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Relationship Between Dike Injection And B-Value For Volcanic Earthquake Swarms, Allen F. Glazner, Stephen R. Mcnutt

School of Geosciences Faculty and Staff Publications

Dike swarms are the fossil remains of regions of the crust that have undergone repeated magma injections. Volcanic earthquake swarms and geodetic measurements are, at least in part, a record of active injection of fluids (water, gas, or magma) into fractures. Here, we link these two ways of observing magmatic systems by noting that dike thicknesses and earthquake magnitudes share similar scaling parameters. In the Jurassic Independence dike swarm of eastern California median dike thickness is ∼1 m, similar to other swarms worldwide, but glacially polished exposures reveal that a typical dike comprises a number of dikelets that are lognormally …

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The Radius Of The Umbrella Cloud Helps Characterize Large Explosive Volcanic Eruptions, Robert Constantinescu, Aurelian Hopulele-Gligor, Charles Connor, Costanza Bonadonna, Laura Connor, Jan Lindsay, Sylvain Charbonnier, Alain C.M. Volentik

School of Geosciences Faculty and Staff Publications

Eruption source parameters (in particular erupted volume and column height) are used by volcanologists to inform volcanic hazard assessments and to classify explosive volcanic eruptions. Estimations of source parameters are associated with large uncertainties due to various factors, including complex tephra sedimentation patterns from gravitationally spreading umbrella clouds. We modify an advection-diffusion model to investigate this effect. Using this model, source parameters for the climactic phase of the 2450 BP eruption of Pululagua, Ecuador, are different with respect to previous estimates (erupted mass: 1.5–5 × 10¹¹ kg, umbrella cloud radius: 10–14 km, plume height: 20–30 km). We suggest large …

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Adequately Reflecting The Severity Of Tropical Cyclones Using The New Tropical Cyclone Severity Scale, Nadia Bloemendaal, Hans De Moel, Jantsje M. Mol, Priscilla R.M. Bosma, Amy Polen, Jennifer M. Collins

School of Geosciences Faculty and Staff Publications

For decades, meteorologists and governments have been warning communities in coastal areas for an imminent tropical cyclone (TC) using the Saffir-Simpson Hurricane Wind Scale (SSHWS). The SSHWS categorizes a TC based on its maximum wind speed, and is used in defining evacuation strategies and humanitarian response. However, the SSHWS considers only the wind hazard of a TC, whereas a TC can also cause severe conditions through its high storm surges and extreme rainfall, triggering coastal and inland flooding. Consequently, the SSHWS fails to mirror the TC's total severity. This becomes evident when looking at past events such as Hurricane Harvey …

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Formation Mechanisms Of Macroscopic Globules In Andesitic Glasses From The Izu–Bonin–Mariana Forearc (Iodp Expedition 352), Raúl O.C. Fonseca, Lina T. Michely, Maria Kirchenbaur, Julie Prytulak, Jeffrey Ryan, Kerstin Hauke, Felipe P. Leitzke, Renat R. Almeev, Chris S. Marien, Axel Gerdes, Rico Schellhorn

School of Geosciences Faculty and Staff Publications

The Izu–Bonin–Mariana volcanic arc is situated at a convergent plate margin where subduction initiation triggered the formation of MORB-like forearc basalts as a result of decompression melting and near-trench spreading. International Ocean Discovery Program (IODP) Expedition 352 recovered samples within the forearc basalt stratigraphy that contained unusual macroscopic globular textures hosted in andesitic glass (Unit 6, Hole 1440B). It is unclear how these andesites, which are unique in a stratigraphic sequence dominated by forearc basalts, and the globular textures therein may have formed. Here, we present detailed textural evidence, major and trace element analysis, as well as B and Sr …

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Linking Landscape Attributes To Salmon And Decision-Making In The Southern Kenai Lowlands, Alaska, Usa, Coowe M. Walker, Dennis F. Whigham, I. Syverine Bentz, Jacob M. Argueta, Ryan S. King, Mark C. Rains, Charles A. Simenstad, Chris Guo, Steven J. Baird, Conrad J. Field

