TIDAL HEATING ON IO AND EUROPA AND ITS IMPLICATIONS FOR PLANETARY GEOPHYSICS

Because of their size, the Galilean moons of Jupiter should not have sufficient latent energy from accretion to heat their interiors to the point of melting. However, the two closest moons, Io and Europa, both exhibit extensive volcanism on their surfaces. This volcanism most likely results from tidal flexing of the moons which leads to concentration of heat in the interiors. The source of this heat is, of course, mechanically different from melting by heat of accretion and this study seeks to create a model to determine if the rheology of the moons is affected by this difference. A model of a homogenous interior for each satellite is discussed and then models of concentric layers of published dimensions and physical properties is discussed. It is determined that the geothermal gradient of the moons is indeed different under a tidally heated system than it would be for a system heated principally by radioactive decay. The tidally generated temperatures calculated for the interiors are also several orders of magnitude greater than radiogenic temperatures. These thermal gradient also reaches high temperatures at fairly shallow depths, which has implications for the types of lava compositions that would form the volcanic diapirs on these satellites as well as for the interaction of water with Europa's mantle.