Conductivity Profiles from Global Data

Hobbs, B. A.

doi:10.1007/978-3-0348-7373-4_10

Cited by 4 publications

(3 citation statements)

References 9 publications

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“…This method has been successfully used to infer the electrical conductivity of the Earth (Banks, 1969;Chapman and Price, 1930;Hobbs, 1987;Kuvshinov and Olsen, 2006;Lahiri and Price, 1939;Rikitake, 1966;Roberts, 1986;Schuster, 1889;Tarits, 1994) and the Moon (Schubert and Schwartz, 1969;Sonett, 1982;Sonett et al, 1971). It has also been used to find subsurface liquid salt water oceans on the Galilean satellites Europa, Ganymede, and Callisto (Khurana et al, 1998;Kivelson et al, 1999Kivelson et al, , 2000Kivelson et al, , 2002Kivelson et al, , 2004Zimmer et al, 2000) and a subsurface magma ocean on Io (Khurana et al, 2011).…”

Section: Electromagneticsmentioning

confidence: 99%

Interior Structure, Composition, and Mineralogy of the Terrestrial Planets

Sohl

Schubert²

2015

Treatise on Geophysics

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Section: Electromagneticsmentioning

confidence: 99%

Interior Structure, Composition, and Mineralogy of the Terrestrial Planets

Sohl

Schubert²

2015

Treatise on Geophysics

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“…The Parker & Whaler (1981) approximation scheme described in the previous section was applied to some real data to search for a suitable value of N * . This preliminary work was carried out on data from two sources: (i) Hobbs (1987). 8 frequencies considered ranging between 0.094 and 0.750 cycles per day (cpd); (ii) Larsen (1975).…”

Section: Inversion Of Synthetic Modelsmentioning

confidence: 99%

“…It was hoped that such a frequency range would enable the estimation of at least the first few pole locations of the response function. The data were derived using a technique similar to that employed by Hobbs (1987) in the analysis of six magnetic storms considered by Marshall (1980). The results of Marshall, who separated the external and internal field components corresponding to the harmonic n = 1 for each storm at hourly intervals, were taken as the raw data.…”

Section: The Derivation O F a Response Set A N D Its S U B S E Q U E mentioning

confidence: 99%

An inversion method of Gel'fand-Levitan type for the electromagnetic induction problem

Bassom

Jady

1988

Geophysical Journal International

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SUMMARY The inverse problem of electromagnetic induction for an assumed spherically symmetric conductivity distribution within the Earth is considered. In particular an adaptation (applicable in the case of external source fields) is made of the method proposed by Johnson & Smylie. This is based on the Gel'fand‐Levitan integral equation and is relevant to the determination of electrical conductivity in the lower mantle and internally generated source‐fields. A characteristic of this approach is that the predicted conductivity is a twice differentiable function with respect to the Earth's radius. It is shown here that the inversion procedure satisfactorily recovers the conductivity profile with data generated from a variety of synthetic conductivity structures. Typical response measurements covering a range of frequencies from 0.1 cycles per year to 11 cycles per day for the Earth allowed estimates of the conductivity profile for depths to about 2000 km.

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Response Function Estimates for Sq.

Hobbs

1992

J. geomagn. geoelec

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Hourly values of the earth's magnetic field recorded at world-wide magnetic observatories have traditionally been used to study Sq variations and this can lead in particular to the construction the earth's response function at the daily period and its sub-harmonics. As an alternative to least squares analyses of the Sq potential, PRICE and WILKINS (1963) proposed a method involving interpolation, line integral constraints and surface integral separation of the potential into internal and external parts. The philosophy of the first two steps of their procedure is adopted here and these steps are rendered automatic. Spherical spline interpolation is used to convert the observatory X, Y, Z values to those over a regular surface grid and the use of line integral constraints to ensure the X, Y values represent a true potential is cast as a linear inverse problem with an exact solution. With regular data now available, stable spherical harmonic analysis can be applied to separate the total field into internal and external parts and the ratio of these taken to construct the Q-response. The method is illustrated on synthetic data and is then applied to the Price-Wilkins observatory data from the 1932-3 International Polar Year. Several estimates of the Q-response at periods of 24, 12 and 8 hours are converted to Schmucker's c-response and compared to longer period data from other analyses.

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Conductivity Profiles from Global Data

Cited by 4 publications

References 9 publications

Interior Structure, Composition, and Mineralogy of the Terrestrial Planets

Interior Structure, Composition, and Mineralogy of the Terrestrial Planets

An inversion method of Gel'fand-Levitan type for the electromagnetic induction problem

Response Function Estimates for Sq.

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