Geophysics and Seismology Commons^™

Ground-Penetrating Radar And Thermal Modeling Of Active Layer Thaw Beneath Arctic Streams, Troy Richard Brosten

Boise State University Theses and Dissertations

Seasonal thaw depth beneath arctic streams significantly impacts physical and biological processes within arctic stream environments. The impact of greater seasonal thaw for extended periods of time can alter ecosystems that have, in the past, resulted from more prevalent permafrost environments. Effects of climatic change on arctic stream environments necessitate the need for more information on characteristics of seasonal thaw and processes that occur within the thawed layer. Multiple ground-penetrating radar (GPR) methods and one-dimensional (1D) thermal modeling were used to investigate seasonal thaw beneath arctic streams and determine the dominant thermal process.

Study sites were selected to include stream …

Modeling The Deformation Of Fayalite, Greg Hoth, Mike Brawner, Pamela Burnley

Undergraduate Research Opportunities Program (UROP)

We are studying how the mineral fayalite deforms under stress while it is subject to high pressures and temperatures. Specifically, we are analyzing x-ray diffraction spectra obtained from experiments with the D-DIA apparatus at Brookhaven national labs. By fitting peaks to the diffraction spectra, we can calculate the spacing between lattice planes of fayalite and so we can observe how this spacing changes over time as the crystal structure deforms We hope to show that this deformation can be modeled using an Elastic Plastic Self Consistent model. In such a model, the material is treated as a cluster of independently …

Phonon Density Of States Of Iron Solid Solutions At Ambient And High Pressures Using Nuclear Inelastic X-Ray Scattering (Nrixs), Samantha L. Combs, Elizabeth A. Tanis, Malcolm Nicol

Undergraduate Research Opportunities Program (UROP)

Nuclear resonant inelastic x-ray scattering (NRIXS) of synchrotron radiation uses the energy transferred during the inelastic nuclear absorption of photons to determine phonon density of states for solid Mössbauer isotopes. This type of experiment can be conducted at ambient and high pressures with the use of a diamond anvil cell (DAC) and a rhenium gasket. Here, we are concerned with the phonon DOS of α-FePt 10% at pressures up to 30 GPa, as well as FeAl 4.3%, 6.4%, and 27.1% at ambient pressures. The iron samples used are doped in order to increase the pressure at which the alpha to …

Geology And Hydrology Of Karst In West-Central And North-Central Florida, Lee J. Florea

Earth, Environmental, and Atmospheric Sciences Faculty Publications

The state of Florida is blessed with the highest density of large springs in North America and hundreds of smaller springs where the water from limestone aquifers returns to the surface (Scott et al., 2004). Spectacular underwater caves supply water to these springs. Lesser known are the equally fantastic air-filled caves of Florida and South Georgia (Florea, 2006; Lane, 1986). This paper features these underwater and airfilled caves, explores the impact of changes in sea level on karst in this near-coastal environment, and establishes several geologic and hydrologic characteristics that distinguish karst in the limestones of the southeast from karst …

An Interactive Bayesian Geostatistical Inverse Protocol For Hydraulic Tomography, Michael N. Fienen, Tom Clemo, Peter K. Kitanidis

CGISS Publications and Presentations

Hydraulic tomography is a powerful technique for characterizing heterogeneous hydrogeologic parameters. An explicit trade-off between characterization based on measurement misfit and subjective characterization using prior information is presented. We apply a Bayesian geostatistical inverse approach that is well suited to accommodate a flexible model with the level of complexity driven by the data and explicitly considering uncertainty. Prior information is incorporated through the selection of a parameter covariance model characterizing continuity and providing stability. Often, discontinuities in the parameter field, typically caused by geologic contacts between contrasting lithologic units, necessitate subdivision into zones across which there is no correlation among …

Hyporheic Exchange And Water Chemistry Of Two Arctic Tundra Streams Of Contrasting Geomorphology, Morgan J. Greenwald, William B. Bowden, Michael N. Gooseff, Jay P. Zarnetske, James P. Mcnamara, John H. Bradford, Troy R. Brosten

