Volcanology Commons^™

Investigation Of Jet Dynamics In Cross-Flow: Quantifying Volcanic Plume Behavior, Graham Freedland

Dissertations and Theses

Volcanic eruption columns inject high concentrations of ash into the atmosphere. Some of this ash is carried downwind forming ash clouds in the atmosphere that are hazardous for private and commercial aviation. Current models rely on inputs such as plume height, duration, eruption rate, and meteorological wind fields. Eruption rate is estimated from plume height using relations that depend on the rate of air entrainment into the plume, which is not well quantified. A wind tunnel experiment has been designed to investigate these models by injecting a vertical air jet into a cross-flow. The ratio of the cross-flow and jet …

Change Detection Of Mount Nyiragongo Post Eruption, Molly E. Karnes

Scholars Week

Because of the dangerous nature of volcanic eruptions, it makes them very difficult to study, however this makes them even more important for us to study because of how much destruction they can cause in such a short amount of time. We need to study all parts of an eruption to gain more insight into the specifics of how a volcano works. Having a better understanding of how large of an area is effected by an eruption will allow governments to decide on evacuation procedures. The goal of my project is to answer a very simple question, “How can we …

Birth And Evolution Of The Rio Grande Fluvial System In The Last 8 Ma:Progressive Downward Integration And Interplay Between Tectonics, Volcanism, Climate, And River Evolution, Marisa N. Repasch

Earth and Planetary Sciences ETDs

The Rio Grande-Rio Chama (RG-RC) fluvial system has evolved dramatically over the last 8 Ma, undergoing channel migrations, drainage capture and integration events, volcanic damming, and carving and refilling of paleocanyons. Volcanism concurrent with the development of the river system provides a unique opportunity to apply multiple geochronometers to the study of its incision and drainage evolution. This paper reports 19 new ⁴⁰Ar/³⁹Ar basalt ages and 19 detrital mineral samples (zircon and sanidine) collected from RG-RC alluvium overlain by dated basalt flows in the context of a compilation of published ⁴⁰Ar/³⁹Ar basalt ages. The …

Silicic Volcanism At The Northern And Western Extent Of The Columbia River Basalt Rhyolite Flare-Up: Rhyolites Of Buchanan Volcanic Complex And Dooley Mountain Volcanic Complex, Oregon, Adam M. Large

Dissertations and Theses

Two mid-Miocene (16.5-15 Ma) rhyolite volcanic centers in eastern Oregon, the Buchanan rhyolite complex and Dooley Mountain rhyolite complex, were investigated to characterize eruptive units through field and laboratory analysis. Results of petrographic and geochemical analysis add to field observations to differentiate and discriminate the eruptive units. Additionally, new geochemical data are used to correlate stratigraphically younger and older basalt and ash-flow tuff units with regional eruptive units to constrain the eruptive periods with modern Ar-Ar age dates.

Previous work at the Buchanan rhyolite complex was limited to regional mapping (Piper et al., 1939; Greene et al., 1972) and brief …

Tube Coalescence In The Jingfudong Lava Tube And Implications For Lava Flow Hazard Of Tengchong Volcanism, Zhengquan Chen, Yongshun Liu, Haiquan Wei, Jiandong Xu, Wenfeng Guo

International Journal of Speleology

Tube-fed structure occurs as a general phenomenon in Tengchong basic lavas, such as lava tubes, lava plugs and tube-related collapse depressions. We deduced the development of Laoguipo lava flows, which is the longest lava tube (Jingfudong lava tube) evolved in Tengchong volcanic area. Following the detailed documentation of the tube morphology of the Jingfudong lava tube, we propose that the Jingfudong lava tube was formed through vertical coalescence of at least three tubes. The coalescence and bifurcation process are re-constructed by interpretation of tube floor continuity, the distribution of remnant tubes and the scales of lava tube branches (shapes of …

Living In Lahar Zones: Assessing Hazard Exposure, Risk Perception, And Preparedness Behaviors In Communities Within The Mount Baker And Glacier Peak Volcanic Hazard Zones, Kimberley Anne Corwin

