@article {doran_calibration_2019, title = {Calibration of Differential Pressure Gauges Through In Situ Testing}, journal = {Earth and Space Science}, volume = {6}, number = {12}, year = {2019}, note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2019EA000783}, pages = {2663{\textendash}2670}, abstract = {Differential pressure gauges (DPGs) are a standard component of modern broadband ocean-bottom seismometer instruments and have proven useful for observing a wide range of seismic and oceanographic phenomena. However, the response function of the DPG remains poorly known, limiting our ability to recover amplitude and phase information from seafloor pressure signals with high fidelity. The sensitivity and long-period response are difficult to calibrate in the lab, as they are known to vary with temperature and pressure and perhaps between sensors of the same design. We present the results of a field experiment designed to determine empirical response functions in situ by inducing a pre-defined pressure offset on a deployed instrument. The results compare favorably with calibrations estimated independently through post-deployment data analyses. Our study demonstrates that observed response functions can deviate from the nominal response by a factor of two or greater with regards to both the sensitivity and the time constant. Incorporating calibration devices such as those described here into future deployments may prove to be a cost-effective way to improve the accuracy and utility of differential pressure data.}, issn = {2333-5084}, doi = {10.1029/2019EA000783}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2019EA000783}, author = {Doran, A.k. and Rapa, M. and Laske, G. and Babcock, J. and McPeak, S.} } @article {doran_seismic_2019, title = {Seismic Structure of Marine Sediments and Upper Oceanic Crust Surrounding Hawaii}, journal = {Journal of Geophysical Research: Solid Earth}, volume = {124}, number = {2}, year = {2019}, note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2018JB016548}, pages = {2038{\textendash}2056}, abstract = {We present models of compressional and shear velocity structure of the oceanic sediments and upper crust surrounding the Hawaiian islands. The models were derived from analysis of seafloor compliance data and measurements of Ps converted phases originating at the sediment-bedrock interface. These data were estimated from continuous broadband ocean bottom seismometer acceleration and pressure records collected during the Plume-Lithosphere Undersea Mantle Experiment, an amphibious array of wideband and broadband instruments with an aperture of over 1,000 km. Our images result from a joint inversion of compliance and Ps delay data using a nonlinear inversion scheme whereby deviation from a priori constraints is minimized. In our final model, sediment thickness increases from 50 m at distal sites to over 1.5 km immediately adjacent to the islands. The sedimentary shear velocity profiles exhibit large regional variations. While sedimentary structure accounts for the majority of the compliance signal, we infer variations in shear velocity in the uppermost bedrock on the order of {\textpm}5\%. We also require relatively high values of Poisson{\textquoteright}s ratio in the uppermost crust. Lower crustal velocities are generally seen to the north and west of the islands but do not appear well correlated with the Hawaiian Swell bathymetry. A region of strong low velocity anomalies to the northeast of Hawaii may be associated with the Molokai fracture zone.}, issn = {2169-9356}, doi = {10.1029/2018JB016548}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2018JB016548}, author = {Doran, A. K. and Laske, G.} } @article {Berger2016, title = {An ocean bottom seismic observatory with near real-time telemetry}, journal = {Earth and Space Science}, volume = {3}, number = {2}, year = {2016}, month = {feb}, pages = {68{\textendash}77}, issn = {2333-5084}, doi = {10.1002/2015EA000137}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/2015EA000137}, author = {Berger, J. and Laske, G. and Babcock, J. and Orcutt, J.} }