interplate

Interplate is an adjective used in geology and geophysics to describe processes that occur at or involve the boundaries between tectonic plates, or the motion between plates. It contrasts with intraplate processes, which take place within a single plate rather than at its edges. The concept is central to plate tectonics, where the lithosphere is segmented into moving plates.

Most of the Earth’s seismic and volcanic activity is interplate in origin, occurring where plates interact. The three main boundary types—divergent (where plates move apart), convergent (where plates collide and one may subduct beneath another), and transform (where plates slide horizontally past each other)—are all interplate boundaries. Interplate earthquakes typically originate on faults at these boundaries, including large megathrust earthquakes at subduction zones and various shallow faulting systems along transform and divergent margins. Interplate volcanism occurs along plate boundaries as partial melting and magma migration accompany boundary motion, producing mid-ocean ridge volcanism and volcanic arcs at subduction zones.

Interplate deformation can be measured with geodetic tools such as GPS and InSAR, revealing relative plate velocities that vary by region. In contrast, intraplate processes refer to tectonic activity that happens away from plate boundaries, within a single plate.

In summary, interplate encompasses the range of geological phenomena that arise from the interaction of tectonic plates at their margins, including most large earthquakes and boundary-associated volcanism, and it is a fundamental concept for understanding global geodynamics and seismic hazard.