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| Titel |
Interior structure of the Moon - constraints from seismic tomography, gravity and topography |
| VerfasserIn |
Bernhard Steinberger, Dapeng Zhao, Stephanie Werner |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250088565
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| Publikation (Nr.) |
 EGU/EGU2014-2682.pdf |
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| Zusammenfassung |
| Seismic tomography can be combined with constraints from geoid, topography and other
surface observations to gain information about mantle structure and dynamics. This approach
has been taken with much success for the Earth mantle, and here it is, for the first time,
applied to the Moon. Lunar tomography has much lower resolution as for the Earth
and is mostly restricted to the near side, nevertheless we can assess under what
assumptions the fit between predicted geoid (based on a tomography model) and
observed geoid is best: Among the models tested, we find the most similar pattern
(correlation about 0.5) if we only consider tomography below 225 km depth, if density
anomalies cause little or no dynamic topography and if we compare to the geoid with
the flattening (l = 2,m = 0) term removed. This could mean that (a) like for the
Earth, seismic anomalies shallower than 225 km are caused by a combination of
thermal and compositional effects and therefore cannot be simply converted to density
anomalies; (b) the lithosphere is sufficiently thick to prevent dynamic topography
more than a small fraction of total topography; and (c) flattening is a “fossil” bulge
unrelated to present-day mantle anomalies. However, we have to be cautious with
interpreting our results, because the amplitude of the predicted geoid is much lower than
observed for models with high correlation: This could either mean that the tomography
model is strongly damped, or that the geoid is mostly due to shallow causes such as
crustal thickness variations, with only a small part coming from the deeper mantle. |
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