2:30 PM - 2:45 PM
[PPS01-16] Beyond InSight - Seismological Exploration of Ocean Worlds
Keywords:Seismology, Icy ocean worlds, Europa
Plans for a proposed NASA Europa Lander include a seismometer, which could operate for more than 20 days on the surface. Together with gravity and magnetometry studies from the JUICE and NASA's Europa Mission, the seismometer would allow measurements of the radial depths of compositional interfaces in the ice, the ocean and the deeper interior. We present estimations of Europa's seismic wavefield using state-of-the-art finite-element simulations, taking into account seismic sources from tidal ice cracking as well as ocean circulation, building on prior studies (Kovach and Chyba 2001, Lee et al. 2003, Cammarano et al. 2006, Panning et al. 2006, Leighton et al. 2008) .
The results show that determination of the ice thickness, the ocean depth and the thickness of a sediment layer on the ocean bottom would be possible with performances comparable to those of an evolution of the InSight SP instrument, as proposed in the recent report of the NASA Science Definition Team.
We will also describe preliminary analyses of other ocean worlds, Enceladus, Titan, Ganymede, and Callisto, where seismic investigations may address unique science questions about their structure, composition, and possible habitability through time. Seismology may provide information about fluid motions within or beneath ice, and can record the dynamics of ice layers, which would reveal mechanisms and spatiotemporal occurrence of crack formation and propagation. Investigating these structures and processes in the future calls for detailed modeling of seismic sources and signatures, building on observations in terrestrial cryoseismology (Zhan et al. 2014, Podolskiy & Walter 2016) in order to develop the most suitable instrumentation.
Kovach, R. L., & Chyba, C. F. (2001). Seismic Detectability of a Subsurface Ocean on Europa. Icarus, 150(2), 279–287. https://doi.org/10.1006/icar.2000.6577
Lee, S., Zanolin, M., Thode, A. M., Pappalardo, R. T., & Makris, N. C. (2003). Probing Europa’s interior with natural sound sources. Icarus, 165, 144–167. https://doi.org/10.1016/S0019-1035(03)00150-7
Cammarano, F., Lekic, V., Manga, M., Panning, M. P., & Romanowicz, B. (2006). Long-period seismology on Europa: 1. Physically consistent interior models. Journal of Geophysical Research, 111(E12), E12009. https://doi.org/10.1029/2006JE002710
Panning, M. P., Lekic, V., Manga, M., Cammarano, F., & Romanowicz, B. (2006). Long-period seismology on Europa: 2. Predicted seismic response. Journal of Geophysical Research, 111(E12), E12008. https://doi.org/10.1029/2006JE002712
Leighton, T. G., & Petculescu, A. (2008). Hydroacoustics Sounds in Space : the Potential Uses for Acoustics in the Exploration of Other Worlds. Hydroacoustics, 11, 225–238.
Zhan, Z., Tsai, V. C., Jackson, J. M., & Helmberger, D. (2014). Ambient noise correlation on the amery ice shelf, east Antarctica. Geophysical Journal International, 196(3), 1796–1802. https://doi.org/10.1093/gji/ggt488
Podolskiy, E. A., & Walter, F. (2016). Cryoseismology. Reviews of Geophysics, S4. https://doi.org/10.1002/2016RG000526