Scientists say Spain and Portugal are slowly turning – and no one can feel it

It sounds counter-intuitive, even a little unsettling, but according to geologists, Spain and Portugal are not sitting as still as we might think. In fact, new research suggests the Iberian Peninsula is slowly rotating on itself, squeezed between two immense geological forces that never stop pushing.

We’re talking about movements so slow that no one will ever feel them. No spinning cities, no shifting horizons. But measured over thousands or millions of years, the motion is real – and it helps explain why earthquakes in Spain and Portugal often seem to come from nowhere.

Caught between Africa and Europe

The story begins deep beneath our feet. Like all continents, Spain and Portugal sit on a tectonic plate, floating very slowly on a softer layer of the Earth’s mantle. These plates move constantly, usually drifting in fairly predictable directions.

Africa and Eurasia, however, are moving towards each other, closing the gap by four to six millimetres every year. In many parts of the world, that kind of movement produces clear fault lines or subduction zones, where one plate dives beneath another.

But southern Iberia doesn’t play by those rules.

According to a recent study published in Gondwana Research, the boundary between the African and Eurasian plates in the western Mediterranean is blurred and complex, not sharply defined. Instead of the pressure being released along one major fault, it is spread across a wide area — including Spain and Portugal themselves.

The result? Rather than simply shifting north with the rest of Europe, the Iberian block is twisting, slowly turning clockwise, like a gear caught between two moving parts.

Gibraltar: where things get complicated

One region plays a particularly important role in this movement: the Alboran domain, stretching between southern Spain and northern Morocco. Trapped between the two plates, this area is being pushed westwards, adding a sideways force to the pressure already building up from the south.

This movement helped shape the Gibraltar Arc, the curved mountain belt that links southern Spain’s Betic ranges with Morocco’s Rif mountains. It’s also one of the reasons the geology around the Strait of Gibraltar is so difficult to read.

Because this sideways motion isn’t uniform, the Earth’s crust responds differently depending on location. In some places, the African plate pushes directly into Eurasia, compressing the crust. In others, part of that energy escapes laterally, allowing the ground to slide rather than crash head-on.

To the south-west of the Strait of Gibraltar, the pressure is more frontal. There, Africa acts like a giant piston, nudging the Iberian Peninsula in a way that forces it to rotate.

This subtle but persistent motion has been detected using seismic records and satellite GPS measurements, capable of picking up shifts of just a few millimetres a year.

Why this matters for earthquakes

All of this might sound abstract, but it has very real implications. Spain and Portugal experience earthquakes surprisingly often, and many of them don’t line up neatly with visible fault lines.

Geologist Asier Madarieta points out that there are numerous areas in Iberia where deformation and seismic activity are clearly happening, yet the responsible tectonic structures remain hidden underground.

Understanding that the entire peninsula is slowly rotating gives scientists a new way of reading the landscape. It doesn’t mean earthquakes can suddenly be predicted, but it does help identify where stress is building up and which structures may be active, even if they aren’t obvious at the surface.

In short, Spain and Portugal aren’t becoming more dangerous overnight. But they are revealing that their geological story is far more dynamic than it looks.

The ground beneath our feet may feel solid and unmoving, but on a planetary timescale, the Iberian Peninsula is quietly turning – reshaped by forces that have been at work long before humans arrived, and that will continue long after.