@article{wall_bohnenstiehl_levine_millhauser_mcgill_wegmann_melomo_2023, title={A geospatial and archaeological investigation of an African-American cemetery in Raleigh, North Carolina, USA}, volume={12}, ISSN={["1099-0763"]}, DOI={10.1002/arp.1921}, abstractNote={Abstract}, journal={ARCHAEOLOGICAL PROSPECTION}, author={Wall, John and Bohnenstiehl, DelWayne R. and Levine, Norman S. and Millhauser, John K. and Mcgill, Dru E. and Wegmann, Karl W. and Melomo, Vincent}, year={2023}, month={Dec} }
 @article{bohnenstiehl_2023, title={Automated cataloging of oyster toadfish (Opsanus tau) boatwhistle calls using template matching and machine learning}, volume={77}, ISSN={["1878-0512"]}, DOI={10.1016/j.ecoinf.2023.102268}, abstractNote={Oyster toadfish (Opsanus tau) represent an ecologically significant species found throughout estuaries along the eastern coast of the United States. While these crevice-dwelling fish can be challenging to observe in their habitats, it is possible to infer their distribution and aspects of their behavior by recording the sounds they produce. The task of cataloging the distinctive advertisement boatwhistle sounds produced by male toadfish to attract females throughout the spring and summer is automated using a multi-step process. Candidate boatwhistles are first identified by template matching using a suite of synthetic spectrogram kernels formed to mimic the two lowest frequency harmonic tones within the boatwhistle. Candidate boatwhistle calls are identified based on the correlation between these kernels and a low-frequency spectrogram of the data. Next, frequency-reassigned spectrogram images of these candidates are formed and input into the pre-trained ResNet-50 convolutional neural network. Finally, the activations from a deep, fully connected layer within this network are extracted and passed to a one-vs-all support-vector-machine classifier, which separates boatwhistles from the larger set of candidate signals. This classifier model was trained and evaluated using a labeled dataset of over 20,000 candidate signals generated over diverse acoustic conditions within Pamlico Sound, North Carolina, USA. The accompanying software provides an effective and efficient tool to monitor boatwhistle calls, which may facilitate a deeper understanding of the spatial distribution, behavioral patterns, and ecological roles played by oyster toadfish.}, journal={ECOLOGICAL INFORMATICS}, author={Bohnenstiehl, DelWayne R.}, year={2023}, month={Nov} }
 @article{bohnenstiehl_2023, title={Automated cataloguing of American silver perch (Bairdiella chrysoura) calls using machine learning}, ISSN={["2165-0586"]}, DOI={10.1080/09524622.2023.2197863}, abstractNote={ABSTRACT The American silver perch (Bairdiella chrysoura) is a numerically dominant and ecologically important species found throughout coastal habitats along the eastern United States and Gulf of Mexico. During spawning in the spring and summer, male silver perch produce distinctive knocking sounds to attract females. These sounds are readily identifiable through aural and visual analysis of underwater acoustic recordings, providing a means to track the distribution and spawning activity of these fish. However, as the volume of passive acoustic datasets grows, there is an essential need to automate the process of cataloguing silver perch vocalisations. The approach presented here utilises a (1) detection stage, where candidate calls are identified based on the properties of signal kurtosis and signal-to-noise ratio, (2) a feature extraction stage where layer activations are returned from the pre-trained ResNet-50 convolutional neural network operating on a wavelet scalogram of these signals, and (3) a one-vs-all support-vector-machine classifier. The labelled data used to build the classifier consists of 6000 perch calls and 6000 other signals that sample diverse acoustic conditions within the Pamlico Sound estuary, USA. The model accuracy is 98.9%, and the accompanying software provides an efficient tool to investigate silver perch calling patterns within passive acoustic data.}, journal={BIOACOUSTICS-THE INTERNATIONAL JOURNAL OF ANIMAL SOUND AND ITS RECORDING}, author={Bohnenstiehl, DelWayne R. R.}, year={2023}, month={Apr} }
 @article{atkins_byrne_bohnenstiehl_wegmann_2022, title={A Morphometric Investigation of Large-Scale Crustal Shortening on Mars}, volume={127}, ISSN={["2169-9100"]}, url={https://doi.org/10.1029/2021JE007110}, DOI={10.1029/2021JE007110}, abstractNote={Abstract}, number={5}, journal={JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS}, publisher={American Geophysical Union (AGU)}, author={Atkins, R. M. and Byrne, P. K. and Bohnenstiehl, D. R. and Wegmann, K. W.}, year={2022}, month={May} }
 @article{atkins_wegmann_bohnenstiehl_2022, title={Channel head response to anthropogenic landscape modification: A case study from the North Carolina Piedmont, USA, with implications for water quality}, volume={48}, ISSN={0197-9337 1096-9837}, url={http://dx.doi.org/10.1002/esp.5495}, DOI={10.1002/esp.5495}, abstractNote={Abstract}, number={2}, journal={Earth Surface Processes and Landforms}, publisher={Wiley}, author={Atkins, Rachel M. and Wegmann, Karl W. and Bohnenstiehl, Del Wayne R.}, year={2022}, month={Oct}, pages={433–451} }
 @article{dziak_copeland_sirovic_bohnenstiehl_opzeeland_2022, title={Editorial: Innovation and Discoveries in Marine Soundscape Research}, volume={9}, ISSN={["2296-7745"]}, DOI={10.3389/fmars.2022.879051}, abstractNote={National Oceanic and Atmospheric Administration (NOAA), Pacific Marine Environmental Laboratory, Newport, OR, United States, National Oceanic and Atmospheric Administration (NOAA), Ocean Exploration, Silver Spring, MD, United States, Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway, North Carolina State University, Raleigh, NC, United States, 5 Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany}, journal={FRONTIERS IN MARINE SCIENCE}, author={Dziak, Robert P. and Copeland, Adrienne and Sirovic, Ana and Bohnenstiehl, DelWayne R. and Opzeeland, Ilse}, year={2022}, month={Mar} }
 @article{ricci_bohnenstiehl_2022, title={Monitoring visitation at North Carolina artificial reef sites using high spatiotemporal resolution PlanetScope imagery}, volume={55}, ISSN={["2352-4855"]}, url={http://dx.doi.org/10.1016/j.rsma.2022.102511}, DOI={10.1016/j.rsma.2022.102511}, abstractNote={Historically, the recreational use of reefs has been assessed through on-water observations, which often provide limited spatiotemporal coverage, and boater interviews, which may have low response rates. To overcome these limitations, an object detection model was trained and deployed to identify small boats within high resolution (∼3 m/pixel) PlanetScope imagery at four North Carolina offshore artificial reefs during 2019. The resulting visitation time series consisted of 1319 stationary and 201 underway vessels detections. This is ∼12 times the number of visitations reported during 2019 from the Marine Recreational Information Program (MRIP) boat-ramp interviews and ∼20 times the number captured using Automatic Identification System (AIS) vessel-tracking data. Although the MRIP surveys do not report any visitations during the winter months, imagery-based detections show that the use of these reefs extends throughout the winter. Detections also show steady use of the sites on weekends, whereas the MRIP interviews indicate relatively fewer visitors on Sundays. Imagery-based detections and MRIP results show AR-315 to be the most visited reef. However, whereas the MRIP results indicate limited use of the other sites, the imagery-based visitation shows that AR-370 and AR-425 reefs are visited nearly as often, with AR-160 being under-utilized relative to these sites. These comparisons show how the low survey response rate and sparsity of tracking beacons on small vessels may lead to a biased assessment of visitation patterns. The clustering of detections within sites highlights the relative popularity of different reef materials among users. Leveraging the growing availability of high spatiotemporal resolution satellite imagery, this automated framework can be used to detect boats around other areas and times of interest. Visitation information is essential in assessing the socioeconomic impacts of these reefs, and important in the design and maintenance of current and future reefs to support local coastal economies and recreation.}, journal={REGIONAL STUDIES IN MARINE SCIENCE}, publisher={Elsevier BV}, author={Ricci, Shannon W. and Bohnenstiehl, DelWayne R.}, year={2022}, month={Sep} }
 @article{simmons_bohnenstiehl_eggleston_2022, title={Spatiotemporal Variation in Coral Assemblages and Reef Habitat Complexity among Shallow Fore-Reef Sites in the Florida Keys National Marine Sanctuary}, volume={14}, ISSN={["1424-2818"]}, DOI={10.3390/d14030153}, abstractNote={With the unprecedented degradation and loss of coral reefs at multiple scales, the underlying changes in abiotic and biotic features relevant to the three-dimensional architecture of coral reefs are critical to conservation and restoration. This study characterized the spatiotemporal variation of habitat metrics at eight fore-reef sites representing three management zones in the Florida Keys, USA using visual habitat surveys (2017–2018) acquired before and after Hurricane Irma. Post-hurricane, five of those sites were surveyed using structure-from-motion photogrammetry to further investigate coral morphology on structural complexity. Multivariate results for visual surveys identified moderate separation among sites, with fished sites characterized by complex physical features such as depth and vertical hard relief while protected sites generally harbored high abundances of live coral cover. Three-dimensional models of mapped sites showed within site variation as another driver in site separation. Additionally, fine-scale orthoimage analyses identified significant differences in dominant coral morphologies at each mapped site. This study suggests protected reef sites generally harbor higher live coral cover despite some fished sites being structurally similar in seabed topography. Our work provides fine-scale spatial data on several managed sites within a marine sanctuary and highlights the contribution of diverse coral assemblages to the coral reef framework.}, number={3}, journal={DIVERSITY-BASEL}, author={Simmons, Kayelyn R. and Bohnenstiehl, DelWayne R. and Eggleston, David B.}, year={2022}, month={Mar} }
 @article{simmons_eggleston_bohnenstiehl_2021, title={Hurricane impacts on a coral reef soundscape}, volume={16}, ISSN={["1932-6203"]}, DOI={10.1371/journal.pone.0244599}, abstractNote={Soundscape ecology is an emerging field in both terrestrial and aquatic ecosystems, and provides a powerful approach for assessing habitat quality and the ecological response of sound-producing species to natural and anthropogenic perturbations. Little is known of how underwater soundscapes respond during and after severe episodic disturbances, such as hurricanes. This study addresses the impacts of Hurricane Irma on the coral reef soundscape at two spur-and-groove fore-reef sites within the Florida Keys USA, using passive acoustic data collected before and during the storm at Western Dry Rocks (WDR) and before, during and after the storm at Eastern Sambo (ESB). As the storm passed, the cumulative acoustic exposure near the seabed at these sites was comparable to a small vessel operating continuously overhead for 1–2 weeks. Before the storm, sound pressure levels (SPLs) showed a distinct pattern of low frequency diel variation and increased high frequency sound during crepuscular periods. The low frequency band was partitioned in two groups representative of soniferous reef fish, whereas the high frequency band represented snapping shrimp sound production. Daily daytime patterns in low-frequency sound production largely persisted in the weeks following the hurricane. Crepuscular sound production by snapping shrimp was maintained post-hurricane with only a small shift (~1.5dB) in the level of daytime vs nighttime sound production for this high frequency band. This study suggests that on short time scales, temporal patterns in the coral reef soundscape were relatively resilient to acoustic energy exposure during the storm, as well as changes in the benthic habitat and environmental conditions resulting from hurricane damage.}, number={2}, journal={PLOS ONE}, author={Simmons, Kayelyn R. and Eggleston, David B. and Bohnenstiehl, DelWayne R.}, year={2021}, month={Feb} }
 @article{van hoeck_paxton_bohnenstiehl_taylor_fodrie_peterson_2021, title={Passive acoustic monitoring complements traditional methods for assessing marine habitat enhancement outcomes}, volume={12}, ISSN={["2150-8925"]}, DOI={10.1002/ecs2.3840}, abstractNote={Abstract}, number={11}, journal={ECOSPHERE}, author={Van Hoeck, Rebecca V. and Paxton, Avery B. and Bohnenstiehl, DelWayne R. and Taylor, J. Christopher and Fodrie, F. Joel and Peterson, Charles H.}, year={2021}, month={Nov} }
 @article{caretti_bohnenstiehl_eggleston_2021, title={Spatiotemporal Variability in Sedimentation Drives Habitat Loss on Restored Subtidal Oyster Reefs}, volume={44}, ISSN={["1559-2731"]}, DOI={10.1007/s12237-021-00921-6}, number={8}, journal={ESTUARIES AND COASTS}, author={Caretti, Olivia N. and Bohnenstiehl, DelWayne R. and Eggleston, David B.}, year={2021}, month={Dec}, pages={2100–2117} }
 @article{moyer_boettcher_bohnenstiehl_abercrombie_2020, title={Crustal Strength Variations Inferred From Earthquake Stress Drop at Axial Seamount Surrounding the 2015 Eruption}, volume={47}, ISSN={["1944-8007"]}, DOI={10.1029/2020GL088447}, abstractNote={Abstract}, number={16}, journal={GEOPHYSICAL RESEARCH LETTERS}, author={Moyer, Pamela A. and Boettcher, Margaret S. and Bohnenstiehl, DelWayne R. and Abercrombie, Rachel E.}, year={2020}, month={Aug} }
 @article{le saout_bohnenstiehl_paduan_clague_2020, title={Quantification of Eruption Dynamics on the North Rift at Axial Seamount, Juan de Fuca Ridge}, volume={21}, ISSN={["1525-2027"]}, DOI={10.1029/2020GC009136}, abstractNote={Abstract}, number={9}, journal={GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS}, author={Le Saout, M. and Bohnenstiehl, D. R. and Paduan, J. B. and Clague, D. A.}, year={2020}, month={Sep} }
 @article{hefner_nooner_chadwick_bohnenstiehl_2020, title={Revised Magmatic Source Models for the 2015 Eruption at Axial Seamount Including Estimates of Fault-Induced Deformation}, volume={125}, ISSN={["2169-9356"]}, DOI={10.1029/2020JB019356}, abstractNote={Abstract}, number={4}, journal={JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH}, author={Hefner, William L. and Nooner, Scott L. and Chadwick, William W., Jr. and Bohnenstiehl, DelWayne R.}, year={2020}, month={Apr} }
