Geophysics and Seismology Commons^™

Seasonality Of Solute Flux And Water Source Chemistry In A Coastal Glacierized Watershed Undergoing Rapid Change: Wolverine Glacier Watershed, Alaska, Anna Bergstrom, Joshua C. Koch, Shad O'Neel, Emily Baker

Geosciences Faculty Publications and Presentations

As glaciers around the world rapidly lose mass, the tight coupling between glaciers and downstream ecosystems is resulting in widespread impacts on global hydrologic and biogeochemical cycling. However, a range of challenges make it difficult to conduct research in glacierized systems, and our knowledge of seasonally changing hydrologic processes and solute sources and signatures is limited. This in turn hampers our ability to make predictions on solute composition and flux. We conducted a broad water sampling campaign in order to understand the present-day partitioning of water sources and associated solutes in Alaska's Wolverine Glacier watershed. We established a relationship between …

Automated Detection Of Marine Glacier Calving Fronts Using The 2-D Wavelet Transform Modulus Maxima Segmentation Method, Julia Liu, Ellyn M. Enderlin, Hans-Peter Marshall, Andre Khalil

Geosciences Faculty Publications and Presentations

Changes in the calving front position of marine-terminating glaciers strongly influence the mass balance of glaciers, ice caps, and ice sheets. At present, quantification of frontal position change primarily relies on time-consuming and subjective manual mapping techniques, limiting our ability to understand changes to glacier calving fronts. Here we describe a newly developed automated method of mapping glacier calving fronts in satellite imagery using observations from a representative sample of Greenland’s peripheral marine-terminating glaciers. Our method is adapted from the 2-D wavelet transform modulus maxima (WTMM) segmentation method, which has been used previously for image segmentation in biomedical and other …

Spatiotemporal Variations In Liquid Water Content In A Seasonal Snowpack: Implications For Radar Remote Sensing, Randall Bonnell, Daniel Mcgrath, Keith Williams, Ryan Webb, Steven R. Fassnacht, Hans-Peter Marshall

Geosciences Faculty Publications and Presentations

Radar instruments have been widely used to measure snow water equivalent (SWE) and Interferometric Synthetic Aperture Radar is a promising approach for doing so from spaceborne platforms. Electromagnetic waves propagate through the snowpack at a velocity determined by its dielectric permittivity. Velocity estimates are a significant source of uncertainty in radar SWE retrievals, especially in wet snow. In dry snow, velocity can be calculated from relations between permittivity and snow density. However, wet snow velocity is a function of both snow density and liquid water content (LWC); the latter exhibits high spatiotemporal variability, there is no standard observation method, and …

In Situ Determination Of Dry And Wet Snow Permittivity: Improving Equations For Low Frequency Radar Applications, Ryan Webb, Adrian Marziliano, Daniel Mcgrath, Randall Bonnell, Tate G. Meehan, Carrie Vuyovich, Hans-Peter Marshall

Geosciences Faculty Publications and Presentations

Extensive efforts have been made to observe the accumulation and melting of seasonal snow. However, making accurate observations of snow water equivalent (SWE) at global scales is challenging. Active radar systems show promise, provided the dielectric properties of the snowpack are accurately constrained. The dielectric constant (k) determines the velocity of a radar wave through snow, which is a critical component of time-of-flight radar techniques such as ground penetrating radar and interferometric synthetic aperture radar (InSAR). However, equations used to estimate k have been validated only for specific conditions with limited in situ validation for seasonal snow applications. …

Tracking Secondary Lahar Flow Paths And Characterizing Pulses And Surges Using Infrasound Array Networks At Volcán De Fuego, Guatemala, Ashley R. Bosa, Jeffrey B. Johnson, Silvio De Angelis, John J. Lyons, Amilcar Roca, Jacob F. Anderson, Amando Pineda

Geosciences Faculty Publications and Presentations

Lahars are one of the greatest hazards at many volcanoes, including Volcán de Fuego (Guatemala). On 1 December 2018 at 8:00 pm local Guatemala time (~2:06:00 UTC), an hour-long lahar event was detected at Volcán de Fuego by two permanent seismo-acoustic stations along the Las Lajas drainage on the southeast side. To establish the timing, duration, and speed of the lahar, infrasound array records were examined to identify both the source direction(s) and the correlated energy fluctuations at the two stations. Co-located seismic and acoustic signals were also examined, which indicated at least five distinct energy pulses within the lahar …

