Receiver Function Studies Of Crustal Structure, Composition, And Evolution Beneath The Afar Depression, Ethiopia,
2011
Missouri University of Science and Technology
Receiver Function Studies Of Crustal Structure, Composition, And Evolution Beneath The Afar Depression, Ethiopia, Sattam A. Almadani
Doctoral Dissertations
"The dissertation utilizes a set of sophisticated computer programs developed at the Geophysics group at Missouri S&T to characterize crustal properties beneath the Afar Depression in Ethiopia where extensional tectonics dominates. In this study, measurements of crustal thickness (H), crustal mean Vp/Vs [which is related to Poisson's ratio (Σ)], and the sharpness of the Moho (R) were determined using teleseismic data from 18 broadband seismic sensors that we deployed along a profile of 250 km long with a station spacing of ~ 10 km. The stations had been recording continuously for an entire year from December 2009 until December 2010. …
Morpho-Tectonic Analysis Of The Tekeze And The Blue Nile Drainage Systems Of Northwestern Ethiopian Plateau, Ethiopia,
2011
Missouri University of Science and Technology
Morpho-Tectonic Analysis Of The Tekeze And The Blue Nile Drainage Systems Of Northwestern Ethiopian Plateau, Ethiopia, Elamin Hassan Dai Ismail
Masters Theses
"This study examines the morpho-tectonic evolution of the drainage system in the northwestern Ethiopian plateau by focusing on the Tekeze and the Blue Nile Rivers. The plateau is underlain by Precambrian crystalline rocks, overlain by Mesozoic sedimentary section that is topped with a 1-3 km thick pile of Oligocene-Quaternary volcanic rocks. It is bounded in the east and southeast by the Afar Depression (AD) and the Main Ethiopian Rift (MER). Satellite derived Digital Elevation Models are analyzed using ArcGIS and RiverTools to extract morpho-tectonic parameters of tributaries of the Tekeze and Blue Nile Rivers including Normalized Steepness Index (Ksn …
The Origin Of Quartz Glomerocrysts: Insights From The Rhyolite Dike At Medicine Park, Ok,
2011
Missouri University of Science and Technology
The Origin Of Quartz Glomerocrysts: Insights From The Rhyolite Dike At Medicine Park, Ok, Sedeg Ahmed E. Ahmed
Masters Theses
"The origin of quartz glomerocrysts a distinctive petrographic feature of the rhyolite dike in Medicine Park, Oklahoma, was investigated using transmitted light and cathodoluminescence microscopy to determine if quartz glomerocrysts formed during quartz crystallization or during quartz dissolution. Quartz glomerocrysts are typically comprised of two to six individual phenocrysts of quartz and commonly exhibit subhedral partially embayed crystal forms with very rare euhedral phenocrysts in both glomerocrysts and individual quartz phenocrysts. The size range of the individual quartz phenocrysts are 0.08mm to 1.7mm while the size range is 0.08mm to 3.25mm for quartz glomerocrysts . Cathodoluminescence revealed that individual quartz …
Investigation Of Spatial And Temporal Processes Of Lake–Aquifer Interactions In The Nebraska Sand Hills,
2010
University of Nebraska-Lincoln
Investigation Of Spatial And Temporal Processes Of Lake–Aquifer Interactions In The Nebraska Sand Hills, John T. Ong
Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research
Interaction between surface water and groundwater is an important component of the water cycle that affects the physicochemical and biological characteristics of lakes, streams, wetlands, and seacoasts. Due to the complex interaction of geologic, topographic, and hydrologic factors, flow between lakes and groundwater remains poorly understood. Evolution of conceptual models over the past 30 years describes processes of advection, dispersion, and free convection that occur in different lake flow regimes. Few detailed field studies document the validity of these conceptual models because of the difficulty of studying the subsurface and the prohibitive cost of instrumenting large areas. In the semi-arid …
An Application And Refinement Of The Karst Disturbance Index Through Evaluating Variability In Island Karst Disturbance In Puerto Rico,
2010
Western Kentucky University
An Application And Refinement Of The Karst Disturbance Index Through Evaluating Variability In Island Karst Disturbance In Puerto Rico, Brandon Lee Porter
Masters Theses & Specialist Projects
Karst environments are unique landscapes that contain important resources, including freshwater aquifers and specialized ecosystems, which are easily disturbed due to the interconnected nature of the surface and subsurface. The anthropogenic impacts on karst are deleterious to the ecosystems that are dependent on the karst environment and also to groundwater supplies. The Karst Disturbance Index (KDI) is a holistic tool used to measure anthropogenic impacts associated with karst environments, which has been applied and refined through studies performed in Florida and Italy, yet still remains untested and susceptible to modification for other areas. Application of the KDI in Arecibo, Puerto …
Late Holocene Relationships Among Fire, Climate, And Vegetation In Rangeland Ecosystems Of Southwestern Idaho,
