000005172 001__ 5172
000005172 005__ 20210125152106.0
000005172 037__ $$aPOSTER-2021-0011
000005172 100__ $$aBeuthe, Mikael
000005172 245__ $$aMinimum stress isostasy with Love
000005172 260__ $$c2020
000005172 269__ $$c2020-12-01
000005172 500__ $$aPoster P081-0010
000005172 520__ $$aThe outer shape and gravity field are not sufficient to constrain the interior of icy moons and dwarf planets unless they are supplemented by a mechanical model of the interior such as isostatic equilibrium. Classical isostasy, however, is not self-consistent, neglects internal stresses and geoid contributions to topographical support, and yields ambiguous predictions of geoid anomalies. A more correct theory of isostasy can be defined instead by minimizing deviatoric elastic stresses within the crust, as proposed a long time ago by Harold Jeffreys. This idea is best implemented in the ‘Isostasy with Love’ framework, which formulates isostasy as the simultaneous response - fully described by Love numbers - of an elastic or viscoelastic shell to top and bottom loads. The minimum stress constraint can be combined with different boundary conditions resulting in a 1-parameter isostatic family. Minimum Stress Isostasy is dual to Zero-Deflection Isostasy (elastic isostasy with zero radial deforma- tion), in the sense that their isostatic family parameters are in one-to-one correspondence. Zero-Deflection Isostasy is in turn equivalent to viscous or viscoelastic isostasy with sta- tionary boundary conditions (Stokes-Rayleigh analogy). Thus, Minimum Stress Isostasy is identical to time-independent viscous isostasy, whereas time-dependent viscous isostasy results in slightly different predictions of geoid anomalies. The elastic-viscous equivalence shows that choosing the right boundary conditions matters more than choosing an elastic, viscoelastic, or viscous approach. Nevertheless, the influence of boundary conditions dis- appears in the thin shell limit as all approaches yield the same isostatic ratios. If the shell is homogeneous and incompressible, isostatic ratios (shape ratio, compensation factor, etc) can be obtained as analytical formulas in all isostatic models.
000005172 536__ $$aPRODEX program managed by ESA and BELSPO/$$cPRODEX program managed by ESA and BELSPO/$$fPRODEX program managed by ESA and BELSPO
000005172 594__ $$aNO
000005172 773__ $$tAmerican Geophysical Union Fall Meeting, virtual meeting held online
000005172 8560_ $$fmikael.beuthe@observatoire.be
000005172 85642 $$ahttps://agu.confex.com/agu/fm20/webprogram/Paper661315.html
000005172 980__ $$aCPOSTER