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Utilizing The Hvsr Second Peak For Surface Wave Inversions In The Mississippi Embayment, Ashraf Kamal Himel 2018 University of Arkansas, Fayetteville

Utilizing The Hvsr Second Peak For Surface Wave Inversions In The Mississippi Embayment, Ashraf Kamal Himel

Theses and Dissertations

Ambient noise data from 24 sites within the Mississippi Embayment were analyzed to estimate the fundamental frequency using the horizontal to vertical spectral ratio (HVSR) method. The fundamental frequency ranged from 0.17 to 3.43 Hz for the tested sites. At seventeen of the sites, a second higher frequency HVSR peak, which ranged from 0.617 Hz to 2.154 Hz, was observed in addition to the fundamental HVSR peak. The second peak frequency in the HVSR curve has been attributed by previous researchers as either an odd harmonic of the fundamental peak or a shallow impedance contrast from ...


Robust Earthquake Site Classification Assessment At Ontario Bridge Sites., Alex Bilson Darko 2018 The University of Western Ontario

Robust Earthquake Site Classification Assessment At Ontario Bridge Sites., Alex Bilson Darko

Electronic Thesis and Dissertation Repository

Canadian seismic design guidelines classify subsurface ground conditions based on the average shear-wave velocity (VS) of the upper 30 meters (VS30). We seek to optimize a robust earthquake site classification procedure for Ontario bridge sites, assessed primarily from blind comparison of non-invasive VS depth profiling techniques. Non-invasive seismic testing is performed at 10 bridge sites in southern Ontario co-located with invasive penetration and/or borehole VS measurements. Non-invasive surface wave dispersion and site amplification functions are jointly inverted to retrieve VS profiles at each site. A general correlation between corrected VS and cone tip ...


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 2018 Colorado State University

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 ...


Empirical Characterization Of Induced Seismicity In Alberta And Oklahoma, Mark Novakovic 2018 The University of Western Ontario

Empirical Characterization Of Induced Seismicity In Alberta And Oklahoma, Mark Novakovic

Electronic Thesis and Dissertation Repository

This thesis characterizes ground motions from induced seismic events in Alberta and Oklahoma, following an overall methodology that uses ground-motion recordings to calibrate the parameters of a seismological model. This body of work is carried out in three related studies.

In the first study, we perform a preliminary evaluation of ground motions in Alberta using thousands of observations of natural, induced and blast events of magnitude 1 to 4, recorded on a newly-deployed regional seismograph array. We evaluate the applicability of a moment magnitude (M) estimation algorithm for the events and compare the observed ground motions with expectations based on ...


The Undeniable Attraction Of Lunar Swirls, Cierra Waller, Dhananjay Ravat 2018 University of Kentucky

The Undeniable Attraction Of Lunar Swirls, Cierra Waller, Dhananjay Ravat

Posters-at-the-Capitol

Lunar swirls are complex patterns on the Moon with distinct brightness signatures and magnetic characteristics. Current research has suggested that the formation of lunar swirls relies on local magnetic fields to shield impinging solar wind, based on a shift in electromagnetic wavelength peaks related to solar radiation and space weathering. Our research combined recent models and methods to characterize these anomalies at the surface of the Moon, exploring the effects of field strength and position. We have produced a high resolution map of a famous swirl named Reiner Gamma using magnetic dipole modeling. These maps and models are considered when ...


Imaging The Subsurface: The Effect Of Logjams On Groundwater-Surface Water Exchange, Teodora Mitroi, Megan Doughty, Jackie Randall, Kamini Singha 2018 Georgia State University

Imaging The Subsurface: The Effect Of Logjams On Groundwater-Surface Water Exchange, Teodora Mitroi, Megan Doughty, Jackie Randall, Kamini Singha

Georgia Undergraduate Research Conference (GURC)

Conventional methods of quantifying subsurface interactions in streams are often insufficient in characterizing hydrological processes and demand better techniques to measure complex dynamics. Point-measurements are incomplete and do not provide direct data on hyporheic exchange, a mixing of surface and subsurface water under and around a stream capable of influencing ecosystem processes. Fortunately, geophysical techniques can improve analysis of the hyporheic zone. For the first time in a field setting, we apply electrical resistivity imaging (ERI) to a mountainous stream below a channel-spanning logjam to estimate the extent of hyporheic exchange. Previous studies suggest logjams increase hydraulic resistance and drive ...


