Physical Sciences and Mathematics Commons^™

Precaspian Isthmus Emergence Triggered The Early Sakmarian Glaciation (Paleontologic, Sedimentologic And Geochemical Proxies), Vladimir I. Davydov

Geosciences Faculty Publications and Presentations

The sub-meridional seaway that connected Paleo-Arctic and Paleo-Tethys basins was one of the most important geographical attributes of the Late Paleozoic Pangea landscape, paleogeography and paleoclimate. Existing models about the timing of the disconnection of the Paleo-Arctic and the Paleo-Tethyan oceans is very controversial and poorly documented. Warm-water benthic foraminifera (WWBF) were utilized to establish the precise timing of the closure of the Urals-Precaspian-Paleo-Tethys Seaway (UPTS) during Cisuralian time. The WWBF of Paleo-Tethys and those of the Ural-Precaspian Basins during the Gzhelian-Asselian, display a considerably high level of similarity. Beginning from the Sakmarian, the faunas of these two regions became …

Cross-Scale Interactions Between Atmospheric And Hydrologic Processes In A Topographically Complex, Snow-Dominated Watershed As Revealed Through An Integrated Hydrologic Model, Miguel A. Aguayo Arias

Boise State University Theses and Dissertations

In much of the world, water for agricultural, domestic, and hydroelectric power generation uses are derived from snow-dominated mountain basins. In these regions, water management requires accurate and timely knowledge of runoff generation by snowmelt. This information is used to plan reservoir releases for downstream users and is generated by models of biophysical processes associated with varying degrees of fidelity to physical processes and/or spatial heterogeneities. The large variability in the characteristic spatial and temporal scales of atmospheric forcings, land-surface water and energy balance, and groundwater flow contribute to significant uncertainties in resolved hydrologic states and fluxes. Underlying sources of …

Pressure Waves And Tephra Dispersal From Volcanic Explosions: Models, Observations, And Instrumentation, Jacob Fortner Anderson

Boise State University Theses and Dissertations

Real-time study of erupting vents is important for both monitoring and scientific purposes; because direct in-situ study of erupting vents is impractical, our best tools for studying eruptions in real time involve monitoring eruptive products and waves that travel far from the volcano. The atmosphere is a particularly advantageous medium for studying propagation and transport of volcanic waves and products: acoustic waves pass through it with minimal scattering, particles follow predictable trajectories, and the atmospheric structure that affects both is well-monitored. Analyses of acoustic waves and tephra deposits can provide important information on eruptions including total explosive energy, volume, and …

Stable Isotope Geochemistry Of Bioapatite, Amanda E. Drewicz

Boise State University Theses and Dissertations

The Cenozoic Era was a time period where dynamic shifts in climate created for both warm-wet greenhouse environments of the mid-Miocene Climatic Optimum (MMCO), and cool-dry, glacial periods of the late Pleistocene. The Cenozoic is close to our own time period, and although past climate reconstructions cannot be used as direct analogs for future climate change, understanding previous environmental responses can help inform policy surrounding future climate change. Presented here are climate reconstructions of the interior western United States, from two different geologic time periods. Each had a different climate, that differed greatly from modern day environments. The use of …

Crustal Composition Beneath Southern Idaho: Insights From Teleseismic Receiver Functions, Thomas Branson Harper

Boise State University Theses and Dissertations

Receiver functions derived from teleseismic earthquakes contain seismic amplitude and velocity information that relate to compositional changes within the Earth’s crust and upper mantle. The receiver function waveform is a combination of P-S converted waves that have reverberated within the lithosphere. Although the largest seismic velocity boundary is found at the base of the crust, I explore the use of lower amplitude receiver function arrivals that represent smaller velocity contrasts within the crust. In my thesis, I calculate and model receiver functions via a Metropolis algorithm approach to extract seismic velocity distributions in the lithosphere. I use the results to …

Investigating The Annual Water Balance Of A High-Altitude Watershed Using Near-Real Time Lidar Data Integration Into A Physically Based Snowmelt Model, Andrew R. Hedrick

