How do we determine the rate at which tectonic plates move?

Plate motion. Euler's contributions. In the 18th century, Swiss mathematician Leonhard Euler showed that the movement of a rigid body across the surface of a sphere can be described as a rotation around an axis that goes through the centre of the sphere, known as the axis of rotation. read more

Among the three techniques, to date the GPS has been the most useful for studying the Earth's crustal movements. Twenty-one satellites are currently in orbit 20,000 km above the Earth as part of the NavStar system of the U.S. Department of Defense. These satellites continuously transmit radio signals back to Earth. read more

We can tell from two different lines of evidence—geodetic and geologic—that the lithospheric plates move. Even better, we can trace those movements back in geologic time. Geodetic Plate Motion. Geodesy, the science of measuring the Earth's shape and positions on it, lets us measure plate motions directly using GPS, the Global Positioning System. read more

Scientists now have a fairly good understanding of how the plates move and how such movements relate to earthquake activity. Most movement occurs along narrow zones between plates where the results of plate-tectonic forces are most evident. read more