Long-period seismology on Europa
References (click for pdf)
Summary
NASA image of Europa from Wikipedia
Europa, one of the Galilean moons of Jupiter, is of great interest to the planetary community, primarily due to evidence of an extensive liquid water ocean below the outer ice shell. Determining the thickness of that ice shell can be accomplished using seismological observations, perhaps even from orbit.
Vertical component seismograms for different ice shell thicknesses and for a model with no liquid ocean.
In order to explore the importance of long period data (periods from 10 to 1000 seconds) in constraining this and deeper structure, we first determined a range of thermodynamically self-consistent models (Paper I published in JGR Planets). These models were then used to predict the seismic response using a normal modes summation method (Paper II).
We conclude that the Rayleigh wave group velocity dispersion, which is marked by a characteristic transition to a flexural mode which depends on ice shell thickness in this frequency band, may be used to determine the ice shell thickness even if the tectonic event can not be located.
