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| Titel |
SPani, a whole-mantle V P and V S model: Implications on thermo-chemical structure. |
| VerfasserIn |
Andrea Tesoniero, Ludwig Auer, Lapo Boschi, Fabio Cammarano |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250110511
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| Publikation (Nr.) |
 EGU/EGU2015-10514.pdf |
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| Zusammenfassung |
| We have derived a joint model of radially anisotropic P- and S-wave velocity (V P, V S)
heterogeneity in the whole mantle, partly based on the S-velocity model SAVANI of Auer et
al., 2014. Sensitivity to P velocity is provided by a large set of global teleseismic P-wave
travel time data, as well as observations of Rayleigh-wave fundamental-mode and
overtone dispersion curves. P- and S-sensitive data are inverted jointly, and the P- and
S-inversions are "coupled" by (i) Rayleigh-wave data, which are sensitive to both
S and P, and (ii) a-priori mineralogical constraints on the relationship between P
and S-velocity. We conduct extensive testing of the effects of such mineralogical
constraints, and assess in detail potential trade-offs between P- and S-wave speeds
and radial anisotropy. Importantly, our model exhibits interesting anomalies in the
ratio between V P and V S in the upper mantle (at around 150 km depth) within the
Asian plate, at continental regions and along mid-ocean ridges. In light of the well
known limitations inherent to any tomographic method we perform a qualitative
interpretation of these features, based on the joint analysis of radial anisotropy
and V P/V S ratio, and infer the anomalous zones to be likely caused by (i) a high
concentration of water in the western pacific subduction system and (ii) chemical
depletion of continental lithosphere below the American and the East European cratons. |
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