Detection of Seismic Events originating from Europa’s Silicate Interior:
Implications for constraining interior dynamics
Abstract
Here we explore the detection limits of a seismic event originating from
Europa’s silicate interior. Such an event could be used to constrain the
tectonic regime, rheology, and internal dynamics of Europa’s deep
interior. We use PlanetProfile to generate interior structure models of
Europa with ice shell ranging from 5-50 km in thickness. We then use the
models as inputs for AxiSEM and InstaSeis to generate a database of
seismograms. Realistic noise is added using the approach of Panning et
al. 2018. We show that a deep event (depth 155km) would produce seismic
signals 1/10- 1/75 the amplitude of shallow (depth 3km) events. Thinner
ice shells allow for more ground motion, and thus, a seismometer could
detect a smaller magnitude event than if the ice shell was thick. A Mw
3.5 could overcome background noise, but a Mw 4.5 or greater is
necessary to be detectable by even the most sensitive seismic
instrumentation. A Mw 5.0 or greater is likely needed to be seen by a
seismometer on Europa’s surface. Constraining deep seismicity would
allow for better constraints on the deep internal structure and dynamics
of Europa.