Geosciences Faculty Publications and Presentations

The North Slope of Alaska’s Brooks Range is underlain by continuous permafrost, but an active layer of thawed sediments develops at the tundra surface and beneath streambeds during the summer, facilitating hyporheic exchange. Our goal was to understand how active layer extent and stream geomorphology influence hyporheic exchange and nutrient chemistry. We studied two arctic tundra streams of contrasting geomorphology: a high-gradient, alluvial stream with riffle-pool sequences and a low-gradient, peat-bottomed stream with large deep pools connected by deep runs. Hyporheic exchange occurred to ~50 cm beneath the alluvial streambed and to only ~15 cm beneath the peat streambed. The …

Comparison Of Instantaneous And Constant-Rate Stream Tracer Experiments Through Parametric Analysis Of Residence Time Distributions, Robert A. Payn, Michael N. Gooseff, David A. Benson, Olaf A. Cirpka, Jay P. Zarnetske, W. Breck Bowden, James P. Mcnamara, John H. Bradford

Geosciences Faculty Publications and Presentations

Artificial tracers are frequently employed to characterize solute residence times in stream systems and infer the nature of water retention. When the duration of tracer application is different between experiments, tracer breakthrough curves at downstream locations are difficult to compare directly. We explore methods for deriving stream solute residence time distributions (RTD) from tracer test data, allowing direct, non-parametric comparison of results from experiments of different durations. Paired short- and long-duration field experiments were performed using instantaneous and constant-rate tracer releases, respectively. The experiments were conducted in two study reaches that were morphologically distinct in channel structure and substrate size. …

Sediment And Nutrient Delivery From Thermokarst Features In The Foothills Of The North Slope, Alaska: Potential Impacts On Headwater Stream Ecosystems, W. B. Bowden, M. N. Gooseff, A. Balser, A. Green, B. J. Peterson, John H. Bradford

CGISS Publications and Presentations

Permafrost is a defining characteristic of the Arctic environment. However, climate warming is thawing permafrost in many areas leading to failures in soil structure called thermokarst. An extensive survey of a 600 km² area in and around the Toolik Lake Natural Research Area (TLNRA) revealed at least 34 thermokarst features, two thirds of which were new since ~1980 when a high resolution aerial survey of the area was done. Most of these thermokarst features were associated with headwater streams or lakes. We have measured significantly increased sediment and nutrient loading from thermokarst features to streams in two well-studied locations …

Geotechnical Investigation Of The New Site Of The American University In Cairo, Yehia Abdel Maksoud Abdallah Eissa

Archived Theses and Dissertations

No abstract provided.

Finding Concealed Active Faults: Extending The Southern Whidbey Island Fault Across The Puget Lowland, Washington, Brian L. Sherrod, Richard J. Blakely, Craig S. Weaver, Harvey M. Kelsey, Elizabeth Barnett, Lee Liberty, Karen L. Meagher, Kristin Pape

CGISS Publications and Presentations

The southern Whidbey Island fault zone (SWIF), as previously mapped using borehole data, potential field anomalies, and marine seismic reflection surveys, consists of three subparallel, northwest trending strands extending ~100 km from near Vancouver Island to the northern Puget Lowland. East of Puget Sound, the SWIF makes landfall between the cities of Seattle and Everett but is concealed beneath a thick mantle of young glacial deposits and vegetation. A ~20-km-wide, northwest trending swath of subparallel, low-amplitude aeromagnetic anomalies crosses this region of the Puget Lowland and is on strike with the SWIF. The most prominent aeromagnetic anomaly, the Cottage Lake …

Application Of Time-Lapse Ert Imaging To Watershed Characterization, Carlyle R. Miller, Partha S. Routh, Troy R. Brosten, James P. Mcnamara

Geosciences Faculty Publications and Presentations

Time-lapse electrical resistivity tomography (ERT) has many practical applications to the study of subsurface properties and processes. When inverting time-lapse ERT data, it is useful to proceed beyond straightforward inversion of data differences and take advantage of the time-lapse nature of the data. We assess various approaches for inverting and interpreting time-lapse ERT data and determine that two approaches work well. The first approach is model subtraction after separate inversion of the data from two time periods, and the second approach is to use the inverted model from a base data set as the reference model or prior information for …

Imaging The Southern Trace Of The Black Hills Fault, Clark County, Nevada, Shelley A. Zaragoza

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Black Hills fault (BHF) is a SE-dipping normal fault forming the northwestern structural boundary of the Eldorado basin, ∼20 km southeast of Las Vegas, Nevada (Langenheim and Schmidt, 1996). The fault offsets Holocene strata and is thus considered to be active (Fossett, 2005). Therefore, the BHF poses a significant seismic hazard to the greater Las Vegas area.

