Global seismology in the interior of Enceladus

Enceladus is an astrobiologically compelling target for scientific study and is predicted to have high seismic activity for its size, particularly at its south pole. We conduct ray-theoretical and full-waveform seismic simulations for three 1D models of Enceladus to compare the effects of ice shell and ocean thickness, as well as core structure and composition, on the waveforms recorded by a single seismometer. The 1D models are constructed using self-consistent modelling techniques to enable direct comparisons between the wavefields of each model. We investigate phases sampling the ice, ocean, and core layers at up to 8 Hz, complementing previous studies focussed on lower-frequency phases concentrated in the ice shell. We conclude that even at low epicentral distances (< 30(degrees)) from a source at the south pole, core-transmitted and -reflected phases can likely both be observed, providing constraints on ocean depth and core structure. We further confirm that a high-attenuation scenario for the ice shell does not preclude the generation of seismic signals above mission-candidate instrument sensitivity thresholds, and in fact may serve to remove unwanted signals from seismograms.

Automated summary

This study investigates the effects of ice shell and ocean thickness, as well as core structure and composition, on the waveforms recorded by a single seismometer for three 1D models of Enceladus. The results suggest that core-transmitted and -reflected phases can be observed even at low epicentral distances, providing constraints on ocean depth and core structure.