Seismic wave propagationIn addition to a significant change in wave velocity at a depth of about 33 km in the earth's interior (here calledMoho interfaceIs the relationship between the crust and the mantleDividing line）In addition, at a depth of about 2900km, the seismic wave propagation state will also change significantly, which is called the Gutenberg interface.The mantle lies between the Moho interface and the Gutenberg interface.Because the earthOuter nucleusThe seismic waves in the mantle are liquidS-wave(S wave istransverse wave, the shear wave can only propagate in the solid) cannot pass through this interface and propagate in the outer core.P-wave(refers tolongitudinal wave）The speed of the curve at this interface also decreases sharply.
In 1914, Gutenberg, a German scholar, discovered that there wasseismic waveSpeed discontinuity,First, the shadow area where seismic waves exist is found, which is interpreted asearth 's core, followed bypropagation velocitySignificant changes have taken place[2]，longitudinal waveThere was a cross section that suddenly decreased from 13.6 km/s to 7.98 km/s, and the shear wave suddenly disappeared.And in theDiscontinuitiesThe upper seismic wave shows extremely obvious reflectionRefraction phenomenon。It was later confirmed that this is the core of the earthmantleThe boundary layer of.ThisDiscontinuityThe surface is called Gutenberg surface.From above GutenbergMoho surfaceThe part of the earth between is called mantle;The part of the earth below Gutenberg to the center of the earth is called the core.[1]
Gutenberg interface isMantle sphereAndOuter nucleusThe interface of the hydrosphere.The whole mantle circle is composed ofupper mantle(33~410km deep layer B, 410~1000km deep layer C, also known as transition zone layer)Lower mantleD ′ layer (1000 ～ 2700 km depth) and D ″ layer of lower mantle (2700 ～ 2900 km depth).geophysicalIt is shown that there is a strong transverse direction in D ″ ′ layerNonuniformity。The degree of unevenness can even beRock stratumCompared with quasi, it is not onlyearth 's coreHeat transfer tomantleOfThermal boundary layerAnd it is probably different from the mantlechemical compositionChemical stratification.[1]
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In 1914, a German scholar (naturalized in the United States in 1936) Gutenberg found that 2885 kilometers undergroundseismic waveSpeed discontinuity,The first is to find the shadow area with seismic waves[2], interpreted as existingearth 's core, followed bypropagation velocitySignificant changes have taken place,longitudinal waveThere is a section that suddenly reduces from 13.6 km/s to 7.98 km/s, andtransverse waveThen suddenly disappeared.And in theDiscontinuitiesThe upper seismic wave shows extremely obvious reflectionRefraction phenomenon。It was later confirmed that this is the core of the earthmantleThe boundary layer of.ThisDiscontinuityThe surface is called Gutenberg surface.From above GutenbergMoho surfaceThe part of the earth between is called mantle;The part of the earth below Gutenberg to the center of the earth is called the core.People call this interface "Gutenberg Interface".Between the late 1950s and the early 1960s,National Science Foundationexecutive committeeA proposal was adopted to drill holes in the seabed of the ocean to get there.This program is called ProjijGutenberg.However, the plan never received enough support, and the proposal was also approved byUnited States CongressCancel.In September 2007, Japan's largest global ocean exploration vessel, "Earth", began to be relatively thin in the South China SeaTroughOfSea layerExploration is the target exploration to this interface.The whole project is expected to be completed by 2019.
