Estimates of Europa's ice shell thickness from elastically-supported topography

Abstract

The thickness of Europa's solid ice shell is uncertain, and has important implications for Europa's habitability and thermal history, and the design of future spacecraft missions. Here we obtain an estimate of the ice shell thickness from observations of a plateau SW of Cilix impact crater. Stereo topographic profiles suggest that the plateau is flexurally supported, with an effective elastic thickness te of 6+5-2 km. For a conductive temperature profile this te value implies a solid ice shell thickness of 15+20-9 km; if the shell is convecting, this estimate is lower bound. Combined with independent estimates, we infer a probable shell thickness of ~ 25 km. The shell thickness is likely to be uniform over the entire satellite.