A team of researchers including Scripps Institution of Oceanography, UC San Diego geophysicist Dave Stegman has developed a new theory to explain the global motions of tectonic plates on the earth’s surface.The new theory extends the theory of plate tectonics — a kinematic description of plate motion without reference to the forces behind it .

This discovery explains why the Australian, Nazca and Pacific plates move up to four times faster than the smaller African, Eurasian and Juan de Fuca plates.

The computer models demonstrate that the subducted portion of a tectonic plate pulls on the portion of the plate that remains on the earth’s surface. This pull results in either the motion of the plate, or the motion of the plate boundary, with the size of the subduction zone determining how much of each.

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