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Main Authors: Hay, Hamish C. F. C., Hewitt, Ian, Rovira-Navarro, Marc, Katz, Richard F.
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2507.11266
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author Hay, Hamish C. F. C.
Hewitt, Ian
Rovira-Navarro, Marc
Katz, Richard F.
author_facet Hay, Hamish C. F. C.
Hewitt, Ian
Rovira-Navarro, Marc
Katz, Richard F.
contents Io's tidally driven global volcanism indicates widespread partial melting in its mantle. How this melt participates in the interior dynamics, and, in particular, the role it plays in tidal dissipation, is poorly understood. We model Io's tidal deformation by treating its mantle as a two-phase (solid and melt) system. By combining poro-viscous and poro-elastic compaction theories in a Maxwell framework with a consistent model of tidal and self-gravitation, we produce the first self-consistent evaluation of Io's tidal heating rate due to shearing, compaction, and Darcy flow. We find that Darcy dissipation can potentially exceed shear heating, but only for large (0.05 to 0.2) melt fractions, and if the grain size is large or melt viscosity ultra-low. Since grain sizes larger than 1cm are unlikely, this suggests that Darcy dissipation is secondary to shear dissipation. Compaction dissipation is maximised when the asthenosphere is highly resistive to isotropic stresses, but contributes at most 1% of Io's observed heating rate. This work represents a crucial step toward a self-consistent quantitative theory for the dynamics of Io's partially molten interior.
format Preprint
id arxiv_https___arxiv_org_abs_2507_11266
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Poro-viscoelastic tidal heating of Io
Hay, Hamish C. F. C.
Hewitt, Ian
Rovira-Navarro, Marc
Katz, Richard F.
Earth and Planetary Astrophysics
Io's tidally driven global volcanism indicates widespread partial melting in its mantle. How this melt participates in the interior dynamics, and, in particular, the role it plays in tidal dissipation, is poorly understood. We model Io's tidal deformation by treating its mantle as a two-phase (solid and melt) system. By combining poro-viscous and poro-elastic compaction theories in a Maxwell framework with a consistent model of tidal and self-gravitation, we produce the first self-consistent evaluation of Io's tidal heating rate due to shearing, compaction, and Darcy flow. We find that Darcy dissipation can potentially exceed shear heating, but only for large (0.05 to 0.2) melt fractions, and if the grain size is large or melt viscosity ultra-low. Since grain sizes larger than 1cm are unlikely, this suggests that Darcy dissipation is secondary to shear dissipation. Compaction dissipation is maximised when the asthenosphere is highly resistive to isotropic stresses, but contributes at most 1% of Io's observed heating rate. This work represents a crucial step toward a self-consistent quantitative theory for the dynamics of Io's partially molten interior.
title Poro-viscoelastic tidal heating of Io
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2507.11266