Postseismic Restoration Of The Ecological Environment In The Wenchuan Region Using Satellite Data, Zhibin Huang, Min Xu, Wei Chen, Xiaojuan Lin, Chunxiang Cao, Ramesh Singh 2018 Chinese Academy of Sciences

Postseismic Restoration Of The Ecological Environment In The Wenchuan Region Using Satellite Data, Zhibin Huang, Min Xu, Wei Chen, Xiaojuan Lin, Chunxiang Cao, Ramesh Singh

Mathematics, Physics, and Computer Science Faculty Articles and Research

Using Landsat remote-sensing data combined with geological information extracted from ALOS and Sentinel-1A radar data, the ecological environment was evaluated in the years 2007, 2008, 2013, and 2017 through gray correlation analysis on the basis of the construction of the pressure-state-response model. The main objective of this research was to assess the ecological environment changes in Wenchuan County before and after the earthquake, and to provide reference for future social development and policy implementation. The grading map of the ecological environment was obtained for every year, and the ecological restoration status of Wenchuan County after the earthquake was evaluated. The ...


The Cyrilka Cave—The Longest Crevice-Type Cave In Czechia: Structural Controls, Genesis, And Age, Jan Lenart, Martin Kašing, Petr Tábořík, Natalia Piotrowska, Jacek Pawlyta 2018 University of Ostrava

The Cyrilka Cave—The Longest Crevice-Type Cave In Czechia: Structural Controls, Genesis, And Age, Jan Lenart, Martin Kašing, Petr Tábořík, Natalia Piotrowska, Jacek Pawlyta

International Journal of Speleology

The Cyrilka Cave is the second longest pseudokarst cave and the longest crevice-type cave in Czechia. Developed within the headscarp area of a deep-seated landslide, the cave became a focus of scientific research in recent years when new passages were discovered. Structural analysis provided a general tectonic plan of the cave, as well as more detailed data on geometry and kinematics of the relaxed rock massif. The primary structure of NNE- to ENE-striking bedding is broken by a system of NNE-striking fissures interconnected by two continuous ENE-striking dextral fracture zones. Abundant signs of recent sinistral strike-slips within the rock massif ...


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 2018 Boise State University

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 2018 University of Nebraska-Lincoln

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 bitterbrush ...


Predicted Deepwater Bathymetry From Satellite Altimetry: Non-Fourier Transform Alternatives, Maxsimo Salazar 2018 The University of Southern Mississippi

Predicted Deepwater Bathymetry From Satellite Altimetry: Non-Fourier Transform Alternatives, Maxsimo Salazar

Dissertations

Robert Parker (1972) demonstrated the effectiveness of Fourier Transforms (FT) to compute gravitational potential anomalies caused by uneven, non-uniform layers of material. This important calculation relates the gravitational potential anomaly to sea-floor topography. As outlined by Sandwell and Smith (1997), a six-step procedure, utilizing the FT, then demonstrated how satellite altimetry measurements of marine geoid height are inverted into seafloor topography. However, FTs are not local in space and produce Gibb’s phenomenon around discontinuities. Seafloor features exhibit spatial locality and features such as seamounts and ridges often have sharp inclines. Initial tests compared the windowed-FT to wavelets in reconstruction ...


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 2018 Boise State University

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 imagery ...


Nested Scales Of Spatial And Temporal Variability Of Soil Water Content Across A Semiarid Montane Catchment, Kendra E. Kaiser, Brian L. McGlynn 2018 Boise State University

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 ...


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 2018 Boise State University

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 ...


Reverse-Time Migration From Rugged Topography To Image Ground-Penetrating Radar Data In Complex Environments, John H. Bradford, Janna Privette, David Wilkins, Richard Ford 2018 Boise State University

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 ...


