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The Lehmann discontinuity is an abrupt increase of P -wave and S -wave velocities at the depth of 220 km (140 mi) in Earth's mantle, discovered by seismologist Inge Lehmann. [2][3][4] The thickness is 220 km [citation needed]. It appears beneath continents, but not usually beneath oceans, [5] and does not readily appear in globally averaged ...
The boundary between the inner and outer cores is sometimes called the "Lehmann discontinuity", [13] although the name usually refers to another discontinuity. The name "Bullen" or "Lehmann-Bullen discontinuity", after Keith Edward Bullen, has been proposed, [14] but its use seems to be rare. The rigidity of the inner core was confirmed in 1971.
core–mantle boundary. outer core–inner core boundary. The core–mantle boundary (CMB) of Earth lies between the planet's silicate mantle and its liquid iron–nickel outer core, at a depth of 2,891 km (1,796 mi) below Earth's surface. The boundary is observed via the discontinuity in seismic wave velocities at that depth due to the ...
The Mohorovičić discontinuity (/ ˌmoʊhəˈroʊvɪtʃɪtʃ / 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. It is defined by the distinct change in velocity of seismic waves as they pass through ...
Inge Lehmann. Inge Lehmann ForMemRS (13 May 1888 – 21 February 1993) was a Danish seismologist and geophysicist who is known for her discovery in 1936 of the solid inner core that exists within the molten outer core of the Earth. The seismic discontinuity in the speed of seismic waves at depths between 190 and 250 km is named the Lehmann ...
The Lehmann discontinuity is an abrupt increase of P-wave and S-wave velocities at a depth of 220 km (140 mi) [5] (Note that this is a different "Lehmann discontinuity" than the one between the Earth's inner and outer cores labeled in the image on the right.)
Mohorovičić discontinuity: the boundary between the crust and the mantle, located approximately 30–50 km below the continental crust and 5–10 km beneath the oceanic crust. [5] 410 km discontinuity: a phase transition where olivine becomes wadsleyite. [35] 520 km discontinuity: a phase transition where wadsleyite becomes ringwoodite. [30]
Earth's inner core is the innermost geologic layer of the planet Earth. It is primarily a solid ball with a radius of about 1,220 km (760 mi), which is about 19% of Earth's radius [0.7% of volume] or 70% of the Moon 's radius. [32][33] The inner core was discovered in 1936 by Inge Lehmann and is generally composed primarily of iron and some nickel.