BBOBS_Noise_Properties_Review

We present a new compilation and analysis of broadband ocean bottom
seismometer noise properties from 15 years of seismic deployments. We
compile a comprehensive dataset of representative four-component
(seismometer and pressure gauge) noise spectra and cross-spectral
properties (coherence, phase, and admittance) for 551 unique stations
spanning 18 US-led experiments. This is matched with a comprehensive
compilation of metadata parameters related to instrumentation and
environmental properties for each station. We systematically investigate
the similarity of noise spectra by grouping them according to these
metadata parameters to determine which factors are the most important in
determining noise characteristics. We find evidence for improvements in
similarity of noise properties when grouped across parameters, with
groupings by seismometer type and deployment water depth yielding the most
significant and interpretable results. Instrument design, that is the
entire deployed package, also plays an important role, although it
strongly covaries with seismometer and water depth. We assess the presence
of traditional sources of tilt, compliance, and microseismic noise to
characterize their relative role across a variety of commonly used seismic
frequency bands. We find that the presence of tilt noise is primarily
dependent on the type of seismometer used (covariant with a particular
subset of instrument design), that compliance noise follows anticipated
relationships with water depth, and that shallow, oceanic shelf
environments have systematically different microseism noise properties
(which are, in turn, different from instruments deployed in shallow lake
environments). These observations have important implications for the
viability of commonly used seismic analysis techniques. Finally, we
compare spectra and coherences before and after vertical channel tilt and
compliance noise removal to evaluate the efficacy and limitations of these
now standard processing techniques. These findings may assist in future
experiment planning and instrument development, and our newly compiled
noise dataset serves as a building block for more targeted future
investigations by the marine seismology community.