Boise State University Theses and Dissertations

Knowledge of the amount of water stored in the mountain snowpack is crucial for flood prevention, drought mitigation, and energy production in the Western United States. In modeling terms, the most important component of the hydrologic water balance is the precipitation input to the system. Determining where and how much precipitation falls in mountain catchments, however, is the most difficult problem with regards to closing the water balance. The work presented in this dissertation details the modeling portion of the NASA Airborne Snow Observatory (ASO) using the iSnobal physically based snow model. This combination of remote sensing and modeling at …

Correlating The Spatial Distribution Of Snow Depth To Forest Canopy Parameters Derived From Terrestrial Laser Scans, Zachary Uhlmann

Boise State University Theses and Dissertations

In nonpolar, cold climate zones, snow accounts for 17% of the total terrestrial water storage. Estimating the amount of water stored in a snowpack, the snow water equivalent (SWE), and its spatial distribution is crucial to providing water managers with parameters to predict runoff timing, duration and amount. Reservoir management, hydropower and flood forecasting depend on SWE estimates. While landscape features such as aspect and slope are dominant controls on radiative energy in non-forested areas, forest cover can shift the energy balance composition from turbulent exchange in exposed, windy sites to primarily radiative inputs in the subcanopy. Additionally, forest cover …

Volcano Infrasound Monitoring With Applications For Statistical Forecasting Of Explosions At Sakurajima (Japan), Matthew R. Vonlintig

Boise State University Theses and Dissertations

Volcanic eruptions are powerful natural phenomena that often occur unpredictably in time and magnitude. Nearby communities are put at risk during volcanic unrest; however, when hazards are well understood and clearly defined risk can be mitigated. This thesis addresses the problem of forecasting the likelihood of future explosive volcanic behavior by monitoring ongoing eruptive history with infrasound. I parameterize inter-event temporal behavior to determine the eruption controlling processes is material failure opposed to changes in magma and volatile supply.

I analyze data from Sakurajima, a type-example open volcano, using two local (4 km from the vent) microphone arrays, which recorded …

Evaluating Stable Isotope And Geochronologic Techniques For Paleoclimate Reconstruction: Case Study Of The Santa Cruz Formation, Argentina, Robin B. Trayler

Boise State University Theses and Dissertations

Stable isotope analysis has become the method of choice for many studies investigating the paleoecology and paleoclimate of fossil mammal faunas. While organic tissues (collagen, keratins, proteins) persist for < 10⁵ years highly mineralized tooth enamel is resistant to alteration and degradation and faithfully preserves its isotopic composition for millions (> 10⁶) years. Reconstructing past climates from these records relies on both understanding both micro-scale mechanisms of isotope incorporation into individual teeth, and macro-scale changes in isotope compositions over hundreds of thousands or millions of years. In this dissertation I address three questions.

First, how does the geometry and …

Post-Fire Variation In Aeolian Deposition In The Northern Great Basin, Clayton Roehner

Boise State University Theses and Dissertations

Aeolian processes play a significant role in the redistribution of sediment and nutrients in sparsely vegetated sagebrush-steppe ecosystems. When fire is introduced to the landscape, decreased surface roughness and associated threshold friction velocities allow for the increased mobility of surface sediments and burnt organic material, mobilizing previously stable material. Once material is entrained, interactions between a dynamic atmosphere and complex topography control the spatial distribution of aeolian deposition over a landscape. Given the significant impact of fire on aeolian processes in semi-arid deserts, we posit that postfire aeolian redistribution of material is an important control on the spatial variability of …

Interannual Snow Accumulation Variability On Glaciers Derived From Repeat, Spatially Extensive Ground-Penetrating Radar Surveys, Daniel Mcgrath, Louis Sass, Shad O'Neel, Chris Mcneil, Salvatore G. Candela, Emily H. Baker, Hans-Peter Marshall

