Geophysics and Seismology Commons^™

Reflection Waveform Inversion Of Ground-Penetrating Radar Data For Characterizing Thin And Ultrathin Layers Of Nonaqueous Phase Liquid Contaminants In Stratified Media, Esther Babcock, John H. Bradford

CGISS Publications and Presentations

Accurately quantifying thin-layer parameters by applying a targeted reflection waveform inversion methodology to ground-penetrating radar (GPR) reflection data may provide a useful tool for near-surface investigation and especially for contaminated site investigation where nonaqueous phase liquid (NAPL) contaminants are present. We implemented a targeted reflection waveform inversion algorithm to quantify thin-layer permittivity, thickness, and conductivity for NAPL thin (≤ 1/2 dominant wavelength λ) and ultrathin (≤ 1/8λ) layers using GPR reflection data. The inversion used a nonlinear grid search with a Monte Carlo scheme to initialize starting values to find the global minimum. By taking a targeted approach using a …

Beyond The Angle Of Repose: A Review And Synthesis Of Landslide Processes In Response To Rapid Uplift, Eel River, Northern Eel River, Northern California, Joshua J. Roering, Benjamin H. Mackey, Alexander L. Handwerger, Adam M. Booth, David A. Schmidt, Georgina L. Bennett, Corina Cerovski-Darriau

Geology Faculty Publications and Presentations

In mountainous settings, increases in rock uplift are often followed by a commensurate uptick in denudation as rivers incise and steepen hillslopes, making them increasingly prone to landsliding as slope angles approach a limiting value. For decades, the threshold slope model has been invoked to account for landslide-driven increases in sediment flux that limit topographic relief, but the manner by which slope failures organize themselves spatially and temporally in order for erosion to keep pace with rock uplift has not been well documented. Here, we review past work and present new findings from remote sensing, cosmogenic adionuclides, suspended sediment records, …

Comparing Flow-Through And Static Ice Cave Models For Shoshone Ice Cave, Kaj E. Williams, Christopher Mckay

International Journal of Speleology

In this paper we suggest a new ice cave type: the “flow-through” ice cave. In a flow-through ice cave external winds blow into the cave and wet cave walls chill the incoming air to the wet-bulb temperature, thereby achieving extra cooling of the cave air. We have investigated an ice cave in Idaho, located in a lava tube that is reported to have airflow through porous wet end-walls and could therefore be a flow-through cave. We have instrumented the site and collected data for one year. In order to determine the actual ice cave type present at Shoshone, we have …

Real-Time Monitoring Of Tectonic Displacements In The Pacific Northwest Through An Array Of Gps Receivers, Răzvan Popovici, Răzvan Andonie, Walter M. Szeliga, Timothy I. Melbourne, Craig W. Scrivner

All Faculty Scholarship for the College of the Sciences

The Pacific Northwest Geodesic Array at Central Washington University collects telemetered streaming data from 450 GPS stations. These real-time data are used to monitor and mitigate natural hazards arising from earthquakes, volcanic eruptions, landslides, and coastal sea-level hazards in the Pacific Northwest. The displacement measurements are performed at millimeter-scale, and require stringent analysis and parameter estimation techniques. Recent improvements in both accuracy of positioning measurements and latency of terrestrial data communication have led to the ability to collect data with higher sampling rates, of up to 1 Hz. For seismic monitoring applications, this means 1350 separate position streams from stations …

Tectono-Metamorphic History Of The Eastern Taureau Shear Zone, Mauricie Area, Québec: Implications For The Exhumation Of The Mid-Crust In The Grenville Province, Renaud Soucy La Roche, Félix Gervais, Alain Tremblay, James L. Crowley, Gilles Ruffet

Geosciences Faculty Publications and Presentations

This study investigates the tectono-metamorphic history and exhumation mechanisms of the mid-crustal Mékinac-Taureau domain of the Mauricie area, central Grenville Province. Macro- and micro-structural analyses reveal the top-down-to-the-ESE sense of shear on the eastern Taureau shear zone, a major extensional structure that exhumed the mid-crustal Mékinac-Taureau domain and juxtaposed it against the lower grade rocks of the Shawinigan domain. Peak metamorphism in the Mékinac-Taureau domain, inferred to be the result of northwestward thrusting and regional crustal thickening, took place under P–T conditions of 1000–1100 MPa and 820–880 °C prior to 1082 ± 20 Ma. Retrograde conditions varying from …