Fossett (2005) estimated that the BHF is capable of producing a M _W 6.4 to 6.8 earthquake. However, this suggests a subsurface rupture length greater than the scarp length (Fossett, 2005). To test this hypothesis, remote sensing, geologic mapping, and high-resolution seismic …

A View Toward The Future Of Subsurface Characterization: Cat Scanning Groundwater Basins, Warren Barrash

CGISS Publications and Presentations

In this opinion paper we contend that high-resolution characterization, monitoring, and prediction are the key elements to advancing and reducing uncertainty in our understanding and prediction of subsurface processes at basin scales. First, we advocate that recently developed tomographic surveying is an effective and high-resolution approach for characterizing the field-scale subsurface. Fusion of different types of tomographic surveys further enhances the characterization. A basin is an appropriate scale for many water resources management purposes. We thereby propose the expansion of the tomographic surveying and data fusion concept to basin-scale characterization. In order to facilitate basin-scale tomographic surveys, different types of …

Geomorphology Of The Southernmost Longitudinal Valley Fault: Implications For Evolution Of The Active Suture Of Eastern Taiwan, J. Bruce H. Shyu, Kerry Sieh, Yue-Gau Chen, Ray Y. Chuang, Yu Wang, Ling-Ho Chung

All Faculty Scholarship for the College of the Sciences

In order to understand fully the deformational patterns of the Longitudinal Valley fault system, a major structure along the eastern suture of Taiwan, we mapped geomorphic features near the southern end of the Longitudinal Valley, where many well‐developed fluvial landforms record deformation along multiple strands of the fault. Our analysis shows that the Longitudinal Valley fault there comprises two major strands. The Luyeh strand, on the west, has predominantly reverse motion. The Peinan strand, on the east, has a significant left‐lateral component. Between the two strands, late Quaternary fluvial sediments and surfaces exhibit progressive deformation. The Luyeh strand dies out …

Exceptional Ground Accelerations And Velocities Caused By Earthquakes, John G. Anderson, James N. Brune

Publications (YM)

This project aims to understand the characteristics of the free-field strong-motion records that have yielded the 100 largest peak accelerations and the 100 largest peak velocities recorded to date. The peak is defined as the maximum magnitude of the acceleration or velocity vector during the strong shaking. This compilation includes 35 records with peak acceleration greater than gravity, and 41 records with peak velocities greater than 100 cm/s. The results represent an estimated 150,000 instrument-years of strong-motion recordings. The mean horizontal acceleration or velocity, as used for the NGA ground motion models, is typically 0.76 times the magnitude of this …

Influence Of Morphology And Permafrost Dynamics On Hyporheic Exchange In Arctic Headwater Streams Under Warming Climate Conditions, Jay P. Zarnetske, Michael N. Gooseff, W. Breck Bowden, Morgan J. Greenwald, Troy R. Brosten, John H. Bradford, James P. Mcnamara

CGISS Publications and Presentations

We investigated surface-subsurface (hyporheic) exchange in two morphologically distinct arctic headwater streams experiencing warming (thawing) sub-channel conditions. Empirically parameterized and calibrated groundwater flow models were used to assess the influence of sub-channel thaw on hyporheic exchange. Average thaw depths were at least two-fold greater under the higher-energy, alluvial stream than under the lowenergy, peat-lined stream. Alluvial hyporheic exchange had shorter residence times and longer flowpaths that occurred across greater portions of the thawed sediments. For both reaches, the morphologic (longitudinal bed topography) and hydraulic conditions (surface and groundwater flow properties) set the potential for hyporheic flow. Simulations of deeper thaw, …

Water, Inertial Damping, And The Complex Shear Modulus, Paul Michaels

CGISS Publications and Presentations

The author proposes an alternative to the traditional representation of soil damping. Rather than using damping ratio, this author advocates using viscosity as the specific soil property, especially for saturated permeable soils. Thus represented, the imaginary part of the complex shear modulus will vary directly with frequency. The point is particularly relevant in cases where the water table may change, thus affecting the dynamic design of foundations or structures composed of soils.

