The Iberian Peninsula — including Spain and Portugal — is undergoing a very slow clockwise rotation, according to a new study in Gondwana Research. Researchers from Italy and Spain combined satellite GPS measurements and earthquake data to map crustal deformation along the complex Africa–Eurasia plate boundary. Differential stresses east and west of the Strait of Gibraltar produce a torque that turns the peninsula. The findings help locate faults and improve earthquake-hazard assessments and can be applied to other poorly understood plate boundaries.
Why Spain Is Spinning: The Slow Clockwise Rotation of the Iberian Peninsula
Lead image: zelvan / Shutterstock
New research shows that the Iberian Peninsula — including Spain and Portugal — is rotating very slowly in a clockwise direction. A team of scientists from Italy and Spain reports this finding in the journal Gondwana Research, after combining satellite measurements and seismic records to map how crust near the Africa–Eurasia plate boundary is deforming.
What the researchers did
The team analyzed GPS and satellite data alongside earthquake activity to build a clearer picture of the stresses and strain affecting the crust where the Eurasian and African plates interact. Although the two plates are converging at a modest rate (less than a quarter inch per year), the boundary beneath and just south of Iberia is complex and has long resisted a simple geological description.
“Until now we didn’t know exactly what that boundary was like in that environment, and what geodynamic processes are taking place is under discussion,” said co-author Asier Madarieta, a geologist at the University of the Basque Country.
How the peninsula rotates
The study finds a regional pattern of forces that produces a gentle clockwise torque on the peninsula. East of the Strait of Gibraltar, crustal deformation produced by the converging plates helps relieve strain across Iberia. West of the strait, however, the peninsular crust is pushed from the southwest as the African and Eurasian plates collide, creating a differential stress that induces rotation. In plain terms, uneven pushing and pulling on different sides of the landmass causes the slow pirouette.
Why it matters
Beyond the evocative image of a slowly spinning peninsula, the findings have practical value. Mapping the detailed deformation helps pinpoint faults and folds whose motion could generate earthquakes. The combined satellite-and-seismic approach the team used can be applied to other poorly characterized plate-boundary regions to improve hazard assessment and our understanding of crustal dynamics.
As our planet continues its slow motions, studies like this reveal the subtle, long-term processes that shape the ground beneath our feet.
