Solidity of the Inner Core of the Earth inferred from Normal Mode Observations

@article{Dziewoski1971SolidityOT,
  title={Solidity of the Inner Core of the Earth inferred from Normal Mode Observations},
  author={Adam M. Dziewoński and Ferhat Gilbert},
  journal={Nature},
  year={1971},
  volume={234},
  pages={465-466}
}
SOLIDITY of the inner core was originally inferred on the basis of the assumption that the inner core has the same composition as the surrounding material of the outer core1. If, however, the observed increase in compressional velocity is related to a compositional change or, as suggested by Elsasser and Isenberg2, to a new phase of iron with rearranged electronic orbits, then the inner core might be liquid3. It was believed that conclusive evidence of solidity of the inner core would come from… 

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References

SHOWING 1-7 OF 7 REFERENCES

Elasticity and Constitution of the Earth's Interior

The observed variation of the seismic velocities with depth, below the crust, is examined with reference to the variation to be expected in a homogeneous medium. A general equation is derived for the

Overtones of Free Oscillations and the Structure of the Earth's Interior

Identification of 82 percent of all possible spheroidal overtones with greater than 300 seconds increases the resolving power of the set of gross searth data. Results of inversion indicate a change

Numerical Applications of a Formalism for Geophysical Inverse Problems

Summary A gross datum of the Earth is a single measurable number describing some property of the whole Earth, such as mass, moment of inertia, or the frequency of oscillation of some identified

Free oscillation observations through 1968

abstract All observations of the free oscillations of the Earth published through 1968 are weighted to produce a set of means and standard errors of the means. Fundamental orders 0 to 97 for

How Thick is the Lithosphere ?

A rapid decrease in shear velocity in the suboceanic mantle is used to infer the thickness of the lithosphere. It is proposed that new and highly precise group velocity data constrain the solutions