Scientists measure plate tectonics using GPS satellites, and they use computer models that simulate the motions of Earth's tectonic plates to try to predict future plate movements. By using GPS satellites in tandem with GPS receivers on the ground, scientists measure the rate of movement of the Earth's crust.
Scientists first started using GPS satellites to measure plate tectonics in the 1980s. A magnitude-7.1 earthquake that hit San Francisco allowed scientists to measure the movements of GPS markers that were already in place along the San Andrea fault. This GPS data allowed scientists to determine the direction and pattern of the fault's movement.
The precision of GPS satellites gives scientists the means to measure multiple types of plate movements. Researchers install GPS receivers at certain monitoring points and collect data once every year or so, which allows them to measure the slow movement of plates between earthquakes. For the rapid seismic motion that occurs during and after an earthquake, scientists capture the movement using permanent GPS receivers that collect data at a rapid rate.
Scientists use computer models to research the way that the flow of the mantle beneath the earth's crust affects plate tectonics. These models simulate how the upper layers of the mantle push and pull the tectonic plates above them.