Geophysics and Seismology Commons^™

Enhancing Infrasonic Signal Detection And Event Localization Through Advanced Computational Methods, Fransiska Dannemann Dugick

Earth Sciences Theses and Dissertations

The installation of worldwide infrasound and seismo-acoustic networks at both global and regional scales necessitates automated techniques and algorithms for accurate and efficient data processing and analysis. Signals recorded across the networks originate from a number of natural and anthropogenic sources. Data processing efforts focus on the separation of signals of interest from background noise, followed by the identification, or detection of signals of interest. Once signals are identified, association and location processing produces estimates of a signal's source. This dissertation focuses on the evaluation of automated processes for identifying and locating sources of interest.

Chapter two applies two state-of-the-art …

Characterization Of Landslide Processes From Radar Remote Sensing And Hydromechanical Modeling, Yuankun Xu

Earth Sciences Theses and Dissertations

Landsides are a natural geomorphic process yet a dangerous hazard which annually causes thousands of casualties and billions of property loss in a global scale. Understanding landslide motion kinematics from early initiation to final deposition is critical for monitoring, assessing, and forecasting landslide movement in order to mitigate their hazards. Landslides occur under diverse environmental settings and appear in variable types; however, all types of landslides can be mechanically attributed to shearing failure at the basal surface due to stress regime shift contributed by internal and/or external forcing. Typical internal factors include soil/rock weathering, whereas typical external triggering forces encompass …

Tree Canopy And Snow Depth Relationships At Fine Scales With Terrestrial Laser Scanning, Ahmed Hojatimalekshah, Zachary Uhlmann, Nancy F. Glenn, Jake D. Graham, Hans-Peter Marshall, James P. Mcnamara, Josh Enterkine

Geosciences Faculty Publications and Presentations

Understanding the impact of tree structure on snow depth and extent is important in order to make predictions of snow amounts and how changes in forest cover may affect future water resources. In this work, we investigate snow depth under tree canopies and in open areas to quantify the role of tree structure in controlling snow depth, as well as the controls from wind and topography. We use fine-scale terrestrial laser scanning (TLS) data collected across Grand Mesa, Colorado, USA (winter 2016–2017), to measure the snow depth and extract horizontal and vertical tree descriptors (metrics) at six sites. We utilize …

The Influence Of The Permian-Triassic Magmatism In The Tunguska Basin, Siberia On The Regional Floristic Biota Of The Permian-Triassic Transition In The Region, V. I. Davydov, E. V. Karasev

Geosciences Faculty Publications and Presentations

The end-Permian extinction event (EPEE) considered to have been caused by the eruption of the Siberian Large Igneous Province (SLIP), the age of which is critical for extinction-SLIP model evaluation. The Tunguska Basin flora during this time, in accordance with the EPEE model, supposed to have been killed by the massive injection into the atmosphere of poisonous substances such as methane, sulfates, mercury and massive combastion of coals. In addition, supposed numerous fires presumably devastated the regional flora. However, the diversity of the Tunguska Basin flora drasticly increased at the beginning of Induan or slightly earlier and become diverse at …

Nasa's Surface Biology And Geology Designated Observable: A Perspective On Surface Imaging Algorithms, Nancy F. Glenn

Geosciences Faculty Publications and Presentations

The 2017–2027 National Academies' Decadal Survey, Thriving on Our Changing Planet, recommended Surface Biology and Geology (SBG) as a “Designated Targeted Observable” (DO). The SBG DO is based on the need for capabilities to acquire global, high spatial resolution, visible to shortwave infrared (VSWIR; 380–2500 nm; ~30 m pixel resolution) hyperspectral (imaging spectroscopy) and multispectral midwave and thermal infrared (MWIR: 3–5 μm; TIR: 8–12 μm; ~60 m pixel resolution) measurements with sub-monthly temporal revisits over terrestrial, freshwater, and coastal marine habitats. To address the various mission design needs, an SBG Algorithms Working Group of multidisciplinary researchers has been formed …

Shallow 3d Shear Wave Velocity Model And Revised Site Period Prediction Map For The Mexico City Basin, Rendon Martin Rieth

Graduate Theses and Dissertations

The goal of this study was to revise the existing site period prediction map and to develop a shallow 3D shear wave velocity model of the Mexico City Basin. To accomplish this goal, an extensive literature review was performed to compile as much pertinent shear wave velocity and site period data for the region. In total, 75 sites were used to revise the site period prediction map and 40 sites were used to develop the shear wave velocity model. The 2004 Complementary Technical Standards of Mexico site period prediction map was adjusted with new site period measurements across the basin …

Characterization And Delineation Of Potential Evaporite Geohazards Using Electrical Resistivity Methods Along Fm 2185, Culberson County, Texas, Lenora Diane Perkins

