Scientific study of the deformation of the rocks that make up the Earth's crust and the forces that produce such deformation. It deals with the folding and faulting associated with mountain building; the large-scale, gradual, upward and downward movements of the crust; and sudden horizontal displacements along faults. Other phenomena studied include igneous processes and metamorphism. The chief working principle of tectonics is the concept of plate tectonics. Seealso continental drift; seafloor spreading.
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Theory that the Earth's lithosphere (the crust and upper portion of the mantle) is divided into about 12 large plates and several small ones that float on and travel independently over the asthenosphere. The theory revolutionized the geological sciences in the 1960s by combining the earlier idea of continental drift and the new concept of seafloor spreading into a coherent whole. Each plate consists of rigid rock created by upwelling magma at oceanic ridges, where plates diverge. Where two plates converge, a subduction zone forms, in which one plate is forced under another and into the Earth's mantle. The majority of the earthquakes and volcanoes on the Earth's surface occur along the margins of tectonic plates. The interior of a plate moves as a rigid body, with only minor flexing, few earthquakes, and relatively little volcanic activity.
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Tectonics, (from the Greek for "builder", tekton), is a field of study within geology concerned generally with the structures within the crust of the Earth (or other planets) and particularly with the forces and movements that have operated in a region to create these structures. Tectonics is concerned with the orogenies and tectonic development of cratons and tectonic terranes as well as the earthquake and volcanic belts which directly affect much of the global population. Tectonic studies are also important for understanding erosion patterns in geomorphology and as guides for the economic geologist searching for petroleum and metallic ores.
Tectonic studies have application to lunar and planetary studies, whether or not those bodies have active tectonic plate systems.
Since the 1960s, plate tectonics has become by far the dominant theory to explain the origin and forces responsible for the tectonic features of the continents and ocean basins.
There are three main types of tectonic regime