CGISS Publications and Presentations

There is significant uncertainty regarding the spatiotemporal distribution of seasonal snow on glaciers, despite being a fundamental component of glacier mass balance. To address this knowledge gap, we collected repeat, spatially extensive high-frequency ground-penetrating radar (GPR) observations on two glaciers in Alaska during the spring of 5 consecutive years. GPR measurements showed steep snow water equivalent (SWE) elevation gradients at both sites; continental Gulkana Glacier's SWE gradient averaged 115 mm 100 m⁻¹ and maritime Wolverine Glacier's gradient averaged 440 mm 100 m⁻¹ (over > 1000 m). We extrapolated GPR point observations across the glacier surface using terrain parameters derived …

Direct Insertion Of Nasa Airborne Snow Observatory-Derived Snow Depth Time Series Into The Isnobal Energy Balance Snow Model, Andrew R. Hedrick, Hans-Peter Marshall

CGISS Publications and Presentations

Accurately simulating the spatiotemporal distribution of mountain snow water equivalent improves estimates of available meltwater and benefits the water resource management community. In this paper we present the first integration of lidar-derived distributed snow depth data into a physics-based snow model using direct insertion. Over four winter seasons (2013–2016) the National Aeronautics and Space Administration/Jet Propulsion Laboratory (NASA/JPL) Airborne Snow Observatory (ASO) performed near-weekly lidar surveys throughout the snowmelt season to measure snow depth at high resolution over the Tuolumne River Basin above Hetch Hetchy Reservoir in the Sierra Nevada Mountains of California. The modeling component of the ASO program …

Climate Change And Curtailment: Evaluating Water Management Practices In The Context Of Changing Runoff Regimes In A Snowmelt-Dominated Basin, Amy L. Steimke, Bangshuai Han, Jodi S. Brandt, Alejandro N. Flores

Geosciences Faculty Publications and Presentations

Hydrologic scientists and water resource managers often focus on different facets of flow regimes in changing climates. The objective of this work is to examine potential hydrological changes in the Upper Boise River Basin, Idaho, USA in the context of biophysical variables and their impacts a key variable governing administration of water resources in the region in an integrated way. This snowmelt-dominated, mountainous watershed supplies water to a semi-arid, agriculturally intensive, but rapidly urbanizing, region. Using the Envision integrated modeling framework, we created a hydrological model to simulate hydrological response to the year 2100 using six alternative future climate trajectories. …

Imaging Spectroscopic Analysis Of Biochemical Traits For Shrub Species In Great Basin, Usa, Yi Qi, Susan L. Ustin, Nancy F. Glenn

Geosciences Faculty Publications and Presentations

The biochemical traits of plant canopies are important predictors of photosynthetic capacity and nutrient cycling. However, remote sensing of biochemical traits in shrub species in dryland ecosystems has been limited mainly due to the sparse vegetation cover, manifold shrub structures, and complex light interaction between the land surface and canopy. In order to examine the performance of airborne imaging spectroscopy for retrieving biochemical traits in shrub species, we collected Airborne Visible Infrared Imaging Spectrometer—Next Generation (AVIRIS-NG) images and surveyed four foliar biochemical traits (leaf mass per area, water content, nitrogen content and carbon) of sagebrush (Artemesia tridentata) and …

Reverse-Time Migration From Rugged Topography To Image Ground-Penetrating Radar Data In Complex Environments, John H. Bradford, Janna Privette, David Wilkins, Richard Ford

Geosciences Faculty Publications and Presentations

In ground-penetrating radar (GPR) imaging, it is common for the depth of investigation to be on the same order as the variability in surface topography. In such cases, migration fails when it is carried out from a datum after the application of elevation statics. We introduce a reverse-time migration (RTM) algorithm based on the second-order decoupled form of Maxwell’s equations, which requires computation of only the electric field. The wavefield extrapolation is computed directly from the acquisition surface without the need for datuming. In a synthetic case study, the algorithm significantly improves image accuracy over a processing sequence in which …

Nested Scales Of Spatial And Temporal Variability Of Soil Water Content Across A Semiarid Montane Catchment, Kendra E. Kaiser, Brian L. Mcglynn

