Levyosiointi

Levyosiointi, often translated as "plate tectonics" in English, is a scientific theory describing the large-scale motion of seven large plates and the movements of numerous smaller plates of the Earth's lithosphere, over the past several hundred million years. The lithosphere, which is the rigid outer shell of the Earth, is broken into these tectonic plates. These plates "float" on the semi-fluid asthenosphere, a layer of the Earth's mantle beneath the lithosphere.

The movement of these plates is driven by convection currents within the Earth's mantle. Hotter, less dense material rises, cools, and then sinks, creating a continuous cycle that drags the plates along. The interactions at the boundaries between these plates are responsible for many of the Earth's most dramatic geological phenomena.

There are three main types of plate boundaries. At divergent boundaries, plates move apart, leading to the formation of new crust, such as at mid-ocean ridges. At convergent boundaries, plates collide. This can result in one plate being forced beneath another (subduction), leading to volcanoes and deep ocean trenches, or in mountain building if both plates are continental. At transform boundaries, plates slide past each other horizontally, causing earthquakes. The theory of levyosiointi explains the distribution of earthquakes, volcanoes, mountain ranges, and the formation and breakup of continents over geological time.