Attenuation of seismic energy in the upper mantle

Anderson, Don L.; Ben‐Menahem, Ari; Archambeau, Charles B.

doi:10.1029/jz070i006p01441

Cited by 387 publications

(161 citation statements)

References 12 publications

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“…These perturbations can, in turn, be used for the calculation of the attenuation of surface waves as a function of period for realistic anelastic earth models [Anderson and Archam-1964;Anderson et al, 1965]. Integral relations similar to (7) and (8) can also be obtained for the medium response.…”

Section: Symbolsmentioning

confidence: 99%

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Surface wave energy from point sources in plane layered Earth models

Harkrider¹,

Anderson²

1966

J. Geophys. Res.

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The total energy contained in a surface wave can be computed from its propagation-corrected spectrum by integrating over the surface of the earth and over the depth of the wave guide. The former requires knowledge of the radiation pattern of the source. The latter requires only a knowledge of the variation of physical properties with depth. In this paper the depth integration is performed for a continental and an oceanic earth model for three Rayleigh modes and four Love modes. The results are presented in tables and graphs in such a way that it is convenient to convert an observed surface wave displacement or displacement spectrum to total energy density. If the surface radiation pattern is known, the surface integration then yields the total energy in the observed spectrum. The partioning of energy between surface wave modes is computed for several simple sources at the surface and at depth, making it possible to estimate the energy contained in frequency bands or modes which are inaccessible for direct analysis. The increasing importance of the higher modes in the total energy budget at short periods and for channel depth sources is demonstrated. The shapes of the spectrums are diagnostic of source orientation and depth.

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Section: Symbolsmentioning

confidence: 99%

“…(c) The attenuation of surface waves, given the variation of anelasticity with depth [Anderson and Archambeait, 1964;Anderson et al, 1965].…”

Section: Introductionmentioning

confidence: 99%

Surface wave energy from point sources in plane layered Earth models

Harkrider¹,

Anderson²

1966

J. Geophys. Res.

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“…Surface-wave attenuation studies for the Pacific and Atlantic Oceans have provided a good knowledge of the Q structure under both oceans (e.g., ANDERSON et al, 1965;TSAI and AKI, 1969;MITCHELL, 1976;MITCHELL et al, 1976). Local and regionalized studies in these oceans (e.g., SOLOMON, 1973;CANAS and MITCHELL, 1978;CANAS et al, 1980;CANAS and MITCHELL, 1981;CANAS, 1982) have shown that the Q structure is a function of the oceanic sea floor age, the Q values being lower as the oceanic regions become younger.…”

Section: Introductionmentioning

confidence: 99%

Rayleigh wave attenuation across the Atlantic-Indian ridge.

Cañas

1988

J,Phys,Earth

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The regionalization method has been applied to the attenuation coefficients of the vertical components of Rayleigh waves for the Southern Atlantic-Indian Ocean to obtain the attenuation across the ridge region.The obtained ridge attenuation coefficients are similar to those for the North Atlantic ridge and much lower than the values for the East Pacific Rise.Inversion theory, in its stochastic form, shows that the low-Q zone under the ridge sems to be located between 50 km and 200 km depth, with the maximum Q-1 value (15 x 10-3) at a depth of about 140 km.Comparison of the ridge model in this study with models for the North Atlantic ridge and East Pacific Rise, obtained by others, indicates that the attenuation coefficients for the study region are similar to those for the North Atlantic ridge, and much weaker than those for the East Pacific Rise. Since the spreading rate in the southern part of the Atlantic-Indian Ocean is similar to that in the North Atlantic, and lower than the corresponding rate in the Pacific, it seems that there is a close relation between spreading rates and low-Q regions under the ridges, with the Q values being higher in the region where the spreading rates are lower.The above results suggest that the creep rate under the ridge of the Southern Atlantic-Indian Ocean may be similar to that for the Atlantic, and much lower than for the Pacific Ocean for regions of comparable ages.

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“…Early studies of Q in the Earth were primarily based on the decay of free oscillation peaks and long-period surface wave amplitudes (e.g. Anderson et al, 1965;Canas & Mitchell, 1978;Anderson & Hart, 1978;Sailor & Dziewonski, 1978. They established that attenuation in shear largely dominates over attenuation associated to bulk deformation, meaning that Q μ << Q κ almost anywhere in the Earth.…”

Section: Description Of Seismic Wave Attenuation Basic Observables Amentioning

confidence: 99%