 @article{van hoeck_paxton_bohnenstiehl_taylor_fodrie_nowacek_voss_peterson_2020, title={Soundscapes of natural and artificial temperate reefs: similar temporal patterns but distinct spectral content}, volume={649}, ISSN={["1616-1599"]}, DOI={10.3354/meps13434}, abstractNote={Marine soundscapes often differ among habitats; however, relatively little is known about whether soundscapes on naturally occurring habitats differ from soundscapes on human-made structures. To address this knowledge gap, we investigated whether temporal and spectral characteristics of biological sound production differ between natural and artificial offshore reefs. Specifically, we analyzed recordings from 5 week-long hydrophone deployments on 2 natural rocky reefs and 2 artificial reefs on the North Carolina, USA, continental shelf. Analysis of sound pressure levels (SPLs) on hourly and seasonal scales revealed similar temporal patterns between the reef types. These patterns were largely driven by 4 dominant fish vocalizers with seasonal chorusing patterns, including a toadfishOpsanussp. Despite similar temporal patterns within reef types, soundscape spectral content was more similar within than between reef types, especially during the April deployment, which had the most acoustic activity. Our findings suggest that the soundscapes of shipwreck artificial reefs may differ from the soundscapes of natural rocky reefs, possibly due to differing community composition. As sound plays an important role in the navigation and settlement of many marine species, soundscape differences between natural and artificial habitats could affect ecosystem function through species behavior and interactions.}, journal={MARINE ECOLOGY PROGRESS SERIES}, author={Van Hoeck, Rebecca V. and Paxton, Avery B. and Bohnenstiehl, DelWayne R. and Taylor, J. Christopher and Fodrie, F. Joel and Nowacek, Douglas P. and Voss, Christine M. and Peterson, Charles H.}, year={2020}, month={Sep}, pages={35–51} }
 @article{mcgill_millhauser_mcgill_melomo_bohnenstiehl_wall_2020, title={Wealth in people and the value of historic Oberlin Cemetery, Raleigh, North Carolina}, volume={7}, ISSN={["2330-4847"]}, url={http://dx.doi.org/10.1002/sea2.12173}, DOI={10.1002/sea2.12173}, abstractNote={In its origins as a concept, wealth in people depended on the circulation and accumulation of rights and obligations among and over the living. But if a person is a source of wealth, what happens when the person dies? Would the person be excised from the relationships upon which wealth in people depends, or might his or her wealth remain accessible to the living? To address this question, we present the case of Oberlin Cemetery in Raleigh, North Carolina. The cemetery was the core of Oberlin Village, a freedperson's African American community founded in the mid‐nineteenth century. Today, development threatens historic resources surrounding the cemetery, but a community organization founded by descendants and neighbors has emerged to preserve and promote their heritage. We are a group of anthropologists, geologists, and historians who live and work near Oberlin Village and who collaborate to help this organization achieve its goals. Here we report how our efforts to document the cemetery's history have bolstered their advocacy and validated their claims to wealth in the people buried there. Thus we show how wealth in people extends to the dead when graves and the people within them are potent sources of value for the living.}, number={2}, journal={ECONOMIC ANTHROPOLOGY}, author={McGill, Dru and Millhauser, John K. and McGill, Alicia and Melomo, Vincent and Bohnenstiehl, Del and Wall, John}, year={2020}, month={Jun}, pages={176–189} }
 @article{smith_wegmann_leithold_bohnenstiehl_2019, title={A 4000-year record of hydrologic variability from the Olympic Mountains, Washington, USA}, volume={29}, ISSN={["1477-0911"]}, DOI={10.1177/0959683619846975}, abstractNote={ Sedimentological and geochemical analyses of gravity and piston cores retrieved from Lake Quinault, Washington, reveal an ~4000-year flood-dominated depositional record. Individual flood event layers are identified by combining core stratigraphy, sedimentology, and the ratio of incoherent to coherently scattered x-ray radiation ( inc/coh) from µXRF (x-ray fluorescence) core scans. The inc/coh time series is used as a proxy for sediment grain size and, in combination with radiocarbon-anchored core age–depth models, enables the reconstruction of late-Holocene hydrologic variability for the Quinault River catchment. Decadal to centennial variability in inc/coh is interpreted to reflect trends in ocean-atmosphere teleconnections favorable for the formation of land-falling atmospheric rivers along the Pacific Ocean flank of the Olympic Mountains. Such processes likely modulate the rate of flooding and may explain notable increases in the frequency of flood event layers observed during the periods 2350–2450 cal. yr BP and the most recent century (AD 1910–2010). Understanding past hydrologic variability has important implications for the landscape and ecosystem response of Olympic Mountain catchments to future climate warming. }, number={8}, journal={HOLOCENE}, author={Smith, Stephen G. and Wegmann, Karl W. and Leithold, Elana L. and Bohnenstiehl, Delwayne R.}, year={2019}, month={Aug}, pages={1273–1291} }
 @article{crone_bohnenstiehl_2019, title={Acoustic evidence of a long-lived gas-driven submarine volcanic eruption in the Bismarck Sea}, volume={217}, ISSN={["1365-246X"]}, DOI={10.1093/gji/ggy542}, abstractNote={Understanding the temporal variability of volcanic activity in the deep ocean is critical for estimating the fluxes of heat and chemicals between the lithosphere and the overlying ocean, and for characterizing the relationships between hydrothermal processes and the subseafloor biosphere. Because there is a growing interest in the development of mineral resources in seafloor hydrothermal settings, it is also important to understand the hydroacoustic environment near submarine volcanoes, which could be impacted by mining operations. To evaluate pre-industrialization sound levels at one proposed site of seafloor mining, a deep-sea hydrophone recording system was deployed for a period of 5 months in the Manus Basin, Bismarck Sea, in the territorial waters of Papua New Guinea. During the deployment the system recorded evidence of a long-lived (∼60-d) gas-driven explosive volcanic eruption. The signals observed were similar to those recorded at two other backarc volcanoes (West Mata and NW Rota-1), and considering the recent geological history of the region, are likely related to the continued growth of a volcanic cryptodome on the south side of North Su volcano. The data show that eruptive events can start and stop abruptly, can last for months, and can increase the local RMS sound pressure levels by about 12 dB on average. The estimated average acoustic source power of the volcanic eruption is roughly equivalent to that of a large commercial shipping vessel.}, number={1}, journal={GEOPHYSICAL JOURNAL INTERNATIONAL}, author={Crone, Timothy J. and Bohnenstiehl, DelWayne R.}, year={2019}, month={Apr}, pages={169–178} }
 @article{lyon_eggleston_bohnenstiehl_layman_ricci_allgeier_2019, title={Fish community structure, habitat complexity, and soundscape characteristics of patch reefs in a tropical, back-reef system}, volume={609}, ISSN={["1616-1599"]}, url={http://dx.doi.org/10.3354/meps12829}, DOI={10.3354/meps12829}, abstractNote={Fig. S1. Box plots for nightly low frequency (0.1 – 1.5 kHz) SPL (a) and high frequency (4 – 20 kHz) SPL (b) for reef 5 for each lunar quarter. Red lines indicate median SPLs, ticks indicate maximum and minimum values, horizontal blue lines indicate 75% and 25% quantiles, and angled blue lines indicate the 95% upper and lower confidence levels in the median. Kruskal-Wallis tests were used to test for differences in SPL between lunar quarters. Relationships between water temperature (in C) and low frequency (0.1 – 1.5 kHz) SPL (c) and high frequency (4 – 20 kHz) SPL (d) were evaluated using linear regression models. 2 = 2.52 p = 0.47}, journal={MARINE ECOLOGY PROGRESS SERIES}, publisher={Inter-Research Science Center}, author={Lyon, R. Patrick and Eggleston, David B. and Bohnenstiehl, DelWayne R. and Layman, Craig A. and Ricci, Shannon W. and Allgeier, Jacob E.}, year={2019}, month={Jan}, pages={33–48} }
 @article{bohnenstiehl_dziak_2019, title={Mid-Ocean Ridge Seismicity}, DOI={10.1016/B978-0-12-409548-9.11489-7}, journal={ENCYCLOPEDIA OF OCEAN SCIENCES, VOL 4: SEAFLOOR PROCESSES, 3RD EDITION}, author={Bohnenstiehl, DelWayne R. and Dziak, Robert P.}, year={2019}, pages={391–404} }
 @article{leithold_wegmann_bohnenstiehl_joyner_pollen_2019, title={Repeated megaturbidite deposition in Lake Crescent, Washington, USA, triggered by Holocene ruptures of the Lake Creek-Boundary Creek fault system}, volume={131}, ISSN={["1943-2674"]}, DOI={10.1130/B35076.1}, abstractNote={Abstract}, number={11-12}, journal={GEOLOGICAL SOCIETY OF AMERICA BULLETIN}, author={Leithold, Elana L. and Wegmann, Karl W. and Bohnenstiehl, D. R. and Joyner, Catelyn N. and Pollen, Audrianna F.}, year={2019}, pages={2039–2055} }
 @article{levy_bohnenstiehl_sprinkle_boettcher_wilcock_tolstoy_waldhauser_2018, title={Mechanics of fault reactivation before, during, and after the 2015 eruption of Axial Seamount}, volume={46}, ISSN={["1943-2682"]}, DOI={10.1130/g39978.1}, abstractNote={Ocean-bottom seismic and seafloor pressure data from the Ocean Observatories Initiative’s Cabled Array were used to study fault reactivation within Axial Seamount (offshore Oregon, USA). Microearthquakes that occurred during 2015–2016 were located on portions of an outward-dipping ring fault system that was reactivated in response to the inflation and deflation of the underlying magma chamber. Prior to an eruption in April 2015, focal mechanisms showed a pattern of normal slip consistent with the differential vertical uplift of the caldera floor relative to the rim. During the eruption, seismic activity remained localized along these outward-dipping structures; however, the slip direction was reversed as the caldera floor subsided. After the eruption, as the volcano reinflated and the caldera floor uplifted, these faults exhibited sparser seismicity with a more heterogeneous pattern of slip. Monitoring the evolution of ring fault behavior through time may have utility as a metric in future eruption forecasts. INTRODUCTION At active volcanoes, as magma is withdrawn from a chamber during an eruption, faults commonly form in response to the subsidence and collapse of the overlying material—developing as either inward-dipping (normal) or outwarddipping (reverse) structures, depending on the amount of subsidence, geometry of the magma chamber, and tectonic setting (Cole et al., 2005; Holohan et al., 2005; Acocella, 2007; Martí et al., 2008). These collapse structures often exhibit a circular to elliptical pattern in plan view and are commonly referred to as ring faults. Reactivation of ring faults has been documented in regional earthquakes studies (e.g., Nettles and Ekström, 1998; Shuler et al., 2013; Gudmundsson et al., 2016); however, the mechanical role of these structures during different phases of the volcanic cycle remains poorly understood. Axial Seamount is a basaltic shield volcano located at the intersection of the Cobb-Eickelberg hotspot and Juan de Fuca Ridge (offshore Oregon, USA; intermediate spreading rate of 55–60 mm/yr). The summit hosts a caldera at 1500 m below sea level (bsl) that is an elongate depression ~3 km wide and 8.5 km long, with walls up to ~150 m high that are buried by younger lavas to the south (Fig. 1). Multichannel seismic reflection studies have imaged a 3-km-wide by 14-km-long magma chamber offset slightly to the east of the caldera at a depth of 1.1−2.3 km beneath the caldera floor (Arnulf et al., 2014). Volume-predictable eruptive behavior has been proposed based on bottom-pressure recorder (BPR) studies that have tracked the inflation and deflation of Axial Seamount for nearly two decades, capturing diking events in 1998, 2011, and 2015 (Chadwick al., 2012; Nooner and Chadwick, 2016). Seismicity associated with the 1998 and 2011 eruptions was recorded by regional hydrophone arrays (Dziak and Fox, 1999) and by ocean bottom hydrophones (Dziak et al., 2012), respectively. Following the 1998 eruption, temporary arrays of 4–10 ocean bottom seismometers (OBSs) monitored local seismicity for 15 mo (Sohn et al., 2004). During the 1998 and 2011 eruptions, pointsource elastic deformation models indicate that the volume of the magma reservoir decreased by ~0.21 km3 and ~0.15 km3, as dikes propagated 55 km and 33 km, respectively, along the southern rift zone (Chadwick et al., 2012). The most recent eruption at Axial Seamount began on 24 April 2015 and was recorded by a seven-station network of three-component OBSs installed within the caldera as part of the Ocean Observatories Initiative (OOI; http://oceanobservatories.org; Kelley et al., 2014). A dike propagated northward from the eastern margin of the magma chamber, erupting a series of lava flows extending from the northeast caldera floor along the north rift zone up to ~14 km north of the caldera (Chadwick et al., 2016). Seafloor explosions associated with the emplacement of these flows indicate that the 2015 eruption persisted over a period of ~26 d (Wilcock et al., 2016), during which time the volume of the magma reservoir (modeled as a prolate spheroid) decreased by ~0.29 km3 (Nooner and Chadwick, 2016). During the time period immediately surrounding the eruption (January–September 2015), Wilcock et al. (2016) identified two steeply dipping, outward-facing planes of microearthquakes beneath the southern portion of the caldera. These structures were interpreted to represent portions of a ring fault system reactivated in response to the inflation and deflation of the magma chamber. In this study, we created an independent catalog of microearthquakes (median Mw ~1.0) for a longer time period between January 2015 and December 2016. These data confirmed the proposed fault geometry and allowed us to track changes in fault slip direction over a nearly 2 yr period. OBS data were used to generate a time series of composite focal mechanism solutions GEOLOGY, May 2018; v. 46; no. 5; p. 1–4 | GSA Data Repository item 2018138 | https://doi.org/10.1130/G39978.1 | Published online XX Month 2018 © 2018 eological Society of A erica. For permission to copy, contact editing@geosociety.org. A’}, number={5}, journal={GEOLOGY}, author={Levy, S. and Bohnenstiehl, D. R. and Sprinkle, P. and Boettcher, M. S. and Wilcock, W. S. D. and Tolstoy, M. and Waldhauser, F.}, year={2018}, month={May}, pages={447–450} }
 @article{wilcock_dziak_tolstoy_chadwick_nooner_bohnenstiehl_caplan-auerbach_waldhauser_arnulf_baillard_et al._2018, title={THE RECENT VOLCANIC HISTORY OF AXIAL SEAMOUNT Geophysical Insights into Past Eruption Dynamics with an Eye Toward Enhanced Observations of Future Eruptions}, volume={31}, ISSN={["1042-8275"]}, DOI={10.5670/oceanog.2018.117}, number={1}, journal={OCEANOGRAPHY}, author={Wilcock, William S. D. and Dziak, Robert P. and Tolstoy, Maya and Chadwick, William W., Jr. and Nooner, Scott L. and Bohnenstiehl, DelWayne R. and Caplan-Auerbach, Jacqueline and Waldhauser, Felix and Arnulf, Adrien F. and Baillard, Christian and et al.}, year={2018}, month={Mar}, pages={114–123} }
 @article{tan_tolstoy_waldhauser_bohnenstiehl_2018, title={Tidal Triggering of Microearthquakes Over an Eruption Cycle at 9 degrees 50 ' N East Pacific Rise}, volume={45}, ISSN={["1944-8007"]}, DOI={10.1002/2017gl076497}, abstractNote={Abstract}, number={4}, journal={GEOPHYSICAL RESEARCH LETTERS}, author={Tan, Yen Joe and Tolstoy, Maya and Waldhauser, Felix and Bohnenstiehl, DelWayne R.}, year={2018}, month={Feb}, pages={1825–1831} }
