Volcanology Commons^™

The Fold Illusion: The Origins And Implications Of Ogives On Silicic Lavas, Graham Dm Andrews, Stuart Kenderes, Alan Whittington, Shelby L. Isom, Sarah Brown, Holly Danielle Pettus, Brenna Cole, Kailee Gokey

Faculty & Staff Scholarship

Folds on the surfaces of mafic lavas are among the most readily recognized geological structures and are used as first-order criteria for identifying ancient lavas on Earth and other planetary bodies. However, the presence of surface-folds on the surface of silicic lavas is contested in this study and we challenge the widely accepted interpretation that silicic lava surfaces contain folds using examples from the western United States and Sardinia, Italy. We interpret the ridges and troughs on their upper surfaces, typically referred to as ‘ogives’ or ‘pressure ridges’, as fracture-bound structures rather than folds. We report on the absence of …

Changes In Crater Geometry Revealed By Inversion Of Harmonic Infrasound Observations: 24 December 2018 Eruption Of Mount Etna, Italy, Leighton M. Watson, Jeffrey B. Johnson, Mariangela Sciotto, Andrea Cannata

Geosciences Faculty Publications and Presentations

In December 2018, Mount Etna (Italy) experienced a period of increased eruptive activity that culminated in a fissure eruption on the southeast flank. After the onset of the flank eruption, the peak frequency of the summit infrasound signals decreased while resonance increased. We invert infrasound observations for crater geometry and show that crater depth and radius increased during the eruption, which suggests that the flank eruption drained magma from the summit and that eruptive activity led to erosion of the crater wall. By inverting the entire infrasound amplitude spectra rather than just the peak frequency, we are able to place …

Interpretations Of Lava Flow Properties From Radar Remote Sensing Data, Gavin Douglas Tolometti, Catherine Neish, Gordon R. Osinski, Scott S. Hughes, Shannon E. Kobs-Nawotniak

Earth Sciences Publications

The surface morphology and roughness of a lava flow provides insight on its lava properties and emplacement processes. This is essential information for understanding the eruption history of lava fields, and magmatic processes beneath the surface of Earth and other planetary bodies such as the Moon. The surface morphology is influenced by lava properties such as viscosity, temperature, composition, and rate of shear. In this work, we seek to understand how we can interpret the emplacement processes and lava properties of lava flows using remote sensing data. Craters of the Moon (COTM) National Monument and Preserve in Idaho hosts a …

Experimental And Thermodynamic Constraints On Mineral Equilibrium In Pantelleritic Magmas., Pierangelo Romano, Bruno Scaillet, John C. White, Joan Andujar, Ida Di Carlo, Silvio G. Rotolo

EKU Faculty and Staff Scholarship

Crystallization experiments on two pantellerites from Pantelleria, Italy, provide new evidence for the relation-ships between mineral phases in pantelleritic rocks as well as the influence of temperature and redox conditionson mineral assemblages. Experiments were performed at 1 kbar with temperature ranging between 750–900°C,andfluid saturation conditions with XH2O (=H2O/H2O+CO2) between 0 and 1. Redox conditions were fixed at, or slightly below, the FMQ buffer. Results show that at temperature of 900 °C pantelleritic magmas are well above the liquidus regardless their water content; we also observed a decrease in liquidus temperature (800°C) with increasingly reducing conditions. Mineral assemblages of the natural …

Volcano Video Data Characterized And Classified Using Computer Vision And Machine Learning Algorithms, Alex J. C. Witsil, Jeffrey B. Johnson

Geosciences Faculty Publications and Presentations

Video cameras are common at volcano observatories, but their utility is often limited during periods of crisis due to the large data volume from continuous acquisition and time requirements for manual analysis. For cameras to serve as effective monitoring tools, video frames must be synthesized into relevant time series signals and further analyzed to classify and characterize observable activity. In this study, we use computer vision and machine learning algorithms to identify periods of volcanic activity and quantify plume rise velocities from video observations. Data were collected at Villarrica Volcano, Chile from two visible band cameras located ~17 km from …