2010
Boise State University
Late Holocene Relationships Among Fire, Climate, And Vegetation In Rangeland Ecosystems Of Southwestern Idaho, Nathan A. Nelson, Jennifer Pierce
Geosciences Faculty Publications and Presentations
Rangelands are characterized by more arid climates than forested regions; therefore, establishing fire histories using traditional methods (e.g. fire-scars from trees or charcoal in lake sediments) is problematic. This study uses radiocarbon dating of charcoal preserved in alluvial fans and stream deposits to reconstruct a record of fire and geomorphic response in rangelands of southwestern Idaho. Samples indicate three primary periods of fire-related activity: 4400 – 4000, 2000 – 1400, and 650-400 cal yr BP. Charcoal macrofossil identification and comparison with other regional climate and fire records indicate this area has likely switched between a "fuel-limited" system (fires limited by …
Stable Isotopes Of Fossil Teeth Corroborate Key General Circulation Model Predictions For The Last Glacial Maximum In North America,
2010
Boise State University
Stable Isotopes Of Fossil Teeth Corroborate Key General Circulation Model Predictions For The Last Glacial Maximum In North America, Matthew J. Kohn, Moriah Mckay
Geosciences Faculty Publications and Presentations
Oxygen isotope data provide a key test of general circulation models (GCMs) for the Last Glacial Maximum (LGM) in North America, which have otherwise proved difficult to validate. High δ18O pedogenic carbonates in central Wyoming have been interpreted to indicate increased summer precipitation sourced from the Gulf of Mexico. Here we show that tooth enamel δ18O of large mammals, which is strongly correlated with local water and precipitation δ18O, is lower during the LGM in Wyoming, not higher. Similar data from Texas, California, Florida and Arizona indicate higher δ18O values than in the Holocene, which is also predicted by GCMs. …
Carbon Isotope Compositions Of Terrestrial C3 Plants As Indicators Of (Paleo)Ecology And (Paleo)Climate,
2010
Boise State University
Carbon Isotope Compositions Of Terrestrial C3 Plants As Indicators Of (Paleo)Ecology And (Paleo)Climate, Matthew J. Kohn
Geosciences Faculty Publications and Presentations
A broad compilation of modern carbon isotope compositions in all C3 plant types shows a monotonic increase in δ13C with decreasing mean annual precipitation (MAP) that differs from previous models. Corrections for temperature, altitude, or latitude are smaller than previously estimated. As corrected for altitude, latitude, and the δ13C of atmospheric CO2, these data permit refined interpretation of MAP, paleodiet, and paleoecology of ecosystems dominated by C3 plants, either prior to 7–8 million years ago (Ma), or more recently at mid- to high latitudes. Twenty-nine published paleontological studies suggest preservational or scientific bias toward …
Rare Earth And High Field Strength Element Partitioning Between Iron-Rich Clinopyroxenes And Felsic Liquids,
2010
Boise State University
Rare Earth And High Field Strength Element Partitioning Between Iron-Rich Clinopyroxenes And Felsic Liquids, Paul H. Olin, John A. Wolff
Geosciences Faculty Publications and Presentations
Rare earth elements are commonly assumed to substitute only for Ca in clinopyroxene because of the similarity of ionic radii for REE3+ and Ca2+ in 8-fold coordination. The assumption is valid for Mg-rich clinopyroxenes for which observed mineral/melt partition coefficients are readily predicted by the lattice strain model for substitution onto a single site (e.g. Wood and Blundy, 1997). We show that natural Fe-rich pyroxenes in both silica-undersaturated and -oversaturated magmatic systems deviate from this behavior. Salites (Mg# 48 to 59) in phonolites from Tenerife, ferrohedenbergites (Mg# 14.2 to 16.2) from the rhyolitic Bandelier Tuff, and ferroaugites (Mg# …
Loring-Greenough House, North Yard Archaeogeophysics, Jamaica Plain, Massachusetts,
2010
University of Massachusetts Boston
Loring-Greenough House, North Yard Archaeogeophysics, Jamaica Plain, Massachusetts, John M. Steinberg, Christa M. Beranek, John Schoenfelder, Kathryn A. Catlin
Andrew Fiske Memorial Center for Archaeological Research Publications
An archaeogeophysical survey was carried out in May 2010 using Geonics EM-38 RT and a Malå Ground Penetrating Radar (GPR) system with a 500 MHz antenna over an 28x26 m grid immediately northeast of the Loring-Greenough house in Jamaica Plain, MA. Three major anomalies were identified. These anomalies have not been ground truthed, but they appear to be archaeological features. First, we suggest that there is builders trench just north of the house. Second, we suggest that there could be three east-west garden paths or other landscape features about 30 cm below the surface crossing the entire length of the …
Geogram 2010,
2010
Western Kentucky University
Geogram 2010, David J. Keeling Editor, Wku Department Of Geography And Geology
Earth, Environmental, and Atmospheric Sciences Publications
No abstract provided.
