Look at a map and Spain and Portugal seem like a solid, unmoving corner of Europe. But new research shows that the entire Iberian Peninsula is slowly turning clockwise, pushed by the collision of two slabs of the Earth’s crust. No one can feel this motion, yet over long periods it quietly reshapes the region.
The study, led by geologist Asier Madarieta-Txurruka at the University of the Basque Country, ties this slow twist to the way the African and Eurasian tectonic plates are squeezing together south of Iberia. Using decades of earthquake records and satellite positioning data, described in a recent press release, the team traced how the crust between southern Spain and northwest Africa is being deformed and concluded that the resulting forces are making Iberia rotate.
What does it mean for a peninsula to rotate?
The peninsula is not spinning like a toy top or turning a full circle in a human lifetime. Instead, the block of crust that carries Spain and Portugal is rotating at a rate so slow that only sensitive instruments can detect it. Over hundreds of thousands or millions of years, though, that tiny movement can shift coastlines and mountain ranges by many miles.
To get the picture, think of plate tectonics as a cracked shell floating on a thick, slowly moving layer deeper inside the planet. The outer shell is broken into large plates that carry continents and oceans, and they creep past or into each other by a few millimeters a year. Where the African and Eurasian plates meet around the Strait of Gibraltar and across the western Mediterranean, that steady squeeze builds up stress in the rocks and sometimes releases it as earthquakes.
How scientists measured the slow twist
Madarieta’s group began by analyzing several decades of earthquake data from the western Mediterranean. Each quake leaves a kind of fingerprint that shows how rocks were pushed, pulled, or twisted when a fault slipped deep underground. By stacking thousands of these fingerprints together, the team built a detailed map of stress in the crust beneath and around the Iberian Peninsula.
They then compared that stress map with measurements from satellite navigation stations, similar to GPS, spread across Spain, Portugal, Morocco, and the nearby seas. These instruments track how points on the surface move by a few millimeters a year, revealing where the ground is being stretched, squeezed, or slid sideways. Combining both kinds of data allowed the researchers to see not only where the crust feels the strongest forces but also how the surface is deforming in response.
Earlier GPS work along the Africa-Iberia plate boundary in a 2011 study had already hinted that smaller crustal blocks in the region move in complex ways, sometimes rotating on their own. The new research goes further by tying those block motions to detailed stress and strain patterns and by confirming that the peninsula as a whole is turning clockwise. Together, the old and new data offer a much sharper picture of how Africa and Europe are interacting in this corner of the world.
Why this slow spin matters for earthquakes
People in Spain, Portugal, and Morocco already know that the region is prone to earth quakes, even if most are small and pass with little notice. The new maps of stress and surface deformation show where the crust is working hardest and where hidden faults are likely to lie. That helps scientists decide where to send field teams to map fractures in the rocks and to search sediments and old shorelines for traces of past quakes.
This kind of information feeds into hazard maps and building rules for cities like Lisbon, Seville, or Granada. The study also shows that some areas far from the obvious plate boundary can still be under strain, even if they seem quiet at the surface. In practical terms, that means planners may need to think about earthquake risk not only along the coast but also inland.
At the same time, researchers warn that the data record is still short compared with the timescales of plate motion. Earthquake catalogs go back only a few decades, and precise satellite measurements began in the late 1990s, while tectonic changes unfold over millions of years. So this result is an important step, not the final word, in figuring out how the slow clockwise spin of Iberia fits into the wider story of Africa and Europe colliding.
For ordinary life, the peninsula’s movement is invisible, even on your next beach trip or commute. Yet this slow twist shapes the forces that decide where the next big quake might strike and how communities can prepare.
The main study has been published in Gondwana Research.