Synchronous Emplacement Of The Anorthosite Xenolith-Bearing Beaver River Diabase And One Of The Largest Lava Flows On Earth, Yiming Zhang, Nicholas L. Swanson-Hysell, Mark D. Schmitz, James D. Miller, Margaret S. Avery

Geosciences Faculty Publications and Presentations

New geochronologic and paleomagnetic data from the North American Midcontinent Rift (MCR) reveal the synchronous emplacement of the Beaver River diabase, the anorthosite xenoliths within it, and the Greenstone Flow—one of the largest lava flows on Earth. A U-Pb zircon date of 1091.83 ± 0.21 Ma (2σ) from one of the anorthosite xenoliths is consistent with the anorthosite cumulate forming as part of the MCR and provides a maximum age constraint for the Beaver River diabase. Paired with the minimum age constraint of a cross-cutting Silver Bay intrusion (1091.61 ± 0.14 Ma; 2σ), these data tightly …

The Hera Orebody: A Complex Distal (Au–Zn–Pb–Ag–Cu) Skarn In The Cobar Basin Of Central New South Wales, Australia, Corey Wall

Geosciences Faculty Publications and Presentations

The Hera Au–Pb–Zn–Ag deposit in the southeastern Cobar Basin of central New South Wales preserves calc-silicate veins and remnant sandstone/carbonate-hosted skarn within a reduced anchizonal Siluro-Devonian turbidite sequence. The skarn orebody distribution is controlled by a long-lived, basin margin fault system, that has intersected a sedimentary horizon dominated by siliciclastic turbidite, with lesser gritstone and thick sandstone intervals, and rare carbonate-bearing stratigraphy. Foliation (S1) envelopes the orebody and is crosscut by a series of late-stage east–west and north–south trending faults. Skarn at Hera displays mineralogical zonation along strike, from southern spessartine–grossular–biotite–actinolite-rich associations, to central diopside-rich–zoisite–actinolite/tremolite–grossular-bearing associations, through to the northern …

Trace Fossils, Algae, Invertebrate Remains And New U-Pb Detrital Zircon Geochronology From The Lower Cambrian Torneträsk Formation, Northern Sweden, Stephen Mcloughlin, Vivi Vajda, Timothy P. Topper, James L. Crowley, Fan Liu, Ove Johansson, Christian B. Skovsted

Geosciences Faculty Publications and Presentations

Nineteen ichnotaxa, together with algal and invertebrate remains, and various pseudo-traces and sedimentary structures are described from the Torneträsk Formation exposed near Lake Torneträsk, Lapland, Sweden, representing a marked increase in the diversity of biotic traces recorded from this unit. The “lower siltstone” interval of the Torneträsk Formation contains mostly simple pascichnia, fodinichnia and domichnia burrows and trails of low-energy shoreface to intertidal settings. The assemblage has very few forms characteristic of high-energy, soft-sediment, foreshore or upper shoreface environments (representative of the Skolithos ichnofacies).

Uranium-lead (U-Pb) LA-ICPMS analysis of zircon from a thin claystone layer within the “lower siltstone” interval …

A Mélange Of Subduction Ages: Constraints On The Timescale Of Shear Zone Development And Underplating At The Subduction Interface, Catalina Schist (Ca, Usa), K. M. Harvey, S. Walker, P. G. Starr, S. C. Penniston-Dorland, M. J. Kohn, E. F. Baxter

Geosciences Faculty Publications and Presentations

The presence of mélange at the subduction interface influences numerous geochemical and geophysical processes. However, the relationship between the timescales of mélange development, deformation, and resultant mass transport is poorly understood. Here, we use Sm-Nd garnet geochronology to elucidate the timing of peak metamorphism for five garnet amphibolite tectonic blocks from the amphibolite-facies mélange zone of the Catalina Schist (Santa Catalina Island, CA). Ages range from 108 to 116 Ma and do not appear to correlate with the peak metamorphic temperature recorded by each block (between 640 and 740°C). The lack of correlation between age and peak temperature favors the …

