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Articles 1 - 15 of 15
Full-Text Articles in Geophysics and Seismology
Accurate Inversion Of High-Resolution Snow Penetrometer Signals For Microstructural And Micromechanical Properties, Hans-Peter Marshall, Jerome B. Johnson
Accurate Inversion Of High-Resolution Snow Penetrometer Signals For Microstructural And Micromechanical Properties, Hans-Peter Marshall, Jerome B. Johnson
CGISS Publications and Presentations
Measurements of snow using a high-resolution micropenetrometer can be used to discriminate between different snow types; in lower-density snow the signal is sensitive to microstructure, and micromechanical properties can be estimated. Although a physics-based snow penetration theory was first developed almost a decade ago, since that time the majority of studies using snow micropenetrometers have focused on using direct hardness measurements in statistical relationships. We use Monte-Carlo simulations to rigorously test the existing physics-based snow micropenetration theories over a wide range of parameters. These tests revealed four major sources of error in the inversion, which are corrected in this analysis. …
Modeling Soil Depth From Topographic And Land Cover Attributes, Teklu K. Tesfa, David G. Tarboton, David G. Chandler, James P. Mcnamara
Modeling Soil Depth From Topographic And Land Cover Attributes, Teklu K. Tesfa, David G. Tarboton, David G. Chandler, James P. Mcnamara
Geosciences Faculty Publications and Presentations
Soil depth is an important input parameter in hydrological and ecological modeling. Presently, the soil depth data available in national soil databases (STATSGO and SSURGO) from the Natural Resources Conservation Service are provided as averages within generalized land units (map units). Spatial uncertainty within these units limits their applicability for distributed modeling in complex terrain. This work reports statistical models for prediction of soil depth in a semiarid mountainous watershed that are based upon the relationship between soil depth and topographic and land cover attributes. Soil depth was surveyed by driving a rod into the ground until refusal at locations …
Infrasonic Ambient Noise Interferometry From Correlations Of Microbaroms, Matthew M. Haney
Infrasonic Ambient Noise Interferometry From Correlations Of Microbaroms, Matthew M. Haney
CGISS Publications and Presentations
We show that microbaroms, continuous infrasound fluctuations resulting from the interaction of the ocean with the atmosphere, have long-range correlation properties that make it possible to estimate the impulse response between two microphones from passive recordings. The processing is analogous to methods employed in the emerging field of ambient noise seismology, where the random noise source is the ocean coupling with the solid Earth (microseisms) instead of the atmosphere (microbaroms). We find that timedependent temperature fields and temperature inversions determine the character of infrasonic impulse responses at Fourpeaked Volcano in Alaska. Applications include imaging and monitoring the gross structure of …
Estimating Debye Parameters From Gpr Reflection Data Using Spectral Ratios, John H. Bradford
Estimating Debye Parameters From Gpr Reflection Data Using Spectral Ratios, John H. Bradford
Geosciences Faculty Publications and Presentations
In the GPR frequency range, electromagnetic wave attenuation is largely controlled by dielectric relaxation processes. A primary relaxation commonly occurs in the 10 – 100 MHz range for many earth materials in which the GPR signal propagates effectively. This relaxation leads to strong nonlinearity in the frequency dependent attenuation and occurs in a frequency range that is often used for groundwater investigations. This non-linearity complicates data analysis but also may provide additional material property information. I investigate inversion for Debye relaxation parameters directly from GPR reflection data, including increasing the bandwidth of the signal by summing the response from 25 …
Improved Confidence In (U-Th)/He Thermochronology Using The Laser Microprobe: An Example From A Pleistocene Leucogranite, Nanga Parbat, Pakistan, J. W. Boyce, K. V. Hodges, D. King, James L. Crowley, M. Jercinovic, N. Chatterjee, S. A. Bowring, M. Searle
Improved Confidence In (U-Th)/He Thermochronology Using The Laser Microprobe: An Example From A Pleistocene Leucogranite, Nanga Parbat, Pakistan, J. W. Boyce, K. V. Hodges, D. King, James L. Crowley, M. Jercinovic, N. Chatterjee, S. A. Bowring, M. Searle
Geosciences Faculty Publications and Presentations
The newly developed laser microprobe (U-Th)/He thermochronometer permits, for the first time, the ability to generate precise (U-Th)/He cooling ages for even very young (Ma) samples with a spatial resolution on the order of tens of micrometers. This makes it possible to test the reproducibility of independent (U-Th)/He age determinations within individual crystals, further increasing the reliability of the method. As an example, we apply it here to a Pleistocene granite from Nanga Parbat, Pakistan, where previous constraints on the thermal history are consistent with rapid exhumation and cooling. Twenty-one (U-Th)/He dates determined on two monazite crystals from a single …
