Tectonics

Tectonics are the ways that Earth's crust changes shape over time. The word comes from an ancient Greek word meaning "pertaining to building." It helps us learn how Earth works. These processes include how mountains are built, how strong parts of continents called cratons behave, and how large pieces of Earth's outer shell, called plates, move and interact with each other.

Tectonics help explain why earthquakes and volcanic activity happen in some places, which affects many people around the world. Studying tectonics is important for scientists who look for valuable resources like fossil fuels and metal ores. Understanding these processes helps explain many features on Earth's surface, such as how land shapes through erosion.

Main types of tectonic regime

Extensional tectonics

Main article: Extensional tectonics

Extensional tectonics happens when the Earth's crust or its outer layer stretches and becomes thinner. This can occur where plates move apart, in areas where continents are splitting, after continents crash into each other, at bends in certain faults, in special ocean areas, and along the edges of continents where a sliding layer exists.

Thrust (contractional) tectonics

Main article: Thrust tectonics

Thrust tectonics happens when the Earth's crust or its outer layer gets shorter and thicker. This can happen where continents crash into each other, at bends in certain faults, and in special areas along the edges of continents where a sliding layer is present.

Strike-slip tectonics

Main article: Strike-slip tectonics

Strike-slip tectonics happens when parts of the Earth's crust or its outer layer move sideways past each other. This can occur along special faults in the oceans and on continents that connect parts of underwater mountain ranges. It also happens where plates are stretching apart or crashing together, and in areas where continents are colliding at an angle.

Plate tectonics

Main article: Plate tectonics

Plate tectonics is the study of how Earth's outer layer, called the lithosphere, moves. This layer includes the crust and the top part of the mantle. It breaks into pieces called plates. These plates move over a softer layer below, called the asthenosphere.

There are three main ways these plates interact: they can move apart, slide past each other, or come together. When plates move apart, new land forms. When they slide past each other or push together, this movement can cause big earthquakes and many of the world's volcanoes, like those around the Pacific Ring of Fire. Most changes to Earth's surface happen where these plates meet or near these meeting points. Recent research shows Earth's crust has many small pieces, called microplates, that join together to form the larger plates.

Other fields of tectonic studies

Salt tectonics

Main article: Salt tectonics

Salt tectonics looks at how thick layers of rock salt change the shape of rocks around them. Salt is lighter and weaker than other rocks, so it behaves differently when buried deep underground.

Neotectonics

Main article: Neotectonics

Neotectonics studies how Earth's crust moves and changes today and in the recent past. This helps us understand current geological processes and their effects.

Tectonophysics

Main article: Tectonophysics

Tectonophysics examines the physical processes that cause Earth's crust and mantle to change shape, from tiny mineral grains up to large tectonic plates.

Seismotectonics

Main article: Seismotectonics

Seismotectonics explores the link between earthquakes and the movement of Earth's crust. By studying faults, past earthquakes, and land features, scientists can better understand where earthquakes might happen.

Impact tectonics

Impact tectonics studies how high-speed impacts from space change the surface of planets and moons.

Planetary tectonics

We also use techniques from Earth tectonics to study the surfaces of other planets and their moons, especially icy ones.