Coupled Inversion Of Hydraulic And Self-Potential Data From Transient Outflow Experiments To Estimate Soil Petrophysical Properties, Jing Xie, Yian Cui, Qifei Niu

Geosciences Faculty Publications and Presentations

Hydraulicproperties of soils could play an important role in affecting the partitioning of precipitation in the critical zone. In addition to traditional approaches, in the last two decades, many geophysical methods have been used to aid the hydrologic characterization and measurement of geological materials. In particular, the self-potential (SP) method shows great potential in these hydrogeophysical applications. The objective of this study is to evaluate whether the addition of SP data can improve the estimation of hydraulic properties of soils in an outflow experiment. A stochastic, coupled hydrogeophysical inversion was developed, in which the governing equations were solved using the …

(Re)Proposal Of Three Cambrian Subsystems And Their Geochronology, Ed Landing, Gerd Geyer, Mark D. Schmitz, Thomas Wotte, Artem Kouchinsky

Geosciences Faculty Publications and Presentations

The Cambrian is anomalous among geological systems as many reports divide it into three divisions of indeterminate rank. This use of “lower”, “middle”, and “upper” has been a convenient way to subdivide the Cambrian despite agreement it consists of four global series. Traditional divisions of the system into regional series (Lower, Middle, Upper) reflected local biotic developments not interprovincially correlatable with any precision. However, use of “lower”, “middle”, and “upper” is unsatisfactory. These adjectives lack standard definition, evoke the regional series, and are misused. Notably, there is an almost 50 year use of three Cambrian subsystems and a 1997 proposal …

Fragmentation Theory Reveals Processes Controlling Iceberg Size Distributions, Jan Åström, Sue Cook, Ellyn M. Enderlin, David A. Sutherland, Aleksandra Mazur, Neil Glasser

Geosciences Faculty Publications and Presentations

Iceberg calving strongly controls glacier mass loss, but the fracture processes leading to iceberg formation are poorly understood due to the stochastic nature of calving. The size distributions of icebergs produced during the calving process can yield information on the processes driving calving and also affect the timing, magnitude, and spatial distribution of ocean fresh water fluxes near glaciers and ice sheets. In this study, we apply fragmentation theory to describe key calving behaviours, based on observational and modelling data from Greenland and Antarctica. In both regions, iceberg calving is dominated by elastic-brittle fracture processes, where distributions contain both exponential …

Timescales Of Impact Melt Sheet Crystallization And The Precise Age Of The Morokweng Impact Structure, South Africa, Gavin G. Kenny, Claire O. Harrigan, Mark D. Schmitz, James L. Crowley, Corey J. Wall

Geosciences Faculty Publications and Presentations

Impact cratering was a fundamental geological process in the early Solar System and, thus, constraining the timescales over which large impact structures cool is critical to understanding the thermal evolution and habitability of early planetary crusts. Additionally, impacts can induce mass extinctions and establishing the precise timing of the largest impacts on Earth can shed light on their role in such events. Here we report a high-precision zircon U–Pb geochronology study of the Morokweng impact structure, South Africa, which appears to have a maximum present-day diameter of ∼80 km. Our work provides (i) constraints on the cooling of large impact …

Unoccupied Aircraft Systems (Uass) Reveal The Morphological Changes At Stromboli Volcano (Italy) Before, Between, And After The 3 July And 28 August 2019 Paroxysmal Eruptions, Jeffrey B. Johnson

Geosciences Faculty Publications and Presentations

In July and August 2019, two paroxysmal eruptions dramatically changed the morphology of the crater terrace that hosts the active vents of Stromboli volcano (Italy). Here, we document these morphological changes, by using 2259 UAS-derived photographs from eight surveys and Structure-from-Motion (SfM) photogrammetric techniques, resulting in 3D point clouds, orthomosaics, and digital surface models (DSMs) with resolution ranging from 8.1 to 12.4 cm/pixel. We focus on the morphological evolution of volcanic features and volume changes in the crater terrace and the upper part of the underlying slope (Sciara del Fuoco). We identify both crater terrace and lava field variations, with …