 @article{caplan-auerbach_dziak_haxel_bohnenstiehl_garcia_2017, title={Explosive processes during the 2015 eruption of Axial Seamount, as recorded by seafloor hydrophones}, volume={18}, ISSN={["1525-2027"]}, DOI={10.1002/2016gc006734}, abstractNote={Abstract}, number={4}, journal={GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS}, author={Caplan-Auerbach, J. and Dziak, R. P. and Haxel, J. and Bohnenstiehl, D. R. and Garcia, C.}, year={2017}, month={Apr}, pages={1761–1774} }
 @article{wall_bohnenstiehl_wegmann_levine_2017, title={Morphometric comparisons between automated and manual karst depression inventories in Apalachicola National Forest, Florida, and Mammoth Cave National Park, Kentucky, USA}, volume={85}, ISSN={["1573-0840"]}, DOI={10.1007/s11069-016-2600-x}, number={2}, journal={NATURAL HAZARDS}, author={Wall, John and Bohnenstiehl, DelWayne R. and Wegmann, Karl W. and Levine, Norman S.}, year={2017}, month={Jan}, pages={729–749} }
 @article{ricci_bohnenstiehl_eggleston_kellogg_lyon_2017, title={Oyster toadfish (Opsanus tau) boatwhistle call detection and patterns within a large-scale oyster restoration site}, volume={12}, ISSN={["1932-6203"]}, url={http://dx.doi.org/10.1371/journal.pone.0182757}, DOI={10.1371/journal.pone.0182757}, abstractNote={During May 2015, passive acoustic recorders were deployed at eight subtidal oyster reefs within Harris Creek Oyster Sanctuary in Chesapeake Bay, Maryland USA. These sites were selected to represent both restored and unrestored habitats having a range of oyster densities. Throughout the survey, the soundscape within Harris Creek was dominated by the boatwhistle calls of the oyster toadfish, Opsanus tau. A novel, multi-kernel spectral correlation approach was developed to automatically detect these boatwhistle calls using their two lowest harmonic bands. The results provided quantitative information on how call rate and call frequency varied in space and time. Toadfish boatwhistle fundamental frequency ranged from 140 Hz to 260 Hz and was well correlated (r = 0.94) with changes in water temperature, with the fundamental frequency increasing by ~11 Hz for every 1°C increase in temperature. The boatwhistle call rate increased from just a few calls per minute at the start of monitoring on May 7th to ~100 calls/min on May 10th and remained elevated throughout the survey. As male toadfish are known to generate boatwhistles to attract mates, this rapid increase in call rate was interpreted to mark the onset of spring spawning behavior. Call rate was not modulated by water temperature, but showed a consistent diurnal pattern, with a sharp decrease in rate just before sunrise and a peak just after sunset. There was a significant difference in call rate between restored and unrestored reefs, with restored sites having nearly twice the call rate as unrestored sites. This work highlights the benefits of using automated detection techniques that provide quantitative information on species-specific call characteristics and patterns. This type of non-invasive acoustic monitoring provides long-term, semi-continuous information on animal behavior and abundance, and operates effectively in settings that are otherwise difficult to sample.}, number={8}, journal={PLOS ONE}, publisher={Public Library of Science (PLoS)}, author={Ricci, Shannon W. and Bohnenstiehl, DelWayne R. and Eggleston, David B. and Kellogg, M. Lisa and Lyon, R. Patrick}, editor={Li, SonghaiEditor}, year={2017}, month={Aug} }
 @article{leithold_wegmann_bohnenstiehl_smith_noren_o’grady_2017, title={Slope failures within and upstream of Lake Quinault, Washington, as uneven responses to Holocene earthquakes along the Cascadia subduction zone}, volume={89}, ISSN={0033-5894 1096-0287}, url={http://dx.doi.org/10.1017/QUA.2017.96}, DOI={10.1017/QUA.2017.96}, abstractNote={Abstract}, number={1}, journal={Quaternary Research}, publisher={Cambridge University Press (CUP)}, author={Leithold, Elana L. and Wegmann, Karl W. and Bohnenstiehl, Delwayne R. and Smith, Stephen G. and Noren, Anders and O’Grady, Ryan}, year={2017}, month={Nov}, pages={178–200} }
 @article{ricci_eggleston_bohnenstiehl_2017, title={Use of passive acoustic monitoring to characterize fish spawning behavior and habitat use within a complex mosaic of estuarine habitats}, volume={93}, ISSN={["1553-6955"]}, url={http://dx.doi.org/10.5343/bms.2016.1037}, DOI={10.5343/bms.2016.1037}, abstractNote={Structurally complex estuarine habitats, such as seagrass beds, salt marshes, and oyster reefs, are used by fish for foraging, avoiding predators, and spawning. Here, we used passive acoustics to characterize spatiotemporal patterns in the soundscape of an estuarine reserve that contained a mosaic of habitat types, and focused on relating characteristics of the soundscape [e.g., low-frequency (150–1500 Hz) sound pressure levels (SPLs), amount of fish chorusing] to patterns in the seascape (percent cover of estuarine habitats surrounding the recording sites). Over a 3-mo period, 2-min duration underwater sound recordings were made every 20 min at eight sites within Middle Marsh in Back Sound, North Carolina, USA. While habitat composition was not related to spatial patterns in low-frequency SPLs, there was a positive and statistically significant relationship between the percent recordings with fish chorusing, and percent cover of seagrass for silver perch [Bairdiella chrysoura (Lacepede, 1802)], spotted seatrout [Cynoscion nebulosus (Cuvier, 1830)], and other fish, irrespective of spatial scale (10 vs 25 m). Moreover, silver perch and spotted seatrout, soniferous species that share similar spawning locations, exhibited temporal partitioning in the soundscape with seatrout calls occurring just before sunset and peaking several hours after sunset, and declining sharply as perch chorusing increased after sunset with a peak at midnight. Overall, local habitat composition and the soundscape at these sites were not highly correlated; where major sound producing fish species are transient, other seascape characteristics, such as proximity to channels, likely have a larger influence on the resulting soundscape.}, number={2}, journal={BULLETIN OF MARINE SCIENCE}, publisher={Bulletin of Marine Science}, author={Ricci, Shannon W. and Eggleston, David B. and Bohnenstiehl, DelWayne R.}, year={2017}, month={Apr}, pages={439–453} }
 @article{wilcock_tolstoy_waldhauser_garcia_tan_bohnenstiehl_caplan-auerbach_dziak_arnulf_mann_2016, title={Seismic constraints on caldera dynamics from the 2015 Axial Seamount eruption}, volume={354}, ISSN={["1095-9203"]}, DOI={10.1126/science.aah5563}, abstractNote={Volcano monitoring goes into the deep}, number={6318}, journal={SCIENCE}, author={Wilcock, William S. D. and Tolstoy, Maya and Waldhauser, Felix and Garcia, Charles and Tan, Yen Joe and Bohnenstiehl, DelWayne R. and Caplan-Auerbach, Jacqueline and Dziak, Robert P. and Arnulf, Adrien F. and Mann, M. Everett}, year={2016}, month={Dec}, pages={1395–1399} }
 @inbook{lillis_eggleston_bohnenstiehl_2016, title={Soundscapes and Larval Settlement: Characterizing the Stimulus from a Larval Perspective}, ISBN={9781493929801 9781493929818}, ISSN={0065-2598 2214-8019}, url={http://dx.doi.org/10.1007/978-1-4939-2981-8_77}, DOI={10.1007/978-1-4939-2981-8_77}, abstractNote={There is growing evidence that underwater sounds serve as a cue for the larvae of marine organisms to locate suitable settlement habitats; however, the relevant spatiotemporal scales of variability in habitat-related sounds and how this variation scales with larval settlement processes remain largely uncharacterized, particularly in estuarine habitats. Here, we provide an overview of the approaches we have developed to characterize an estuarine soundscape as it relates to larval processes, and a conceptual framework is provided for how habitat-related sounds may influence larval settlement, using oyster reef soundscapes as an example.}, booktitle={The Effects of Noise on Aquatic Life II}, publisher={Springer New York}, author={Lillis, Ashlee and Eggleston, David B. and Bohnenstiehl, DelWayne R.}, year={2016}, pages={637–645} }
 @inbook{eggleston_lillis_bohnenstiehl_2016, title={Soundscapes and Larval Settlement: Larval Bivalve Responses to Habitat-Associated Underwater Sounds}, ISBN={9781493929801 9781493929818}, ISSN={0065-2598 2214-8019}, url={http://dx.doi.org/10.1007/978-1-4939-2981-8_30}, DOI={10.1007/978-1-4939-2981-8_30}, abstractNote={We quantified the effects of habitat-associated sounds on the settlement response of two species of bivalves with contrasting habitat preferences: (1) Crassostrea virginicia (oyster), which prefers to settle on other oysters, and (2) Mercenaria mercenaria (clam), which settles on unstructured habitats. Oyster larval settlement in the laboratory was significantly higher when exposed to oyster reef sound compared with either off-reef or no-sound treatments. Clam larval settlement did not vary according to sound treatments. Similar to laboratory results, field experiments showed that oyster larval settlement in "larval housings" suspended above oyster reefs was significantly higher compared with off-reef sites.}, booktitle={The Effects of Noise on Aquatic Life II}, publisher={Springer New York}, author={Eggleston, David B. and Lillis, Ashlee and Bohnenstiehl, DelWayne R.}, year={2016}, pages={255–263} }
 @article{lillis_eggleston_bohnenstiehl_2016, title={Soundscapes and larval settlement: Characterizing the stimulus from a larval perspective}, volume={875}, journal={Effects of noise on aquatic life ii}, author={Lillis, A. and Eggleston, D. B. and Bohnenstiehl, D. R.}, year={2016}, pages={637–645} }
 @article{eggleston_lillis_bohnenstiehl_2016, title={Soundscapes and larval settlement: larval bivalve responses to habitat-associated underwater sounds}, volume={875}, journal={Effects of noise on aquatic life ii}, author={Eggleston, D. B. and Lillis, A. and Bohnenstiehl, D. R.}, year={2016}, pages={255–263} }
 @article{ricci_eggleston_bohnenstiehl_lillis_2016, title={Temporal soundscape patterns and processes in an estuarine reserve}, volume={550}, ISSN={["1616-1599"]}, url={http://dx.doi.org/10.3354/meps11724}, DOI={10.3354/meps11724}, abstractNote={: Underwater acoustic recordings can be used to measure the distribution and activity of sound-producing species and investigate variability in the physical and biological characteristics of marine ecosystems. This study characterized the summer soundscape of a coastal estuarine reserve, Middle Marsh, near Beaufort Inlet, North Carolina, USA. Passive recorders were de ployed at 8 sites, within a mixture of seagrass, saltmarsh, oyster reef and soft-bottom habitats, and sampled for 2 min every 20 min between June and August 2014. Sound pressure levels (SPLs) in a high-frequency band (7−43 kHz) exhibited a periodicity of once per day, being 11 dB higher during the nighttime. This pattern is correlated with snapping shrimp sounds, with an average excess of ~12% more snaps detected at night. The same analysis for SPLs in a low-frequency band (150−1500 Hz) revealed a periodicity of twice per day, with diurnal sound levels varying by up to 29 dB. Temporal variability in the low-frequency soundscape is correlated with fish chorusing, as well as tidal water level, which may influence both the presence and absence of fish and the propagation of sound in the water column. The greatest SPLs are observed in association with periods of high biological activity during nighttime high tides. Sampling marine animals and their activities over ecologically relevant time scales is challenging using conventional techniques (trawls and throw traps) within complex shallow water habitats, particularly at night. Soundscape monitoring provides an additional method to assess spatiotemporal variation in essential fish habitat use within a complex mosaic of habitat types.}, journal={MARINE ECOLOGY PROGRESS SERIES}, publisher={Inter-Research Science Center}, author={Ricci, Shannon W. and Eggleston, David B. and Bohnenstiehl, DelWayne R. and Lillis, Ashlee}, year={2016}, month={May}, pages={25–38} }
 @article{bohnenstiehl_lillis_eggleston_2016, title={The Curious Acoustic Behavior of Estuarine Snapping Shrimp: Temporal Patterns of Snapping Shrimp Sound in Sub-Tidal Oyster Reef Habitat}, volume={11}, ISSN={["1932-6203"]}, DOI={10.1371/journal.pone.0143691}, abstractNote={Ocean soundscapes convey important sensory information to marine life. Like many mid-to-low latitude coastal areas worldwide, the high-frequency (>1.5 kHz) soundscape of oyster reef habitat within the West Bay Marine Reserve (36°N, 76°W) is dominated by the impulsive, short-duration signals generated by snapping shrimp. Between June 2011 and July 2012, a single hydrophone deployed within West Bay was programmed to record 60 or 30 seconds of acoustic data every 15 or 30 minutes. Envelope correlation and amplitude information were then used to count shrimp snaps within these recordings. The observed snap rates vary from 1500–2000 snaps per minute during summer to <100 snaps per minute during winter. Sound pressure levels are positively correlated with snap rate (r = 0.71–0.92) and vary seasonally by ~15 decibels in the 1.5–20 kHz range. Snap rates are positively correlated with water temperatures (r = 0.81–0.93), as well as potentially influenced by climate-driven changes in water quality. Light availability modulates snap rate on diurnal time scales, with most days exhibiting a significant preference for either nighttime or daytime snapping, and many showing additional crepuscular increases. During mid-summer, the number of snaps occurring at night is 5–10% more than predicted by a random model; however, this pattern is reversed between August and April, with an excess of up to 25% more snaps recorded during the day in the mid-winter. Diurnal variability in sound pressure levels is largest in the mid-winter, when the overall rate of snapping is at its lowest, and the percentage difference between daytime and nighttime activity is at its highest. This work highlights our lack of knowledge regarding the ecology and acoustic behavior of one of the most dominant soniforous invertebrate species in coastal systems. It also underscores the necessity of long-duration, high-temporal-resolution sampling in efforts to understand the bioacoustics of animal behaviors and associated changes within the marine soundscape.}, number={1}, journal={PLOS ONE}, author={Bohnenstiehl, DelWayne R. and Lillis, Ashlee and Eggleston, David B.}, year={2016}, month={Jan} }
 @article{lillis_bohnenstiehl_peters_eggleston_2016, title={Variation in habitat soundscape characteristics influences settlement of a reef-building coral}, volume={4}, ISSN={["2167-8359"]}, DOI={10.7717/peerj.2557}, abstractNote={Coral populations, and the productive reef ecosystems they support, rely on successful recruitment of reef-building species, beginning with settlement of dispersing larvae into habitat favourable to survival. Many substrate cues have been identified as contributors to coral larval habitat selection; however, the potential for ambient acoustic cues to influence coral settlement responses is unknown. Usingin situsettlement chambers that excluded other habitat cues, larval settlement of a dominant Caribbean reef-building coral,Orbicella faveolata, was compared in response to three local soundscapes, with differing acoustic and habitat properties. Differences between reef sites in the number of larvae settled in chambers isolating acoustic cues corresponded to differences in sound levels and reef characteristics, with sounds at the loudest reef generating significantly higher settlement during trials compared to the quietest site (a 29.5 % increase). These results suggest that soundscapes could be an important influence on coral settlement patterns and that acoustic cues associated with reef habitat may be related to larval settlement. This study reports an effect of soundscape variation on larval settlement for a key coral species, and adds to the growing evidence that soundscapes affect marine ecosystems by influencing early life history processes of foundational species.}, journal={PEERJ}, author={Lillis, Ashlee and Bohnenstiehl, DelWayne and Peters, Jason W. and Eggleston, David}, year={2016}, month={Oct} }
