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At school we're taught that Earth's tectonic plates are rigid and fit together like pieces in a puzzle.

But It turns out that this theory may be wrong.

A study has suggested that the plates that make up Earth's outer layer are deformed by temperature changes and that they are in fact 'bendy', not stiff.

A study by US scientists suggests Earth's tectonic plates (shown) are malleable. They say that the plates can cool and change in size and shape. This means they contract faster in certain sections and deform. During this process earthquakes within the plate can form

The study, supported by the National Science Foundation, was carried out by Dr Corné Kreemer at the University of Nevada and his colleague Dr Richard Gordon of Rice University.

Their idea is that plate cooling, which makes the oceans deeper, also affects horizontal movement and that there is shortening and deformation of the plates due to the cooling.

In their study they focused on data from the Pacific plate and found that different parts of it were moving at different rates.

They found that the cooling of the lithosphere, the outermost layer of Earth, makes some sections of the Pacific plate contract horizontally at faster rates than other sections, which causes the plate to deform.

They say that the deformation could explain why some parts of the plate tectonic puzzle don't make sense.

For example they showed that there is a positive correlation between where the plate is predicted to deform and where intraplate earthquakes - ones inside a tectonic plate rather than two rubbing together - occur.

The formation of intraplate earthquakes has been somewhat of a mystery until now. 

'This is plate tectonics 2.0, it revolutionises the concepts of plate rigidity,' said Dr Kreemer.

'We have shown that the Pacific plate deforms, that it is pliable. We are refining the plate tectonic theory and have come up with an explanation for mid-plate seismicity.'

According to the researchers plate cooling, which makes the oceans deeper, also affects horizontal movement and that there is shortening and deformation of the plates due to cooling. Pictured is the Carrizo Plain in California, the most strikingly graphic portion of the San Andreas Fault

Dr Corné Kreemer, associate professor in the College of Science at the University of Nevada, Reno, conducts research on plate tectonics and geodetics. His latest research shows that oceanic tectonic plates deform due to cooling. 'This is plate tectonics 2.0' he said

The oceanic plates are thought to be shortening due to cooling, which causes relative motion inside the plate, Dr Kreemer said.

The oceanic crust of the Pacific plate off the coast of California is moving 0.08 inches (two millimetres) to the south every year relative to the Pacific and Antarctic plate boundary.

'It may not sound like much, but it is significant considering that we can measure crustal motion with GPS within a fraction of a millimeter per year,' he said.

'Unfortunately, all existing GPS stations on Pacific islands are in the old part of the plate that is not expected nor shown to deform.

'New measurements will be needed within the young parts of the plate to confirm this study's predictions, either on very remote islands or through sensors on the ocean floor.' 

To reach their conclusion they used large-scale numerical modeling as well as GPS velocities from the largest GPS data-processing center in the world - the Nevada Geodetic Laboratory at the University of Nevada, Reno.