Publications
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A large refined catalog of earthquake relocations and focal mechanisms for the Island of Hawai'i and its seismotectonic implications
We present high-quality focal mechanisms based on a refined earthquake location catalog for the Island of Hawai'i, focusing on Mauna Loa and Kīlauea volcanoes. The relocation catalog is based on first-arrival times and waveform data of both compressional and shear waves for about 180,000 events on and near the Island of Hawai'i between 1986 and 2009 recorded by the seismic stations at the Hawaiian
Authors
Guoqing Lin, Paul G. Okubo
Slab melting and magma formation beneath the southern Cascade arc
The processes that drive magma formation beneath the Cascade arc and other warm-slab subduction zones have been debated because young oceanic crust is predicted to largely dehydrate beneath the forearc during subduction. In addition, geochemical variability along strike in the Cascades has led to contrasting interpretations about the role of volatiles in magma generation. Here, we focus on the Las
Authors
Kristina J. Walowski, Paul J. Wallace, Michael A. Clynne, D.J. Rasmussen, D. Weis
Potential carbon emissions dominated by carbon dioxide from thawed permafrost soils
Increasing temperatures in northern high latitudes are causing permafrost to thaw, making large amounts of previously frozen organic matter vulnerable to microbial decomposition. Permafrost thaw also creates a fragmented landscape of drier and wetter soil conditions that determine the amount and form (carbon dioxide (CO2), or methane (CH4)) of carbon (C) released to the atmosphere. The rate and fo
Authors
Christina Schädel, Martin K.-F. Bader, Edward A.G. Schuur, Christina Biasi, Rosvel Bracho, Petr Čapek, Sarah De Baets, Kateřina Diáková, Jessica Ernakovich, Cristian Estop-Aragones, David E. Graham, Iain P. Hartley, Colleen M. Iversen, Evan S. Kane, Christian Knoblauch, Massimo Lupascu, Pertti J. Martikainen, Susan M. Natali, Richard J. Norby, Jonathan A. O'Donnell, Taniya Roy Chowdhury, Hana Šantrůčková, Gaius Shaver, Victoria L. Sloan, Claire C. Treat, Merritt R. Turetsky, Mark P. Waldrop, Kimberly P. Wickland
Detection and quantification of hydrocarbons in sediments
A new technology developed by the US Geological Survey now allows for fast, direct detection of hydrocarbon plumes both in rivers and drifting in the deep ocean. Recent experiments show that the method can also detect and quantify hydrocarbons buried in river sediments and estuaries. This approach uses a variant of induced polarization, a surface-sensitive physical property of certain polarizable
Authors
Jeff Wynn, Mike Williamson, Jeff Frank
The 2014 annual report for the Hawaiian Volcano Observatory
Introduction
This report summarizes team activities and findings of the Hawaiian Volcano Observatory during the year 2014 in geology, geodesy, seismicity, and gas geochemistry. The eruption of Pu‘u ‘Ō‘ō continued into its 32nd year with flows active to the northeast of the vent. One of them, the June 27th lava flow, named for the date in 2014 that the flow started, advanced far and fast enough to
Authors
James P. Kauahikaua, Tim R. Orr, Matt Patrick, Weston A. Thelen, Matthew K. Burgess, Asta Miklius, Michael P. Poland, Kyle R. Anderson, Loren Antolik, Tamar Elias, Jeff Sutton, Christoph Kern, Cindy Werner
Seismic envelope-based detection and location of ground-coupled airwaves from volcanoes in Alaska
Volcanic explosions and other infrasonic sources frequently produce acoustic waves that are recorded by seismometers. Here we explore multiple techniques to detect, locate, and characterize ground‐coupled airwaves (GCA) on volcano seismic networks in Alaska. GCA waveforms are typically incoherent between stations, thus we use envelope‐based techniques in our analyses. For distant sources and plana
Authors
David Fee, Matthew M. Haney, Robin S. Matoza, Curt A.L. Szuberla, John J. Lyons, Christopher F. Waythomas
Extending Alaska's plate boundary: tectonic tremor generated by Yakutat subduction
The tectonics of the eastern end of the Alaska-Aleutian subduction zone are complicated by the inclusion of the Yakutat microplate, which is colliding into and subducting beneath continental North America at near-Pacific-plate rates. The interaction among these plates at depth is not well understood, and further east, even less is known about the plate boundary or the source of Wrangell volcanism.
Authors
Aaron G. Wech
Dimmuborgir: a rootless shield complex in northern Iceland
The origin of Dimmuborgir, a shield-like volcanic structure within the Younger Laxá lava flow field near Lake Mývatn, in northern Iceland, has long been questioned. New airborne laser mapping (light detection and ranging (LiDAR)), combined with ground-penetrating radar results and a detailed field study, suggests that Dimmuborgir is a complex of at least two overlapping rootless shields fed by lav
Authors
Alasdair Skelton, Erik Sturkell, Martin Jakobsson, Draupnir Einarsson, Elin Tollefsen, Tim R. Orr
Holocene evolution of diatom and silicoflagellate paleoceanography in Slocum Arm, a fjord in southeastern Alaska
Diatom and silicoflagellate assemblages in cores EW0408-47JC, -47TC, -46MC (57° 34.5278′ N, 136° 3.7764′ W, 114 m water depth) taken from the outer portion of Slocum Arm, a post-glacial fjord in southeastern Alaska, reveal the paleoclimatic and paleoceanographic evolution of the eastern margin of the Gulf of Alaska (GoA) during the past 10,000 years. Between ~ 10 and 6.8 cal ka, periods of low sal
Authors
John A. Barron, David Bukry, Jason A. Addison, Thomas A. Ager
Late Holocene volcanism at Medicine Lake Volcano, northern California Cascades
Late Holocene volcanism at Medicine Lake volcano in the southern Cascades arc exhibited widespread and compositionally diverse magmatism ranging from basalt to rhyolite. Nine well-characterized eruptions have taken place at this very large rear-arc volcano since 5,200 years ago, an eruptive frequency greater than nearly all other Cascade volcanoes. The lavas are widely distributed, scattered over
Authors
Julie M. Donnelly-Nolan, Duane E. Champion, Timothy L. Grove
Bayesian estimation of magma supply, storage, and eruption rates using a multiphysical volcano model: Kīlauea Volcano, 2000–2012
Estimating rates of magma supply to the world's volcanoes remains one of the most fundamental aims of volcanology. Yet, supply rates can be difficult to estimate even at well-monitored volcanoes, in part because observations are noisy and are usually considered independently rather than as part of a holistic system. In this work we demonstrate a technique for probabilistically estimating time-vari
Authors
Kyle R. Anderson, Michael P. Poland
Where is the hot rock and where is the ground water— Using CSAMT to map beneath and around Mount St. Helens
We have observed several new features in recent controlled-source audio-frequency magnetotelluric (CSAMT) soundings on and around Mount St. Helens, Washington State, USA. We have identified the approximate location of a strong electrical conductor at the edges of and beneath the 2004–08 dome. We interpret this conductor to be hot brine at the hot-intrusive-cold-rock interface. This contact can be
Authors
Jeff Wynn, Adam R. Mosbrucker, Herbert Pierce, Kurt R. Spicer