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The lithosphere–asthenosphere boundary (referred to as the LAB by geophysicists) represents a mechanical difference between layers in Earth's inner structure. Earth's inner structure can be described both chemically (crust, mantle, and core) and mechanically. The lithosphere–asthenosphere boundary lies between Earth's cooler, rigid ...
The asthenosphere (from Ancient Greek ἀσθενός (asthenós) 'without strength') is the mechanically weak [1] and ductile region of the upper mantle of Earth. It lies below the lithosphere, at a depth between ~80 and 200 km (50 and 120 mi) below the surface, and extends as deep as 700 km (430 mi). However, the lower boundary of the ...
Lithosphere. A lithosphere (from Ancient Greek λίθος (líthos) 'rocky' and σφαίρα (sphaíra) 'sphere') is the rigid, [1] outermost rocky shell of a terrestrial planet or natural satellite. On Earth, it is composed of the crust and the lithospheric mantle, the topmost portion of the upper mantle that behaves elastically on time scales ...
The internal structure of Earth are the layers of the Earth, excluding its atmosphere and hydrosphere. The structure consists of an outer silicate solid crust, a highly viscous asthenosphere, and solid mantle, a liquid outer core whose flow generates the Earth's magnetic field, and a solid inner core. Scientific understanding of the internal ...
Earth's mantle is a layer of silicate rock between the crust and the outer core. It has a mass of 4.01 × 10 24 kg (8.84 × 10 24 lb) and makes up 67% of the mass of Earth. [1] It has a thickness of 2,900 kilometers (1,800 mi) [1] making up about 46% of Earth's radius and 84% of Earth's volume. It is predominantly solid but, on geologic time ...
The boundary between these two layers is rheologically based and is not necessarily a strict function of depth. Specifically, oceanic lithosphere (lithosphere underneath the oceanic plates) and subcontinental lithosphere, is defined as a mechanical boundary layer that heats via conduction and the asthenosphere is a convecting adiabatic layer ...
Convergent boundary. A convergent boundary (also known as a destructive boundary) is an area on Earth where two or more lithospheric plates collide. One plate eventually slides beneath the other, a process known as subduction. The subduction zone can be defined by a plane where many earthquakes occur, called the Wadati–Benioff zone. [1]
The seismic velocities very near the surface (≲ 220±30 km) are markedly lower than at greater depths, demarking the LVZ. The low-velocity zone (LVZ) occurs close to the boundary between the lithosphere and the asthenosphere in the upper mantle. It is characterized by unusually low seismic shear wave velocity compared to the surrounding depth ...