Visualization Of Groundwater Flow Within Touching-Vu And Matrix Porosity In An Eogenetic Karst Aquifer, Lee J. Florea, Kevin J. Cunningham, Stephen Altobelli

Earth, Environmental, and Atmospheric Sciences Faculty Publications

In this study, we use an innovative, non-invasive technology, nuclear magnetic resonance imaging (NMRI), to visualize the direction and magnitude of groundwater flow in field samples of late Pleistocene limestone of the Biscayne aquifer. Specific goals of the first set of NMRI experiments are to map the advective velocity of water flowing at two rates of specific discharge (0.00025 and 0.00013 m/s) through a 10-cm-diameter cylindrical, epoxy-resin model. The model interior accurately reproduces a well-connected maze of ichnologically influenced, centimeter-scale, touching-vug macroporosity common within preferred flow zones in parts of the Biscayne aquifer. A second set of NMRI experiments investigates …

Biogenic Porosity And Its Lattice Boltzmann Method Permeability In The Karst Biscayne Aquifer, Kevin Cunningham, Mike Sukop, Haibo Huang, Pedro Alvarez, Allen Curran, Michael Waker, Lee J. Florea, Robert Renken, Joann F. Dixon

Earth, Environmental, and Atmospheric Sciences Faculty Publications

No abstract provided.

Focus Group On Karst Hydrology - Conceptual Models, Aquifer Characterization, And Numerical Modeling, Martin Sauter, Lee J. Florea, Others

Earth, Environmental, and Atmospheric Sciences Faculty Publications

No abstract provided.

Assessing The Felt Reports Of The 1811-12 New Madrid Earthquakes In The Central United States, Ron Street, John D. Kiefer, Jerry L. Raisor

Report of Investigations--KGS

The damage and felt reports describing the New Madrid, Mo., earthquakes of 1811-12 need to be assessed in the historical context in which the events occurred. Log cabins in the frontier settlements along the lower Ohio River Valley, for example, were built with a rudimentary form of base isolation, and their response to the earthquakes should not be evaluated in the same way that a modern wood-frame or brick building would be.

Also, inaccuracies have crept into the databases used for estimating the epicenters and magnitudes of the earthquakes. For example, the magnitude of the December 16, 1811, earthquake has …

Source Mechanisms Of Terrestrial Gamma-Ray Flashes, Joseph R. Dwyer

Aerospace, Physics, and Space Science Faculty Publications

The source of terrestrial gamma-ray flashes (TGFs) has remained a mystery since their discovery in 1994. Recent Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) observations show that these intense bursts of MeV gamma rays likely originate much deeper in the atmosphere than previously inferred from Burst and Transient Source Experiment (BATSE) data, with the source altitude <21 km. Using existing measurements of the intensity and duration of BATSE and RHESSI TGFs, along with limits on the electric field set by the relativistic feedback mechanism involving backward propagating positrons and x-rays, it is found that TGFs cannot be produced by relativistic runaway electron avalanches acting on natural background radiation or extensive cosmic-ray air showers alone, as has been assumed by many previous models. Instead, the energetic seed particle production most likely involves either relativistic feedback or runaway electron production in the strong electric fields associated with lightning lead or streamers, similar to the energetic radiation observed on the ground from lightning.

Quantifying Vertical Mixing In Estuaries, W. Rockwell Geyer, Malcolm E. Scully, David K. Ralston

CCPO Publications

Estuarine turbulence is notable in that both the dissipation rate and the buoyancy frequency extend to much higher values than in other natural environments. The high dissipation rates lead to a distinct inertial subrange in the velocity and scalar spectra, which can be exploited for quantifying the turbulence quantities. However, high buoyancy frequencies lead to small Ozmidov scales, which require high sampling rates and small spatial aperture to resolve the turbulent fluxes. A set of observations in a highly stratified estuary demonstrate the effectiveness of a vessel-mounted turbulence array for resolving turbulent processes, and for relating the turbulence to the …

The 2004 And 1861 Tsunami Deposits On Simeulue Island, Western Sumatra, Katherine Frances Whitlow

All Master's Theses

Megathrust earthquakes and associated tsunamis along the subduction zone along western Sumatra represent a significant seismic hazard that is not well understood. I present the results of mapping, paleoseimologic, and geochronologic studies of tsunami deposits exposed on Simeulue Island, western Sumatra, to document the timing of past tsunamis. Three field sites were targeted to conduct these studies: Inor, Busong Bay, and Langi Bay. Stratigraphic relationships, geochronologic data, and grain size analyses from these field sites show evidence of a tsunami that occurred in 1861 following a Mw ~8.5 earthquake. A wood fragment collected from an excavation at Inor yielded an …

