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The equations that govern the deformation of jointed rocks are the same as those used to describe the motion of a continuum: [13] ˙ + = ˙ = = ˙: + = where (,) is the mass density, ˙ is the material time derivative of , (,) = ˙ (,) is the particle velocity, is the particle displacement, ˙ is the material time derivative of , (,) is the Cauchy stress tensor, (,) is the body force density ...
The depth of compensation (also known as the compensation level, compensation depth, or level of compensation) is the depth below which the pressure is identical across any horizontal surface. In stable regions, it lies in the deep crust, but in active regions, it may lie below the base of the lithosphere. [ 16 ]
Plates in the crust of Earth. Earth's crust is its thick outer shell of rock, referring to less than one percent of the planet's radius and volume.It is the top component of the lithosphere, a solidified division of Earth's layers that includes the crust and the upper part of the mantle. [1]
Another definition of the LAB involves differences in composition of the mantle at depth. Lithospheric mantle is ultramafic and has lost most of its volatile constituents, such as water, calcium, and aluminum. [5] Knowledge of this depletion is based upon the composition of mantle xenoliths.
The average density of the continental crust is about, 2.83 g/cm 3 (0.102 lb/cu in), [6] less dense than the ultramafic material that makes up the mantle, which has a density of around 3.3 g/cm 3 (0.12 lb/cu in). Continental crust is also less dense than oceanic crust, whose density is about 2.9 g/cm 3 (0.10 lb/cu in). At 25 to 70 km (16 to 43 ...
Given the average density of rocks at the Earth's surface and profiles of the P-wave and S-wave speeds as function of depth, it can predict how density increases with depth. [2] It assumes that the compression is adiabatic and that the Earth is spherically symmetric, homogeneous, and in hydrostatic equilibrium. It can also be applied to ...
The upper crust is characterized by low density and high porosity, leading to reduced seismic velocity. [23] Two key discontinuities have been observed: one within the crust at a depth of 5 to 10 km, [65] and another which is likely the crust-mantle boundary, occurring at a depth of 30 to 50 km. [22]
Only beneath mid-ocean ridges does it define the lithosphere–asthenosphere boundary (the depth at which the mantle becomes significantly ductile). The Mohorovičić discontinuity is 5 to 10 kilometres (3–6 mi) below the ocean floor , and 20 to 90 kilometres (10–60 mi) beneath typical continental crusts, with an average of 35 kilometres ...