School of Geosciences Faculty and Staff Publications

While Pacific salmon are economically and culturally important worldwide, Alaska, USA is one of the few remaining places on earth where sustainable management of salmon is possible, even in the face of wide-ranging threats, including overharvesting and the impacts of climate change. A continuing challenge that we face is to understand the ecological processes that result in sustainable salmon populations and report that science to stakeholders in a way that promotes decision-making to avoid the destruction of salmon populations that has occurred in most areas of the lower 48 states. To address this challenge, our studies in the southern Kenai …

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Perceptions Of Scientists Held By Us Students Can Be Broadened Through Inclusive Classroom Interventions, Sarah L. Sheffield, Meghan L. Cook, Victor J. Ricchezza, Guizella A. Rocabado, Fenda A. Akiwumi

School of Geosciences Faculty and Staff Publications

More diverse representation in undergraduate classrooms may be an important step towards turning science, technology, engineering, and mathematics (STEM) disciplines into more inclusive communities. In the United States of America, the individuals whose work is discussed in typical introductory science courses collectively do not represent the diversity of students’ identities in the classroom and further reinforce existing stereotypes of scientists as male, white, and aged. Here we report on the implementation of a semester-long intervention in an introductory-level geoscience course at the University of South Florida, USA. We introduced students to individuals with marginalized identities who are either scientists or …

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Ethical Product Havens In The Global Diamond Trade: Using The Wayback Machine To Evaluate Ethical Market Outcomes, Trina Hamilton, Seth Cavello

School of Geosciences Faculty and Staff Publications

Who benefits from ethical product markets? While most ethical products (e.g. fair trade and eco-certified products) are intended to benefit marginalized communities and vulnerable ecosystems, the reality is that the geographic preferences exhibited by so-called ethical markets may, in fact, reinforce global inequities rather than remedy them. It can be difficult to evaluate the outcomes of ethical product markets, however, because we are often limited to data from a small number of industries with widely used standards and certifications. This research pilots a new methodology, using an online archive—the Wayback Machine, to evaluate shifts in countries' ethical market share, focusing …

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Monochromatic Long-Period Seismicity Prior To The 2012 Earthquake Swarm At Little Sitkin Volcano, Alaska, Matthew M. Haney, Helena Buurman, Stephen Holtkamp, Stephen R. Mcnutt

School of Geosciences Faculty and Staff Publications

Detection of the earliest stages of unrest is one of the most challenging and yet critically needed aspects of volcano monitoring. We investigate a sequence of five unusual long-period (LP) earthquakes that occurred in the days prior to the onset of a months-long volcano-tectonic (VT) earthquake swarm beneath Little Sitkin volcano in the Aleutian Islands during late 2012. The long-period earthquakes had two distinctive characteristics: their signals were dominated by a monochromatic spectral peak at approximately 0.57 Hz and they had impulsive P and S-wave arrivals on a seismometer located on Amchitka Island 80 km to the southeast of the …

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Impulsive Volcanic Plumes Generate Volcanic Lightning And Vent Discharges: A Statistical Analysis Of Sakurajima Volcano In 2015, Cassandra M. Smith, Damien Gaudin, Alexa R. Van Eaton, Sonja A. Behnke, Steven Reader, Ronald J. Thomas, Harald Edens, Stephen R. Mcnutt, Corrado Cimarelli

School of Geosciences Faculty and Staff Publications

The origin of electrical activity accompanying volcanic ash plumes is an area of heightened interest in volcanology. However, it is unclear how intense an eruption needs to be to produce lightning flashes as opposed to “vent discharges,” which represent the smallest scale of electrical activity. This study targets 97 carefully monitored plumesJapan, from June 1 to 7, 2015. We use multiparametric measurements from sensors including a nine-station lightning mapping array and an infrared camera to characterize plume ascent. Findings demonstrate that the impulsive, high velocity plumes (>55 m/s) were most likely to create vent discharges, whereas lightning flashes occurred …

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Exploring Best Practices In Geoscience Education: Adapting A Video/Animation On Continental Rifting For Upper-Division Students To A Lower-Division Audience, Siloa Willis, Robert J. Stern, Jeffrey Ryan, Christy Bebeau