Applications Of Geophysical Analysis For Environmental And Geotechnical Problems,
2010
University of Arkansas Little Rock
Applications Of Geophysical Analysis For Environmental And Geotechnical Problems, Basil Miller
Theses and Dissertations
Geophysical investigative techniques including Magnetic, Electric, Ground Penetrating Radar (GPR), and Geochemistry become increasingly essential to study near surface setting as well as deep earth structure. A model was developed of the hot water system in southwest Arkansas using Geochemistry, Magnetic, and Ground Penetrating Radar (GPR) data. The model was constructed using the data collected at the Caddo Gap and Little Missouri Hot Springs in Southeast Arkansas, USA. Understanding the mechanism of the transition from slow flow in porous media to fast flow in a fracture is critical in understanding the hot water flow of the hot spring. The geochemistry …
Autonomous Fmcw Radar Survey Of Antarctic Shear Zone,
2010
US Army Engineer Research and Development Center
Autonomous Fmcw Radar Survey Of Antarctic Shear Zone, Gary Koh, James H. Lever, Steven A. Arcone, Hans-Peter Marshall, Laura E. Ray
CGISS Publications and Presentations
Radar survey of the Antarctic shear zone was conducted using an ultra-wideband (2-10 GHz) frequency modulated continuous wave (FMCW) radar. The radar was mounted on a sled and pulled by a robot that was specifically designed to operate in a harsh polar environment. Our FMCW radar had good penetration through Antarctic snow and we observed snow stratigraphy to a depth of 20 m. The radar images also revealed multiple crevasses in the shear zone. Our results demonstrate that autonomous survey using high frequency radar is feasible and safe approach for detecting hidden crevasses.
2d Ground-Penetrating Radar Avo Response To A 3d Dielectric Permittivity Anomaly,
2010
Boise State University
2d Ground-Penetrating Radar Avo Response To A 3d Dielectric Permittivity Anomaly, John H. Bradford
CGISS Publications and Presentations
To evaluate the amplitude vs offset response of GPR to small distributions of hydrocarbon contamination, I acquired multi-offset 450 MHz GPR data in TE and TM modes over a buried rectangular tank filled with gasoline saturated sand. All dimensions of the tank were less than one wavelength at the characteristic antenna frequency. The permittivity ratio at the moist sand/gasoline sand boundary, estimated by fitting the Fresnel equations to the observed amplitudes and by Brewster's Angle analysis, differed from that obtained through migration velocity analysis by no more than 12%. 2D FDTD modeling reproduced amplitude characteristics for 3 o f 4 …
Arima Model For Forecasting Poisson Data: Application To Long-Term Earthquake Predictions,
2010
University of Nevada, Las Vegas
Arima Model For Forecasting Poisson Data: Application To Long-Term Earthquake Predictions, Wangdong Fu
UNLV Theses, Dissertations, Professional Papers, and Capstones
Earthquakes that occurred worldwide during the period of 1896 to 2009 with magnitude greater than or equal to 8.0 on the Richter scale are assumed to follow a Poisson process. Autoregressive Integrated Moving Average models are presented to fit the empirical recurrence rates, and to predict future large earthquakes. We show valuable modeling and computational techniques for the point processes and time series data. Specifically, for the proposed methodology, we address the following areas: data management and graphic presentation, model fitting and selection, model validation, model and data sensitivity analysis, and forecasting.
