If you take a GPS, like the one you use in your car, and anchor it to the ground, would you be able to see the tectonic plates moving?
Maybe after a couple of hundred years. But if you had a really precise GPS, like those used in the Plate Boundary Observatory (PBO), you would be able to see the tectonic plates moving a few centimeters (about one inch) each year.
To measure the movement of the North American plate, PBO has anchored over one thousand high precision GPS units to the ground. Check out the map image to see what PBO is discovering!
Permanent GPS station
This map shows the movement of some of the PBO GPS stations. A station is located at the base of each red arrow. Each arrow shows how fast and in what direction one GPS station moves per year. The longer the arrow, the faster that spot of earth is moving.