PLATE MOTIONS (KINEMATICS)

WHAT HAPPENS AT PLATE BOUNDARIES, AND HOW PLATES EVOLVE, DEPENDS ON THE DIRECTION & RATE OF MOTION BETWEEN THE PLATES

KEY PRINCIPLES:

– WE CAN FIND THE DIRECTION AND RATE OF MOTION AT POINTS ON THE BOUNDARIES BY USING THE RATES OF SPREADING AT MIDOCEAN RIDGES AND THE DIRECTION OF TRANSFORM FAULTS AND THE MOTION (SLIP) IN EARTHQUAKES

– WE CAN ADD MOTIONS BETWEEN PAIRS OF PLATES (PLATE CIRCUITS) TO FIND THE MOTION OF OTHER PAIRS

– WE CAN DESCRIBE THE MOTION BETWEEN ANY TWO PLATES AS A ROTATION ABOUT AN IMAGINARY POINT, CALLED A “POLE”.

(USGS)