How do plate tectonics move?

Answer 1

Tectonic plates are segments of the Earth's lithosphere, the hard rocky outer shell composed of the crust and the uppermost mantle. This shell is divided by lines of faults, ridges of plate creation, and zones of plate destruction. All in all, there are roughly 30 tectonic plates which cover the entire surface of the planet. Plates can be composed of oceanic crust, continental crust, or a combination of both.

Plate movements occur because the layer of Earth directly below the lithosphere, the asthenosphere, is hot enough, and under enough lithostatic pressure to prevent its melting, that it can deform without fracture. And although convection of heat does play a role in the movement of lithospheric plates, the convection currents themselves may be caused by gravity, which induces the sinking of older dense slabs of oceanic crust at subduction zones (a process known as 'slab pull').

The energy driving all of these processes is heat from the interior of the Earth derived from radioactive decay and residual heat from Earth's formation, and gravity which results in slab pull and push.

Answer 2

== == The main features of plate tectonics are: * The Earth's surface is covered by a series of crustal plates. * The plates are composed of crustal rock and solid upper mantle which is called the lithosphere. * Plates are composed of continental and oceanic crust. * The oceanic crusts are continually moving, spreading from the center, sinking at the edges, in a process of recycling. * Rising legs of convection currents beneath the plates create additional plate material at mid-ocean ridges, sinking legs of convection currents swallow old crustal plates at subduction zones. * The heat driving the convection currents is from radioactive decay of material within the Earth and from residual heat from accretion processes during Earth's formation. Convection cells in the magma of the outer core pull the earth's tectonic plates along the surface. These plates can collide and cause earthquakes.