Peat Formation Concentrates Arsenic Within Sediment Deposits Of The Mekong Delta, Jason W. Stuckey, Michael V. Schaefer, Benjamin D. Kocar, Jessica Dittmar, Juan Lezama Pacheco, Shawn G. Benner, Scott Fendorf

Geosciences Faculty Publications and Presentations

Mekong River Delta sediment bears arsenic that is released to groundwater under anaerobic conditions over the past several thousand years. The oxidation state, speciation, and distribution of arsenic and the associated iron bearing phases are crucial determinants of As reactivity in sediments. Peat from buried mangrove swamps in particular may be an important host, source, or sink of arsenic in the Mekong Delta. The total concentration, speciation, and reactivity of arsenic and iron were examined in sediments in a Mekong Delta wetland by X-ray fluorescence spectrometry (XRF), X-ray absorption spectroscopy (XAS), and selective chemical extractions. Total solid-phase arsenic concentrations in …

The Mantle Transition Zone Beneath West Antarctica: Seismic Evidence For Hydration And Thermal Upwellings, E. L. Emry, A. A. Nyblade, J. Juliá, S. Anandakrishnan, R. C. Aster, D. A. Wiens, Audrey D. Huerta, T. J. Wilson

All Faculty Scholarship for the College of the Sciences

Although prior work suggests that a mantle plume is associated with Cenozoic rifting and volcanism in West Antarctica, the existence of a plume remains conjectural. Here we use P wave receiver functions (PRFs) from the Antarctic POLENET array to estimate mantle transition zone thickness, which is sensitive to temperature perturbations, throughout previously unstudied parts of West Antarctica. We obtain over 8000 high‐quality PRFs using an iterative, time domain deconvolution method filtered with a Gaussian width of 0.5 and 1.0, corresponding to frequencies less than ∼0.24 and ∼0.48 Hz, respectively. Single‐station and common conversion point stacks, migrated to depth using the …

The Mantle Transition Zone Beneath West Antarctica: Seismic Evidence For Hydration And Thermal Upwellings, E. L. Emry, Andrew A. Nyblade, J. Julia, Sridhar Anandakrishnan, R. C. Aster, Douglas A. Wiens, Audrey D. Huerta, Terry J. Wilson

Geological Sciences Faculty Scholarship

Although prior work suggests that a mantle plume is associated with Cenozoic rifting and volcanism in West Antarctica, the existence of a plume remains conjectural. Here we use P wave receiver functions (PRFs) from the Antarctic POLENET array to estimate mantle transition zone thickness, which is sensitive to temperature perturbations, throughout previously unstudied parts of West Antarctica. We obtain over 8000 high-quality PRFs using an iterative, time domain deconvolution method filtered with a Gaussian width of 0.5 and 1.0, corresponding to frequencies less than ∼0.24 and ∼0.48 Hz, respectively. Single-station and common conversion point stacks, migrated to depth using the …

Estimation Of Offsets In Gps Time-Series And Application To The Detection Of Earthquake Deformation In The Far-Field, Jean-Philippe Montillet, S. D. P. Williams, A. Koulali, S. C. Mcclusky

All Faculty Scholarship for the College of the Sciences

Extracting geophysical signals from Global Positioning System (GPS) coordinate time-series is a well-established practice that has led to great insights into how the Earth deforms. Often small discontinuities are found in such time-series and are traceable to either broad-scale deformation (i.e. earthquakes) or discontinuities due to equipment changes and/or failures. Estimating these offsets accurately enables the identification of coseismic deformation estimates in the former case, and the removal of unwanted signals in the latter case which then allows tectonic rates to be estimated more accurately. We develop a method to estimate accurately discontinuities in time series of GPS positions at …

Exploring Radioisotopic Geochronology And Astrochronology, Stephen R. Meyers, Bradley S. Singer, Mark D. Schmitz

Geosciences Faculty Publications and Presentations

Numerical dating of the geologic record provides an essential framework for interpreting the rich history of our planet. Common applications include the determination of dates for extinction events and climate reorganizations, the assessment of rates of paleoenvironmental and paleobiologic change, and the correlation of rocks across vast expanses. Such investigations have yielded crucial insight into the mechanisms that shape Earth's surface environments over geologic time. But as geologists increasingly pursue high (spatial) resolution stratigraphic analyses in "deep time," the short temporal scales (<100,000 years) of the processes investigated push the limits of high-­precision geochronology.

