@article {ashraf_high-resolution_2025,
	title = {A High-Resolution 3-D P-Wave Velocity Structure of the South-Central Cascadia Subduction Zone From Wide-Angle Shore-Crossing Seismic Refraction Data},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {130},
	number = {2},
	year = {2025},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2024JB029525},
	pages = {e2024JB029525},
	abstract = {Abstract This study addresses a significant gap in understanding the features of the south-central Cascadia subduction zone, a region characterized by complex geologic, tectonic, and seismic transitions both offshore and onshore. Unlike other segments along this margin, this area lacks a 3-D velocity model to delineate its structural and geological features on a fine scale. To address this void, we developed a high-resolution 3-D P-wave velocity model using active source seismic data from ship-borne seismic shots recorded on temporary and permanent onshore seismic stations and ocean-bottom seismometers. Our model shows velocity variations across the region with distinct velocity-depth profiles for the Siletz, Franciscan, and Klamath terranes in the overlying plate. We identified seaward dipping high-velocity static backstops associated with the Siletz and Klamath terranes, situated near the shoreline and further inland, respectively. Regions of reduced crustal velocity are associated with crustal faults. Moreover, there is significant along-strike depth variation in the subducting slab, which is about 4 km deeper near the thick, dense Siletz terrane and becomes shallower near the predominantly less-dense Franciscan terrane. This highlights a sudden tectonic and geologic transition at the southern boundary of the Siletz terrane. Our velocity model also indicates slightly increased hydration, though still minimal, in both the oceanic crust and the upper mantle of the subducting plate compared to other parts of the margin.},
	doi = {https://doi.org/10.1029/2024JB029525},
	author = {Ashraf, Asif and Hooft, Emilie E. E. and Toomey, Douglas R. and Tr{\'e}hu, Anne M. and Nolan, Sarah and Wirth, Erin A. and Ward, Kevin M.}
}
@article {atkins_hydroacoustic_2024,
	title = {Hydroacoustic Evidence for Offshore Lava Emplacement During the 2018 Kilauea Eruption},
	journal = {Geophysical Research Letters},
	volume = {51},
	number = {20},
	year = {2024},
	note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2024GL110885},
	month = {10/2024},
	pages = {e2024GL110885},
	abstract = {During the 2018 Kilauea eruption, over half the erupted lava was deposited on the seafloor. Lava flows crossing the shoreline generated sounds that were recorded by a network of hydrophones. We show that short-duration, broadband signals associated with lava-water interactions occurred throughout the eruption but increased in number when the Ahalanui ocean entry initiated on July 11. These terminated in early August coincident with the eruption{\textquoteright}s end. We compare hydroacoustic data with transmission loss models and eruption photographs to show that coastal explosive activity was poorly recorded by the hydrophone network. Similarly, strong hydroacoustic signals did not correlate with observed activity. These results suggest that acoustic signals were generated by lava flowing up to 100 s of meters offshore. Offshore lava flows can be hazardous to boaters, but hydrophones provide a means by which these hazards can be detected.},
	keywords = {hydrophone, hydrovolcanic, Kilauea, lava-water interaction},
	issn = {1944-8007},
	doi = {10.1029/2024GL110885},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2024GL110885},
	author = {Atkins, C. and Costa, O. and Caplan-Auerbach, J.}
}
@article {jian_hydrothermal_2024,
	title = {Hydrothermal flow and serpentinization in oceanic core complexes controlled by mafic intrusions},
	journal = {Nature Geoscience},
	year = {2024},
	note = {Publisher: Nature Publishing Group},
	pages = {1{\textendash}6},
