Seismic Detection of Euroquakes Originating From Europa's Silicate Interior

Abstract

Detecting a seismic event from Europa's silicate interior would provide information about the geologic and tectonic setting of the moon's rocky interior. However, the subsurface ocean will attenuate the signal, possibly preventing the waveforms from being detected by a surface seismometer. Here, we investigate the minimum magnitude of a detectable event originating from Europa's silicate interior. We analyze likely signal-to-noise ratios and compare the predicted signal strengths to current instrument sensitivities. We show that a magnitude Mw ≥ 3.5 would be sufficient to overcome the predicted background noise when the ice shell is 5 km thick. However, a minimum magnitude of Mw ≥ 5.5 would be required for current instrumentation to be able detect the event for any ice shell thickness, at any distance. A thinner ice shell transmits greater ground acceleration amplitudes than a thicker ice shell, which might allow for Mw ≥ 4.5 to be detectable.