Large-scale gravity profiles across subducted plates

Rabinowicz, M.; Lago, B.; Souriau, Marc

doi:10.1111/j.1365-246x.1983.tb03319.x

Cited by 11 publications

(4 citation statements)

References 38 publications

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“…The results shown in Fig. 7 of Parsons & Daly (1984) seem in favour of this generalization but our experiment, for a set of completely different cases, does not (Rabinowicz et al 1983). …”

Section: Ricontrasting

confidence: 53%

“…1981). It is shown that the shape of the gravity signal associated with these cells can be quite different from that of small aspect ratio cells (Rabinowicz, Lago & Souriau 1983). We showed that the negative admittance values necessary to explain the observed gravity signal landward of the subduction zones can be achieved if some dynamical support is given by convection in the lower mantle.…”

Section: Introductionmentioning

confidence: 77%

“…In a former study (Rabinowicz et al 1983, hereafter denoted paper I), mean gravity profiles across Central and South America and Eurasia in the direction normal to the subduction zones deduced from the GEM 10B gravity models have been computed (see Fig. 6 ) : a strong similarity between these profiles can be noted.…”

Section: Geophysical Implicationsmentioning

confidence: 99%

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Admittance for a convection in a layered spherical shell

Lago¹,

Rabinowicz²

1984

Geophysical Journal International

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A formalism based on an analytical approximation for convection in a layered spherical shell leads to the computation of the Green kernels for topography and gravity, and to the admittance of gravity over topography for the harmonics of the Earth. We study the role of increasing viscosity with depth, of two layers of convection, and of the coupling with lithospheric plates. It is found that a planet with constant viscosity will have positive values for the admittance for all wavenumbers. However, when a step of viscosity between the lower and upper mantle is assumed, negative values for the first harmonics are achieved. This result explains some long-wave observations and provides evidence for an increase of viscosity in the lower mantle.

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“…The results shown in Fig. 7 of Parsons & Daly (1984) seem in favour of this generalization but our experiment, for a set of completely different cases, does not (Rabinowicz et al 1983). …”

Section: Ricontrasting

confidence: 53%

Section: Introductionmentioning

confidence: 77%

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Admittance for a convection in a layered spherical shell

Lago¹,

Rabinowicz²

1984

Geophysical Journal International

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“…In the mantle, the largest lateral variations in temperature and density are associated with subducted slabs. Numerous studies have shown that subduction zones have a major signature in the geoid [Kaula, 1972;Koyan, 1975;McAdoo, 1981;Jones, 1983;Rabinowicz et al, 1983].…”

Section: Introductionmentioning

confidence: 99%

Subducted slabs and the geoid: 1. Numerical experiments with temperature‐dependent viscosity

King¹,

Hager²

1994

J. Geophys. Res.

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One of the most powerful constraints on mantle viscosity comes from the correlation of the long‐wavelength (degree 4–9) geoid with that predicted by a density model for subducted slabs. The effect of lateral variations of viscosity should be most pronounced at subduction zones, due to the strong effect of temperature on viscosity. An idealized slab model with temperature‐dependent viscosity is considered, with various lateral and vertical viscosity structures, using a two‐dimensional finite element formulation. The viscosity parameterization affects the amplitude of the long‐wavelength geoid anomaly but not the sign of the correlation between the geoid and density anomalies. Depth‐dependent viscosity models with a high‐viscosity lithospheric layer do not completely match the temperature‐dependent (laterally varying) results, suggesting that the rheology of the slab does have an effect on the long‐wavelength surface topography and geoid; however, this affect is minor, suggesting that the radial models of mantle viscosity inferred from surface observables are correct to first order. In contrast, the short‐wavelength features are dramatically affected by the rheology of the region surrounding the downwelling. Further study of the shorter‐wavelength geoid over subduction zones may provide better insight into subduction zone processes.

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