Pervasive Changes In Stream Intermittency Across The United States, Kendra E. Kaiser

Geosciences Faculty Publications and Presentations

Non-perennial streams are widespread, critical to ecosystems and society, and the subject of ongoing policy debate. Prior large-scale research on stream intermittency has been based on long-term averages, generally using annually aggregated data to characterize a highly variable process. As a result, it is not well understood if, how, or why the hydrology of non-perennial streams is changing. Here, we investigate trends and drivers of three intermittency signatures that describe the duration, timing, and dry-down period of stream intermittency across the continental United States (CONUS). Half of gages exhibited a significant trend through time in at least one of the …

Kinematics Of The Exceptionally-Short Surge Cycles Of Sít’ Kusá (Turner Glacier), Alaska, From 1983 To 2013, Andrew Nolan, William Kochtitzky, Ellyn M. Enderlin, Robert Mcnabb, Karl J. Kreutz

Geosciences Faculty Publications and Presentations

Glacier surges are periodic episodes of mass redistribution characterized by dramatic increases in ice flow velocity and, sometimes, terminus advance. We use optical satellite imagery to document five previously unexamined surge events of Sít’ Kusá (Turner Glacier) in the St. Elias Mountains of Alaska from 1983 to 2013. Surge events had an average recurrence interval of ~5 years, making it the shortest known regular recurrence interval in the world. Surge events appear to initiate in the winter, with speeds reaching up to ~25 m d⁻¹. The surges propagate down-glacier over ~2 years, resulting in maximum thinning of ~100 …

Void Hunting: Ambient Noise Tomography For Spatio-Temporal Subsurface Imaging And Monitoring In Karst Environments, John B. Paustian

Boise State University Theses and Dissertations

Karst environments are characterized by voids, i.e. sinkholes and conduits of varying size that arise from the active dissolution of carbonate rock by acidic groundwater. These voids, whether air-, water-, or soil-filled, can be difficult to image using near-surface geophysical methods due to the limited investigation depths of most active-source methods. In addition, due to the significant effort it takes to collect active-source data, investigators are often unable to monitor spatio-temporal variations in the subsurface. The ability to detect, image, and monitor subsurface voids improves the understanding of processes that create and transform voids, a vitally important insight across a …

Fundamental Resonant Frequencies Derived From Shallow Sediment Properties For The Charleston, South Carolina Area, William Dale Schermerhorn

Boise State University Theses and Dissertations

Large historic earthquakes, low velocity near surface sediments, a poor understanding of earthquake sources, and a growing population base for the Charleston, South Carolina area suggest robust site response and active fault maps are needed. A Boise State University team acquired 14 km of new surface-based seismic data to obtain surface wave dispersion curves and reflection images for the southern isoseismal region of the 1886 earthquake. From these data, I generate shear wave velocity (Vs)-depth profiles through a grid search approach. I integrate my results with other published data to develop a soil thickness and high frequency fundamental resonance maps …

Assessing Controls On Ice Dynamics At Crane Glacier, Antarctic Peninsula Using A Numerical Ice Flow Model, Rainey Aberle

Boise State University Theses and Dissertations

The widespread retreat of glaciers and the collapse of ice shelves along the Antarctic Peninsula has been attributed to atmospheric and oceanic warming, which promotes mass loss. However, several glaciers on the eastern peninsula that were buttressed by the Larsen A and B ice shelves prior to collapse in 1995 and 2002, respectively, have been advancing in recent years. This asymmetric pattern of rapid retreat and long-term re-advance is similar to the tidewater glacier cycle, which can occur largely independent of climate forcing. Here, I use a width- and depth-integrated numerical ice flow model to investigate glacier response to ice …

Laboratory Measurement Of Electrical And Hydraulic Properties Of Regolith Over Granitic Bedrock, Taylor James Bienvenue

