Abstract
Planetary seismology has significantly developed our understanding of Earth,the Moon, and Mars through its ability to discern deep interior structure and give
insights into planetary formation and evolution. Seismic missions are now planned
and proposed to icy ocean worlds including Titan, Enceladus, and Europa. These
are compelling candidates for hosting life as their liquid water subsurface oceans
interact with silicate cores, drawing comparison with hydrothermal vents on Earth
where life may have originated. Mapping the ocean/core boundary and constraining
the material properties of the core are therefore priorities in the exploration of
these worlds.
However, common seismic inversion procedures and assumptions developed for
terrestrial bodies are unreliable for icy moons. Understanding their seismic response
can help predict the opportunities and challenges afforded by their relatively
unfamiliar seismic structures.
Taking advantage of recent advancements in computational seismology, we use ray
theoretical and full-waveform modelling to investigate the global seismic wavefield
of Enceladus. We construct a set of structural models including seismic parameters
such as density, velocity, and attenuation, encompassing the breadth of proposed
present-day interiors arising from different formation and evolution pathways. We
examine and discuss the seismic wavefield produced by generalised one-dimensional
seismic models before expanding our research to include two- and three-dimensional
structures.
We find that seismic phases transiting all major internal layers may be recorded
by a modern seismometer on the surface, with predicted amplitudes exceeding
anticipated noise levels and instrument detection thresholds. This result is found
to be affected by the three-dimensional structure of the ice shell, resulting in
advantageous landing sites close to the south pole. This thesis constitutes a
significant advancement in our understanding of parameters affecting the success
of a seismic mission to Enceladus, which can be built upon to develop models for
other icy bodies and inform future mission design.
| Date of Award | 10 Dec 2024 |
|---|---|
| Original language | English |
| Awarding Institution |
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| Supervisor | Jessica C E Irving (Supervisor) & Nicholas A Teanby (Supervisor) |