Petrophysical Analysis And Rock-Physics Based Prediction Of Sonic Velocities In Carbonates, Yeliz Egemen

Dissertations, Master's Theses and Master's Reports - Open

This study performs a petrophysical analysis and rock-physics modeling of the Traverse Formation, using eleven different wells. In the first part of this study, well logs, crossplots, and mineral identification were used to determine the rock components, lithology, and to predict the sonic velocities of carbonate rocks using conventional methods for two of those wells.

In the second part of this study, rock-physics modeling methods were used to predict the sonic velocities using the Kuster-Toksöz equations. Sonic velocities are very difficult to predict in carbonate rock because of their complex pore systems. To overcome this difficulty, multiple aspect ratios for …

Morphological, Structural, And Spectral Characteristics Of Amorphous Iron Sulfates, Elizabeth Sklute, Heidi Jensen, Deanne Rogers, Richard Reeder

Department of Geosciences Faculty Publications

Current or past brine hydrologic activity on Mars may provide suitable conditions for the formation of amorphous ferric sulfates. Once formed, these phases would likely be stable under current Martian conditions, particularly at low- to mid-latitudes. Therefore, we consider amorphous iron sulfates (AIS) as possible components of Martian surface materials. Laboratory AIS were created through multiple synthesis routes and characterized with total X-ray scattering, thermogravimetric analysis, scanning electron microscopy, visible/near-infrared (VNIR), thermal infrared (TIR), and Mössbauer techniques. We synthesized amorphous ferric sulfates (Fe(III)2(SO4)3 · ~ 6–8H2O) from sulfate-saturated fluids via vacuum dehydration or exposure to low relative humidity (

Identification And Quantification Of Diffuse Fresh Submarine Groundwater Discharge Via Airborne Thermal Infrared Remote Sensing, Joseph T. Tamborski, A Deanne Rogers, Henry J. Bokuniewicz, J Kirk Cochran, Caitlin R. Young

Department of Geosciences Faculty Publications

Airborne thermal infrared (TIR) overflights were combined with shoreline radionuclide surveys to investigate submarine groundwater discharge (SGD) along the north shore of Long Island, NY between June 2013 and September 2014. Regression equations developed for three distinct geomorphological environments suggest a positive linear relationship between the rate of diffuse SGD and the spatial extent of the observed coastal TIR anomalies; such a relationship provides quantitative evidence of the ability to use TIR remote sensing as a tool to remotely identify and measure SGD. Landsat TIR scenes were unable to resolve any of the 18 TIR anomalies identified during the various …

Feldspathic Rocks On Mars: Compositional Constraints From Infrared Spectroscopy And Possible Formation Mechanisms, Deanne Rogers, Hanna Nekvasil

Department of Geosciences Faculty Publications

Rare feldspar-dominated surfaces on Mars were previously reported based on near-infrared (NIR) spectral data and were interpreted to consist of anorthosite or felsic rocks. Using thermal infrared (TIR) data over the feldspar detections with the largest areal extent in Nili Patera and Noachis Terra, we rule out felsic interpretations. Basaltic or anorthositic compositions are consistent with TIR measurements, but the geologic contexts for these regions do not support a plutonic origin. Laboratory NIR spectral measurements demonstrate that large plagioclase crystals (>~840 μm) can be detected in mixtures with as much as 50 vol % mafics, which is higher than …

Examination Of Geophysical Signatures Of Ethanol-Water Mixtures In A Homogeneous Sand Column Using Ground Penetrating Radar And Time-Domain Reflectometry, Angelo Lampousis, Neil Terry, Lee Slater

Publications and Research

In recent years there has been an increase in the frequency of incidents involving ethanol-blended gasoline affecting the groundwater. Near-surface geophysical methods hold promise for site characterization at ethanol contaminated sites. We attempted to record the broadband dielectric properties of ethanol at various concentrations as it was circulating through a closed tank containing either sand or a sand-clay mixture. Two high frequency GPR antennas were positioned symmetrically on either side of the sample holder to obtain transmission measurements. In the first part of the experiment we used a sample consisting of sand. In the second part of the experiment we …

