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The Gutenberg discontinuity occurs within Earth's interior at a depth of about 2,900 km (1,800 mi) below the surface, where there is an abrupt change in the seismic waves (generated by earthquakes or explosions) that travel through Earth. At this depth, primary seismic waves (P waves) decrease in velocity while secondary seismic waves (S waves ...
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 differences between the acoustic impedances of the solid mantle ...
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 ...
Beno Gutenberg (/ ˈ ɡ uː t ən b ɜːr ɡ /; June 4, 1889 – January 25, 1960) was a German-American seismologist who made several important contributions to the science. He was a colleague and mentor of Charles Francis Richter at the California Institute of Technology and Richter's collaborator in developing the Richter magnitude scale for measuring an earthquake's magnitude.
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 ...
This sharp decline is observed at the core-mantle boundary, also referred to as the D'' region or Gutenberg discontinuity. [ 12 ] Furthermore, the reduction in seismic velocity in the outer core suggests the presence of lighter elements like oxygen , silicon , sulfur , and hydrogen , which lower the density of the outer core.
Project Gutenberg (PG) is a volunteer effort to digitize and archive cultural works, as well as to "encourage the creation and distribution of eBooks." [2] It was founded in 1971 by American writer Michael S. Hart and is the oldest digital library. [3] Most of the items in its collection are the full texts of books or individual stories in the ...
The transition zone is the part of Earth's mantle that is located between the lower and the upper mantle, most strictly between the seismic-discontinuity depths of about 410 to 660 kilometres (250 to 410 mi), but more broadly defined as the zone encompassing those discontinuities, i.e., between about 300 and 850 kilometres (190 and 530 mi) depth. [1]