 @article{supak_brothers_bohnenstiehl_devine_2015, title={Geospatial analytics for federally managed tourism destinations and their demand markets}, volume={4}, ISSN={2212-571X}, url={http://dx.doi.org/10.1016/J.JDMM.2015.05.002}, DOI={10.1016/J.JDMM.2015.05.002}, abstractNote={Understanding geospatial demand for destinations can improve management decisions affecting destination planning, marketing, natural preservation, and resident as well as visitor experiences. Visualization and analysis of demand markets are significantly enhanced by the capabilities of Geographic Information System (GIS) technology and help to support management objectives. This study implements traditional desktop GIS as well as a free, web-delivered decision-support tool for tourism planning and marketing to assess ~7.5 million overnight accommodation reservations made for federal recreational facilities between 1999 and 2007. Visitor origin frequency and median travel distance for overnight accommodations are summarized by visitor zip code and by facility. National results indicate: (1) facilities in the west, the Great Lakes and the southern Appalachians regions draw overnight visitors from the greatest median distances; (2) residents in the Northeast have the lowest per-capita utilization; (3) residents within the south-central Midwest and central-west Southern States have the highest percapita utilization and tend strongly toward local overnight reservations. Three selected national park regions are used to illustrate destinations characterized by highly localized utilization (Hot Springs National Park, AR), both local and regional utilization (Yosemite National Park, CA) and regionally to nationally dispersed utilization with few local residents reserving overnight accommodations (Canyonlands National Park, UT). Market profiling derived from local, regional and national customer origin markets can help any tourism destination, including national parks and their gateway communities, make smarter management and marketing decisions.}, number={3}, journal={Journal of Destination Marketing & Management}, publisher={Elsevier BV}, author={Supak, Stacy and Brothers, Gene and Bohnenstiehl, DelWayne and Devine, Hugh}, year={2015}, month={Oct}, pages={173–186} }
 @article{supak_brothers_bohnenstiehl_2015, title={Geospatial analytics for federally managed tourism destinations and their demand markets}, volume={4}, number={3}, journal={Journal of Destination Marketing & Management}, author={Supak, S. and Brothers, G. and Bohnenstiehl, D.}, year={2015}, pages={173–176} }
 @article{dziak_bohnenstiehl_baker_matsumoto_caplan-auerbach_embley_merle_walker_lau_chadwick_2015, title={Long-term explosive degassing and debris flow activity at West Mata submarine volcano}, volume={42}, ISSN={["1944-8007"]}, DOI={10.1002/2014gl062603}, abstractNote={Abstract}, number={5}, journal={GEOPHYSICAL RESEARCH LETTERS}, author={Dziak, R. P. and Bohnenstiehl, D. R. and Baker, E. T. and Matsumoto, H. and Caplan-Auerbach, J. and Embley, R. W. and Merle, S. G. and Walker, S. L. and Lau, T-K. and Chadwick, W. W., Jr.}, year={2015}, month={Mar}, pages={1480–1487} }
 @article{royer_chateau_dziak_bohnenstiehl_2015, title={Seafloor seismicity, Antarctic ice-sounds, cetacean vocalizations and long-term ambient sound in the Indian Ocean basin}, volume={202}, ISSN={["1365-246X"]}, DOI={10.1093/gji/ggv178}, abstractNote={This paper presents the results from the Deflo-hydroacoustic experiment in the Southern Indian Ocean using three autonomous underwater hydrophones, complemented by two permanent hydroacoustic stations. The array monitored for 14 months, from November 2006 to December 2007, a 3000 x 3000 km wide area, encompassing large segments of the three Indian spreading ridges that meet at the Indian Triple Junction. A catalogue of 11 105 acoustic events is derived from the recorded data, of which 55 per cent are located from three hydrophones, 38 per cent from 4, 6 per cent from five and less than 1 per cent by six hydrophones. From a comparison with land-based seismic catalogues, the smallest detected earthquakes are m(b) 2.6 in size, the range of recorded magnitudes is about twice that of land-based networks and the number of detected events is 5-16 times larger. Seismicity patterns vary between the three spreading ridges, with activity mainly focused on transform faults along the fast spreading Southeast Indian Ridge and more evenly distributed along spreading segments and transforms on the slow spreading Central and ultra-slow spreading Southwest Indian ridges; the Central Indian Ridge is the most active of the three with an average of 1.9 events/100 km/month. Along the Sunda Trench, acoustic events mostly radiate from the inner wall of the trench and show a 200-km-long seismic gap between 2 degrees S and the Equator. The array also detected more than 3600 cryogenic events, with different seasonal trends observed for events from the Antarctic margin, compared to those from drifting icebergs at lower (up to 50 degrees S) latitudes. Vocalizations of five species and subspecies of large baleen whales were also observed and exhibit clear seasonal variability. On the three autonomous hydrophones, whale vocalizations dominate sound levels in the 20-30 and 100 Hz frequency bands, whereas earthquakes and ice tremor are a dominant source of ambient sound at frequencies < 20 Hz.}, number={2}, journal={GEOPHYSICAL JOURNAL INTERNATIONAL}, author={Royer, J. -Y. and Chateau, R. and Dziak, R. P. and Bohnenstiehl, D. R.}, year={2015}, month={Aug}, pages={748–762} }
 @article{lillis_bohnenstiehl_eggleston_2015, title={Soundscape manipulation enhances larval recruitment of a reef-building mollusk}, volume={3}, ISSN={["2167-8359"]}, DOI={10.7717/peerj.999}, abstractNote={Marine seafloor ecosystems, and efforts to restore them, depend critically on the influx and settlement of larvae following their pelagic dispersal period. Larval dispersal and settlement patterns are driven by a combination of physical oceanography and behavioral responses of larvae to a suite of sensory cues both in the water column and at settlement sites. There is growing evidence that the biological and physical sounds associated with adult habitats (i.e., the “soundscape”) influence larval settlement and habitat selection; however, the significance of acoustic cues is rarely tested. Here we show in a field experiment that the free-swimming larvae of an estuarine invertebrate, the eastern oyster, respond to the addition of replayed habitat-related sounds. Oyster larval recruitment was significantly higher on larval collectors exposed to oyster reef sounds compared to no-sound controls. These results provide the first field evidence that soundscape cues may attract the larval settlers of a reef-building estuarine invertebrate.}, journal={PEERJ}, author={Lillis, Ashlee and Bohnenstiehl, DelWayne R. and Eggleston, David B.}, year={2015}, month={Jun} }
 @article{dziak_bohnenstiehl_stafford_matsumoto_park_lee_fowler_lau_haxel_mellinger_2015, title={Sources and Levels of Ambient Ocean Sound near the Antarctic Peninsula}, volume={10}, ISSN={["1932-6203"]}, DOI={10.1371/journal.pone.0123425}, abstractNote={Arrays of hydrophones were deployed within the Bransfield Strait and Scotia Sea (Antarctic Peninsula region) from 2005 to 2009 to record ambient ocean sound at frequencies of up to 125 and 500 Hz. Icequakes, which are broadband, short duration signals derived from fracturing of large free-floating icebergs, are a prominent feature of the ocean soundscape. Icequake activity peaks during austral summer and is minimum during winter, likely following freeze-thaw cycles. Iceberg grounding and rapid disintegration also releases significant acoustic energy, equivalent to large-scale geophysical events. Overall ambient sound levels can be as much as ~10–20 dB higher in the open, deep ocean of the Scotia Sea compared to the relatively shallow Bransfield Strait. Noise levels become lowest during the austral winter, as sea-ice cover suppresses wind and wave noise. Ambient noise levels are highest during austral spring and summer, as surface noise, ice cracking and biological activity intensifies. Vocalizations of blue (Balaenoptera musculus) and fin (B. physalus) whales also dominate the long-term spectra records in the 15–28 and 89 Hz bands. Blue whale call energy is a maximum during austral summer-fall in the Drake Passage and Bransfield Strait when ambient noise levels are a maximum and sea-ice cover is a minimum. Fin whale vocalizations were also most common during austral summer-early fall months in both the Bransfield Strait and Scotia Sea. The hydrophone data overall do not show sustained anthropogenic sources (ships and airguns), likely due to low coastal traffic and the typically rough weather and sea conditions of the Southern Ocean.}, number={4}, journal={PLOS ONE}, author={Dziak, Robert P. and Bohnenstiehl, DelWayne R. and Stafford, Kathleen M. and Matsumoto, Haruyoshi and Park, Minkyu and Lee, Won Sang and Fowler, Matt J. and Lau, Tai-Kwan and Haxel, Joseph H. and Mellinger, David K.}, year={2015}, month={Apr} }
 @article{bohnenstiehl_dziak_matsumoto_conder_2014, title={Acoustic response of submarine volcanoes in the Tofua Arc and northern Lau Basin to two great earthquakes}, volume={196}, ISSN={["1365-246X"]}, DOI={10.1093/gji/ggt472}, abstractNote={potentially increasing the short-term flux of magma and volcanic gas into the overlying ocean.}, number={3}, journal={GEOPHYSICAL JOURNAL INTERNATIONAL}, author={Bohnenstiehl, DelWayne R. and Dziak, Robert P. and Matsumoto, Haru and Conder, James A.}, year={2014}, month={Mar}, pages={1657–1675} }
 @article{gallen_wegmann_bohnenstiehl_pazzaglia_brandon_fassoulas_2014, title={Active simultaneous uplift and margin-normal extension in a forearc high, Crete, Greece}, volume={398}, ISSN={["1385-013X"]}, DOI={10.1016/j.epsl.2014.04.038}, abstractNote={The island of Crete occupies a forearc high in the central Hellenic subduction zone and is characterized by sustained exhumation, surface uplift and extension. The processes governing orogenesis and topographic development here remain poorly understood. Dramatic topographic relief (2–6km) astride the southern coastline of Crete is associated with large margin-parallel faults responsible for deep bathymetric depressions known as the Hellenic troughs. These structures have been interpreted as both active and inactive with either contractional, strike-slip, or extensional movement histories. Distinguishing between these different structural styles and kinematic histories here allows us to explore more general models for improving our global understanding of the tectonic and geodynamic processes of syn-convergent extension. We present new observations from the south–central coastline of Crete that clarifies the role of these faults in the late Cenozoic evolution of the central Hellenic margin and the processes controlling Quaternary surface uplift. Pleistocene marine terraces are used in conjunction with optically stimulated luminesce dating and correlation to the Quaternary eustatic curve to document coastal uplift and identify active faults. Two south-dipping normal faults are observed, which extend offshore, offset these marine terrace deposits and indicate active N–S (margin-normal) extension. Further, marine terraces preserved in the footwall and hanging wall of both faults demonstrate that regional net uplift of Crete is occurring despite active extension. Field mapping and geometric reconstructions of an active onshore normal fault reveal that the subaqueous range-front fault of south–central Crete is synthetic to the south-dipping normal faults on shore. These findings are inconsistent with models of active horizontal shortening in the upper crust of the Hellenic forearc. Rather, they are consistent with topographic growth of the forearc in a viscous orogenic wedge, where crustal thickening and uplift are a result of basal underplating of material that is accompanied by extension in the upper portions of the wedge. Within this framework a new conceptual model is presented for the late Cenozoic vertical tectonics of the Hellenic forearc.}, journal={EARTH AND PLANETARY SCIENCE LETTERS}, author={Gallen, S. F. and Wegmann, K. W. and Bohnenstiehl, D. R. and Pazzaglia, F. J. and Brandon, M. T. and Fassoulas, C.}, year={2014}, month={Jul}, pages={11–24} }
 @article{matsumoto_bohnenstiehl_tournadre_dziak_haxel_lau_fowler_salo_2014, title={Antarctic icebergs: A significant natural ocean sound source in the Southern Hemisphere}, volume={15}, DOI={10.1002/2014gc005454}, abstractNote={Abstract}, number={8}, journal={Geochemistry, Geophysics, Geosystems}, author={Matsumoto, H. and Bohnenstiehl, D. R. and Tournadre, J. and Dziak, R. P. and Haxel, J. H. and Lau, T. K. A. and Fowler, M. and Salo, S. A.}, year={2014}, pages={3448–3458} }
 @article{lillis_eggleston_bohnenstiehl_2014, title={Estuarine soundscapes: distinct acoustic characteristics of oyster reefs compared to soft-bottom habitats}, volume={505}, ISSN={["1616-1599"]}, DOI={10.3354/meps10805}, abstractNote={Different types of benthic habitats likely produce distinct soundscapes due to differences in the physical and biological contributors to ambient sound. Despite their potential importance to ecologi- cal processes such as larval settlement, the sound- scapes of most coastal and estuarine habitats have not been characterized. We investigated whether an es- tuarine soundscape is a reliable indicator of habitat type by measuring the sounds of oyster reefs and nearby off-reef soft-bottom areas in Pamlico Sound, North Carolina, USA. Acoustic sampling in 3 areas across the estuary revealed distinct acoustic patterns in oyster reef habitats compared to surrounding off- reef areas, with reef soundscapes dominated by snap- ping shrimp sounds and the vocalizations of reef- dwelling fish species. Compared to soft-bottom habitat, oyster reefs had significantly higher sound pressure levels in the 2−23 kHz frequency band and higher acoustic diversity index values at each concurrent sampling event. Spectral differences between adja- cent reef/off-reef habitats were present throughout the summer and fall sampling season and across 2 sampling years, but the acoustic signal strength dif- fered between reef sites. Passive sound propagation surveys found that the distinct acoustic characteristics of oyster reefs within the 2−23 kHz frequency band were highly localized, with effective source levels of 108.8 to 120.0 dB re 1 μPa @ 1 m and transmission loss approximating a cylindrical geometric spreading model. This soundscape characterization study sug- gests that spatial heterogeneity in ambient sound could serve as a reliable indicator of habitat type and potentially convey habitat quality information to dis- persing organisms.}, journal={MARINE ECOLOGY PROGRESS SERIES}, author={Lillis, Ashlee and Eggleston, David B. and Bohnenstiehl, DelWayne R.}, year={2014}, pages={1–17} }
