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Mantle seismic waves

Toomey DR, Wilcock WSD, Solomon SC, Hammond WC, Orcntt JA (1998) Mantle seismic structure beneath the MELT region of the East Pacific Rise from P and S wave tomography. Science 280 1224-1227... [Pg.211]

The very high apparent seismic wave velocities of about 9 km/sec obtained for the layer below the crust imply that the lunar mantle is differentiated and its composition varies with depth. [Pg.148]

Most seismological constraints on mantle composition are derived by comparison of values of seismic wave velocities inferred for particular regions within the Earth to the values measured in the laboratory for particular minerals or mineral assemblages, with such comparisons being made under comparable regimes of pressure (P) and temperature (T). The primary parameters of interest, then, are the compressional (or P-) wave velocities (Vp) and the shear (or S-) wave velocities (Ej). These wave velocities are simply related to the density (p) and to the two isotropic elastic moduli, the adiabatic bulk modulus (Ks)... [Pg.743]

Helffrich G. and Stein S. (1993) Study of the structure of the slab-mantle interface using reflected and converted seismic waves. Geophys. J. Int. 115, 14-40. [Pg.761]

Helffrich G., Stein S., and Wood B. J. (1989) Subduction zone thermal structure and mineralogy and their relationship to seismic wave reflections and conversions at the slab/mantle interface. J. Geophys. Res. 94, 753-763. [Pg.761]

Jackson, I. 2000. Laboratory measurement of seismic wave dispersion and attenuation recent progress. In The Earth s Deep Interior Mantle Physics and Tomography from the Atomic to the Global Scale. Geophysical Monogaph, American Geophysical Union, 117, 265-289. [Pg.63]

Because the part of the mantle that we can access (Chapters 2.04 and 2.05) shares compositional similarities with primitive meteorites and the Sun, the approach pursued in Chapter 2.01 has proved to be very powerful in predicting the composition expected for the bulk Earth, knowledge of which allows estimates of the degree to which mantle composition has been affected by core (Chapters 2.14 and 2.15) and cmst (Chapter 2.03) formation. One must ask, however, whether the mantle that we can sample from the surface is representative of the mantle as a whole. To address this question, we turn to two quite different approaches examination of Earth s interior with seismic waves (Chapter 2.02) and mass-balance modeling relating crust, mantle, and core compositions (Chapters 2.03 and 2.15). [Pg.603]

FIGURE 3.2 Tomographic image of the Earth s mantle beneath the Japanese Arc, down to the core-mantle boundary showing the distribution of slow and fast seismic waves. The wave velocity distribution also reflects temperature distribution and shows the penetration of a cold subducting slab through the transition zone into the lower mantle (after Fukao et al., 2001). [Pg.74]

The principal observation behind the Helffrich and Wood (2001) model of the mantle is that the scattering of seismic waves in the lower mantle indicates that small heterogeneities are present, mostly about 4 km in size. As with all seismic methods the physical cause of the seismic scattering anomalies could theoretically be either thermal or compositional in origin. Helffrich and Wood (2001)... [Pg.127]

Moho (Mohorovidc discontinuity) A discontinuity within the earth that marks the junction between the crust and the underlying mantle. Below the discontinuity earthquake seismic waves undergo a sudden increase in velocity, a feamre that was first observed in 1909 by the Croatian geophysicist Andtija Mohoroviac (1857-1936), after whom the discontinuity was named. The Moho lies at a depth of about 10-12 km below the oceans and about 33-35 km below the continents. [Pg.535]

The geosphere denotes the mineral part of the Earth it consists of successive concentric layers from the outer crust down to the inner core, (see Figure 13.1). The structure of the interior of the Earth can be zoned by either its physical properties (e.g., density, velocity of P and S seismic waves, and temperature) or its chemical and mineralogical composition. The classification of the geosphere according to its chemical composition identifies three main chemical entities the crust, the mantle, and the core, while physical properties identify five homogeneous entities the lithosphere, the asthenosphere, the mesosphere, the outer core and the inner core. [Pg.886]


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See also in sourсe #XX -- [ Pg.39 , Pg.42 ]




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