Slip Distribution Of The 1952 Kamchatka Great Earthquake Based On Near-Field Tsunami Deposits And Historical Records,
2010
University of Washington - Seattle Campus
Slip Distribution Of The 1952 Kamchatka Great Earthquake Based On Near-Field Tsunami Deposits And Historical Records, Breanyn Macinnes, Robert Weiss, Joanne Bourgeois, Tatiana K. Pinegina
All Faculty Scholarship for the College of the Sciences
We explore the magnitude and slip distribution of the 1952 Kamchatka earthquake (MW 8.8–9.0) using constraints from the 1952 Kamchatka tsunami. Our new field data provide more comprehensive coverage of the near-field tsunami than had been available to date. We examine the effects of internal slip distribution within complex earthquake ruptures on near-field tsunami runup and evaluate some of the limitations of this approach. Our approach compares tsunami-deposit distribution with simulated runup from tsunamis generated by different configurations of seafloor deformation from hypothetical earthquakes resembling that of the 1952 Kamchatka earthquake. We identify areas of high slip because different …
Ground-Penetrating-Radar Reflection Attenuation Tomography With An Adaptive Mesh,
2010
Boise State University
Ground-Penetrating-Radar Reflection Attenuation Tomography With An Adaptive Mesh, Emily A. Hinz, John H. Bradford
CGISS Publications and Presentations
Ground-penetrating radar (GPR) attenuation-difference analysis can be a useful tool for studying fluid transport in the subsurface. Surface-based reflection attenuation-difference tomography poses a number of challenges that are not faced by crosshole attenuation surveys. We create and analyze a synthetic attenuation-difference GPR data set to determine methods for processing amplitude changes and inverting for conductivity differences from reflection data sets. Instead of using a traditional grid-based inversion, we use a data-driven adaptive-meshing algorithm to alter the model space and to create amore even distribution of resolution. Adaptive meshing provides a method for improving the resolution of the model space while …
Arctic Landscapes In Transition: Responses To Thawing Permafrost,
2010
Boise State University
Arctic Landscapes In Transition: Responses To Thawing Permafrost, James P. Mcnamara
Geosciences Faculty Publications and Presentations
Observations indicate that over the past several decades, geomorphic processes in the Arctic have been changing or intensifying. Coastal erosion, which currently supplies most of the sediment and carbon to the Arctic Ocean [Rachold et al., 2000], may have doubled since 1955 [Mars and Houseknecht, 2007]. Further inland, expansion of channel networks [Toniolo et al., 2009] and increased river bank erosion [Costard et al., 2007] have been attributed to warming. Lakes, ponds, and wetlands appear to be more dynamic, growing in some areas, shrinking in others, and changing distribution across lowland regions …
Characterization Of Englacial Voids Using Radar Velocity Anisotropy,
2010
Boise State University
Characterization Of Englacial Voids Using Radar Velocity Anisotropy, Joshua D. Nichols
Boise State University Theses and Dissertations
Glacial hydrology plays an important role in the motion and melt of glaciers. The transport of water through glacial ice is still poorly understood. Previous studies show that much of the water is stored and routed through planar voids within the glacier. From borehole observations and previous radar surveys, the voids appear to have a preferential orientation. Transverse waves, including radar waves, and shear seismic waves, travel at different velocities when polarized at different orientations relative to aligned inclusions. I conducted two georadar surveys on Bench glacier, in the Chugach Mountains, AK. Bench glacier has been the field site of …
Reproducibility Of Soil Moisture Ensembles When Representing Soil Parameter Uncertainty Using A Latin Hypercube-Based Approach With Correlation Control,
2010
Boise State University
Reproducibility Of Soil Moisture Ensembles When Representing Soil Parameter Uncertainty Using A Latin Hypercube-Based Approach With Correlation Control, Alejandro N. Flores, Dara Entekhabi, Rafael L. Bras
Geosciences Faculty Publications and Presentations
Representation of model input uncertainty is critical in ensemble‐based data assimilation. Monte Carlo sampling of model inputs produces uncertainty in the hydrologic state through the model dynamics. Small Monte Carlo ensemble sizes are desirable because of model complexity and dimensionality but potentially lead to sampling errors and correspondingly poor representation of probabilistic structure of the hydrologic state. We compare two techniques to sample soil hydraulic and thermal properties (SHTPs): (1) Latin Hypercube (LH) based sampling with correlation control and (2) random sampling from SHTP marginal distributions. A hydrology model is used to project SHTP uncertainty onto the soil moisture state …