Geosciences Faculty Publications and Presentations

Topographic redistribution of water has been represented by various terrain metrics (e.g., topographic wetness index, slope, and upslope accumulated area). This type of landscape characterization has promoted the use of terrain metrics to inform how spatial patterns of soil volumetric water content (VWC) influence streamflow, ecological processes, and associated nutrient fluxes. However, evaluation of what these static terrain metrics reflect has only been accomplished in a few catchments. Additionally, previous research suggests that relationships between topographic metrics and VWC could be different across catchments through time. Here we measured VWC from snowmelt through summer drydown across a semiarid montane catchment. …

Submarine Deep-Water Lava Flows At The Base Of The Western Galápagos Platform, Molly Anderson, V. Dorsey Wanless, Darin M. Schwartz, Emma Mccully, Daniel J. Fornari, Meghan R. Jones, S. Adam Soule

Geosciences Faculty Publications and Presentations

To investigate the initial phases of magmatism at the leading edge of the upwelling mantle plume, we mapped, photographed, and collected samples from two long, deep-water lava flows located at the western base of the Galápagos Platform using the remotely operated vehicle Hercules. Lavas were recovered from four areas on the seafloor west of Fernandina volcano, including the western flow fronts of two deep-water flows, heavily sedimented terrain between the two flows, and the eastern, shallower end of one flow. The sediment cover and morphologies are distinct between the western flow fronts and the eastern region based on seafloor …

The Final Stages Of Slip And Volcanism On An Oceanic Detachment Fault At 13°48′N, Mid-Atlantic Ridge, V. D. Wanless

Geosciences Faculty Publications and Presentations

While processes associated with initiation and maintenance of oceanic detachment faults are becoming better constrained, much less is known about the tectonic and magmatic conditions that lead to fault abandonment. Here we present results from near‐bottom investigations using the submersible Alvin and autonomous underwater vehicle Sentry at a recently extinct detachment fault near 13°48′N, Mid‐Atlantic Ridge, that allow documentation of the final stages of fault activity and magmatism. Seafloor imagery, sampling, and near‐bottom magnetic data show that the detachment footwall is intersected by an ~850 m‐wide volcanic outcrop including pillow lavas. Saturation pressures in these vesicular basalts, based on dissolved …

Revelation Of Early Detection Of Coseismic Ionospheric Perturbations In Gps-Tec From Realistic Modelling Approach: Case Study, Dhanya Thomas, Mala S. Bagiya, Poikayil Sukumaran Sunil, Lucie Rolland, Anakuzhikkal Sudarsanan Sunil, T. Dylan Mikesell, Srinivas Nayak, Subrahmanyam Mangalampalli, Durbha Sai Ramesh

CGISS Publications and Presentations

GPS-derived Total Electron Content (TEC) is an integrated quantity; hence it is difficult to relate the detection of ionospheric perturbations in TEC to a precise altitude. As TEC is weighted by the maximum ionospheric density, the corresponding altitude (hmF2) is, generally, assumed as the perturbation detection altitude. To investigate the validity of this assumption in detail, we conduct an accurate analysis of the GPS-TEC measured early ionospheric signatures related to the vertical surface displacement of the Mw 7.4 Sanriku-Oki earthquake (Sanriku-Oki Tohoku foreshock). Using 3D acoustic ray tracing model to describe the evolution of the propagating seismo-acoustic wave in space …

From Snow To Flow: Exploring Relationships Between Snotel Ablation Curves And Peak Streamflow Timing, Kara Jane Ferguson

Boise State University Theses and Dissertations

Predictions of peak streamflow timing in snow-dominated river systems are essential for proper water management and recreational availability. This study evaluates historic snow and streamflow data from 14 river basins throughout Idaho to investigate the relationship between snowmelt timing at SNOw TELemetry (SNOTEL) sites and peak streamflow within each basin. The goal is to provide a simple operational tool that estimates the probability of peak streamflow occurring within a certain number of days as ablation progresses from 0 to 100% melted. For individual basins we evaluate meltout levels in increments of 10% from each SNOTEL site and use a probabilistic …

