Spain and Portugal are “rotating” and “moving northwards,” according to a new study. Scientists say the two European countries are slowly undergoing a “clockwise rotation” on their axis.

Previously the Iberian Peninsula had been considered by geologists as an “immobile block”. But a new study has found that it is moving northward and heading towards the Eurasian tectonic plate. And while the change, around four to six millimetres a year, isn’t something that will have an impact on daily life, it has changed the way geologists understand the tectonics of Europe, reports Executive.

It comes as scientists have previously concluded that both plates on either side of the Gibraltar Strait are moving, theorising that they will one day close, joining Africa and Europe once more.

Researcher Asier Madarieta from the University of the Basque Country, said: “Every year the Eurasian and African plates are moving 4–6 mm closer to each other. The boundary between the plates around the Atlantic Ocean and Algeria is very clear, whereas in the south of the Iberian Peninsula the boundary is much more blurred and complex.”

He added that the new data “confirms that the Iberian Peninsula is rotating clockwise. The data indicate that the Gibraltar Arc is playing a significant role on the Eurasia-Africa boundary. To the east of the Straits of Gibraltar the crust of the Gibraltar Arc is absorbing the deformation caused by the Eurasia-Africa collision, thus preventing the stresses being transmitted to Iberia.

“On the other hand, to the west of the Straits of Gibraltar the direct collision between the Iberia (Eurasia) and Africa plates is taking place, and we believe that could affect the stresses being transmitted to the southwest of Iberia, by pushing Iberia from the southwest and making it rotate clockwise.”

Scientists believe pressure caused by the Alboran Domain has caused an “unequal interaction of forces” between the African and Eurasian plates. It has caused slight movements in southern Spain and Portugal.

While the movement is minimal, it has been enough to change the way geologists think about tectonic evolution. The study says the area around the Gibraltar Arc has been fundamental to the new study.

It is where the Betic Cordillera mountain range and Moroccan Rif are both located. These mountainous regions help distribute the stresses across smaller structures, says Executive.

The study has been conducted using permanent GPS stations that have been installed across the Iberian Peninsula. They record any tiny ground movements, which are then cross-referenced with regional seismic activity.

It provides a more precise picture of the movement compared to more linear measurements. And while Spain and Portugal aren’t Europe’s most seismic regions, they have historically seen earthquakes.

In 1755 Lisbon was hit by a huge earthquake. Known as the Great Lisbon Earthquake, it hit a magnitude of 7.7 and almost completely destroyed the city as well as the surrounding area.

It is estimated that anywhere between 30,000 and 40,000 people died in the quake. The new model, researchers say, explains why earthquakes can appear in areas without visible faults on the surface.