Boise State University Theses and Dissertations

Characterizing water flux within the critical zone (CZ) is essential for a multitude of studies and applications related to irrigation, drainage, water management, and contaminant transport. Trying to measure water flux in the critical zone, specifically in the subsurface, is difficult due to the associated structural heterogeneity and complex interactions taking place between biological, chemical, and physical processes. Current methods (i.e., inferred from soil suction and soil moisture measurements) to characterize water flux within the critical zone can be time consuming and are not directly related to water flux. Recent literature has provided evidence that self-potential (SP) is a promising …

Dynamic Mass Loss From Greenland's Peripheral Glaciers, Katherine E. Bollen

Boise State University Theses and Dissertations

While global glacier mass balance has decreased rapidly over the last two decades, mass loss has been greatest in regions with marine-terminating glaciers. In Greenland, peripheral glaciers and ice caps (GICs) cover only ~5% of Greenland’s area but contributed ~14-20% of the island’s ice mass loss between 2003-2008. Although Greenland GIC’s mass loss due to surface meltwater runoff have been estimated using atmospheric models, mass loss due to changes in ice discharge into surrounding ocean basins (i.e., dynamic mass loss) remains unquantified. Here, we use the flux gate method to estimate discharge from Greenland’s 594 marine-terminating peripheral glaciers between 1985 …

Seismic Imaging Of Active And Ancient Co2 Pathways In The Little Grand Wash Fault, Jonathan Yelton

Boise State University Theses and Dissertations

Understanding the migration behavior of carbon dioxide (CO2) during long-term geological storage is crucial to the success of carbon capture and sequestration technology. I explore p-wave and s-wave seismic properties across the Little Grand Wash fault in east-central Utah, a natural CO2 seep and analogue for a long-failed sequestration site. Travertines dated to at least 113,000 k.y. and geochemical surveys confirm both modern and ancient CO2 leakage along the fault. Outgassing is currently focused in damage zones where the total fluid pressure may reduce the minimum horizontal effective stress. Regional stress changes may be responsible for decadal- to millennial-scale changes …

An Integrative Approach For Environmental Assessment And Water Resources Management Using Direct Current Resistivity (Dc), Geographic Information System (Gis), Remote Sensing, And Gain And Loss Method, Dina Ragab Desouki Abdelmoneim

Boise State University Theses and Dissertations

Sustainable water resource management is a crucial national and global issue (Currell et al., 2012). In arid areas, groundwater is often the major source of water or at least a crucial supplement to other freshwater resources for agriculture, industry and domestic consumption (Vrba and Renaud, 2016). The complexity associated with groundwater-surface water interactions creates uncertainty about water resource sustainability in semi-arid environments, especially with urbanization and population growth. Flood irrigation in the early 1900s increased the shallow groundwater table in the Treasure Valley (TV), but with increasing irrigation efficiencies, they have been declining since the 1960s with a mean decline …

3-D Ambient Noise Tomography Of Llaima Volcano, Chile, Claudia Kristina Rossavik

Boise State University Theses and Dissertations

Llaima is a glaciated, basaltic-andesitic stratocone in the South-Central Andean Volcanic Zone. It is one of the largest and most active volcanoes in Chile. However, uncertainty remains regarding the depths and geometry of where magma is stored and the routes which it takes towards the Earth's surface. To provide a structural framework for the interpretation of petrological and geochemical data, I apply ambient noise tomography (ANT) to produce a 3-D shear wave velocity (v_s) model of Llaima's magmatic plumbing. The results of this project show slow shear wave velocity anomalies within the upper 8 km of the …

Silicate Melt Inclusions In The New Millennium: A Review Of Recommended Practices For Preparation, Analysis, And Data Presentation, D. Schwartz

Geosciences Faculty Publications and Presentations

Mineral-hosted melt inclusions have become an important source of information on magmatic processes. As the number of melt inclusion studies increases, so does the need to establish recommended practice guidelines for collecting and reporting melt inclusion data. These guidelines are intended to ensure certain quality criteria are met and to achieve consistency among published melt inclusion data in order to maximize their utility in the future. Indeed, with the improvement of analytical techniques, new processes affecting melt inclusions are identified. It is thus critical to be able to reprocess any previously published data, such that reporting the raw data is …

Beyond Streamflow: Call For A National Data Repository Of Streamflow Presence For Streams And Rivers In The United States, Kendra E. Kaiser