School of Geosciences Faculty and Staff Publications

Well-crafted and scientifically accurate videos and animations can be effective ways to teach dynamic Earth processes such as continental rifting, both in live course offerings as well as in online settings. However, a quick search of the internet reveals too few high-quality videos/animations describing deep Earth processes. We have modified a hybrid 10.5 min video/animation about continental rifting and the formation of new oceans and passive continental margins created for an upper-division geology audience, retailoring it for a lower-division geology audience. A key challenge in successfully modifying such resources is aligning the cognitive load that the video/animation imposes on students, …

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Large-Volume And Shallow Magma Intrusions In The Blackfoot Reservoir Volcanic Field (Idaho, Usa), M. S. Hastings, C. B. Connor, P. Wetmore, R. Malservisi, L. J. Connor, M. Rodgers, P. C. Femina

School of Geosciences Faculty and Staff Publications

he Blackfoot Reservoir volcanic field (BRVF), Idaho, USA, is a bimodal volcanic field that has hosted silicic eruptions during at least two episodes, as recently as 58 ka. Using newly collected ground and boat-based gravity data, two large negative anomalies (-16 mGal) are modeled as shallow (< 1 km) intrusions beneath a NE-trending alignment of BRVF rhyolite domes and tuff rings. Given the trade-off between density contrast and model volume, best-fit gravity inversion models yield a total intrusion volume of 50-120 km³; a density contrast of -400 kg m^-3 results in two intrusions, each ~9 km x 4.5 km and about 0.5 km thick, with cumulative volume of 100 km³. A network of 340°-360° trending faults lies directly above and on the margins of the mapped gravity anomalies. Most of …

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Magmatic Response To Subduction Initiation, Part Ii: Boninites And Related Rocks Of The Izu‐Bonin Arc From Iopd Expedition 352, John W. Shervais, Mark K. Reagan, Marguerite Godard, Julie Prytulak, Jeffrey G. Ryan

School of Geosciences Faculty and Staff Publications

International Ocean Discovery Program Expedition 352 to the Izu‐Bonin forearc cored over 800 m of basement comprising boninite and boninite‐series lavas. This is the most extensive, well‐constrained suite of boninite series lavas ever obtained from in situ oceanic crust. The boninites are characterized as high‐silica boninite (HSB), low‐silica boninite (LSB), or basaltic boninite based on their SiO₂‐MgO‐TiO₂ relations. The principal fractionation products of all three series are high‐Mg andesites (HMA). Lavas recovered >250 meters below seafloor (mbsf) erupted at a forearc spreading axis and are dominated by LSB and HMA. Lavas recovered fromoff‐axis and are dominated by …

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Molybdenum Isotopes Unmask Slab Dehydration And Melting Beneath The Mariana Arc, Hong-Yan Li, Rui-Peng Zhao, Jie Li, Yoshihiko Tamura, Christopher Spencer, Robert J. Stern, Jeffrey G. Ryan, Yi-Gang Xu

School of Geosciences Faculty and Staff Publications

How serpentinites in the forearc mantle and subducted lithosphere become involved in enriching the subarc mantle source of arc magmas is controversial. Here we report molybdenum isotopes for primitive submarine lavas and serpentinites from active volcanoes and serpentinite mud volcanoes in the Mariana arc. These data, in combination with radiogenic isotopes and elemental ratios, allow development of a model whereby shallow, partially serpentinized and subducted forearc mantle transfers fluid and melt from the subducted slab into the subarc mantle. These entrained forearc mantle fragments are further metasomatized by slab fluids/melts derived from the dehydration of serpentinites in the subducted lithospheric …

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Magma Source Evolution Following Subduction Initiation: Evidence From The Element Concentrations, Stable Isotope Ratios, And Water Contents Of Volcanic Glasses From The Bonin Forearc (Iodp Expedition 352), Daniel A. Coulthard, Mark K. Reagan, Kenji Shimizu, Ilya N. Bindeman, Maryjo Brounce, Renat R. Almeev, Jeffrey Ryan, Timothy Chapman, John Shervais, Julian A. Pearce

School of Geosciences Faculty and Staff Publications

International Ocean Discovery Program Expedition 352 to the Bonin forearc drilled the sequence of volcanic rocks erupted in the immediate aftermath of subduction initiation along the western margin of the Pacific Plate. Pristine volcanic glasses collected during this expedition were analyzed for major and trace elements, halogens, sulfur, and H and O isotopes with goals of characterizing the fluids and melts of subducted materials that were involved in generating the nascent upper plate crust. Incompatible trace element compositions of the oldest lavas (forearc basalts [FAB]) are similar to those of the most depleted mid‐ocean ridge basalts globally. Most FAB were …