 @article{caplan-auerbach_dziak_bohnenstiehl_chadwick_lau_2014, title={Hydroacoustic investigation of submarine landslides at West Mata volcano, Lau Basin}, volume={41}, ISSN={["1944-8007"]}, DOI={10.1002/2014gl060964}, abstractNote={Abstract}, number={16}, journal={GEOPHYSICAL RESEARCH LETTERS}, author={Caplan-Auerbach, J. and Dziak, R. P. and Bohnenstiehl, D. R. and Chadwick, W. W. and Lau, T. -K.}, year={2014}, month={Aug}, pages={5927–5934} }
 @article{lillis_eggleston_bohnenstiehl_2014, title={Soundscape variation from a larval perspective: the case for habitat-associated sound as a settlement cue for weakly swimming estuarine larvae}, volume={509}, ISSN={["1616-1599"]}, DOI={10.3354/meps10917}, abstractNote={Settlement is a critical phase in the life history of most benthic marine organisms and has important implications for their survival and reproductive success, and ultimately for pop - ulation and community dynamics. Larval encounter with settlement habitats is likely facilitated through the use of habitat-specific physical and chemical cues, but the scales over which particular habitat-related environmental cues may operate are rarely measured. In Pamlico Sound, North Carolina, USA we used passively drifting acoustic recorders to measure the varia- tion in habitat-related underwater sound, a potential broad-scale settlement cue, at spatio - temporal scales relevant to dispersing bivalve larvae in the estuary. Sound levels increased by up to 30 dB during passage over oyster reefs compared to off-reef soft bottom areas, and sound level fluctuations in the 2000 to 23 000 Hz frequency range closely corresponded to the presence of oyster reef patches below drifters, indicating that sound characteristics could reliably provide a signal of benthic habitat type to planktonic larvae. Using these soundscape measurements and the known descent capabilities of oyster larvae, we demonstrate with a conceptual model that response to habitat-related sound cues is a feasible mechanism for enhanced larval encounter with settlement substrate.}, journal={MARINE ECOLOGY PROGRESS SERIES}, author={Lillis, Ashlee and Eggleston, David B. and Bohnenstiehl, DelWayne R.}, year={2014}, pages={57–70} }
 @article{voli_wegmann_bohnenstiehl_leithold_osburn_polyakov_2013, title={Fingerprinting the sources of suspended sediment delivery to a large municipal drinking water reservoir: Falls Lake, Neuse River, North Carolina, USA}, volume={13}, ISSN={["1614-7480"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84887284036&partnerID=MN8TOARS}, DOI={10.1007/s11368-013-0758-3}, number={10}, journal={JOURNAL OF SOILS AND SEDIMENTS}, publisher={Springer Science \mathplus Business Media}, author={Voli, Mark T. and Wegmann, Karl W. and Bohnenstiehl, DelWayne R. and Leithold, Elana and Osburn, Christopher L. and Polyakov, Viktor}, year={2013}, month={Dec}, pages={1692–1707} }
 @article{dziak_fowler_matsumoto_bohnenstiehl_park_warren_lee_2013, title={Life and Death Sounds of Iceberg A53a}, volume={26}, ISSN={["1042-8275"]}, DOI={10.5670/oceanog.2013.20}, number={2}, journal={OCEANOGRAPHY}, author={Dziak, Robert P. and Fowler, Matthew J. and Matsumoto, Haruyoshi and Bohnenstiehl, Delwayne R. and Park, Minkyu and Warren, Kyle and Lee, Won Sang}, year={2013}, month={Jun}, pages={10–12} }
 @article{lillis_eggleston_bohnenstiehl_2013, title={Oyster Larvae Settle in Response to Habitat-Associated Underwater Sounds}, volume={8}, ISSN={["1932-6203"]}, DOI={10.1371/journal.pone.0079337}, abstractNote={Following a planktonic dispersal period of days to months, the larvae of benthic marine organisms must locate suitable seafloor habitat in which to settle and metamorphose. For animals that are sessile or sedentary as adults, settlement onto substrates that are adequate for survival and reproduction is particularly critical, yet represents a challenge since patchily distributed settlement sites may be difficult to find along a coast or within an estuary. Recent studies have demonstrated that the underwater soundscape, the distinct sounds that emanate from habitats and contain information about their biological and physical characteristics, may serve as broad-scale environmental cue for marine larvae to find satisfactory settlement sites. Here, we contrast the acoustic characteristics of oyster reef and off-reef soft bottoms, and investigate the effect of habitat-associated estuarine sound on the settlement patterns of an economically and ecologically important reef-building bivalve, the Eastern oyster (Crassostrea virginica). Subtidal oyster reefs in coastal North Carolina, USA show distinct acoustic signatures compared to adjacent off-reef soft bottom habitats, characterized by consistently higher levels of sound in the 1.5–20 kHz range. Manipulative laboratory playback experiments found increased settlement in larval oyster cultures exposed to oyster reef sound compared to unstructured soft bottom sound or no sound treatments. In field experiments, ambient reef sound produced higher levels of oyster settlement in larval cultures than did off-reef sound treatments. The results suggest that oyster larvae have the ability to respond to sounds indicative of optimal settlement sites, and this is the first evidence that habitat-related differences in estuarine sounds influence the settlement of a mollusk. Habitat-specific sound characteristics may represent an important settlement and habitat selection cue for estuarine invertebrates and could play a role in driving settlement and recruitment patterns in marine communities.}, number={10}, journal={PLOS ONE}, author={Lillis, Ashlee and Eggleston, David B. and Bohnenstiehl, DelWayne R.}, year={2013}, month={Oct} }
 @article{bohnenstiehl_dziak_matsumoto_lau_2013, title={Underwater acoustic records from the March 2009 eruption of Hunga Ha'apai-Hunga Tonga volcano in the Kingdom of Tonga}, volume={249}, ISSN={["1872-6097"]}, DOI={10.1016/j.jvolgeores.2012.08.014}, abstractNote={Abstract A network of autonomous underwater hydrophones is used to monitor acoustic activity associated with Hunga Ha'apai-Hunga Tonga volcano during a period of 15 months. The data provide a continuous record spanning a surtseyan eruption (VEI 2) in March of 2009, which input ~ 10 13  J of acoustic energy into the ocean soundscape. In the months before the eruption, the volcano can be identified as an intermittent source of ambient noise. The period of seismic unrest that precedes the eruption begins at 15:11 UTC on 16 March (04:11 LT on 17 March), approximately 7 h before the first satellite confirmation of eruptive activity and 14 h before the first eyewitness reports. The initial seismic activity, which includes a single 4.8 m b event at 15:25, evolves as a typical foreshock–mainshock–aftershock sequence. By 15:38, however, the rate of small earthquakes begins to increase, marking the onset of the seismic swarm. The period of highest-amplitude acoustic energy release between 16:40 and ~ 17:10 is interpreted to mark the opening of the volcanic conduit. By 19:00 on 16 March, the acoustic signature of the volcano is marked by a continuous wide-band (1–20 Hz) noise and a set of transient very-broadband (1–125 Hz) explosion signals. This activity is characteristic of the main surtseyan phase of the eruption. Both the intensity of explosions and the amplitude of the lower frequency wide-band noise decay through time, and eruptive activity likely ends at ~ 09:00 on 19 March, ~ 2.7 days after the initiation of seismic activity. At this time the continuous low frequency noise decays to near background levels and signal coherence drops suddenly. Low-level acoustic unrest persists through June of 2009, after which the volcano becomes acoustically dormant during the remaining ten months of monitoring. The analysis of volcano-acoustic signals associated with Hunga Ha'apai-Hunga Tonga volcano highlights the potential role of regional hydroacoustic monitoring in assessing volcanic hazards in arc settings.}, journal={JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH}, author={Bohnenstiehl, DelWayne R. and Dziak, Robert P. and Matsumoto, Haru and Lau, T. -K. Andy}, year={2013}, month={Jan}, pages={12–24} }
 @article{bohnenstiehl_howell_white_hey_2012, title={A modified basal outlining algorithm for identifying topographic highs from gridded elevation data, Part 1: Motivation and methods}, volume={49}, ISSN={0098-3004}, url={http://dx.doi.org/10.1016/j.cageo.2012.04.023}, DOI={10.1016/j.cageo.2012.04.023}, abstractNote={A new approach is developed to improve the automated identification and characterization of topographic highs having quasi-elliptical basal shapes. It is designed for the study of volcanic edifices in subaerial and submarine environments, but may be applied to identify any enclosed topography feature within a digital elevation model. The procedure utilizes the results of a standard closed-contouring approach, but then adjusts the elevation of the volcanic base by evaluating the shape of the edifice along a series of topographic profiles. The algorithm overcomes the principal limitations of a stand-alone closed-contouring approach and provides improved estimates of edifice size that are less sensitive to topographic gradients and the choice of contour search interval.}, journal={Computers & Geosciences}, publisher={Elsevier BV}, author={Bohnenstiehl, DelWayne R. and Howell, Julia K. and White, Scott M. and Hey, Richard N.}, year={2012}, month={Dec}, pages={308–314} }
 @article{howell_white_bohnenstiehl_2012, title={A modified basal outlining algorithm for identifying topographic highs in gridded elevation data, part 2: Application to Springerville Volcanic Field}, volume={49}, ISSN={0098-3004}, url={http://dx.doi.org/10.1016/j.cageo.2012.04.024}, DOI={10.1016/j.cageo.2012.04.024}, abstractNote={Delineating boundaries of volcanic edifices from surrounding topography is often difficult, time-consuming and subjective. For large volcanic fields, with hundreds of volcanoes, developing methods to efficiently and consistently identify and isolate volcanoes from surrounding topography is of utmost importance. Advances in technology for collecting and processing digital elevation datasets have significantly improved the spatial coverage and accuracy of digital elevation models. This study evaluates the efficacy of two automated methods, a simple closed-contouring algorithm and the newly developed extension of this method, known as the Modified Basal Outlining Algorithm (MBOA), to identify and isolate volcanic cones within the Springerville Volcanic Field in southeastern Arizona. Results from the automated methods are compared to geologically mapped cone boundaries isolated using petrographic and topographic characteristics (Condit, C., 2010. Geosphere 6, 430-443, doi:10.1130/GES00531.1). The MBOA reproduces the maximum height, area and volume for the Springerville Volcanic Field to within a few percent of the values obtained by field mapping; whereas the closed-contour algorithm systematically underestimates the size of the volcanic edifices. Cone steepness, which is often considered to reflect the integrated history of eruptive and erosional processes shaping an edifice, is found to be insensitive to method used to delineate the cone boundary. For all three methods, a negative exponential model can be used to describe the resulting height-frequency distribution of cones, with small differences in the estimated scaling parameters. Results from this study show the MBOA is an effective automated method for identifying and isolating volcanic edifices within a large volcanic field and an improvement over closed-contour algorithms.}, journal={Computers & Geosciences}, publisher={Elsevier BV}, author={Howell, Julia K. and White, Scott M. and Bohnenstiehl, DelWayne R.}, year={2012}, month={Dec}, pages={315–322} }
 @article{bohnenstiehl_scheip_matsumoto_dziak_2012, title={Acoustics variability of air gun signals recorded at intermediate ranges within the Lau Basin}, volume={13}, ISSN={1525-2027 1525-2027}, url={http://dx.doi.org/10.1029/2012GC004337}, DOI={10.1029/2012GC004337}, abstractNote={During January–February 2009, an active‐source seismic survey was performed over the Eastern Lau Spreading Center in the Lau Back‐Arc Basin (21°S, 176°S). Acoustic signals generated by theR/V Langseth's 36‐gun pneumatic source array were recorded within the deep sound channel at offsets of 29–416 km. The local ocean acoustic environment is everywhere bottom limited, with seafloor depths within the study domain ranging from ∼1700–2800 m. Low‐frequency (4–125 Hz) sound levels are monitored using root‐mean‐square, energy‐flux‐density and zero‐to‐peak measurement techniques. From these field data, transmission loss is found to exceed the predictions of a geometric spherical spreading model. At similar ranges, arrival amplitudes vary by up to 20 dB and durations vary by a factor of three to six. The depth of the seafloor beneath the air gun source exhibits a positive correlation with arrival duration and a negative correlation with range‐corrected amplitude, explaining up to 30% of the observed variation in both parameters. The strength of this correlation, however, varies for stations lying at different azimuths, highlighting the importance of seafloor aspect and slope in the coupling of bottom‐interacting acoustic energy into the sound channel. Range‐dependent ray tracing shows that shots deployed over shallower seafloor are more likely to produce sound channel trapped signals that propagate with limited bottom interaction. This results in arrivals that are more impulsive, with shorter durations and higher amplitudes. Shots deployed in deeper water typically undergo a larger number of bounces and are characterized by more emergent, longer duration and smaller amplitude arrivals.}, number={11}, journal={Geochemistry, Geophysics, Geosystems}, publisher={American Geophysical Union (AGU)}, author={Bohnenstiehl, DelWayne R. and Scheip, Corey M. and Matsumoto, Haru and Dziak, Robert P.}, year={2012}, month={Nov} }
 @article{wegmann_bohnenstiehl_bowman_homburg_windingstad_beery_2012, title={Assessing Coastal Landscape Change for Archaeological Purposes: Integrating Shallow Geophysics, Historical Archives and Geomorphology at Port Angeles, Washington, USA}, volume={19}, ISSN={["1075-2196"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84870725049&partnerID=MN8TOARS}, DOI={10.1002/arp.1431}, abstractNote={ABSTRACT}, number={4}, journal={ARCHAEOLOGICAL PROSPECTION}, author={Wegmann, Karl W. and Bohnenstiehl, Delwayne R. and Bowman, Jeffrey D. and Homburg, Jeffrey A. and Windingstad, Jason D. and Beery, Derek}, year={2012}, pages={229–252} }