Top–Down Control On Eruptive Style At Masaya Volcano Inferred From Melt Composition, Lisa Hlinka

Student Theses

Highly explosive, Plinian-type eruptions of basaltic magma are enigmatic because basaltic melts have lower viscosities than more silicic melts which have traditionally been considered essential for such explosive eruption style. Masaya volcano, Nicaragua, is one of the few basaltic volcanoes to have generated a wide range of eruptive styles, from effusive lava lake activity to voluminous Plinian fall deposits. This volcano thus offers a unique case study to better constrain ideas on basaltic eruption style controls.

We analyze olivine-, plagioclase- and clinopyroxene-hosted melt inclusions as well as matrix glasses from lava lake (LL) ejecta and two Plinian tephra deposits—the 2.1 …

Volcanic Record Of The Arc-To-Rift Transition Onshore Of The Guaymas Basin In The Santa Rosalía Area, Gulf Of California, Baja California, Graham Dm Andrews

Faculty & Staff Scholarship

The Gulf of California is an archetype of continental rupture through transtensional rifting, and exploitation of a thermally weakened arc to produce a rift. Volcanic rocks of central Baja California record the transition from calcalkaline arc magmatism, due to subduction of the Farallon plate (ca. 24–12 Ma), to rift magmatism, related to the opening of the Gulf of California (<12 Ma). In addition, a suite of postsubduction rocks (<12 Ma), referred to as “bajaites,” are enriched in light rare-earth and other incompatible elements (e.g., Ba and Sr). These are further subdivided into high-magnesian andesite (with 50%–58% SiO2 and MgO >4%) and adakite (>56% SiO2 and MgO <3%). The bajaites correlate spatially with a fossil slab imaged under central Baja and are inferred to record postsubduction melting of the slab and subduction-modified mantle by asthenospheric upwelling associated with rifting or slab breakoff. We report on volcanic rocks of all three suites, which surround and underlie the Santa Rosalía sedimentary rift basin. This area represents the western margin of the Guaymas basin, the most magmatically robust segment of the Gulf of California rift, where seafloor spreading occurred in isolation for 3–4 m.y. (starting at 6 Ma) before transtensional pull-apart basins to the north and south ruptured the continental crust. Outcrops of the Santa Rosalía area thus offer the opportunity to understand the magmatic evolution of the Guaymas rift, which has been the focus of numerous oceanographic expeditions.

We describe 21 distinct volcanic and hypabyssal map units in the Santa Rosalía area, using field characteristics, petrographic data, and major- and trace-element geochemical data, as well as zircon isotopic data and …

Uas-Based Tracking Of The Santiaguito Lava Dome, Guatemala, Edgar U. Zorn, Thomas R. Walter, Jeffrey B. Johnson, René Mania

Geosciences Faculty Publications and Presentations

Imaging growing lava domes has remained a great challenge in volcanology due to their inaccessibility and the severe hazard of collapse or explosion. Changes in surface movement, temperature, or lava viscosity are considered crucial data for hazard assessments at active lava domes and thus valuable study targets. Here, we present results from a series of repeated survey flights with both optical and thermal cameras at the Caliente lava dome, part of the Santiaguito complex at Santa Maria volcano, Guatemala, using an Unoccupied Aircraft System (UAS) to create topography data and orthophotos of the lava dome. This enabled us to track …

Diffuse Flux And Carbon Isotope Composition Of Carbon Dioxide Emitted From Valles Caldera, Yellowstone Caldera, And Southwestern Utah Geothermal Sites, Kristen Rahilly

