 times faster than previously thought.
Until now, geologists have not sampled marine terraces at such high elevations for luminescence dating, because it was believed the terraces are about 1 million years old and therefore exceed the limits of this method. However, the team successfully applied that process to the samples, supporting Dorsey's hypothesis that the high-elevation terraces are much younger than currently inferred by most geologists.
Her findings were published Nov. 6 in Communications Earth and Environment. Dorsey's research unearths new clues to what's happening with the Ionian slab, an oceanic segment of the African tectonic plate. The results challenge prevailing explanations for the rising marine terraces and make a strong case for an alternative cause: the Ionian slab is tearing directly beneath southern Calabria.
Studying the dynamics of slab detachment in Italy's well-documented subduction zone will help scientists understand seismic hazards in this and other active areas such as the Cascadia Subduction Zone in the Pacific Northwest.