 @article{dziak_baker_shaw_bohnenstiehl_chadwick_haxel_matsumoto_walker_2012, title={Flux measurements of explosive degassing using a yearlong hydroacoustic record at an erupting submarine volcano}, volume={13}, ISSN={1525-2027 1525-2027}, url={http://dx.doi.org/10.1029/2012GC004211}, DOI={10.1029/2012GC004211}, abstractNote={The output of gas and tephra from volcanoes is an inherently disorganized process that makes reliable flux estimates challenging to obtain. Continuous monitoring of gas flux has been achieved in only a few instances at subaerial volcanoes, but never for submarine volcanoes. Here we use the first sustained (yearlong) hydroacoustic monitoring of an erupting submarine volcano (NW Rota‐1, Mariana arc) to make calculations of explosive gas flux from a volcano into the ocean. Bursts of Strombolian explosive degassing at the volcano summit (520 m deep) occurred at 1–2 min intervals during the entire 12‐month hydrophone record and commonly exhibited cyclic step‐function changes between high and low intensity. Total gas flux calculated from the hydroacoustic record is 5.4 ± 0.6 Tg a−1, where the magmatic gases driving eruptions at NW Rota‐1 are primarily H2O, SO2, and CO2. Instantaneous fluxes varied by a factor of ∼100 over the deployment. Using melt inclusion information to estimate the concentration of CO2 in the explosive gases as 6.9 ± 0.7 wt %, we calculate an annual CO2 eruption flux of 0.4 ± 0.1 Tg a−1. This result is within the range of measured CO2 fluxes at continuously erupting subaerial volcanoes, and represents ∼0.2–0.6% of the annual estimated output of CO2from all subaerial arc volcanoes, and ∼0.4–0.6% of the mid‐ocean ridge flux. The multiyear eruptive history of NW Rota‐1 demonstrates that submarine volcanoes can be significant and sustained sources of CO2 to the shallow ocean.}, number={11}, journal={Geochemistry, Geophysics, Geosystems}, publisher={American Geophysical Union (AGU)}, author={Dziak, R. P. and Baker, E. T. and Shaw, A. M. and Bohnenstiehl, D. R. and Chadwick, W. W., Jr. and Haxel, J. H. and Matsumoto, H. and Walker, S. L.}, year={2012}, month={Nov} }
 @article{dziak_bohnenstiehl_smith_2012, title={HYDROACOUSTIC MONITORING OF OCEANIC SPREADING CENTERS Past, Present, and Future}, volume={25}, ISSN={["1042-8275"]}, DOI={10.5670/oceanog.2012.10}, abstractNote={This is the publisher’s final pdf. The published article is copyrighted by The Oceanography Society and can be found at: http://www.tos.org/}, number={1}, journal={OCEANOGRAPHY}, author={Dziak, Robert P. and Bohnenstiehl, DelWayne R. and Smith, Deborah K.}, year={2012}, month={Mar}, pages={116–127} }
 @article{dziak_haxel_bohnenstiehl_chadwick_nooner_fowler_matsumoto_butterfield_2012, title={Seismic precursors and magma ascent before the April 2011 eruption at Axial Seamount}, volume={5}, ISSN={["1752-0894"]}, DOI={10.1038/ngeo1490}, abstractNote={For volcanoes at submarine rift zones, a direct link between seismicity, seafloor deformation and magma intrusion has not been demonstrated. Recordings from ocean-bottom hydrophones and bottom-pressure recorders map an increasing rate of seismicity at Axial Seamount, northeast Pacific, over several years before its eruption in April 2011. Volcanoes at spreading centres on land often exhibit seismicity and ground inflation months to years before an eruption, caused by a gradual influx of magma to the source reservoir1,2,3,4. Deflation and seismicity can occur on time scales of hours to days, and result from the injection of magma into adjacent rift zones5,6,7,8. Volcanoes at submarine rift zones, such as Axial Seamount in the northeast Pacific Ocean, have exhibited similar behaviour9,10,11,12, but a direct link between seismicity, seafloor deformation and magma intrusion has never been demonstrated. Here we present recordings from ocean-bottom hydrophones and an established array of bottom-pressure recorders that reveal patterns of both microearthquakes and seafloor deformation at Axial Seamount on the Juan de Fuca Ridge, before it erupted in April 2011. Our observations show that the rate of seismicity increased steadily during a period of several years, leading up to an intrusion and eruption of magma that began on 6 April 2011. We also detected a sudden increase in seismo-acoustic energy about 2.6 h before the eruption began. Our data indicate that access to real-time seismic data, projected to be available in the near future, might facilitate short-term forecasting and provide sufficient lead-time to prepare in situ instrumentation before future intrusion and eruption events.}, number={7}, journal={NATURE GEOSCIENCE}, author={Dziak, R. P. and Haxel, J. H. and Bohnenstiehl, D. R. and Chadwick, W. W., Jr. and Nooner, S. L. and Fowler, M. J. and Matsumoto, H. and Butterfield, D. A.}, year={2012}, month={Jul}, pages={478–482} }
 @article{matsumoto_haxel_dziak_bohnenstiehl_embley_2011, title={Mapping the sound field of an erupting submarine volcano using an acoustic glider}, volume={129}, ISSN={["1520-8524"]}, DOI={10.1121/1.3547720}, abstractNote={An underwater glider with an acoustic data logger flew toward a recently discovered erupting submarine volcano in the northern Lau basin. With the volcano providing a wide-band sound source, recordings from the two-day survey produced a two-dimensional sound level map spanning 1 km (depth) × 40 km(distance). The observed sound field shows depth- and range-dependence, with the first-order spa tial pattern being consistent with the predictions of a range-dependent propagation model. The results allow constraining the acoustic source level of the volcanic activity and suggest that the glider provides an effective platform for monitoring natural and anthropogenic ocean sounds.}, number={3}, journal={JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA}, author={Matsumoto, Haru and Haxel, Joseph H. and Dziak, Robert P. and Bohnenstiehl, Delwayne R. and Embley, Robert W.}, year={2011}, month={Mar}, pages={EL94–EL99} }
 @article{stafford_chapp_bohnenstiel_tolstoy_2011, title={Seasonal detection of three types of "pygmy" blue whale calls in the Indian Ocean}, volume={27}, ISSN={["0824-0469"]}, DOI={10.1111/j.1748-7692.2010.00437.x}, abstractNote={Abstract}, number={4}, journal={MARINE MAMMAL SCIENCE}, author={Stafford, Kathleen M. and Chapp, Emily and Bohnenstiel, DelWayne R. and Tolstoy, Maya}, year={2011}, month={Oct}, pages={828–840} }
 @book{wegmann_homburg_bohnenstiehl_bowman_windingstad_huber_2010, place={Tuscon, AZ}, title={Geomorphology of the City of Port Angeles Waterfront}, number={10-82}, institution={Statistical Research, Inc.}, author={Wegmann, K.W. and Homburg, J.A. and Bohnenstiehl, D.R. and Bowman, J.D. and Windingstad, J.D. and Huber, E.K.}, year={2010} }
 @article{dziak_park_lee_matsumoto_bohnenstiehl_haxel_2010, title={Tectonomagmatic activity and ice dynamics in the Bransfield Strait back-arc basin, Antarctica}, volume={115}, ISSN={["2169-9356"]}, DOI={10.1029/2009jb006295}, abstractNote={An array of moored hydrophones was used to monitor the spatiotemporal distribution of small‐ to moderate‐sized earthquakes and ice‐generated sounds within the Bransfield Strait, Antarctica. During a 2 year period, a total of 3900 earthquakes, 5925 icequakes and numerous ice tremor events were located throughout the region. The seismic activity included eight space‐time earthquake clusters, positioned along the central neovolcanic rift zone of the young Bransfield back‐arc basin. These sequences of small magnitude earthquakes, or swarms, suggest ongoing magmatic activity that becomes localized along isolated volcanic features and fissure‐like ridges in the southwest portion of the basin. A total of 122 earthquakes were located along the South Shetland trench, indicating continued deformation and possibly ongoing subduction along this margin. The large number of icequakes observed show a temporal pattern related to seasonal freeze‐thaw cycles and a spatial distribution consistent with channeling of sea ice along submarine canyons from glacier fronts. Several harmonic tremor episodes were sourced from a large (∼30 km2) iceberg that entered northeast portion of the basin. The spectral character of these signals suggests they were produced by either resonance of a small chamber of fluid within the iceberg, or more likely, due to periodicity of discrete stick‐slip events caused by contact of the moving iceberg with the seafloor. These pressure waves appear to have been excited by abrasion of the iceberg along the seafloor as it passed Clarence and Elephant Islands.}, journal={JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH}, author={Dziak, Robert P. and Park, Minkyu and Lee, Won Sang and Matsumoto, Haru and Bohnenstiehl, DelWayne R. and Haxel, Joseph H.}, year={2010}, month={Jan} }
 @article{tolstoy_diebold_doermann_nooner_webb_bohnenstiehl_crone_holmes_2009, title={Broadband calibration of the R/V Marcus G. Langseth four-string seismic sources}, volume={10}, ISSN={["1525-2027"]}, DOI={10.1029/2009gc002451}, abstractNote={The R/V Marcus G. Langseth is the first 3‐D seismic vessel operated by the U.S. academic community. With up to a four‐string, 36‐element source and four 6‐km‐long solid state hydrophone arrays, this vessel promises significant new insights into Earth science processes. The potential impact of anthropogenic sound sources on marine life is an important topic to the marine seismic community. To ensure that operations fully comply with existing and future marine mammal permitting requirements, a calibration experiment was conducted in the Gulf of Mexico in 2007–2008. Results are presented from deep (∼1.6 km) and shallow (∼50 m) water sites, obtained using the full 36‐element (6600 cubic inches) seismic source. This array configuration will require the largest safety radii, and the deep and shallow sites provide two contrasting operational environments. Results show that safety radii and the offset between root‐mean‐square and sound exposure level measurements were highly dependent on water depth.}, journal={GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS}, author={Tolstoy, M. and Diebold, J. and Doermann, L. and Nooner, S. and Webb, S. C. and Bohnenstiehl, D. R. and Crone, T. J. and Holmes, R. C.}, year={2009}, month={Aug} }
 @article{nedimovic_bohnenstiehl_carbotte_canales_dziak_2009, title={Faulting and hydration of the Juan de Fuca plate system}, volume={284}, ISSN={["1385-013X"]}, DOI={10.1016/j.epsl.2009.04.013}, abstractNote={Multichannel seismic observations provide the first direct images of crustal scale normal faults within the Juan de Fuca plate system and indicate that brittle deformation extends up to ~ 200 km seaward of the Cascadia trench. Within the sedimentary layering steeply dipping faults are identified by stratigraphic offsets, with maximum throws of 110 ± 10 m found near the trench. Fault throws diminish both upsection and seaward from the trench. Long-term throw rates are estimated to be 13 ± 2 mm/kyr. Faulted offsets within the sedimentary layering are typically linked to larger offset scarps in the basement topography, suggesting reactivation of the normal fault systems formed at the spreading center. Imaged reflections within the gabbroic igneous crust indicate swallowing fault dips at depth. These reflections require local alteration to produce an impedance contrast, indicating that the imaged fault structures provide pathways for fluid transport and hydration. As the depth extent of imaged faulting within this young and sediment insulated oceanic plate is primarily limited to approximately Moho depths, fault-controlled hydration appears to be largely restricted to crustal levels. If dehydration embrittlement is an important mechanism for triggering intermediate-depth earthquakes within the subducting slab, then the limited occurrence rate and magnitude of intraslab seismicity at the Cascadia margin may in part be explained by the limited amount of water imbedded into the uppermost oceanic mantle prior to subduction. The distribution of submarine earthquakes within the Juan de Fuca plate system indicates that propagator wake areas are likely to be more faulted and therefore more hydrated than other parts of this plate system. However, being largely restricted to crustal levels, this localized increase in hydration generally does not appear to have a measurable effect on the intraslab seismicity along most of the subducted propagator wakes at the Cascadia margin.}, number={1-2}, journal={EARTH AND PLANETARY SCIENCE LETTERS}, author={Nedimovic, Mladen R. and Bohnenstiehl, DelWayne R. and Carbotte, Suzanne M. and Canales, J. Pablo and Dziak, Robert P.}, year={2009}, month={Jun}, pages={94–102} }
 @article{dziak_bohnenstiehl_matsumoto_fowler_haxel_tolstoy_waldhauser_2009, title={January 2006 seafloor-spreading event at 9 degrees 50 ' N, East Pacific Rise: Ridge dike intrusion and transform fault interactions from regional hydroacoustic}, volume={10}, ISSN={["1525-2027"]}, DOI={10.1029/2009gc002388}, abstractNote={An array of autonomous underwater hydrophones is used to investigate regional seismicity associated with the 22 January 2006 seafloor‐spreading event on the northern East Pacific Rise near 9°50′N. Significant earthquake activity was observed beginning 3 weeks prior to the eruption, where a total of 255 earthquakes were detected within the vicinity of the 9°50′N area. This was followed by a series of 252 events on 22 January and a rapid decline to background seismicity levels during the subsequent 3 days. Because of their small magnitudes, accurate locations could be derived for only 20 of these events, 18 of which occurred during a 1‐h period on 22 January. These earthquakes cluster near 9°45′N and 9°55′N, at the distal ends of the young lava flows identified posteruption, where the activity displays a distinct spatial‐temporal pattern, alternating from the north to the south and then back to the north. This implies either rapid bilateral propagation along the rift or the near‐simultaneous injection of melt vertically from the axial magma lens. Short‐duration T wave risetimes are consistent with the eruption of lavas in the vicinity of 9°50′N on 22 January 2006. Eruptions on 12 and 15–16 January also may be inferred from the risetime data; however, the locations of these smaller‐magnitude events cannot be determined accurately. Roughly 15 h after the last earthquakes were located adjacent to the eruption site, a sequence of 16 earthquakes began to the north‐northeast at a distance of 25–40 km from the 9°50′N site. These events are located in vicinity of the Clipperton Transform and its western inside corner, an area from which the regional hydrophone network routinely detects seismicity. Coulomb stress modeling indicates that a dike intrusion spanning the known eruptive zone to the south (9°46′–9°56′N) would act to promote normal faulting or a combination of normal faulting and transform slip within this region, with stress changes on the order of 1–10 kPa.}, journal={GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS}, author={Dziak, Robert P. and Bohnenstiehl, Delwayne R. and Matsumoto, Haruyoshi and Fowler, Matthew J. and Haxel, Joseph H. and Tolstoy, Maya and Waldhauser, Felix}, year={2009}, month={Jun} }