Electronic Theses and Dissertations

Extensive karst development within the Delaware Basin of West Texas and southeastern New Mexico poses a significant geohazard threat to infrastructure. Dissolution of regional evaporite strata have led to manifestations of karst geohazard phenomena including sinkholes, subsidence features, and caves. The study area is located within the Gypsum Plain in Culberson County, Texas, and includes outcrops of Castile and Rustler strata that host gypsum karst geohazards. Land reconnaissance surveys conducted during the summer of 2019 documented numerous surficial manifestations of karst features proximal to Farm to Market Road 2185 (FM 2185). In combination with traditional survey techniques, electrical resistivity methods …

Soil Inhomogeneity Effects On Seismic Wind Noise, Bipin Koirala

Honors Theses

Wind causes local pressure fluctuations over the ground. The pressure waves couples with the ground and transmits into the ground as seismic waves. The seismic wave, in turn, causes ground motion. Naderyan et al. [9] developed a prediction of the ground displacements spectra from the measured ground properties and predicted pressure and shear stress at the ground surface. Naderyan modeled the ground as a linearly elastic half space bounded by an infinite plane on one side. The quasi-static model for predicting displacement components in the ground is effective for the vertical component of the displacement response, but the model significantly …

Seismic Tomographic Modeling Of The Coast Mountains Batholith, British Columbia, Canada, Sarah M. Quinonez

Open Access Theses & Dissertations

The Coast Mountains Batholith on the west coast of British Columbia, Canada, comprises a series of granitic to tonalitic plutons. The felsic continental crust is generated from mafic oceanic crust subduction by partial melting and fractionation, leaving ultra-mafic roots. In July of 2009, a sizeable controlled-source experiment was conducted along a 400km east-west transect from Bella Bella into central British Columbia. Student volunteers from multiple universities deployed 1,800 one-component and 200 three-component geophones connected to Texan data recorders with 200-m spacing intervals and shot spacing at 30-km. The 18-point sources ranged from 160 to 1,000 kg of high yield explosives. …

Dynamic Topography Of The St. Francois Mountains, Joshua Carpenter

Undergraduate Research Conference at Missouri S&T

The purpose of this research project was to search for evidence of relict topographic surfaces in the St. Francois Mountains that preserve a history of regional and/or global forces. To accomplish this, topographic cross-sections were taken in Google Earth to examine changes in the region's topography with focus towards the following features: sub-horizontal surfaces, knickpoints, and valley floors. Elevation data was then collected and plotted in Excel. This revealed sub-horizontal surfaces between elevations of ~1780-1545 ft; knickpoints between ~1700-900 ft; and valley floors at ~1470-1350 ft. and ~1200-900 ft. The sub-horizontal surfaces are interpreted as relict peneplains preserved during periods …

Co-Evolution Of Xylem Water And Soil Water Stable Isotopic Composition In A Northern Mixed Forest Biome, Jenna R. Snelgrove, James M. Buttle, Matthew J. Kohn, Dörthe Tetzlaff

Geosciences Faculty Publications and Presentations

Plant–soil water isotopic dynamics in northern forests have been understudied relative to other forest types; nevertheless, such information can provide insight into how such forests may respond to hydroclimatic change. This study examines the co-evolution of xylem water and soil water stable isotopic compositions in a northern mixed forest in Ontario, Canada. Gross precipitation, bulk soil water and xylem water were sampled from pre-leaf out to post-senescence in 2016 for eastern white cedar, eastern hemlock, red oak and eastern white pine. Near-bole soil water contents and mobile soil water isotopic compositions were measured for the last three species. Mobile soil …

Investigating The Hydrology Of The Western Greenland Ice Sheet: Spatiotemporal Variability And Implications On Ice-Dynamics, Jessica Z. Mejia

USF Tampa Graduate Theses and Dissertations

Since the 1990's the Greenland Ice Sheet (GrIS) has been losing mass at an accelerating rate in response to climatic warming and is currently the largest terrestrial contributor to sea-level rise. While ice sheet models agree the GrIS will continue losing mass throughout the century, there are significant uncertainties associated with future sea-level rise contributions. Predicting the GrIS's response to future climate warming scenarios is limited by gaps in our understanding of the links between ice sheet hydrology and dynamics. Meltwater produced on the ice surface flows within supraglacial streams that deliver it to crevasses or moulins—vertical conduits extending from …

Reconstruction Of Historical Surface Mass Balance, 1984–2017 From Greentraacs Multi-Offset Ground-Penetrating Radar, Tate G. Meehan, H.P. Marshall

Geosciences Faculty Publications and Presentations

We present continuous estimates of snow and firn density, layer depth and accumulation from a multi-channel, multi-offset, ground-penetrating radar traverse. Our method uses the electromagnetic velocity, estimated from waveform travel-times measured at common-midpoints between sources and receivers. Previously, common-midpoint radar experiments on ice sheets have been limited to point observations. We completed radar velocity analysis in the upper ∼2 m to estimate the surface and average snow density of the Greenland Ice Sheet. We parameterized the Herron and Langway (1980) firn density and age model using the radar-derived snow density, radar-derived surface mass balance (2015–2017) and reanalysis-derived temperature data. We …

