Constraining the Thickness of the Conductive Portion of Europa's Ice Shell Using Sparse Radar Echoes

Abstract

AbstractIce penetrating radar sounding is the primary geophysical technique for imaging the subsurface of planetary ice shells and has the potential to directly detect the ice–ocean interface. However, many sounding measurements may lack laterally extensive features that would aid their physical interpretation. In this scenario, the detection of sparse echoes can also provide rich information on ice shell properties. To explore and demonstrate this possibility, we consider three cases of isolated radar signatures: pore‐curing, eutectic melt, and unattributed echoes. We show that through detection of unattributed sparse echoes, the thickness of the conductive portion of Europa's ice shell can be constrained. These constraints can be improved by attributing sparse echoes to thermally diagnostic signatures such as pore‐curing and eutectic melt. Notably, this approach to radar sounding echo analysis is particularly compatible with joint inversions with other planetary geophysical observations such as tidal deformation, magnetic induction, and rotation state.