Earth and Planetary Sciences ETDs

Carbon dioxide (CO₂) has the lowest solubility in silicate melt and is one of the most abundant and earliest degassed species present in volcanic and geothermal systems. A significant quantity of CO₂ is passively degassed through soils in volcanic and geothermal systems, called diffuse degassing. In Chapter 1, I measure the diffuse CO₂ flux over the site of a prospective enhanced geothermal system in southwestern Utah. I conclude that the CO₂ emitted from soils in the enhanced geothermal site is biogenically-sourced. In Chapter 3, I examine the diffuse CO₂ flux from Roosevelt Hot Springs …

Geochemistry Of The Lazufre Volcanic Complex: Determining The Geometries And Processes Of The Magmatic Sources In The Central Andean Volcanic Zone, Brooke Erin Benz

Graduate Theses/Dissertations

The Central Andes in South America contain many active volcanoes and volcano complexes due to constant subduction producing extrusive rocks varying in composition. The Lazufre Complex, Chile-Argentina border, consists of two Pleistocene volcanic centers, Lastarria and Cordon del Azufre andesite and dacite lava flows and domes. Whole-rock K-Ar dates of lavas from Cordon del Azufre place the most recent eruptions at 0.6-0.3 Ma ±0.3 Ma. Major-element data of plagioclase and pyroxene show homogeneous compositions between the centers, which is consistent with whole rock major- and trace-element compositions. The primary composition of the pyroxenes are augite and diopsides for cpx and …

Geology And Geophysics Of The Mogollon Mining District And The Bearwallow Mountain 7.5 Minute Quadrangle, Catron County, New Mexico, Charles Frost Hoffman

Graduate Theses/Dissertations

The Mogollon Mining District and the Bearwallow Mountain 7.5-minute quadrangle are located in southwestern New Mexico, and are comprised of mid-Tertiary volcanic rocks that were the result of voluminous eruptions within the Mogollon-Datil Volcanic Field. This thesis aims to better understand the geology and structure of the Bearwallow Mountain 7.5-minute quadrangle and the Mogollon Mining District, and to analyze the use of Very Low Frequency electromagnetic techniques to delineate buried structures in volcanic terranes. I use Very Low Frequency electromagnetic methods and field mapping to evaluate the effectiveness of the method, and to better understand the geology and ore bodies …

Pumice Compositions And Mineral Chemistry From Lascar Volcano, Chile, Madelaine M. Stearn

Graduate Theses/Dissertations

Lascar volcano is one the most active volcano in the Central Volcanic Zone of the Andean Cordillera, with 36 Holocene eruptions including a VEI 4 eruption in April 1993. Activity has not been consistent throughout time, and therefore, the processes behind it are poorly understood. Lascar volcano has cyclic behavior and has had four stages of activity, each of which had a unique eruptive style and product composition. Stage I (<43 >ka) had primarily mafic andesite lavas erupted effusively from a stratocone. Stage II initiated with dome building events ESE of the original vent and culminated in the 26.45 ka …

Analysis Of Cryptotephra At Whitney Mesa Nature Preserve, Henderson, Nevada, Alex Newsom

Calvert Undergraduate Research Awards

Advanced Undergraduate Winner

Cryptotephra (small volcanic shards ranging 20-80 microns in size) were discovered within Unit X of the Las Vegas Formation at Whitney Mesa Nature Preserve, Henderson, Nevada. Cryptotephra are deposited soon after a volcanic eruption and can be used as a dating tool to create narrow time constraints for surrounding sediments. Cryptotephra have many applications but are mainly useful as a dating tool. Their study has important implications for the understanding of the timing of palaeoclimatological and paleoenvironmental events as well as for archaeological studies to date important events in human history.