Obtaining Parsimonious Hydraulic Conductivity Fields Using Head And Transport Observations: A Bayesian Geostatistical Parameter Estimation Approach, Michael Fienen, R. Hunt, D. Krabbenhoft, Tom Clemo
Obtaining Parsimonious Hydraulic Conductivity Fields Using Head And Transport Observations: A Bayesian Geostatistical Parameter Estimation Approach, Michael Fienen, R. Hunt, D. Krabbenhoft, Tom Clemo
CGISS Publications and Presentations
Flow path delineation is a valuable tool for interpreting the subsurface hydrogeochemical environment. Different types of data, such as groundwater flow and transport, inform different aspects of hydrogeologic parameter values (hydraulic conductivity in this case) which, in turn, determine flow paths. This work combines flow and transport information to estimate a unified set of hydrogeologic parameters using the Bayesian geostatistical inverse approach. Parameter flexibility is allowed by using a highly parameterized approach with the level of complexity informed by the data. Despite the effort to adhere to the ideal of minimal a priori structure imposed on the problem, extreme contrasts …
Complex Dielectric Permittivity Measurements From Ground-Penetrating Radar Data To Estimate Snow Liquid Water Content In The Pendular Regime, John H. Bradford, Joel T. Harper, Joel Brown
Complex Dielectric Permittivity Measurements From Ground-Penetrating Radar Data To Estimate Snow Liquid Water Content In The Pendular Regime, John H. Bradford, Joel T. Harper, Joel Brown
CGISS Publications and Presentations
Monitoring the snow water equivalent (SWE) is critical to effective management of water resources in many parts of the world that depend on the mountain snowpack for water storage. There are currently no methods to remotely sense SWE with accuracy over large lateral distances in the steep and often forested terrain of mountain basins. Previous studies have shown that measurements of ground-penetrating radar (GPR) velocity can provide accurate estimates of SWE in dry snow. Introduction of liquid water into the snowpack results in a three-phase system that cannot be accurately characterized with GPR velocity alone. We show that measuring the …
Seismic Wave Attenuation In Carbonates, Ludmila Adam, M. Batzle, K. T. Lewallen, Kasper Van Wijk
Seismic Wave Attenuation In Carbonates, Ludmila Adam, M. Batzle, K. T. Lewallen, Kasper Van Wijk
CGISS Publications and Presentations
The effect of pore fluids on seismic wave attenuation in carbonate rocks is important for interpreting remote sensing observations of carbonate reservoirs undergoing enhanced oil recovery. Here we measure the elastic moduli and attenuation in the laboratory for five carbonate samples with 20% to 30% porosity and permeability between 0.03 and 58.1 mdarcy. Contrary to most observations in sandstones, bulk compressibility losses dominate over shear wave losses for dry samples and samples fully saturated with either liquid butane or brine. This observation holds for four out of five samples at seismic (10–1000 Hz) and ultrasonic frequencies (0.8 MHz) and reservoir …
Observation And Modeling Of Source Effects In Coda Wave Interferometry At Pavlof Volcano, Matthew M. Haney, Kasper Van Wijk, Leiph A. Preston, David F. Aldridge
Observation And Modeling Of Source Effects In Coda Wave Interferometry At Pavlof Volcano, Matthew M. Haney, Kasper Van Wijk, Leiph A. Preston, David F. Aldridge
CGISS Publications and Presentations
We examine seismic records of repeating explosions from Pavlof volcano, Alaska, during its 2007 eruption. Repetitive explosions are typical of Strombolian-style eruptions and allow measurement of relative time shifts between similar late-arriving phases using the technique called coda wave interferometry (Snieder et al., 2002). The measurements enable the detection of small changes in the volcanic interior of Pavlof. We are able to resolve an increase in the relative traveltime change of late-arriving seismic waves on the order of 0.3% over the course of two weeks. Based on the spectra of the explosions, their location inside the magma conduit, previous studies …
Numerical Modeling Of Time-Lapse Seismic Experiments To Monitor Co2 Sequestration In A Layered Basalt Reservoir, Murari Khatiwada
Numerical Modeling Of Time-Lapse Seismic Experiments To Monitor Co2 Sequestration In A Layered Basalt Reservoir, Murari Khatiwada
Boise State University Theses and Dissertations
Instead of allowing carbon dioxide (CO2) generated from the burning of hydrocarbons to escape into the atmosphere, CO2 can be captured and stored. For the long term mitigation of the increasing amount of CO2 emissions, its sequestration in geological formations is promising. As a measure, its short and long term monitoring is equally important for environmental and health safety issues. The seismic method is proposed as a non-invasive monitoring technique for geological sequestration of CO2. Based on the positive results obtained from reservoir monitoring during enhanced oil recovery with CO2 floods, geoscientists plan …