The Carbonatite-Hosted Apatite Deposit Of Jacupiranga, Se Brazil: Styles Of Mineralization, Ore Characterization And Association With Mineral Processing, Paula Regina Alves

Masters Theses

"The carbonatite-hosted apatite deposit of Jacupiranga is located in southeastern Brazil. The major styles of apatite mineralization are veins or veinlets, small pods or patches, disseminated apatite, and massive aggregates (locally). The concentration of apatite involves grinding of the carbonatite, removal of magnetite with a magnet drum, size classification with cyclones, and flotation to suppress carbonates and collect apatite. Samples of carbonatite were collected from more recent exposures of the mine and drill holes. This study utilized a variety of microscopy methods, namely transmitted and reflected light, cathodoluminescence (CL), and scanning electron microscopy (with wavelength-dispersive spectrometers for mineral compositions)"--Abstract, page …

Textural Analysis Of A Rhyolite Dike Of The Southern Oklahoma Aulacogen At Medicine Park, Oklahoma, Sean Patrick O'Donnell

Masters Theses

"Detailed analysis of the modal abundance and crystal size distribution (CSD) of glomerocrystic quartz and alkali feldspar phenocrysts in a porphyritic "rhyolite" dike at Medicine Park, Oklahoma were integrated with known phase relationships in the system SiO₂-NaAlSi₃O₈-KAlSi₃-O₈-H₂O to constrain the history of this intrusion"--Abstract, page iv.

Lateral Reservoir Compartmentalization Of The Woodford Shale In The Arkoma Basin, Southeastern Oklahoma, Adedapo Omotunde Ajibade

Masters Theses

"Analysis of geochemistry, mineralogy, total organic content (TOC) and rock evaluation pyrolysis on Woodford Shale well cuttings taken from a horizontal well (Quaid 13-30H) drilled in the Arkoma Basin (Pittsburg County), Oklahoma shows no significant variation in the thermal maturity, type, and/or quantity of organic matter. This is interpreted to mean that the organic matter of the Woodford Shale is relatively homogeneous and has all undergone similar thermal history. In addition, the analysis shows that there are lateral variations in the gas geochemistry in which the shale appears to be broken up into sections, some of which are more enhanced …

Petrogenetic Processes Characterizing The Mount Bachelor, Oregon Magmatic System: Open- Versus Closed-System Processes, Sara Elizabeth Johnson

All Master's Theses

Mount Bachelor volcanic chain (MBVC), located in central Oregon, is one of the larger basalt and basaltic-andesite edifices in central Oregon. Preliminary studies have defined how eruptions have changed composition with time, but a detailed assessment of magma chamber processes has not been conducted. To gain a more thorough understanding of the magmatic processes that have contributed to the observed compositional evolution, this study focuses on one of four eruptive episodes, specifically episode III, the most voluminous episode of the four. Magmatic processes are assessed by focusing on both whole-rock and single crystal data.

The geochemistry and textural diversity of …

Energy Budget Analysis Of Slow-Slip Tremor Events Along The Cascadia Subduction Zone Using Continuous Gps Array Data, James Steven Chapman

All Master's Theses

Seismic hazards poised to cities by subduction zones are strongly controlled by fault slip along the deeper extent of the two plate interaction closest to population densities. In Cascadia, where Mw=9 size events are known to occur from a variety of sources, modeling of leveling data has suggested that the region of maximum slip lies well offshore and diminishes rapidly inland. However, over two dozen slow slip distributions have been imaged using Global Positioning System (GPS) along the lower reaches of the northern Cascadia locked zone between 30 and 40 km in depth. Averaged over many episodic tremor and slip …

Imaging Thermal Stratigraphy In Freshwater Lakes Using Georadar, John H. Bradford, Cody R. Johnson, Troy Brosten, James P. Mcnamara, Michael N. Gooseff

CGISS Publications and Presentations

Thermal stratification exerts significant control over biogeochemical processing in freshwater lakes. Thus, the temporal and spatial distribution of the thermal structure is an important component in understanding lake ecosystems. We present the first reported observations of lake thermal stratification from surface based georadar measurements acquired over two small freshwater lakes. This method is very useful because it can provide rapid acquisition of 2D or 3D lotic stratification.