Seismic Detection of Euroquakes Originating From Europa's Silicate Interior. Issue 6 (8th June 2022)

• Record Type: Journal Article
• Authors: Marusiak, A. G.; Panning, M. P.; Vance, S. D.; Nunn, C.; Stähler, S. C.; Tharimena, S.
• Is Part Of: Earth and space science. Volume 9:Issue 6(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-06-08
• Subjects: seismology -- Europa; Space sciences -- Periodicals; Geophysics -- Periodicals; 500.5
• DOI: 10.1029/2021EA002041
• Languages: English
• ISSNs: 2333-5084

Abstract

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 M w ≥ 3.5 would be sufficient to overcome the predicted background noise when the ice shell is 5 km thick. However, a minimum magnitude of M w ≥ 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 M w ≥ 4.5 to be detectable. Plain Language Summary: Europa, one of Jupiter's moons, has an icy surface overlying a subsurface ocean and rocky interior. Europa's surface is likely geologically active and its rocky interior may also produce seismic events. Here, we investigate if data from a seismometer could detect and record signals originating from the rocky interior, thus allowing a science team to accurately determine if the interior is also geologically active. We compare the resulting ground motion from a deep event to predicted background noise and instrument capabilities. We find that an event with a magnitude of at least a 3.5 would overcome background noise. However, current instrumentation would require an event of at least a magnitude 5.5 to be detectable from anywhere on Europa's surface. If such an event were to occur, we could use the recorded signal from a seismometer on Europa's surface to constrain the near‐surface and deep interior structure, and also to study the geologic setting and activity of the rocky interior. Key Points: Seismic events from Europa's silicate interior could reveal interior composition and structure The subsurface ocean will likely dampen events and filter out shear waves A euroquake will likely need to be over a M w 5.0 to be detectable by current seismic instrumentation