Capacitive Conductivity Logging And Electrical Stratigraphy In A High-Resistivity Aquifer, Boise Hydrogeophysical Research Site, C. Jonathan Mwenifumbo, Warren Barrash, Michael D. Knoll
Capacitive Conductivity Logging And Electrical Stratigraphy In A High-Resistivity Aquifer, Boise Hydrogeophysical Research Site, C. Jonathan Mwenifumbo, Warren Barrash, Michael D. Knoll
CGISS Publications and Presentations
We tested a prototype capacitive-conductivity borehole tool in a shallow, unconfined aquifer with coarse, unconsolidated sediments and very-low-conductivity water at the Boise Hydrogeophysical Research Site (BHRS). Examining such a high-resistivity system provides a good test for the capacitive- conductivity tool because the conventional induction- conductivity tool (known to have limited effectiveness in high-resistivity systems) did not generate expressive well logs at the BHRS. The capacitive-conductivity tool demonstrated highly repeatable, low-noise behavior but poor correlation with the induction tool in the lower-conductivity portions of the stratigraphy where the induction tool was relatively unresponsive. Singular spectrum analysis of capacitive- conductivity logs reveals …
The Virtual Refraction: Useful Spurious Energy In Seismic Interferometry, Dylan Mikesell, Kasper Van Wijk, Alexander Calvert, Matthew M. Haney
The Virtual Refraction: Useful Spurious Energy In Seismic Interferometry, Dylan Mikesell, Kasper Van Wijk, Alexander Calvert, Matthew M. Haney
CGISS Publications and Presentations
Seismic interferometry is rapidly becoming an established technique to recover the Green’s function between receivers, but practical limitations in the source-energy distribution inevitably lead to spurious energy in the results. Instead of attempting to suppress all such energy, we use a spurious wave associated with the crosscorrelation of refracted energy at both receivers to infer estimates of subsurface parameters. We named this spurious event the virtual refraction. Illustrated by a numerical two-layer example, we found that the slope of the virtual refraction defines the velocity of the faster medium and that the stationary-phase point in the correlation gather provides the …
Estimating Porosity With Ground-Penetrating Radar Reflection Tomography: A Controlled 3-D Experiment At The Boise Hydrogeophysical Research Site, John H. Bradford, William P. Clement, Warren Barrash
Estimating Porosity With Ground-Penetrating Radar Reflection Tomography: A Controlled 3-D Experiment At The Boise Hydrogeophysical Research Site, John H. Bradford, William P. Clement, Warren Barrash
CGISS Publications and Presentations
To evaluate the uncertainty of water-saturated sediment velocity and porosity estimates derived from surface-based, ground-penetrating radar reflection tomography, we conducted a controlled field experiment at the Boise Hydrogeophysical Research Site (BHRS). The BHRS is an experimental well field located near Boise, Idaho. The experimental data set consisted of 3-D multioffset radar acquired on an orthogonal 20 × 30 m surface grid that encompassed a set of 13 boreholes. Experimental control included (1) 1-D vertical velocity functions determined from traveltime inversion of vertical radar profiles (VRP) and (2) neutron porosity logs. We estimated the porosity distribution in the saturated zone using …
Experimental Evidence Of Non-Linear Dissipation Using Acoustic Micro-Lapses, G. Quiroga-Goode, K. Van Wijk
Experimental Evidence Of Non-Linear Dissipation Using Acoustic Micro-Lapses, G. Quiroga-Goode, K. Van Wijk
Geosciences Faculty Publications and Presentations
Non-linear material behaviour is observed experimentally in a laboratory using a new method called Acoustic Micro-Lapses (AML). In this approach, the shooting of two waves is synchronised in a way that the second wave (TW) is to sense the fluctuations in material stiffness induced by the first (PW). The tests include four samples; twenty trials are performed for each sample by increasing time-delays between the waves. The recorded waves are decoupled and compared to determine spectral differences by computing a quantity proportional to the energy difference as function of the increasing time delay (). For a tight sandstone and aluminium …
Models Of Garnet Differential Geochronology, Matthew J. Kohn
Models Of Garnet Differential Geochronology, Matthew J. Kohn
Geosciences Faculty Publications and Presentations
Rayleigh distillation models are developed to describe theoretical growth zoning of Lu, Hf, Rb, Sr, Sm and Nd in typical garnet crystals from metapelites and metabasites. Effects of diffusion limited transport within the matrix and intracrystalline diffusion are also considered qualitatively. Theoretical zoning profiles show strong depletions of Lu in garnet rims compared to cores, but virtually invariant Hf, Rb, Sr, Sm, and Nd profiles, generally consistent with natural profiles for Lu and Hf and previously published models. Theoretical isochron diagrams for Lu-Hf exhibit distinctive arcuate distributions and high MSWD’s consistent both with Himalayan data, and with expectations that garnet …