Timescales Of Partial Melting And Melt Crystallization In The Eastern Himalayan Orogen: Insights From Zircon Petrochronology, Huxia Ding, Zeming Zhang, Matthew J. Kohn, Zhenbin Gou

Geosciences Faculty Publications and Presentations

Revealing the timescales of metamorphic and anatectic processes is central to our understanding of tectonic evolution of collisional orogens. High‐temperature migmatites and leucogranites are well exposed in the Himalayan orogenic core, making it an ideal region to study the timing and duration of partial melting and melt crystallization of the orogen. Here, we report an integrated and comprehensive data set of petrography, U‐Pb age, and trace element data for zircon from a pelitic granulite and associated leucosomes of the Greater Himalayan Sequence (GHS) in the Yadong area, eastern Himalaya. Zircon grains with complex internal structure retain variable ages ranging from …

Autocorrelation Infrasound Interferometry, Hugo D. Ortiz, Robin S. Matoza, Jeffrey B. Johnson, Stephen Hernandez, Juan C. Anzieta, Mario C. Ruiz

Geosciences Faculty Publications and Presentations

Seismic and infrasound multistation ambient‐noise interferometry has been widely used to infer ground and atmospheric properties, and single‐station and autocorrelation seismic interferometry has also shown potential for characterizing Earth structure at multiple scales. We extend autocorrelation seismic interferometry to ambient atmospheric infrasound recordings that contain persistent local noise from waterfalls and rivers. Across a range of geographic settings, we retrieve relative sound‐speed changes that exhibit clear diurnal oscillations consistent with temperature and wind variations. We estimate ambient air temperatures from variations in relative sound speeds. The frequency band from 1 to 2 Hz appears most suitable to retrieve weather parameters …

The Miocene: The Future Of The Past, M. J. Kohn

Geosciences Faculty Publications and Presentations

The Miocene epoch (23.03–5.33 Ma) was a time interval of global warmth, relative to today. Continental configurations and mountain topography transitioned toward modern conditions, and many flora and fauna evolved into the same taxa that exist today. Miocene climate was dynamic: long periods of early and late glaciation bracketed a ∼2 Myr greenhouse interval—the Miocene Climatic Optimum (MCO). Floras, faunas, ice sheets, precipitation, pCO₂, and ocean and atmospheric circulation mostly (but not ubiquitously) covaried with these large changes in climate. With higher temperatures and moderately higher pCO₂ (∼400–600 ppm), the MCO has been suggested as …

A Broad, Distributed Active Fault Zone Lies Beneath Salt Lake City, Utah, Lee M. Liberty, James St. Clair, Adam P. Mckean

Geosciences Faculty Publications and Presentations

Although the Wasatch fault is currently known to have a high‐seismic hazard from motion along range‐bounding faults, new seismic data reveal faulted and folded 13,000–30,000‐yr‐old Lake Bonneville strata beneath Salt Lake City (SLC). Coupled with previous excavation trench, borehole, and other geologic and geophysical observations, we conclude that a zone of latest Pleistocene and/or Holocene faulting and folding kinematically links the East Bench and Warm Springs faults through a 3 km wide relay structure and transfer zone. We characterize faults beneath downtown SLC as active, and these faults may displace or deform the ground surface during an earthquake. Through offset …

Spatial Variations Of Upper Crustal Anisotropy Along The San Jacinto Fault Zone In Southern California: Constraints From Shear Wave Splitting Analysis, Enyuan Jiang, Kelly H. Liu, Yuan Gao, Xiaofei Fu, Stephen S. Gao

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

To discern spatial and explore possible existence of temporal variations of upper crustal anisotropy in an ∼15 km section of the San Jacinto Fault Zone (SJFZ) that is composed of the Buck Ridge and Clark faults in southern California, we conduct a systematic shear wave splitting investigation using local S-wave data recorded by three broadband seismic stations located near the surface expression of the SJFZ. An automatic data selection and splitting measurement procedure is first applied, and the resulting splitting measurements are then manually screened to ensure reliability of the results. Strong spatial variations in crustal anisotropy are revealed by …

Rutile As A Provenance Indicator For The Camerino Sandstone Of The Camerino Basin, Apennine Mountain Region, Italy, Wendy Bogil

Honors Capstones

No abstract provided.

Chemical Mapping To Evaluate Post-Depositional Diagenesis Among The Earliest Ceramics In The Teotihuacan Valley, Mexico, Wesley D. Stoner, Barry J. Shaulis

Anthropology Faculty Publications and Presentations

Chemical and mineral sourcing techniques are commonly employed in archaeology to reconstruct patterns of ceramic exchange and raw material procurement practices for the past, but the effects of post-depositional diagenesis are still often ignored despite a number of key studies warning that the composition of ceramics from archaeological deposits often diverges greatly from their original composition at the time of production. This current study on diagenesis derives from a large chemical and petrographic analysis of some of the earliest ceramics (1500-100 cal Before Common Era [BCE]) in the Basin of Mexico at a time when the development of ceramic trade …