	abstract = {Deep-sea hydrothermal systems at slow/ultraslow-spreading mid-ocean ridges are often located within ultramafic rocks that are part of oceanic core complexes. These complexes contain lower-crustal and mantle sections exhumed due to detachment faulting. Hydrothermal circulation in these environments leads to massive sulfide deposits, hydration of oceanic lithosphere and conditions resembling early Earth{\textquoteright}s life origin. However, the relationship between hydrothermal pathways in these environments and crustal and mantle lithologies, faulting, magmatism, serpentinization and alteration is poorly understood. Here we present seismic models of a Mid-Atlantic Ridge core complex and its ultramafic-hosted hydrothermal system derived from full waveform inversion of controlled-source seismic data and from local earthquake tomography. The models and derived rock properties reveal high-permeability channels within serpentinized peridotite along the flanks of the core complex. These channels converge beneath active and fossil hydrothermal fields and are diverted around mechanically strong, impermeable shallow mafic intrusions (2{\textendash}3 km wide, \textasciitilde1 km thick), causing hydrothermal outflow and the formation of massive sulfide deposits around the intrusions{\textquoteright} edges. These mafic intrusions also act as lids that limit fluid downflow{\textemdash}and thus serpentinization{\textemdash}in the centre of the core complex. Our results demonstrate that hydrothermal flow in ultramafic settings is controlled by lithology contacts, with mafic intrusions modulating hydrothermal pathways and extent of mantle serpentinization at depth.},
	keywords = {3706 Geophysics, Economic geology, Element cycles, Geodynamics, Tectonics},
	issn = {1752-0908},
	doi = {10.1038/s41561-024-01444-y},
	url = {https://www.nature.com/articles/s41561-024-01444-y},
	author = {Jian, Hanchao and Canales, J. Pablo and Dunn, Robert and Nedimovi{\'c}, Mladen R.}
}
@article {banerjee_hydrovolcanic_2023,
	title = {Hydrovolcanic Explosions at the Lava Ocean Entry of the 2018 Kilauea Eruption Recorded by Ocean-Bottom Seismometers},
	journal = {Seismological Research Letters},
	year = {2023},
	month = {mar},
	abstract = {From the beginning of May 2018, the Kilauea Volcano on the island of Hawaii experienced its largest eruption in 200~yr followed by a period of unrest for months. Because hot molten lava entered the ocean from the ocean-entry point near the lower East Rift Zone, the lava{\textendash}water interaction led to explosions. Some explosions were near the water surface and ejected fragments of lava, also known as lava bombs. In the early morning on 16 July 2018, one of those lava bombs, which was almost the size of a basketball, hit a sightseeing boat and injured 23 people. In this study, we analyzed the hydrophone data recorded from July to mid-September by ocean-bottom seismometers (OBSs) deployed offshore near the ocean entry point to identify and locate the hydroacoustic signals of the lava{\textendash}water explosions. Acoustic signals of hydrovolcanic explosions are characterized by a short duration (less than a few seconds) and a broad frequency range (at least up to 100~Hz). To automate event detection, a short-term average versus long-term average method was applied to the complete dataset. Approximately 4300 events were detected and located near the coastline and further used to prepare a catalog. The distribution of the lava{\textendash}water explosions is consistent with the pattern of the offshore lava delta formed during the 2018 eruption. Identifying such hydroacoustic signals recorded by OBSs may provide new avenues of research using various seismoacoustic events associated with volcanic eruptions.},
	issn = {0895-0695},
	doi = {10.1785/0220220195},
	url = {https://doi.org/10.1785/0220220195},
	author = {Banerjee, Puja and Shen, Yang}
}
@article {wei_high_2020,
	title = {High Bulk and Shear Attenuation Due to Partial Melt in the Tonga-Lau Back-arc Mantle},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {125},
	number = {1},
	year = {2020},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2019JB017527},
	pages = {e2019JB017527},
	abstract = {Seismic attenuation measures energy loss during seismic wave propagation and quantifies the relaxation of rocks{\textquoteright} elastic moduli. Abundant seismic studies have observed shear attenuation, but few have quantified bulk attenuation (bulk modulus relaxation), and these studies controversially locate finite bulk attenuation in different parts of the Earth, from the asthenosphere to the inner core. Here we present conclusive evidence localizing bulk attenuation to a specific region of the uppermost mantle. By analyzing amplitude spectral decay of P and S waves from Tonga earthquakes recorded at local seismic stations, we observe unusually low QP/QS ratios (<1.5) in the Tonga-Lau mantle wedge. All seismic raypaths with significant path-average bulk attenuation (Qκ-1 > 0.01 or Qκ < 100) are confined to the region immediately beneath the Lau back-arc spreading centers west of the Tonga Arc. Tomography results show that the highest bulk attenuation (Qκ-1 = 0.037 {\textpm} 0.008 or Qκ = 27.0 {\textpm} 0.2) is about 75\% of the in situ shear attenuation. The observed high bulk attenuation anomalies coincide with an inferred zone of partial melting, suggesting that the causative mechanism involves either infinitesimal movement of melt through pores or changes in melt fraction in response to seismic waves.},