The Whitney Mesa cryptotephra were correlated …

Characterization Of Magma Storage And Dynamics At Akutan, Semisopochnoi, And Okmok Volcanoes From Analytical And Numerical Models Of Geodetic, Seismic, And Petrologic Data, Kimberly Degrandpre

Earth Sciences Theses and Dissertations

Volcanic eruptions can cause significant socioeconomic loss, but a better understanding of the processes and dynamics influencing the evolution of volcanic plumbing systems will advance the development of eruption forecasting models that will ultimately mitigate hazards and risks associated with eruptive events. Geologic and geophysical data must be integrated in 3D, finite- element, multiphysical, numerical models to define the coupled evolution of magmatic and crustal stress regimes in volcanic environments, but in data limited regions this is not always an option. The remote nature of the Aleutian Island Arc restricts ground-based monitoring and sampling efforts, and due to sparse temporal …

Climate Change Effects On Volcanoes In The Tropics: A Review Of The Deglaciation Of Antisana And Its Effects On Subsequent Water Streams And Rivers Over 20 Years, Callie C. Rominger

Independent Study Project (ISP) Collection

Located in the Northern end of Ecuador lies the stunning glacier of Antisana which attracts many tourists and whose runoff provides a significant amount of water supply for Quito. Climate change is posing threats to many ecosystems world wide but will have a more substantial impact on the volcanoes in the tropics because they do not have a seasonally altered climate. Small changes in the air temperature can have larger impacts on these areas that are adapted to constant temperatures with seasonal precipitation changes. Climate change, in recent years, had caused an increase in the glacial retreat of the Antisana …

Changes In Atmospheric, Meteorological, And Ocean Parameters Associated With The 12 January 2020 Taal Volcanic Eruption, Feng Jing, Akshansa Chauhan, Ramesh P. Singh, Prasanjit Dash

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The Taal volcano erupted on 12 January 2020, the first time since 1977. About 35 mild earthquakes (magnitude greater than 4.0) were observed on 12 January 2020 induced from the eruption. In the present paper, we analyzed optical properties of volcanic aerosols, volcanic gas emission, ocean parameters using multi-satellite sensors, namely, MODIS (Moderate Resolution Imaging Spectroradiometer), AIRS (Atmospheric Infrared Sounder), OMI (Ozone Monitoring Instrument), TROPOMI (TROPOspheric Monitoring Instrument) and ground observations, namely, Argo, and AERONET (AErosol RObotic NETwork) data. Our detailed analysis shows pronounced changes in all the parameters, which mainly occurred in the western and south-western regions because the …

Ashfall Fossil Beds: From Waterhole To Rhino Barn, Sandy Mosel

University of Nebraska State Museum: Programs Information

Twelve million years ago a volcanic super-eruption in what is now southwestern Idaho created an enormous ashfall that blanketed the Great Plains with several inches of volcanic ash, devastating the local wildlife. Evidence of this geologic event lies within the hills of the Niobrara River Valley in northeast Nebraska, at a place aptly named the Ashfall Fossil Beds State Historical Park. Located near the tiny village of Royal, the Ashfall Park has been developed around a waterhole where animals succumbed after breathing in the volcanic dust. Buried deeply by windblown volcanic ash in the weeks following the eruption, the skeletons …

Geochemical Constraints On Mantle Sources And Basalt Petrogenesis In The Strait Of Sicily Rift Zone (Italy): Insights Into The Importance Of Short Lengthscale Mantle Heterogeneity., John C. White, David A. Neave, Silvio G. Rotolo, Don F. Parker

EKU Faculty and Staff Scholarship

Igneous activity from the late Miocene to historic time (most recently 1891 ce) in the Strait of Sicily has created two islands (Pantelleria and Linosa) and several seamounts. These volcanoes are dominated by transitional (ol+hy-normative) to alkaline (ne-normative) basaltic lavas and scoriae; peralkaline felsic rocks (trachyte-rhyolite) crop out only on Pantelleria. Although most likely erupted through continental crust, basalts demonstrate no evidence of crustal contamination and are geochemically similar to oceanic island basalts (OIB). Despite their isotopic similarities, there are considerable compositional differences with respect to major and trace element geochemistry both between and within the two islands that are …

Hydrothermal Activity And Seismicity At Teahitia Seamount: Reactivation Of The Society Islands Hotspot?, Christopher R. German, Joseph A. Resing, Guangyu Xu, Isobel A. Yeo, Sharon L. Walker, Colin W. Devey, James W. Moffett, Gregory A. Cutter, Olivier Hyvernaud, Dominique Reymond

