portion of the lithosphere of variable size (from hundreds to thousands of km in length) and thickness between 10 and 200 km. It can hold both continental masses and oceans, like the Euro-Asian plate, or be exclusively oceanic, like the Nazca plate. 52 tectonic plates are recognized and 14 are considered as the main ones. These plates are not static, moving as if they were on a conveyor belt - the asthenosphere. Their edges or boundaries (margins) may be divergent, convergent or passive, depending if the plate’s retreat, approach or maintain position. These plates are created in divergence zones or rift zones, and are destroyed in subduction zones. The highest seismic and volcanic activity is registered in the boundary of the plates.