	keywords = {bulk attenuation, Lau back-arc basin, mantle partial melting, QP/QS ratio, Tonga subduction zone},
	issn = {2169-9356},
	doi = {10.1029/2019JB017527},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2019JB017527},
	author = {Wei, S. Shawn and Wiens, Douglas A.}
}
@article {Russell2019,
	title = {High-Resolution Constraints on Pacific Upper Mantle Petrofabric Inferred From Surface-Wave Anisotropy},
	journal = {Journal of Geophysical Research: Solid Earth},
	volume = {124},
	number = {1},
	year = {2019},
	month = {jan},
	pages = {631{\textendash}657},
	issn = {2169-9313},
	doi = {10.1029/2018JB016598},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2018JB016598},
	author = {Russell, Joshua B. and Gaherty, James B. and Lin, Pei-Ying Patty and Lizarralde, Daniel and Collins, John A. and Hirth, Greg and Evans, Rob L.}
}
@article {Eilon2017,
	title = {High seismic attenuation at a mid-ocean ridge reveals the distribution of deep melt},
	journal = {Science Advances},
	volume = {3},
	number = {5},
	year = {2017},
	month = {may},
	pages = {e1602829},
	issn = {2375-2548},
	doi = {10.1126/sciadv.1602829},
	url = {https://advances.sciencemag.org/lookup/doi/10.1126/sciadv.1602829},
	author = {Eilon, Zachary C. and Abers, Geoffrey A.}
}
@article {webb_high-resolution_2016,
	title = {High-Resolution Seafloor Absolute Pressure Gauge Measurements Using a Better Counting Method},
	journal = {Journal of Atmospheric and Oceanic Technology},
	volume = {33},
	number = {9},
	year = {2016},
	note = {Publisher: American Meteorological Society Section: Journal of Atmospheric and Oceanic Technology},
	month = {sep},
	pages = {1859{\textendash}1874},
	abstract = {Abstract Vibrating quartz force transducers are the critical component of most deep-sea pressure and depth gauges in use in oceanography, producing a frequency output that varies with pressure. Accurate and low drift pressure measurements can be obtained by precisely measuring this frequency. In most implementations, the frequency is determined by counting the number of cycles of a high-frequency standard oscillator occurring during a large number of cycles of the lower-frequency quartz force oscillator. Resolution is limited by the sampling interval (length of counting) and the frequency of the frequency standard. Alternative counting methods can provide significant (20{\textendash}40 dB) improvements in resolution at sampling rates above 1 Hz. Each counting method can be described as a different filter applied to the output of a counter of the frequency standard gated at each transition of the transducer quartz oscillator. Improvements in resolution can be understood as the result of minimizing the aliasing of higher-frequency counting noise into the spectrum below the Nyquist frequency. A simple multipole infinite impulse response (IIR) filter designed to limit spectral leakage of high-frequency noise minimizes the noise spectrum and thereby optimizes the resolution of the pressure output. The resultant noise spectrum rises as frequency squared above 1 Hz, independent of the sampling rate. At frequencies below 1 Hz, it is limited by noise in the electronics driving the force transducer quartz oscillator. Resolution increases with frequency of the frequency standard up to about 200 MHz, plateauing for higher frequencies due to other noise sources (likely electronic).},
	issn = {0739-0572, 1520-0426},
	doi = {10.1175/JTECH-D-15-0114.1},
	url = {https://journals.ametsoc.org/view/journals/atot/33/9/jtech-d-15-0114_1.xml},
	author = {Webb, Spahr C. and Nooner, Scott L.}
}
@article {Lin2016,
	title = {High-resolution seismic constraints on flow dynamics in the oceanic asthenosphere},
	journal = {Nature},
	volume = {535},
	number = {7613},
	year = {2016},
	month = {jul},
	pages = {538{\textendash}541},
	issn = {0028-0836},
	doi = {10.1038/nature18012},
	url = {http://www.nature.com/articles/nature18012},
	author = {Lin, Pei-Ying Patty and Gaherty, James B. and Jin, Ge and Collins, John A. and Lizarralde, Daniel and Evans, Rob. L. and Hirth, Greg}
}
