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Deep fluid pathways beneath Mammoth Mountain, California, illuminated by migrating earthquake swarms

Although most volcanic seismicity is shallow (within several kilometers of the surface), some volcanoes exhibit deeper seismicity (10 to 30+ km) that may reflect active processes such as magma resupply and volatile transfer. One such volcano is Mammoth Mountain, California, which has also recently exhibited high rates of CO2 discharge at the surface. We perform high-resolution earthquake detection
Authors
Alicia J. Hotovec-Ellis, David R. Shelly, David P. Hill, Andrew M. Pitt, Phillip B. Dawson, Bernard A. Chouet

Seismic evidence for significant melt beneath the Long Valley Caldera, California, USA

A little more than 760 ka ago, a supervolcano on the eastern edge of California (United States) underwent one of North America's largest Quaternary explosive eruptions. Over this ~6-day-long eruption, pyroclastic flows blanketed the surrounding ~50 km with more than 1400 km3 of the now-iconic Bishop Tuff, with ashfall reaching as far east as Nebraska. Collapse of the volcano's magma reservoir crea
Authors
Ashton F. Flinders, David R. Shelly, Phillip B. Dawson, David P. Hill, Barbara Tripoli, Yang Shen

Volcanic eruptions and threats to respiratory health

In early May 2018, Kīlauea volcano became increasingly active, posing an increase in threat to respiratory health. The emission of gases such as sulfur dioxide from Kīlauea produces large amounts of respirable acid particles as the gases react with water vapor and sunlight, resulting in a visible haze called “vog”. Additionally, the lava lake at Kīlauea’s summit crater has fallen, leading to explo
Authors
W. Graham Carlos, Jane E. Gross, Shazia Jamil, Charles S. Dela Cruz, David Damby, Elizabeth K. Tam

Timescales of magmatic differentiation from alkali basalt to trachyte within the Harrat Rahat volcanic field, Kingdom of Saudi Arabia

A fundamental goal of igneous petrology is to quantify the duration of time required to produce evolved magmas following influx of basalt into the crust. However, in many cases, complex field relations and/or the presence of a long-lived magmatic system make it difficult to assess how basaltic inputs relate to more evolved magmas, therefore, precluding calculation of meaningful timescales. Here, w
Authors
Mark E. Stelten, Drew T. Downs, Hannah R. Dietterich, Gail A. Mahood, Andrew T. Calvert, Thomas W. Sisson, Hani M. Zahran, Jamal Shawali

Hydrothermal discharge from the El Tatio basin, Atacama, Chile

El Tatio in northern Chile is one of the best-studied geothermal fields in South America. However, there remain open questions about the mass and energy budgets, water recharge rates and residence time in the subsurface, origin of dissolved solutes, and processes affecting the phase and chemical composition of groundwater and surface water. We measured and sampled surface manifestations of the geo
Authors
Carolina Munoz-Saez, Michael Manga, Shaul Hurwitz

Prevalence of seismic rate anomalies preceding volcanic eruptions in Alaska

Seismic rate increases often precede eruptions at volcanoes worldwide. However, many eruptions occur without such precursors. Additionally, identifying seismic rate increases near volcanoes with high levels of background seismicity is non-trivial and many periods of elevated seismicity occur without ensuing eruptions, limiting their usefulness for forecasting in some cases. Although these issues a
Authors
Jeremy D. Pesicek, John Wellik, Stephanie Prejean, Sarah E. Ogburn

Linking the Ukinrek 1977 maar-eruption observations to the tephra deposits: New insights into maar depositional processes

The Ukinrek Maars erupted 30 March to 9 April 1977, forming two maars, a line of small pit craters and a tephra blanket extending to ~2 km from the vents. We combine photographic and written observations with stratigraphic analysis to reconstruct the eruption. The eruption began with very low (a few meters high) fountaining from small craters above an inferred east-west-trending dike, creating loc
Authors
Michael Ort, Nathalie Lefebvre, Christina A. Neal, Vicki McConnell, Ken Wohletz

Towards coordinated regional multi-satellite InSAR volcano observations: Results from the Latin America pilot project

Within Latin America, about 319 volcanoes have been active in the Holocene, but 202 of these volcanoes have no seismic, deformation or gas monitoring. Following the 2012 Santorini Report on satellite Earth Observation and Geohazards, the Committee on Earth Observation Satellites (CEOS) developed a 4-year pilot project (2013-2017) to demonstrate how satellite observations can be used to monitor lar
Authors
Matthew Pritchard, Juliet Biggs, Christelle Wauthier, Eugenio Sansosti, David W. D. Arnold, Francisco Delgado, Susanna Ebmeier, Scott Henderson, Kristen Stephens, C. Cooper, Kendall Wnuk, Falk Amelung, Victor Rivera Aguilar, Patricia Mothes, Orlando Macedo, Luis E. Lara, Michael P. Poland, Simona Zoffoli

Using earthquakes, T waves, and infrasound to investigate the eruption of Bogoslof Volcano, Alaska

The 2016‐2017 eruption of Bogoslof volcano, a submarine stratovolcano in the Bering Sea, produced 70 discrete explosive eruptions over 8 months. With no local monitoring data, activity was seismically recorded on nearby islands 50‐100 km away, limiting the detection and resolution of seismic observations. We construct a matched filter catalog of 3199 events from 49 earthquake families, many of whi
Authors
Aaron Wech, Gabrielle Tepp, John J. Lyons, Matthew M. Haney

Accurate predictions of microscale oxygen barometry in basaltic glasses using V K-edge X-ray absorption spectroscopy: A multivariate approach

Because magmatic oxygen fugacity (fO2) exerts a primary control on the discrete vanadium (V) valence states that will exist in quenched melts, V valence proxies for fO2, measured using X-ray absorption near-edge spectroscopy (XANES), can provide highly sensitive measurements of the redox conditions in basaltic melts. However, published calibrations for basaltic glasses primarily relate measured in
Authors
Antonio Lanzirotti, M. Darby Dyar, Steve Sutton, Matthew Newville, Elisabet Head, CJ Carey, Molly McCanta, R. Lopaka Lee, Penelope L. King, John Jones

Discussion of “Shallow water hydro-sediment-morphodynamic equations for fluvial processes” by Zhixian Cao, Chunchen Xia, Gareth Pender, and Qingquan Liu

The original paper concerns the formulation and use of depth-integrated equations of motion to model the dynamics of shallow flows that entrain or deposit bed material. A recurring theme of the original paper is the authors’ criticism of related theoretical results published by Iverson and Ouyang (2015). This discussion explains why that criticism is misguided.
Authors
Richard M. Iverson

Discussion of “Oso, Washington, landslide of March 22, 2014: Dynamic analysis” by Jordan Aaron, Oldrich Hungr, Timothy D. Stark, and Ahmed K. Baghdady

The original paper under discussion states that it “explains the spectacular mobility of the 2014 Oso landslide.” It addresses this objective by using two versions of the DAN model to compute the distribution of deposits produced by the landslide. The main purpose of this discussion is to demonstrate that the authors’ model is incapable of explaining the Oso landslide’s mobility—even though the mo
Authors
Richard M. Iverson