Tidal Response of Mars Constrained From Laboratory-Based Viscoelastic Dissipation Models and Geophysical Data
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Publication Date
2019-11-01Journal Title
Journal of Geophysical Research: Planets
ISSN
2169-9097
Publisher
American Geophysical Union (AGU)
Volume
124
Issue
11
Pages
2703-2727
Type
Article
This Version
AM
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Bagheri, A., Khan, A., Al-Attar, D., Crawford, O., & Giardini, D. (2019). Tidal Response of Mars Constrained From Laboratory-Based Viscoelastic Dissipation Models and Geophysical Data. Journal of Geophysical Research: Planets, 124 (11), 2703-2727. https://doi.org/10.1029/2019JE006015
Abstract
We employ laboratory-based grain-size- and temperature-sensitive rheological models to
16 describe the viscoelastic behavior of terrestrial bodies with focus on Mars. Shear modulus
17 reduction and attenuation related to viscoelastic relaxation occur as a result of diffusion-
18 and dislocation-related creep and grain-boundary processes. We consider five rheological
19 models, including extended Burgers, Andrade, Sundberg-Cooper, a power-law approxima-
20 tion, and Maxwell, and determine Martian tidal response. However, the question of which
21 model provides the most appropriate description of dissipation in planetary bodies, re-
22 mains an open issue. To examine this, crust and mantle models (density and elasticity) are
23 computed self-consistently through phase equilibrium calculations as a function of pres-
24 sure, temperature, and bulk composition, whereas core properties are based on an Fe-FeS
25 parameterisation. We assess the compatibility of the viscoelastic models by inverting the
26 available geophysical data for Mars (tidal response and mean density and moment of in-
27 ertia) for temperature, elastic, and attenuation structure. Our results show that although
28 all viscoelastic models are consistent with data, their predictions for the tidal response at
29 other periods and harmonic degrees are distinct. The results also show that Maxwell is
30 only capable of fitting data for unrealistically low viscosities. Our approach can be used
31 quantitatively to distinguish between the viscoelastic models from seismic and/or tidal ob-
32 servations that will allow for improved constraints on interior structure (e.g., with InSight).
33 Finally, the methodology presented here is generally formulated and applicable to other so-
34 lar and extra-solar system bodies where the study of tidal dissipation presents an important
35 means for determining interior structure.
Identifiers
External DOI: https://doi.org/10.1029/2019JE006015
This record's URL: https://www.repository.cam.ac.uk/handle/1810/296534
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