Lithologic Controls On Focused Erosion And Intraplate Earthquakes In The Eastern Tennessee Seismic Zone, Sean F. Gallen, J. Ryan Thigpen 2018 Colorado State University

Lithologic Controls On Focused Erosion And Intraplate Earthquakes In The Eastern Tennessee Seismic Zone, Sean F. Gallen, J. Ryan Thigpen

Earth and Environmental Sciences Faculty Publications

We present a new geomorphic model for the intraplate eastern Tennessee seismic zone (ETSZ). Previous studies document that the Upper Tennessee drainage basin is in a transient state of adjustment to ~150 m of base level fall that occurred in the Late Miocene. Using quantitative geomorphology, we demonstrate that base level fall resulted in the erosion of ~3,500 km3 of highly erodibility rock in an ~70 km wide by ~350‐km‐long corridor in the Paleozoic fold‐thrust belt above the ETSZ. Models of modern incision rates show a NE‐SW trending swath of elevated erosion ~30 km ...


The Final Stages Of Slip And Volcanism On An Oceanic Detachment Fault At 13°48′N, Mid-Atlantic Ridge, V. D. Wanless 2018 Boise State University

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 ...


Gps Constraints On Deformation In Northern Central America From 1999 To 2017, Part 1 – Time-Dependent Modelling Of Large Regional Earthquakes And Their Post-Seismic Effects, A. Ellis, Charles DeMets, P. Briole, Beatriz Cosenza, Omar Flores, Shannon Graham, Marco Guzmán-Speziale, Douglas Hernandez, Vladimir Kostoglodov, Peter LaFemina, Neal Lord, Cécile Lasserre, Hélène Lyon-Caen, Manuel Rodriguez Maradiaga, Robert McCaffrey, Enrique Molina, Jeffrey Rivera, Robert Rogers, Alejandra Staller 2018 University of Wisconsin-Madison

Gps Constraints On Deformation In Northern Central America From 1999 To 2017, Part 1 – Time-Dependent Modelling Of Large Regional Earthquakes And Their Post-Seismic Effects, A. Ellis, Charles Demets, P. Briole, Beatriz Cosenza, Omar Flores, Shannon Graham, Marco Guzmán-Speziale, Douglas Hernandez, Vladimir Kostoglodov, Peter Lafemina, Neal Lord, Cécile Lasserre, Hélène Lyon-Caen, Manuel Rodriguez Maradiaga, Robert Mccaffrey, Enrique Molina, Jeffrey Rivera, Robert Rogers, Alejandra Staller

Geology Faculty Publications and Presentations

We use continuous and campaign measurements from 215 GPS sites in northern Central America and southern Mexico to estimate coseismic and afterslip solutions for the 2009 Mw = 7.3 Swan Islands fault strike-slip earthquake and the 2012 Mw = 7.3 El Salvador and Mw = 7.4 Guatemala thrust-faulting earthquakes on the Middle America trench. Our simultaneous, time-dependent inversion of more than 350 000 daily GPS site positions gives the first jointly consistent estimates of the coseismic slips for all three earthquakes, their combined time-dependent post-seismic effects and secular station velocities corrected for both the coseismic and post-seismic deformation. Our geodetic ...


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 2018 Indian Institute of Geomagnetism

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 ...


Impact Craters On Titan: Finalizing Titan's Crater Population, Joshua E. Hedgepeth 2018 The University of Western Ontario

Impact Craters On Titan: Finalizing Titan's Crater Population, Joshua E. Hedgepeth

Electronic Thesis and Dissertation Repository

Titan is one of the most dynamic moons in the solar system. It is smaller than Earth and much colder, yet Titan is eerily similar to Earth, with rivers, rain, and seas, as well as sand seas that wrap around the equator. However, the rivers are made of hydrocarbons rather than water and the sand made of organics rather rock. We can use Titan’s impact craters to study how these processes modify the surface by comparing the craters depths, diameters and rim heights of Titan’s craters with fresh craters. Therefore, we have used the complete data set from ...


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