@article {lindner_bayesian_2023,
	title = {Bayesian regional moment tensor from ocean bottom seismograms recorded in the Lesser Antilles: implications for regional stress field},
	journal = {Geophysical Journal International},
	volume = {233},
	number = {2},
	year = {2023},
	month = {12/2022},
	pages = {1036{\textendash}1054},
	abstract = {Seismic activity in the Lesser Antilles (LA) is characterized by strong regional variability along the arc reflecting the complex subduction setting and history. Although routine seismicity monitoring can rely on an increasing number of island stations, the island-arc setting means that high-resolution monitoring and detailed studies of fault structures require a network of ocean bottom seismometers (OBS). As part of the 2016{\textendash}2017 Volatile recycling at the Lesser Antilles arc (VoiLA) project, we deployed 34 OBS stations in the forearc and backarc. During the deployment time, 381 events were recorded within the subduction zone. In this paper, we perform full-waveform regional moment tensor (RMT) inversions, to gain insight into the stress distribution along the arc and at depth. We developed a novel inversion approach, AmΦB{\textemdash}{\textquoteleft}Amphibious Bayesian{\textquoteright}, taking into account uncertainties associated with OBS deployments. Particularly, the orientation of horizontal components (alignment uncertainty) and the high noise level on them due to ocean microseisms are accounted for using AmΦB. The inversion is conducted using a direct, uniform importance sampling of the fault parameters within a multidimensional tree structure: the uniXtree-sampling algorithm. We show that the alignment of the horizontal OBS components, particularly in high noise level marine environments, influences the obtained source mechanism when using standard least-squares (L2) RMT inversion schemes, resulting in systematic errors in the recovered focal mechanisms including high artificial compensated linear vector dipole (CLVD) contributions. Our Bayesian formulation in AmΦB reduces these CLVD components by nearly 60~per~cent and the aberration of the focal geometry as measured by the Kagan angle by around 40~per~cent relative to a standard L2 inversion. Subsequently, we use AmΦB-RMT to obtain 45 (Mw \&gt; 3.8) regional MT solutions, out of which 39 are new to any existing database. Combining our new results with existing solutions, we subsequently analyse a total of 151 solutions in a focal mechanism classification (FMC) diagram and map them to the regional tectonic setting. We also use our newly compiled RMT database to perform stress tensor inversions along the LA subduction zone. On the plate interface, we observe the typical compressional stress regime of a subduction zone and find evidence for upper-plate strike slip and normal fault behaviour in the north that becomes a near arc-perpendicular extensional stress regime towards the south. A dominant slab perpendicular extensional stress regime is found in the slab at 100{\textendash}200~km beneath the central part of the arc. We interpret this stress condition to be a result of slab pull varying along the arc due to partial slab detachment along previously hypothesized lateral slab tear near Grenada, at the southern end of the LA arc, leading to reactivation of pre-existing structures around the subducted Proto-Caribbean ridge.},
	issn = {0956-540X},
	doi = {10.1093/gji/ggac494},
	url = {https://doi.org/10.1093/gji/ggac494},
	author = {Lindner, Mike and Rietbrock, Andreas and Bie, Lidong and Goes, Saskia and Collier, Jenny and Rychert, Catherine and Harmon, Nicholas and Hicks, Stephen P and Henstock, Tim and the VoiLA working group}
}
@article {janiszewski_broad-band_2023,
	title = {Broad-band ocean bottom seismometer noise properties},
	journal = {Geophysical Journal International},
	volume = {233},
	number = {1},
	year = {2022},
	month = {11/2022},
	pages = {297{\textendash}315},
	abstract = {We present a new compilation and analysis of broad-band ocean bottom seismometer noise properties from 15 yr of seismic deployments. We compile a comprehensive data set of representative four-component (seismometer and pressure gauge) noise spectra and cross-spectral properties (coherence, phase and admittance) for 551 unique stations spanning 18 U.S.-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 data set serves as a building block for more targeted future investigations by the marine seismology community.},
	issn = {0956-540X},
	doi = {10.1093/gji/ggac450},
	url = {https://doi.org/10.1093/gji/ggac450},
	author = {Janiszewski, Helen A and Eilon, Z and Russell, J B and Brunsvik, B and Gaherty, J B and Mosher, S G and Hawley, W B and Coats, S}
}
@article {113,
	title = {Body Wave Tomography of the Cascadia Subduction Zone and Juan de Fuca Plate System: Identifying Challenges and Solutions for Shore-Crossing Data},
	journal = {Geochemistry Geophysics Geosystems},
	volume = {21},
	year = {2020},
	type = {Journal Article},
	abstract = {Recent seismic results from the Cascadia Initiative indicate that heterogeneity in the oceanic asthenosphere affects subduction dynamics. Accurate characterization of the oceanic upper mantle is thus necessary to fully understand subduction processes, including the behavioral segmentation of the megathrust. A key challenge is integrating onshore and offshore datasets, which span large variations in near-surface features that teleseismic body wave tomography is ill-posed to resolve. Here, we perform a series of P and S forward modeling predictions to better understand the relative contribution of elevation, crustal thickness, offshore sedimentation, and near-surface velocity structure to teleseismic delay times. Crustal thickness and elevation variations dominate the signal, contributing \~{}1 s of delay time difference for P-waves (roughly double for S). We test several inversion strategies to account for near-surface features, identifying potential artifacts and causes of imaging errors. Undamped station statics are found to absorb mantle structures and introduce low-velocity artifacts beneath the forearc. Our preferred inversion strategy utilizes a three-dimensional starting model (including elevation) of the upper 50 km and heavily damped station statics, which we find leads to better resolution of mantle structure, particularly at asthenospheric depths. These insights guide inversions of observed delay times from the Cascadia subduction zone and Juan de Fuca plate system. We present a new onshore-offshore S model and an updated P model. Major features are common to both models, including localized subslab low-velocity anomalies, along-strike variations in slab structure, and offshore heterogeneity, while regional differences may reflect changes in Vp/Vs.},
	doi = {10.1029/2020gc009316},
	url = {https://app.dimensions.ai/details/publication/pub.1132665170},
	author = {Bodmer, M. and Toomey, D. R. and VanderBeek, B. and Hooft, E. E. and Byrnes, J. S.}
}
@article {Bodmer2018,
	title = {Buoyant Asthenosphere Beneath Cascadia Influences Megathrust Segmentation},
	journal = {Geophysical Research Letters},
	volume = {45},
	number = {14},
	year = {2018},
	month = {jul},
	pages = {6954{\textendash}6962},
	issn = {0094-8276},
	doi = {10.1029/2018GL078700},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2018GL078700},
	author = {Bodmer, Miles and Toomey, Douglas R. and Hooft, Emilie E. E. and Schmandt, Brandon}
}