 @article{monigle_bohnenstiehl_tolstoy_waldhauser_2009, title={Seismic tremor at the 9 degrees 50 ' N East Pacific Rise eruption site}, volume={10}, ISSN={["1525-2027"]}, DOI={10.1029/2009gc002561}, abstractNote={Ocean bottom seismic observations within the 9°50′N region of the East Pacific Rise indicate persistent, low‐amplitude tremor activity throughout the October 2003 through February 2007 period of monitoring. These signals exhibit either monochromatic or polychromatic spectral characteristics, with a ∼6 Hz fundamental frequency and up to two harmonics. Individual events cannot be correlated between nearby (<1 km) stations, implying the presence of multiple, small‐amplitude sources positioned within the shallow crust. Tremor exhibits a semidiurnal periodicity, with some stations recording activity during times of increasing tidal extension and others detecting tremor signals during times of increasing compression. The amplitude, duration, and rate of activity also correlate positively with fortnightly changes in the amplitude of the tides. These spatiotemporal patterns are consistent with tremor generation in response to tidally modulated fluid flow within a network of shallow cracks. Tremor energy flux is spatially and temporally heterogeneous; however, there are extended periods of greater and lesser activity that can be tracked across portions of the array. Despite their shallow crustal origin, changes in tremor amplitude and spectral character occur in the months prior to a major microearthquake swarm and inferred seafloor spreading event on 22 January 2006, with an increase in the degree of correlation between tremor activity and tidal strain in the weeks leading up to this event. After the spreading event, two eruption‐surviving stations near the axis continue to show high rates of tremor activity, whereas these signals are suppressed at the single station recovered from the near‐axis flanks. This off‐axis quiescence may result from the dike‐induced closing of cracks or perhaps from the emplacement of impermeable flows near the station.}, journal={GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS}, author={Monigle, P. W. and Bohnenstiehl, D. R. and Tolstoy, M. and Waldhauser, F.}, year={2009}, month={Nov} }
 @article{stroup_tolstoy_crone_malinverno_bohnenstiehl_waldhauser_2009, title={Systematic along-axis tidal triggering of microearthquakes observed at 9 degrees 50 ' N East Pacific Rise}, volume={36}, ISSN={["1944-8007"]}, DOI={10.1029/2009gl039493}, abstractNote={Hydrothermal fluid circulation at mid‐ocean ridges facilitates the exchange of heat and chemicals between the oceans and the solid Earth, and supports chemosynthetic microbial and macro‐faunal communities. The structure and evolution of newly formed oceanic crust plays a dominant role in controlling the character and longevity of hydrothermal systems; however, direct measurements of subsurface processes remain technologically challenging to obtain. Previous studies have shown that tidally‐induced stresses within the subseafloor modulate both fluid flow and microearthquake origin times. In this study, we observe systematic along‐axis variations between peak microearthquake activity and maximum predicted tidal extension beneath the hydrothermal vent site at 9°50′N East Pacific Rise. We interpret this systematic triggering to result from pore‐pressure perturbations propagating laterally through the hydrothermal system. Based on our observations and a one‐dimensional pore pressure perturbation model, we estimate bulk permeability at ∼10−13 to 10−12 m2 within layer 2B over a calculated diffusive lengthscale of 2.0 km.}, journal={GEOPHYSICAL RESEARCH LETTERS}, author={Stroup, D. F. and Tolstoy, M. and Crone, T. J. and Malinverno, A. and Bohnenstiehl, D. R. and Waldhauser, F.}, year={2009}, month={Sep} }
 @article{bohnenstiehl_howell_hey_2008, title={Distribution of axial lava domes along a superfast overlapping spreading center, 27-32 degrees S on the East Pacific Rise}, volume={9}, ISSN={["1525-2027"]}, DOI={10.1029/2008gc002158}, abstractNote={Deep‐towed DSL‐120 bathymetric data are used to investigate the pattern of lava dome formation along a superfast spreading portion of the southern East Pacific Rise (EPR), including the overlapping limbs of a giant (120 × 120 km) propagator near 29°S. Along the 670 km of the axis surveyed, 1172 small domes were identified using a closed contour algorithm. Their abundance, defined by spatial density, is well correlated with the along‐axis relief of the ridge crest. Where the western and eastern limbs plunge toward the overlap zone, densities are high (3–6 km−2); however, where the axial depth profile is shallow and flat, densities are comparably low (0.4 km−2). Volcanic domes within the low abundance areas are characterized by lower ratios of height to basal radius (0.15 versus 0.22), smaller maximum heights (18 versus 40 m), and a larger relative percentage of small versus large mounds. The zone of high dome abundance encompasses the overlapping limbs of the rift and extends more than 100 km to the north and south beyond the overlap zone. Domes form dominantly during low effusion rate, point‐source eruptions, which suggests that discontinuous melt lenses underlie the ridge axis proximal to the overlapper. Conversely, fissure‐fed sheet flows dominate along the more distal segments, implying the presence of a more continuous axial magma lens. Throughout the survey area, dome abundance increases systematically near second‐order segment boundaries. Within the high abundance zone, some third‐order offsets also correlate with increased dome production, but local peaks in abundance are not tied exclusively to higher‐order ridge offsets. Where dome abundance is low, domes are clustered tightly near second‐order offsets and there is no increase in dome abundance near third‐order segment boundaries.}, journal={GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS}, author={Bohnenstiehl, D. R. and Howell, J. K. and Hey, R. N.}, year={2008}, month={Dec} }
 @article{bohnenstiehl_waldhauser_tolstoy_2008, title={Frequency-magnitude distribution of microearthquakes beneath the 9 degrees 50 ' N region of the East Pacific Rise, October 2003 through April 2004}, volume={9}, ISSN={["1525-2027"]}, DOI={10.1029/2008gc002128}, abstractNote={Relocated hypocentral data from a 7‐month deployment (October 2003 to April 2004) of ocean bottom seismometers provide an opportunity to map microearthquake frequency‐magnitude distributions (FMDs) along the 9°49–52′N region on the East Pacific Rise. These analyses, which incorporate more than 9000 earthquakes, represent the first investigation of the 3‐D spatial and temporal patterns of FMDs along any mid‐ocean ridge spreading center. The data are described well by a Gutenberg‐Richter model, indicating a power law or fractal relationship between earthquake size and frequency. The scaling exponent, or b value, shows significant spatial variability, exceeding a value of 2.0 at the shallowest depths on axis and dropping below 1.0 away from the axial trough. This spatial pattern is consistent with an inverse relationship between b value and ambient stress conditions, with the lowest stress levels at shallow depths and relatively high stress levels (or low pore pressures) observed away from the axial zone. Intermediate b values are observed on‐axis above the ridge system's melt lens; however, within this region there also exists significant spatial variability. This indicates that stress conditions and/or structural heterogeneity may vary at subkilometer scales within the hydrothermal circulation cell. Although the observational period is characterized by increasing seismicity rates, building toward an eruptive episode in January 2006, the first‐order spatial pattern of b values is sustained, with no overall temporal trend. As a byproduct of this b value analysis, the detection capabilities of the array are assessed empirically.}, journal={GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS}, author={Bohnenstiehl, D. R. and Waldhauser, F. and Tolstoy, M.}, year={2008}, month={Oct} }
 @article{tolstoy_waldhauser_bohnenstiehl_weekly_kim_2008, title={Seismic identification of along-axis hydrothermal flow on the East Pacific Rise}, volume={451}, ISSN={0028-0836 1476-4687}, url={http://dx.doi.org/10.1038/nature06424}, DOI={10.1038/nature06424}, abstractNote={Hydrothermal circulation at the axis of mid-ocean ridges affects the chemistry of the lithosphere and overlying ocean, supports chemosynthetic biological communities and is responsible for significant heat transfer from the lithosphere to the ocean. It is commonly thought that flow in these systems is oriented across the ridge axis, with recharge occurring along off-axis faults, but the structure and scale of hydrothermal systems are usually inferred from thermal and geochemical models constrained by the geophysical setting, rather than direct observations. The presence of microearthquakes may shed light on hydrothermal pathways by revealing zones of thermal cracking where cold sea water extracts heat from hot crustal rocks, as well as regions where magmatic and tectonic stresses create fractures that increase porosity and permeability. Here we show that hypocentres beneath a well-studied hydrothermal vent field on the East Pacific Rise cluster in a vertical pipe-like zone near a small axial discontinuity, and in a band that lies directly above the axial magma chamber. The location of the shallow pipe-like cluster relative to the distribution and temperature of hydrothermal vents along this section of the ridge suggests that hydrothermal recharge may be concentrated there as a consequence of the permeability generated by tectonic fracturing. Furthermore, we interpret the band of seismicity above the magma chamber as a zone of hydrothermal cracking, which suggests that hydrothermal circulation may be strongly aligned along the ridge axis. We conclude that models that suggest that hydrothermal cells are oriented across-axis, with diffuse off-axis recharge zones, may not apply to the fast-spreading East Pacific Rise.}, number={7175}, journal={Nature}, publisher={Springer Science and Business Media LLC}, author={Tolstoy, M. and Waldhauser, F. and Bohnenstiehl, D. R. and Weekly, R. T. and Kim, W.-Y.}, year={2008}, month={Jan}, pages={181–184} }
 @article{bohnenstiehl_2007, title={Comment on "The directionality of acoustic T-phase signals from small magnitude submarine earthquakes" [J. Acoust. Soc. Am. 119, 3669-3675 (2006)]}, volume={121}, ISSN={["1520-8524"]}, DOI={10.1121/1.2435982}, abstractNote={In a recent paper, Chapman and Marrett [J. Acoust. Soc. Am. 119, 3669–3675 (2006)] examined the tertiary (T-) waves associated with three subduction-related earthquakes within the South Fiji Basin. In that paper it is argued that acoustic energy is radiated into the sound channel by downslope propagation along abyssal seamounts and ridges that lie distant to the epicenter. A reexamination of the travel-time constraints indicates that this interpretation is not well supported. Rather, the propagation model that is described would require the high-amplitude T-wave components to be sourced well to the east of the region identified, along a relatively flat-lying seafloor.}, number={3}, journal={JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA}, author={Bohnenstiehl, Delwayne R.}, year={2007}, month={Mar}, pages={1293–1296} }
 @article{stroup_bohnenstiehl_tolstoy_waldhauser_weekly_2007, title={Pulse of the seafloor: Tidal triggering of microearthquakes at 9°50′N East Pacific Rise}, volume={34}, ISSN={0094-8276}, url={http://dx.doi.org/10.1029/2007GL030088}, DOI={10.1029/2007GL030088}, abstractNote={Unequivocal evidence of tidal triggering is observed for microearthquakes (−0.4 to 2.0 ML) recorded between October 2003 to April 2004 near 9°50′N on the East Pacific Rise (EPR). Although semidiurnal tidal stress changes are small (<2 kPa), seismicity exhibits a significant (>99.9%) nonrandom temporal distribution, with events occurring preferentially near times of peak extension. Due to the proximity of this site to an ocean tidal node, where changes in sea surface height are minimal, periodic stress changes are dominated by the solid Earth tide. In contrast, previous studies on the Juan de Fuca Ridge have shown microearthquake triggering to be a response to seafloor unloading during times of low ocean tide. The modulation of 9°50′N microearthquakes by small‐amplitude periodic stresses is consistent with earthquake nucleation within a high stressing rate environment that is maintained near a critical state of failure by on‐axis magmatic and hydrothermal processes.}, number={15}, journal={Geophysical Research Letters}, publisher={American Geophysical Union (AGU)}, author={Stroup, D. F. and Bohnenstiehl, D. R. and Tolstoy, M. and Waldhauser, F. and Weekly, R. T.}, year={2007}, month={Aug} }
 @article{dziak_bohnenstiehl_cowen_baker_rubin_haxel_fowler_2007, title={Rapid dike emplacement leads to eruptions and hydrothermal plume release during seafloor spreading events}, volume={35}, ISSN={["0091-7613"]}, DOI={10.1130/g23476a.1}, abstractNote={The creation of ocean crust by rapid injection of magma at mid-ocean ridges can lead to eruptions of lava onto the seafloor and release of “event plumes,” which are huge volumes of anomalously warm water enriched in reduced chemicals that rise up to 1 km above the seafloor. Here, we use seismic data to show that seafloor eruptions and the release of hydrothermal event plumes correspond to diking episodes with high injection velocities and rapid onset of magma emplacement within the rift zone. These attributes result from high excess magma pressure at the dike source, likely due to a new influx of melt from the mantle. These dynamic magmatic conditions can be detected remotely and may predict the likelihood of event plume release during future seafloor spreading events.}, number={7}, journal={GEOLOGY}, author={Dziak, R. P. and Bohnenstiehl, D. R. and Cowen, J. P. and Baker, E. T. and Rubin, K. H. and Haxel, J. H. and Fowler, M. J.}, year={2007}, month={Jul}, pages={579–582} }
 @article{bohnenstiehl_2006, title={A comment on "Bathymetry gradients of lineated abyssal hills: Inferring seafloor spreading vectors and a new model for hills formed at ultra-fast spreading rates" by K.A. Kriner et al. [Earth Planet. Sci. Lett. 242 (2006) 98-110]}, volume={252}, ISSN={["1385-013X"]}, DOI={10.1016/j.epsl.2006.10.012}, number={3-4}, journal={EARTH AND PLANETARY SCIENCE LETTERS}, author={Bohnenstiehl, DelWayne R.}, year={2006}, month={Dec}, pages={490–494} }
 @article{supak_bohnenstiehl_buck_2006, title={Flexing is not stretching: An analogue study of flexure-induced fault populations}, volume={246}, ISSN={0012-821X}, url={http://dx.doi.org/10.1016/j.epsl.2006.03.028}, DOI={10.1016/j.epsl.2006.03.028}, abstractNote={Flexure-induced fractures are predicted to form along the axis of maximum tensile stress within a bending brittle plate. The mechanics of this process differ from extensional fault growth in response to lithosphere stretching, where a distributed set of simultaneously growing fractures evolves through elastic interaction. To simulate extensional fault growth during lithospheric flexure, partially solidified plaster layers resting on a foam rubber substrate were depressed by a linear load and fractured in analogue models. The length- and spacing-frequency distributions of the resulting crack populations were analyzed for a series of nine thin (5 mm) and ten thick (15 mm) layer experiments. Previous analogue stretching models predict power-law length-frequency distributions and clustered spacings (Cv > 1) at low strains (< ~ 10%), evolving toward an exponential distribution and more regular spacings (Cv < 1, often termed anticlusted) at larger stains. Crack populations formed at low strains during these bending experiments, however, exhibit length-frequency distributions that are not well described by either a power-law or exponential distribution model, being somewhat better fit by the exponential model in the thin layer experiments and somewhat better fit by the power-law model in the thick layer experiments. One-dimensional spacing-frequency distributions are well described by an exponential distribution model, and crack spacing can be characterized as anticlustered within both the thin and thick layer experiments. Although similar spacing patterns may develop when fracture growth is limited by mechanical layer thickness, the characteristic spacing does not scale with the layer thickness in these flexural experiments. Alternatively, the development of power-law (fractal) populations may be inhibited by the growth history of flexure-induced faults, whereby nucleation is localized spatially due to the distribution of stresses within bending plate. These analogue experiments may be relevant to the outer-rise regions of subduction zones, where the oceanic plate is flexed downward, and the abyssal flanks adjacent to fast-spreading mid-ocean ridge crests, where recent models for axial high development suggest that the plate is unbent as it rafts away from the axis.}, number={1-2}, journal={Earth and Planetary Science Letters}, publisher={Elsevier BV}, author={Supak, S and Bohnenstiehl, D and Buck, W}, year={2006}, month={Jun}, pages={125–137} }
