36th DPS Meeting, 8-12 November 2004
Session 16 Jovian System
Poster I, Tuesday, November 9, 2004, 4:00-7:00pm, Exhibition Hall 1A

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[16.14] Tidal Stress Patterns’ Dependence on Crustal Thickness: Application to Europa

T.A. Hurford, R. Greenberg (University of Arizona)

On Europa, tidal stresses computed with a thin-shell model have been used successfully to explain many characteristics of the tectonic features observed (Greenberg \emph{et al.}1998 \emph{Icarus} \textbf{135}:64-78; Greenberg and Geissler 2002, \emph{Meteoritics and Planetary Science} \textbf{37}:1685-1710 ). The model assumes a thin deformed elastic outer layer, which is decoupled from the deeper interior of the body by a thick fluid layer. For example, using this model, cycloidal crack formation can be reproduced by tracking crack propagation as the diurnally varying tidal stresses exceeded the tensile strength of the surface ice (Hoppa \emph{et al.}1999 \emph{Science} \textbf{285}:1899-1902). We have now developed a general multi-layered analytical model of tidal deformation that allows us to compute stresses throughout a model planet. Here we apply it to a model of an elastic crust of variable thickness over a fluid interior in order to explore how stress patterns change as a function of thickness of the crust. In principle, such information may allow us to consider in more detail what the crack patterns on Europa may mean regarding interior structure. Our generalized analytical model of tidal deformation and stress may provide a useful tool for exploring the implications of tectonic structures on other planetary surfaces as well. In thicker ice shells, the overall stresses are reduced which could limit cracking. As the crustal thickness approaches 100 km, stress regimes change qualitatively.

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Bulletin of the American Astronomical Society, 36 #4
© 2004. The American Astronomical Soceity.