OES Faculty Publications

Along mid-ocean ridges, submarine venting has been found at all spreading rates and in every ocean basin. By contrast, intraplate hydrothermal activity has only been reported from five locations, worldwide. Here we extend the time series at one of those sites, Teahitia Seamount, which was first shown to be hydrothermally active in 1983 but had not been revisited since 1999. Previously, submersible investigations had led to the discovery of low-temperature (≤30°C) venting associated with the summit of Teahitia Seamount at ≤1500 m. In December 2013 we returned to the same site at the culmination of the US GEOTRACES Eastern South …

Reconstruction Of The 2018 Anak Krakatau Collapse Using Planetscope Imaging And Numerical Modeling, Davide Saviano

Dissertations, Master's Theses and Master's Reports

The study was focused on the Anak Krakatau sector collapse that occurred on 22 December 2018 in the Sunda Strait (Indonesia). The goal of the study was to monitor and analyze changes of the volcanic edifice and to try to understand causes that may have predisposed and triggered the sector collapse.

The use of different remote sensing techniques allowed the acquisition of thermal data, SO₂ emission data, structural data and the identification and analysis of the eruptive events that occurred on Anak Krakatau in the period from 1° January 2016 to 28 February 2019. The acquisition of 1221 thermal …

The Role Of Cumulate Plagioclase Entrainment In The Steens Basalt, Se Oregon: Insights From The Magma Chamber Simulator, Valerie Strasser

All Master's Theses

The Steens Basalt, located in SE Oregon, is the oldest and most mafic member of the Columbia River Basalt Group (CRBG). Because the Steens Basalt contains large (up to 6 cm) and abundant (up to 40%) plagioclase crystals, it is classified as a Giant Plagioclase basalt (GPB). Understanding the origin of these giant plagioclase yields insight into magmatic processes like recharge, crustal assimilation, cumulate entrainment, and fractional crystallization. Because large and abundant plagioclase are found in other flood basalt provinces worldwide, these results could also enhance understanding of magma evolution and storage conditions for GPB worldwide. The Steens basalt is …

Rain Generated Lahars Prior To The 2018 Catastrophic Eruption Of Fuego Volcano, Guatemala, Claudia Buondonno

Dissertations, Master's Theses and Master's Reports

Fuego volcano is one of the most active and hazardous volcanoes in the world. It is located in the northern part of the Central American Volcanic Arc in Guatemala and its activity can be characterized by long term, low-level background activity, and sporadic larger explosive eruptions. Its historical observations of eruptions date back to 1531, but it has been erupting vigorously since 2002 with major activity throughout 2018, producing three main eruptions in February, June and November. Its almost persistent activity generates major ashfalls, pyroclastic flows, lava flows; when heavy rains mobilize its deposits, they can form damaging lahars. Phenomena, …

Anatomy Of The Magmatic Plumbing System Of Los Humeros Caldera (Mexico): Implications For Geothermal Systems., Federico Lucci, Gerardo Carrasco-Nuñez, Federico Rossetti, Thomas Theye, John C. White, Stefano Urbani, Hossein Azzizi, Yosihiro Asahara, Guido Giordano

EKU Faculty and Staff Scholarship

Understanding the anatomy of magma plumbing systems of active volcanoes is essential not only for unraveling magma dynamics and eruptive behaviors but also to define the geometry, depth, and temperature of the heat sources for geothermal exploration. The Pleistocene–Holocene Los Humeros volcanic complex is part of the eastern Trans- Mexican Volcanic Belt (central Mexico), and it constitutes one of the most important exploited geothermal fields in Mexico with ca. 90MWof produced electricity. With the aim to decipher the anatomy (geometry and structure) of the magmatic plumbing system feeding the geothermal field at Los Humeros, we carried out a field-based petrological …