 @article{tolstoy_bohnenstiehl_2006, title={Hydroacoustic contributions to understanding the December 26th 2004 great Sumatra–Andaman Earthquake}, volume={27}, ISSN={0169-3298 1573-0956}, url={http://dx.doi.org/10.1007/s10712-006-9003-6}, DOI={10.1007/s10712-006-9003-6}, number={6}, journal={Surveys in Geophysics}, publisher={Springer Science and Business Media LLC}, author={Tolstoy, Maya and Bohnenstiehl, DelWayne R.}, year={2006}, month={Aug}, pages={633–646} }
 @article{bohnenstiehl_2005, title={A different kind of foreshock}, volume={434}, ISSN={0028-0836 1476-4687}, url={http://dx.doi.org/10.1038/434445a}, DOI={10.1038/434445a}, abstractNote={Underwater sound recordings have been used to monitor transform faults in the equatorial Pacific, implicating a mechanism of foreshock generation distinct from that on most continental fault systems.}, number={7032}, journal={Nature}, publisher={Springer Science and Business Media LLC}, author={Bohnenstiehl, DelWayne R.}, year={2005}, month={Mar}, pages={445–447} }
 @article{chapp_bohnenstiehl_tolstoy_2005, title={Sound-channel observations of ice-generated tremor in the Indian Ocean}, volume={6}, ISSN={1525-2027}, url={http://dx.doi.org/10.1029/2004GC000889}, DOI={10.1029/2004GC000889}, abstractNote={Mid to low southern latitude hydrophone stations within the Indian Ocean have recorded two distinct types of low‐frequency (<100 Hz) tremor that can be correlated with drifting icebergs and glacial features along the Wilkes Land coast of eastern Antarctica. The most common of these signals is a variable harmonic tremor (VHT), with spectral peaks that exhibit frequency fluctuations through time. These signals typically display a 4 to 10 Hz fundamental frequency and may have as many as ten harmonic bands. Individual VHT signal packets have durations of up to ∼30 min and occur throughout the year in clusters that continue for hours to days. A second, less commonly observed signal is characterized by shorter duration (25 to 90 s) pulses with a convex‐upward spectrogram appearance. These cusped pulse tremors (CPT) often exhibit a near‐uniform pulse spacing, with episodes continuing for minutes to hours. Tremor received levels at hydrophones near 32°S, 114°E and 7°S, 72°E reach as high as 142 and 133 dB re 1 μPa (peak to peak), respectively. Propagation likely occurs as a sea surface–reflected phase at high latitudes and a sound channel phase north of the convergence zone, with low‐frequency transmission loss estimates suggesting maximum acoustic source levels of ∼245 dB re 1 μPa at 1 m. Source locations for a subset of the loudest VHT signals correlate with the satellite‐derived locations of a large iceberg (B‐15D) that migrated westward along the Wilkes Land shelf region during 2002 and early 2003. Most VHT sources, however, cannot be correlated with known iceberg locations, suggesting that these signals also may be sourced from smaller unnamed icebergs and/or associated with outlet glaciers distributed along the Wilkes Land coast. CPT signals have a more limited spatial distribution, originating from five specific regions where ice streams are observed. The harmonic nature of both signal types is consistent with the resonance of an ice layer or fluid‐filled cavity within an ice mass.}, number={6}, journal={Geochemistry, Geophysics, Geosystems}, publisher={American Geophysical Union (AGU)}, author={Chapp, Emily and Bohnenstiehl, DelWayne R. and Tolstoy, Maya}, year={2005}, month={Jun} }
 @article{stafford_bohnenstiehl_tolstoy_chapp_mellinger_moore_2004, title={Antarctic-type blue whale calls recorded at low latitudes in the Indian and eastern Pacific Oceans}, volume={51}, ISSN={0967-0637}, url={http://dx.doi.org/10.1016/j.dsr.2004.05.007}, DOI={10.1016/j.dsr.2004.05.007}, abstractNote={Blue whales, Balaenoptera musculus, were once abundant around the Antarctic during the austral summer, but intensive whaling during the first half of the 20th century reduced their numbers by over 99%. Although interannual variability of blue whale occurrence on the Antarctic feeding grounds was documented by whalers, little was known about where the whales spent the winter months. Antarctic blue whales produce calls that are distinct from those produced by blue whales elsewhere in the world. To investigate potential winter migratory destinations of Antarctic blue whales, we examined acoustic data for these signals from two low-latitude locales: the eastern tropical Pacific Ocean and the Indian Ocean. Antarctic-type blue whale calls were detected on hydrophones in both regions during the austral autumn and winter (May–September), with peak detections in July. Calls occurred over relatively brief periods in both oceans, suggesting that there may be only a few animals migrating so far north and/or producing calls. Antarctic blue whales appear to use both the Indian and eastern Pacific Oceans concurrently, indicating that there is not a single migratory destination. Acoustic data from the South Atlantic and from mid-latitudes in the Indian or Pacific Oceans are needed for a more global understanding of migratory patterns and destinations of Antarctic blue whales.}, number={10}, journal={Deep Sea Research Part I: Oceanographic Research Papers}, publisher={Elsevier BV}, author={Stafford, Kathleen M and Bohnenstiehl, DelWayne R and Tolstoy, Maya and Chapp, Emily and Mellinger, David K and Moore, Sue E}, year={2004}, month={Oct}, pages={1337–1346} }
 @article{bohnenstiehl_tolstoy_chapp_2004, title={Breaking into the plate: A 7.6 Mw fracture-zone earthquake adjacent to the Central Indian Ridge}, volume={31}, ISSN={0094-8276}, url={http://dx.doi.org/10.1029/2003GL018981}, DOI={10.1029/2003GL018981}, abstractNote={On 15 July 2003 an extremely large (7.6 Mw) strike‐slip earthquake initiated on or near the end of an active transform along the northern Central Indian Ridge. The event propagated away from the plate boundary along the typically inactive fracture zone, with a sense of slip that opposes the active transform slip direction. Seismically and hydroacoustically determined aftershock locations delineate a 210 ± 25 km long mainshock rupture. The seismic moment and rupture dimensions imply a stress drop of 4.5–6.5 MPa and a mean slip of 3.0 ± 0.5 m. The largest aftershock (5.6 Mw) occurred on the active portion of a neighboring transform at a distance of ∼160 km, where mainshock‐induced static stress changes are predicted to promote failure. Near‐axis fracture‐zone earthquakes may promote and inhibit ridge‐parallel diking along different spreading segments, perhaps contributing to inter‐segment variability in the rate and asymmetry of spreading.}, number={2}, journal={Geophysical Research Letters}, publisher={American Geophysical Union (AGU)}, author={Bohnenstiehl, DelWayne R. and Tolstoy, Maya and Chapp, Emily}, year={2004}, month={Jan} }
 @article{dziak_smith_bohnenstiehl_fox_debruyeres_matsumoto_tolstoy_fornari_2004, title={Evidence of a recent magma dike intrusion at the slow spreading Lucky Strike segment, Mid-Atlantic Ridge}, volume={109}, ISSN={0148-0227}, url={http://dx.doi.org/10.1029/2004JB003141}, DOI={10.1029/2004JB003141}, abstractNote={Mid‐ocean ridge volcanic activity is the fundamental process for creation of ocean crust, yet the dynamics of magma emplacement along the slow spreading Mid‐Atlantic Ridge (MAR) are largely unknown. We present acoustical, seismological, and biological evidence of a magmatic dike intrusion at the Lucky Strike segment, the first detected from the deeper sections (>1500 m) of the MAR. The dike caused the largest teleseismic earthquake swarm recorded at Lucky Strike in >20 years of seismic monitoring, and one of the largest ever recorded on the northern MAR. Hydrophone records indicate that the rate of earthquake activity decays in a nontectonic manner and that the onset of the swarm was accompanied by 30 min of broadband (>3 Hz) intrusion tremor, suggesting a volcanic origin. Two submersible investigations of high‐temperature vents located at the summit of Lucky Strike Seamount 3 months and 1 year after the swarm showed a significant increase in microbial activity and diffuse venting. This magmatic episode may represent one form of volcanism along the MAR, where highly focused pockets of magma are intruded sporadically into the shallow ocean crust beneath long‐lived, discrete volcanic structures recharging preexisting seafloor hydrothermal vents and ecosystems.}, number={B12}, journal={Journal of Geophysical Research: Solid Earth}, publisher={American Geophysical Union (AGU)}, author={Dziak, Robert P. and Smith, Deborah K. and Bohnenstiehl, DelWayne R. and Fox, Christopher G. and Debruyeres, Daniel and Matsumoto, Haru and Tolstoy, Maya and Fornari, Daniel J.}, year={2004}, month={Dec} }
 @article{hey_baker_bohnenstiehl_massoth_kleinrock_martinez_naar_pardee_lupton_feely_et al._2004, title={Tectonic/volcanic segmentation and controls on hydrothermal venting along Earth's fastest seafloor spreading system, EPR 27°-32°S}, volume={5}, ISSN={1525-2027}, url={http://dx.doi.org/10.1029/2004GC000764}, DOI={10.1029/2004GC000764}, abstractNote={We have collected 12 kHz SeaBeam bathymetry and 120 kHz DSL‐120 side‐scan sonar and bathymetry data to determine the tectonic and volcanic segmentation along the fastest spreading (∼150 km/Myr) part of the global mid‐ocean ridge system, the southern East Pacific Rise between the Easter and Juan Fernandez microplates. This area is presently reorganizing by large‐scale dueling rift propagation and possible protomicroplate tectonics. Fracture patterns observed in the side‐scan data define structural segmentation scales along these ridge segments. These sometimes, but not always, correlate with linear volcanic systems defining segmentation in the SeaBeam data. Some of the subsegments behave cohesively, with in‐phase tectonic activity, while fundamental discontinuities occur between other subsegments. We also collected hydrothermal plume data using sensors mounted on the DSL‐120 instrument package, as well as CTDO tow‐yos, to determine detailed structural and volcanic controls on the hydrothermal vent pattern observed along 600 km of the Pacific‐Nazca axis. Here we report the first rigorous correlation between coregistered hydrothermal plume and high‐resolution marine geophysical data on similar scales and over multisegment distances. Major plume concentrations were usually found where axial inflation was relatively high and fracture density was relatively low. These correlations suggest that hydrothermal venting is most active where the apparent magmatic budget is greatest, resulting in recent eruptions that have paved over the neovolcanic zone. Areas of voluminous acoustically dark young lava flows produced from recent fissure eruptions correlate with many of the major hydrothermal vent areas. Increased crustal permeability, as gauged by increased fracture density, does not enhance hydrothermal venting in this area. Axial summit troughs and graben are rare, probably because of frequent volcanic resurfacing in this superfast spreading environment, and are not good predictors of hydrothermal activity here. Many of the hydrothermal areas are found in inflated areas near the ends of segments, suggesting that abundant magma is being supplied to these areas.}, number={12}, journal={Geochemistry, Geophysics, Geosystems}, publisher={American Geophysical Union (AGU)}, author={Hey, Richard and Baker, Edward and Bohnenstiehl, DelWayne and Massoth, Gary and Kleinrock, Martin and Martinez, Fernando and Naar, David and Pardee, Debra and Lupton, John and Feely, Richard and et al.}, year={2004}, month={Dec}, pages={n/a-n/a} }
 @article{bohnenstiehl_dziak_tolstoy_fox_fowler_2004, title={Temporal and spatial history of the 1999-2000 Endeavour Segment seismic series, Juan de Fuca Ridge}, volume={5}, ISSN={1525-2027}, url={http://dx.doi.org/10.1029/2004GC000735}, DOI={10.1029/2004GC000735}, abstractNote={Two large clusters of earthquake activity in June of 1999 and January of 2000 have dominated recent seismicity along the Endeavour Segment of the Juan de Fuca Ridge. The impacts of the June 1999 sequence on the hydrologic system, which include changes in vent temperature and chemistry within the Main Endeavour Vent Field, have been well documented previously. Analysis of seismic and hydroacoustic data indicates that both sequences exhibit a swarm‐like behavior, characterized by the absence of a dominant main shock event. The epicentral locations of events within the two swarms overlap spatially, with centroid positions near 47°49′ and 47°46′N latitude. During the June 1999 swarm, the initial activity spans the along‐axis region where a shallow axial magma chamber reflector was later imaged. The epicenters then migrate ∼12 km to the south at a rate of 0.3 m/s, consistent with lateral dike propagation. A distinct subcluster of events also occurred in the vicinity of Surveyor Volcano on the overlapping portion of the Cobb Segment. Given its distance from the main swarm, this activity may represent a triggered response to dynamic shaking. The January 2000 swarm has a more limited along‐axis extent, relative to the June 1999 swarm, with no indication of lateral migration. Much of this activity is concentrated in a region predicted to have undergone extension due to dike propagation in 1999. Although it contains fewer total events and is of shorter duration, relative to the June 1999 swarm, the January 2000 activity exhibits a higher peak rate of seismicity and greater mean event magnitude. As in situ temperature monitoring was not in place during January 2000 and vent fluids were not sampled until June 2000, the impacts of this swarm on the hydrothermal system are unknown. The southernmost tip of the Endeavour Segment also is found to be a region of repeating swarm activity. Although morphologic evidence indicates the Cobb Segment has been propagating northward recently, this seismic activity suggests that the western limb of the Endeavour‐Cobb overlap zone remains active.}, number={9}, journal={Geochemistry, Geophysics, Geosystems}, publisher={American Geophysical Union (AGU)}, author={Bohnenstiehl, DelWayne R. and Dziak, Robert P. and Tolstoy, Maya and Fox, Christopher G. and Fowler, Mathew}, year={2004}, month={Sep}, pages={n/a-n/a} }