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Full-Text Articles in Entire DC Network

Relationship Between Dike Injection And B-Value For Volcanic Earthquake Swarms, Allen F. Glazner, Stephen R. Mcnutt

School of Geosciences Faculty and Staff Publications

The Radius Of The Umbrella Cloud Helps Characterize Large Explosive Volcanic Eruptions, Robert Constantinescu, Aurelian Hopulele-Gligor, Charles Connor, Costanza Bonadonna, Laura Connor, Jan Lindsay, Sylvain Charbonnier, Alain C.M. Volentik

School of Geosciences Faculty and Staff Publications

Adequately Reflecting The Severity Of Tropical Cyclones Using The New Tropical Cyclone Severity Scale, Nadia Bloemendaal, Hans De Moel, Jantsje M. Mol, Priscilla R.M. Bosma, Amy Polen, Jennifer M. Collins

School of Geosciences Faculty and Staff Publications

School of Geosciences Faculty and Staff Publications

Linking Landscape Attributes To Salmon And Decision-Making In The Southern Kenai Lowlands, Alaska, Usa, Coowe M. Walker, Dennis F. Whigham, I. Syverine Bentz, Jacob M. Argueta, Ryan S. King, Mark C. Rains, Charles A. Simenstad, Chris Guo, Steven J. Baird, Conrad J. Field

School of Geosciences Faculty and Staff Publications

Perceptions Of Scientists Held By Us Students Can Be Broadened Through Inclusive Classroom Interventions, Sarah L. Sheffield, Meghan L. Cook, Victor J. Ricchezza, Guizella A. Rocabado, Fenda A. Akiwumi

School of Geosciences Faculty and Staff Publications

Ethical Product Havens In The Global Diamond Trade: Using The Wayback Machine To Evaluate Ethical Market Outcomes, Trina Hamilton, Seth Cavello

School of Geosciences Faculty and Staff Publications

Monochromatic Long-Period Seismicity Prior To The 2012 Earthquake Swarm At Little Sitkin Volcano, Alaska, Matthew M. Haney, Helena Buurman, Stephen Holtkamp, Stephen R. Mcnutt

School of Geosciences Faculty and Staff Publications

Impulsive Volcanic Plumes Generate Volcanic Lightning And Vent Discharges: A Statistical Analysis Of Sakurajima Volcano In 2015, Cassandra M. Smith, Damien Gaudin, Alexa R. Van Eaton, Sonja A. Behnke, Steven Reader, Ronald J. Thomas, Harald Edens, Stephen R. Mcnutt, Corrado Cimarelli

School of Geosciences Faculty and Staff Publications

Exploring Best Practices In Geoscience Education: Adapting A Video/Animation On Continental Rifting For Upper-Division Students To A Lower-Division Audience, Siloa Willis, Robert J. Stern, Jeffrey Ryan, Christy Bebeau

School of Geosciences Faculty and Staff Publications

Large-Volume And Shallow Magma Intrusions In The Blackfoot Reservoir Volcanic Field (Idaho, Usa), M. S. Hastings, C. B. Connor, P. Wetmore, R. Malservisi, L. J. Connor, M. Rodgers, P. C. Femina

School of Geosciences Faculty and Staff Publications

Magmatic Response To Subduction Initiation, Part Ii: Boninites And Related Rocks Of The Izu‐Bonin Arc From Iopd Expedition 352, John W. Shervais, Mark K. Reagan, Marguerite Godard, Julie Prytulak, Jeffrey G. Ryan

School of Geosciences Faculty and Staff Publications

Molybdenum Isotopes Unmask Slab Dehydration And Melting Beneath The Mariana Arc, Hong-Yan Li, Rui-Peng Zhao, Jie Li, Yoshihiko Tamura, Christopher Spencer, Robert J. Stern, Jeffrey G. Ryan, Yi-Gang Xu

School of Geosciences Faculty and Staff Publications

School of Geosciences Faculty and Staff Publications