Boise State University Theses and Dissertations

As the number of people living at risk from volcanic hazards in the U.S. Pacific Northwest grows, more detailed studies of community hazard exposure, risk perception, and preparedness levels become critical to developing effective mitigation, response, and recovery plans. This thesis uses risk mapping and a knowledge, risk perception, and preparedness survey to examine the risk that lahars from Mount Baker and Glacier Peak volcanoes pose to nearby communities in the Skagit Valley (WA). The risk map component of this research identifies spatial variations in lahar risk and estimates potential losses associated with a maximum envisioned lahar. The survey component …

Transitions Between Explosive And Effusive Phases During The Cataclysmic 2010 Eruption Of Merapi Volcano, Java, Indonesia, Katie Preece, Ralf Gertisser, Jenni Barclay, Sylvain J. Charbonnier, Jean-Christophe Komorowski, Richard A. Herd

School of Geosciences Faculty and Staff Publications

Transitions between explosive and effusive activity are commonly observed during dome-forming eruptions and may be linked to factors such as magma influx, ascent rate and degassing. However, the interplay between these factors is complex and the resulting eruptive behaviour often unpredictable. This paper focuses on the driving forces behind the explosive and effusive activity during the well-documented 2010 eruption of Merapi, the volcano’s largest eruption since 1872. Time-controlled samples were collected from the 2010 deposits, linked to eruption stage and style of activity. These include scoria and pumice from the initial explosions, dense and scoriaceous dome samples formed via effusive …

Field Geology And Petrologic Investigation Of The Strawberry Volcanics, Northeast Oregon, Arron Richard Steiner

Dissertations and Theses

The Strawberry Volcanics of Northeast Oregon are a group of geochemically related lavas with a diverse chemical range (basalt to rhyolite) that erupted between 16.2 and 12.5 Ma and co-erupted with the large, (~200,000 km3) Middle Miocene tholeiitic lavas of the Columbia River Basalt Group (CRBG), which erupted near and geographically surround the Strawberry Volcanics. The rhyolitic lavas of the Strawberry Volcanics produced the oldest 40Ar/39Ar ages measured in this study with ages ranging from 16.2 Ma to 14.6 Ma, and have an estimated total erupted volume of 100 km3. The mafic and intermediate lavas of the Strawberry Volcanics include …

Documenting Mantle And Crustal Contributions To Flood Basalt Magmatism Via Computational Modeling Of The Steens Basalt, Southeast Oregon, Sylvana J. Bendaña

All Master's Theses

Flood basalts are enormous volcanic events with volumes of volcanic cover and intrusive equivalents that are affected by and significantly affect the crust. Steens Basalt represents 31,800 km³ of flood basalt lavas that erupted in eastern Oregon ~16.8 Ma in less than 300,000 years. Analytical data of flows from a 1 km vertical exposure at Steens Mtn. documents time-transgressive changes in composition of two geochemically distinct units: (1) lower Steens, MgO-rich lavas with lower incompatible trace element concentrations and ⁸⁷Sr/⁸⁶Sr, and (2) upper Steens, MgO-poor, with higher incompatible trace element concentrations and ⁸⁷Sr/⁸⁶Sr. …

Evolution Of A Flood Basalt Crustal Magmatic System: In Situ Mineral Data And Computational Modeling Of The Steens Basalt, Megan Graubard

All Master's Theses

Flood basalts are gigantic basaltic eruptions that modify the mass of the crust via intrusion of mantle-derived magma, and change its composition through interaction between magma and crust. The Steens Basalt, located in southeast Oregon, erupted approximately 16.8 million years ago, and is the oldest member of the Columbia River Basalt Group, the youngest and best-exposed flood basalt province on Earth. The Steens Basalt has an eruption volume of approximately 31,800 km³ and the duration of eruption is estimated to be between ~50,000 and 300,000 years. Major- and trace element whole rock data from 111 stratigraphically controlled samples from …