Commercialization Of A Small, Lightweight, Low-Cost Seismic Borehole Receiver, Rachel Adams

Theses and Dissertations--Civil Engineering

Herein, conceptualization of a recently patented seismic borehole receiver and its components is developed for commercialization. The device is significantly cheaper, lighter, and smaller than existing technologies on the market. Additionally, it has the potential to achieve better seismic readings than its competitors via patented sensor-to-borehole coupling mechanism. It is the hope that the commercialization of this device will not only provide a more affordable alternative to engineers and geophysicists in the existing market, but the significant cost difference may open new seismic measurement opportunities in the developing world. Its compact size and light weight will increase mobility, allowing investigators …

Evidence For A Far-Traveled Thrust Sheet In The Greater Himalayan Thrust System, And An Alternative Model To Building The Himalaya, S. Khanal, D. M. Robinson, M. J. Kohn, S. Mandal

Geosciences Faculty Publications and Presentations

The Galchhi shear zone underlies the Kathmandu klippe in central Nepal and has emerged as a key structure for discriminating competing models for the formation of the Himalayan orogenic wedge. New chronologic data from the Galchhi area suggest a new structural and orogenic interpretation. Zircons from quartzites and an orthogneiss restrict protolith deposition to between 467+7/ – 10 Ma and ~570 Ma, with metamorphic zircon growth at 23-29 Ma. Comparable data from the Greater Himalayan Sequence (GHS) at the intra-GHS Langtang thrust, north of Galchhi, similarly restrict GHS deposition to between 475+7/ – 3 and ~660 Ma. Undeformed pegmatites near …

Early Permian Conodont Fauna And Stratigraphy Of The Garden Valley Formation, Eureka County, Nevada, Bruce R. Wardlaw, Dora M. Gallegos, Valery V. Chernykh, Walter S. Snyder

Geosciences Faculty Publications and Presentations

The lower part of the Garden Valley Formation yields two distinct conodont faunas. One of late Asselian age dominated by Mesogondolella and Streptognathodus and one of Artinskian age dominated by Sweetognathus with Mesogondolella. The Asselian fauna contains the same species as those found in the type area of the Asselian in the southern Urals including Mesogondolella dentiseparata, described for the first time outside of the Urals. Apparatuses for Sweetognathus whitei, Diplognathodus stevensi, and Idioprioniodus sp. are described. The Garden Valley Formation represents a marine pro-delta basin and platform, and marine and shore fan delta complex deposition. …

Magmatic Plumbing At Lucky Strike Volcano Based On Olivine-Hosted Melt Inclusion Compositions, V. D. Wanless, A. M. Shaw, M. D. Behn, S. A. Soule, J. Escartín, C. Hamelin

Geosciences Faculty Publications and Presentations

Here we present volatile, major, and trace element concentrations of 64 olivine-hosted melt inclusions from the Lucky Strike segment on the mid-Atlantic ridge. Lucky Strike is one of two locations where a crustal melt lens has been seismically imaged on a slow-spreading ridge. Vapor-saturation pressures, calculated from CO₂ and H₂O contents of Lucky Strike melt inclusions, range from approximately 300-3000 bars, corresponding to depths of 0.5-9.9 km below the seafloor. Approximately 50% of the melt inclusions record crystallization depths of 3-4 km, corresponding to the seismically imaged melt lens depth, while an additional ∼35% crystallize at depths …

Comparison Of The Ground-Motion Attenuation Relationship Between The Wenchuan, China, Area And The Central And Eastern United States, Jiwei Feng, Zhenming Wang, Edward W. Woolery, Shanyou Li

Report of Investigations--KGS

An M_w-7.9 earthquake occurred in Wenchuan, China, in 2008, along the Longmenshan Fault, which is located on the western border of the South China stable continental region. A detailed comparison of the Wenchuan ground-motion attenuation relationships with the relationships for the central and eastern United States (also a stable continental region) showed that the ground-motion prediction equation for the Wenchuan area is similar to those for the central and eastern United States. Thus, the strong-motion records from the Wenchuan earthquake can be used for constraining the ground-motion prediction equation and engineering analysis for the central and eastern United …