Geosciences Faculty Publications and Presentations

Observations of the presence or absence of surface water in streams are useful for characterizing streamflow permanence, which includes the frequency, duration, and spatial extent of surface flow in streams and rivers. Such data are particularly valuable for headwater streams, which comprise the vast majority of channel length in stream networks, are often non-perennial, and are frequently the most data deficient. Datasets of surface water presence exist across multiple data collection groups in the United States but are not well aligned for easy integration. Given the value of these data, a unified approach for organizing information on surface water presence …

Backarc Lithospheric Thickness And Serpentine Stability Control Slab-Mantle Coupling Depths In Subduction Zones, Buchanan C. Kerswell, Matthew J. Kohn, Taras V. Gerya

Geosciences Faculty Publications and Presentations

A key feature of subduction zone geodynamics and thermal structure is the point at which the slab and mantle mechanically couple. This point defines the depth at which traction between slab and mantle begins to drive mantle wedge circulation and also corresponds with a rapid increase in temperature along the slab-mantle interface. Here, we consider the effects of the backarc thermal structure and slab thermal parameter on coupling depth using two-dimensional thermomechanical models of oceanic-continental convergent margins. Coupling depth is strongly correlated with backarc lithospheric thickness, and weakly correlated with slab thermal parameter. Slab-mantle coupling becomes significant where weak, hydrous …

Atmospheric Blocking Drives Recent Albedo Change Across The Western Greenland Ice Sheet Percolation Zone, Hans Peter Marshall, Tate Meehan

Geosciences Faculty Publications and Presentations

Greenland Ice Sheet (GrIS) albedo has decreased over recent decades, contributing to enhanced surface melt and mass loss. However, it remains unclear whether GrIS darkening is due to snow grain size increases, higher concentrations of light-absorbing impurities (LAIs), or a combination. Here, we assess albedo controls in the western GrIS percolation zone using in situ albedo, LAI, and grain size measurements. We find a significant correlation between albedo and snow grain size (p < 0.01), but not with LAIs. Modeling corroborates that LAI concentrations are too low to significantly reduce albedo, but larger grain sizes could reduce albedo by at least ∼3%. Strong atmospheric blocking increases grain sizes and reduces albedo through increased surface temperature, fewer storms, and higher incoming shortwave radiation. These findings clarify the mechanisms by which anomalously strong blocking contributed to recent GrIS albedo decline and mass loss, highlighting the importance of improving projections of future blocking.

Tree Canopy And Snow Depth Relationships At Fine Scales With Terrestrial Laser Scanning, Ahmed Hojatimalekshah, Zachary Uhlmann, Nancy F. Glenn, Jake D. Graham, Hans-Peter Marshall, James P. Mcnamara, Josh Enterkine

Geosciences Faculty Publications and Presentations

Understanding the impact of tree structure on snow depth and extent is important in order to make predictions of snow amounts and how changes in forest cover may affect future water resources. In this work, we investigate snow depth under tree canopies and in open areas to quantify the role of tree structure in controlling snow depth, as well as the controls from wind and topography. We use fine-scale terrestrial laser scanning (TLS) data collected across Grand Mesa, Colorado, USA (winter 2016–2017), to measure the snow depth and extract horizontal and vertical tree descriptors (metrics) at six sites. We utilize …

The Influence Of The Permian-Triassic Magmatism In The Tunguska Basin, Siberia On The Regional Floristic Biota Of The Permian-Triassic Transition In The Region, V. I. Davydov, E. V. Karasev

Geosciences Faculty Publications and Presentations

The end-Permian extinction event (EPEE) considered to have been caused by the eruption of the Siberian Large Igneous Province (SLIP), the age of which is critical for extinction-SLIP model evaluation. The Tunguska Basin flora during this time, in accordance with the EPEE model, supposed to have been killed by the massive injection into the atmosphere of poisonous substances such as methane, sulfates, mercury and massive combastion of coals. In addition, supposed numerous fires presumably devastated the regional flora. However, the diversity of the Tunguska Basin flora drasticly increased at the beginning of Induan or slightly earlier and become diverse at …