Search results
Results from the WOW.Com Content Network
Earth's crust and mantle, Moho discontinuity between bottom of crust and solid uppermost mantle. The Mohorovičić discontinuity (/ ˌ m oʊ h ə ˈ r oʊ v ɪ tʃ ɪ tʃ / MOH-hə-ROH-vih-chitch; Croatian: [moxorôʋiːtʃitɕ]) [1] – usually called the Moho discontinuity, Moho boundary, or just Moho – is the boundary between the crust and the mantle of Earth.
The boundary is observed via the discontinuity in seismic wave velocities at that depth due to the differences between the acoustic impedances of the solid mantle and the molten outer core. P-wave velocities are much slower in the outer core than in the deep mantle while S-waves do not exist at all in the liquid portion of the core.
A discontinuity may exist as a single feature (e.g. fault, isolated joint or fracture) and in some circumstances, a discontinuity is treated as a single discontinuity although it belongs to a discontinuity set, in particular if the spacing is very wide compared to the size of the engineering application or to the size of the geotechnical unit.
The Mohorovičić discontinuity is a distinct change of seismic wave velocity. This is caused by a change in the rock's density [ 17 ] – immediately above the Moho, the velocities of primary seismic waves ( P wave ) are consistent with those through basalt (6.7–7.2 km/s), and below they are similar to those through peridotite or dunite (7.6 ...
The seismic LVZ was first recognized by Beno Gutenberg, whose name is sometimes used to refer to the base of the seismic LAB beneath oceanic lithosphere. [5] The Gutenberg discontinuity coincides with the expected LAB depth in many studies and has also been found to become deeper under older crust, thus supporting the suggestion that the ...
Seismic velocity structure is the distribution and variation of seismic wave speeds within Earth's and other planetary bodies' subsurface. It is reflective of subsurface properties such as material composition, density, porosity, and temperature. [ 1 ]
A seismic shadow zone is an area of the Earth's surface where seismographs cannot detect direct P waves and/or S waves from an earthquake.This is due to liquid layers or structures within the Earth's surface.
On the basis of the seismic data, the inner core is estimated to be about 1221 km in radius (2442 km in diameter), [5] which is about 19% of the radius of the Earth and 70% of the radius of the Moon. Its volume is about 7.6 billion cubic km (7.6 × 10 18 m 3), which is about 1 ⁄ 146 (0.69%) of the volume of the whole Earth.