Exploring The Role Of Deforestation On Regional Hydroclimate In Southeast Africa: An Approach Fusing Models And Data, Megan Maksimowicz

Boise State University Theses and Dissertations

Land cover acts as the gatekeeper to incoming and outgoing energy and water fluxes at the land surface, partitioning energy and water in accordance with the vegetation type and in response to atmospheric forcings. As Land Surface Models become more complex and more capable of simulating the coupled dynamics of the land-atmosphere system in greater spatial detail, the need for accurate representation of spatial distribution of vegetation types and their dynamics through time grows.

As humans modify land cover, there are complex dynamics at play between the vegetation, the surface energy balance and the cycling of water. The resultant hydroclimatic …

Evaporation Depth Controls The Relationship Between Soil Water Mobility And Soil Water Isotopic Composition, John Byars Shuler

Boise State University Theses and Dissertations

Recent studies of plant water uptake assume that soil water isotopic composition can be used to infer soil water mobility. However, the strength of the relationship between mobility and isotopic composition remains poorly constrained. In addition, many ecohydrologic investigations are restricted by low sampling frequencies and insufficient soil moisture and matric potential data to support assumptions of soil water mobility. We sampled bulk soil water every 14 to 21 days in hillslope and riparian profiles during the 2016 and 2017 growing seasons in a semi-arid watershed outside Boise, ID. We collected twig samples of four tree and shrub species concurrently. …

Assessment Of Snow Atmosphere Forcing During Central Idaho Atmospheric Rivers, William Rudisill

Boise State University Theses and Dissertations

Atmospheric Rivers (AR) are globally occuring weather features and the primary mechanism through which water vapor moves from the tropics and subtropics towards the mid-latitudes, doing so at rates comparable to the world’s largest terrestrial rivers. AR that encounter mountains often cause extreme precipitation in the form of rain and snow, high winds, and flooding in many watersheds. They account for as much as 20-30% of cool season precipitation in the central Idaho Mountains. In the Northern Hemisphere, seasonal snow cover during Winter and Spring months is the most variable land surface component in space and time, and acts on …

Tephra From The 3 March 2015 Sustained Column Related To Explosive Lava Fountain Activity At Volcán Villarrica (Chile), Jeffrey B. Johnson

Geosciences Faculty Publications and Presentations

Exceptionally intense lava fountains at open conduit volcanoes are infrequent, hazardous and little-warned events. Studying their tephra falls may reveal conduit dynamics, eruption source parameters and fragmentation mechanisms. Villarrica Volcano (Southern Andes of Chile) has sustained persistent open conduit activity, associated with a dynamic lava lake since at least 1984–85. Increased seismicity and degassing in August 2014 were followed by Strombolian activity starting in February 2015 and culminated with a 1.5 km-high lava fountain on 3 March 2015. This eruption produced tephra fallout, spatter agglutination, clastogenic lavas and mixed avalanche deposits. Here we characterized for first time Villarrica's 3 March …

Identification Of Erosional Terraces On Seamounts: Implications For Interisland Connectivity And Subsidence In The Galápagos Archipelago, Darin M. Schwartz, S. Adam Soule, V. Dorsey Wanless, Meghan R. Jones

Geosciences Faculty Publications and Presentations

Shallow seamounts at ocean island hotspots and in other settings may record emergence histories in the form of submarine erosional terraces. Exposure histories are valuable for constraining paleo-elevations and sea levels in the absence of more traditional markers, such as drowned coral reefs. However, similar features can also be produced through primary volcanic processes, which complicate the use of terraced seamounts as an indicator of paleo-shorelines. In the western Galápagos Archipelago, we utilize newly collected bathymetry along with seafloor observations from human-occupied submersibles to document the location and depth of erosional terraces on seamounts near the islands of Santiago, Santa …

Eleven Years Of Mountain Weather, Snow, Soil Moisture And Streamflow Data From The Rain–Snow Transition Zone – The Johnston Draw Catchment, Reynolds Creek Experimental Watershed And Critical Zone Observatory, Usa, James P. Mcnamara

Geosciences Faculty Publications and Presentations

Detailed hydrometeorological data from the rain-to-snow transition zone in mountain regions are limited. As the climate warms, the transition from rain to snow is moving to higher elevations, and these changes are altering the timing of downslope water delivery. To understand how these changes impact hydrological and biological processes in this climatologically sensitive region, detailed observations from the rain-to-snow transition zone are required. We present a complete hydrometeorological dataset for water years 2004 through 2014 for a watershed that spans the rain-to-snow transition zone (https://doi.org/10.15482/usda.adc/1402076). The Johnston Draw watershed (1.8km²), ranging from 1497 to 1869m in elevation, is …

Hyporheic Source And Sink Of Nitrous Oxide, W. Jeffery Reeder, Annika M. Quick, Tiffany B. Farrell, Shawn G. Benner, Kevin P. Feris, Alessandra Marzadri, Daniele Tonina

Geosciences Faculty Publications and Presentations

Nitrous oxide (N₂O) is a potent greenhouse gas with an estimated 10% of anthropogenic N₂O coming from the hyporheic zone of streams and rivers. However, difficulty in making accurate fine-scale field measurements has prevented detailed understanding of the processes of N₂O production and emission at the bedform and flowline scales. Using large-scale, replicated flume experiments that employed high-density chemical concentration measurements, we have been able to refine the current conceptualization of N₂O production, consumption, and emission from the hyporheic zone. We present a predictive model based on a Damköhler-type transformation (τ̃) in …

Single-Station Seismo-Acoustic Monitoring Of Nyiragongo's Lava Lake Activity (D.R. Congo), Jeffrey B. Johnson

Geosciences Faculty Publications and Presentations

Since its last effusive eruption in 2002, Nyiragongo has been an open-vent volcano characterized by the world's largest persistent lava lake. This lava lake provides a unique opportunity to detect pressure change in the magmatic system by analyzing its level fluctuations. We demonstrate that this information is contained in the seismic and infrasound signals generated by the lava lake's activity. The continuous seismo-acoustic monitoring permits quantification of lava lake dynamics, which is analyzed retrospectively to identify periods of volcanic unrest. Synchronous, high-resolution satellite SAR (Synthetic Aperture Radar) images are used to constrain lava lake level by measuring the length of …

Infrasound Tornillos Produced By Volcán Cotopaxi’S Deep Crater, J. B. Johnson, M. C. Ruiz, H. D. Ortiz, L. M. Watson, G. Viracucha, P. Ramon, M. Almeida

CGISS Publications and Presentations

We characterize and interpret a new type of infrasound signal originating from the summit of Volcán Cotopaxi (Ecuador) that was primarily observed between September 2015 and March 2016, following the 2015 eruptive period. This infrasound waveform is a slowly decaying sinusoid with exceptional low-frequency (f_p = 0.2 Hz) and high quality factor (Q = ~10) and resembles the shape of tornillo seismic waveforms. The repeating events, occurring about once per day in early 2016, are stable in frequency content, and we attribute them to excitation of a vertical-walled crater, with radius of about 125mand length of 300 …

Seismic Imaging Of The Main Frontal Thrust In Nepal Reveals A Shallow Décollement And Blind Thrusting, Rafael V. Almeida, Judith Hubbard, Lee Liberty, Anna Foster, Soma Nath Sapkota

CGISS Publications and Presentations

Because great earthquakes in the Himalaya have an average recurrence interval exceeding 500 yr, most of what we know about past earthquakes comes from paleoseismology and tectonic geomorphology studies of the youngest fault system there, the Main Frontal Thrust (MFT). However, these data are sparse relative to fault segmentation and length, and interpretations are often hard to validate in the absence of information about fault geometry. Here, we image the upper two km of strata in the vicinity of the fault tip of the MFT in central Nepal (around the town of Bardibas) applying a pre-stack migration approach to two …