Geophysics and Seismology Commons^™

Geogram 2009, David J. Keeling Editor, Wku Department Of Geography And Geology

Earth, Environmental, and Atmospheric Sciences Publications

No abstract provided.

Understanding Paleoclimate And Human Evolution Through The Hominin Sites And Paleolakes Drilling Project, Andrew Cohen, Ramon Arrowsmith, Anna K. Behrensmeyer, Christopher Campisano, Craig Feibel, Shimeles Fisseha, Roy Johnson, Zelalem Bedaso, Charles Lockwood, Emma Mbua, Daniel Olago, Richard Potts, Kaye Reed, Robin Renaut, Jean-Jacques Tiercelin, Mohammed Umer

Geology Faculty Publications

Understanding the evolution of humans and our close relatives is one of the enduring scientific issues of modern times. Since the time of Charles Darwin, scientists have speculated on how and when we evolved and what conditions drove this evolutionary story. The detective work required to address these questions is necessarily interdisciplinary, involving research in anthropology, archaeology, human genetics and genomics, and the earth sciences. In addition to the difficult tasks of finding, describing, and interpreting hominin fossils (the taxonomic tribe which includes Homo sapiens and our close fossil relatives from the last 6 Ma), much of modern geological research …

Geometry Of The Trachyte Mesa Intrusion, Henry Mountains, Utah: Implications For The Emplacement Of Small Melt Volumes Into The Upper Crust, Paul H. Wetmore, Charles B. Connor, Sarah E. Kruse, Sean Callihan, Geoffrey Pignotta, Ciprian Stremtan, Andrea Burke

Geology Faculty Publications

The Trachyte Mesa intrusion is one of several small satellite bodies to the larger intrusions of the Henry Mountains, Utah. Most previous studies have worked under the assumptions that Trachyte Mesa is blister shaped and intruded into flat and gently NW dipping strata. In this study we combine structural and geophysical data sets to constrain the structural geology of the host lithologies and the unmodified geometry of the intrusion. Trachyte Mesa intrudes a series of northeast trending upright and open folds formed within the Jurassic Entrada Formation. Truncation of these folds at the contact with the overlying Curtis/Summerville formations indicates …

Moment Release Rate Of Cascadia Tremor Constrained By Gps, Ana C. Aguiar, Timothy I. Melbourne, Craig W. Scrivner

All Faculty Scholarship for the College of the Sciences

A comparison of GPS and seismic analyses of 23 distinct episodic tremor and slip events, located throughout the Cascadia subduction zone over an 11-year period, yields a highly linear relationship between moment release, as estimated from GPS, and total duration of nonvolcanic tremor, as summed from regional seismic arrays. The events last 1–5 weeks, typically produce ~5 mm of static forearc deformation, and show cumulative totals of tremor that range from 40 to 280 h. Moment released by each event is estimated by inverting GPS-measured deformation, which is sensitive to all rates of tremor-synchronous faulting, including aseismic creep, for total …

The Southeastern Coastal Plain: An Overview, Lee J. Florea, H L. Vacher

Lee J Florea, PhD, P.G.

Florida enjoys the highest density of large springs in North America (Scott et al., 2004); Silver Springs is just one of the 33 first-magnitude springs (mean flow greater than 100 cfs (2.8 m3/s), and there are hundreds of smaller springs (Fig. 6.2; see Meinzer, 1927, and Scott et al., 2004). They are supplied by spectacular underwater caves that are internationally recognized in the cave-diving community. Less well known are the many air-filled caves of the region (see Florea, 2006; Moore, 2006; Lane 1986). Though generally smaller than their aquatic counterparts, their beauty can rival the world’s best show caves. This …

The Cumberland Plateau Of Eastern Kentucky, Larry C. Simpson, Lee J. Florea

Lee J Florea, PhD, P.G.

Eastern Kentucky contains almost the same Mississippian limestones that appear at Mammoth Cave in south-central Kentucky (Chapter 3). To the east these strata dip below the Appalachian Basin and reappear as the Greenbrier Group in the Virginias. The limestone outcrop in eastern Kentucky follows the western margin of the Cumberland Plateau and forms a ragged ribbon of karst that is continuous from southeastern Ohio through Kentucky and Tennessee and into northern Alabama. There are more than 2,000 documented caves comprising over 470 km of surveyed passage in the Kentucky segment of the Cumberland Plateau (Fig. 2.115). At least 14 are …

Caves And Karst Of West-Central Florida, Lee J. Florea, David Budd, Robert Brinkmann

Lee J Florea, PhD, P.G.

The real west-central Florida is far from the “Sunshine State” image of white sand beaches and palm trees. Gently rolling hills, dense jungle-like forests, pine and palmetto scrublands, impenetrable cypress swamps, and alligator-laden rivers are more common. Numerous crystal-clear springs offer a glimpse of the hidden world below – a world that could challenge the most imaginative Disney artists (Fig. 6.17).

The Biscayne Aquifer Of Southeastern Florida, Kevin Cunningham, Lee J. Florea

Lee J Florea, PhD, P.G.

In southeastern Florida, locally delineated, small, poorly explored caves and subtle karst are characteristic of the limestone that composes the unconfined Biscayne aquifer – one of the most permeable aquifers in the world. The main units of the Biscayne aquifer are the Fort Thompson Formation and Miami Limestone, both characterized by eogenetic karst.

Seismic Observations Of Transient Subglacial Water-Flow Beneath Macayeal Ice Stream, West Antarctica, J. Paul Winberry, Sridhar Anandakrishnan, Richard B. Alley

All Faculty Scholarship for the College of the Sciences

New seismic observations of harmonic tremors beneath MacAyeal Ice Stream, West Antarctica are reported. Each of the two tremor events that we recorded during a six week period had sustained arrival of 3 Hz energy for approximately 10 minutes. During that time the source location migrated a few kilometers. The harmonic nature of the tremors is interpreted as the result of resonance in subglacial water-filled cracks and conduits. The duration, monochromatic nature, and movement of the tremor indicate that the source mechanism is likely flow in the subglacial water system resulting from the discharge from a small subglacial lake. Our …

Numerical Modeling Of Fracturing In Non-Cylindrical Folds: Case Studies In Fracture Prediction Using Structural Restoration, John Ryan Shackleton

Open Access Dissertations

This thesis contains several distinct studies aimed at better understanding fracturing in compressional fault-cored folds. At outcrops of growth strata in the Oliana anticline in the Spanish Pyrenees, the relationship of two joint sets may reflect changing mechanical properties (i.e. via diagenesis) during the folding process. Using a Schmidt hammer, I assess the rigidity contrast between the individual units and suggest that late-stage, throughgoing joints formed in strata with conditions similar to those of the present day and that early, bed-contained joints formed when the rigidity contrast between beds was significantly greater than the present day contrast. Modeling algorithms that …

Eastern Mediterranean Pore Waters: Clues Into The Geochemical Pathways From Evaporated Seawater To Basinal Brines, Jessica A. Mumphrey

Honors Theses

No abstract provided.

The Storm 2.0 Project Next Generation Hurricane Data Collection, Santhana Krishnan Balaji

Honors Theses

No abstract provided.

Basal Mechanics Of Ice Streams: Insights From The Stick-Slip Motion Of Whillans Ice Stream, West Antarctica, J. Paul Winberry, Sridhar Anandakrishnan, Richard B. Alley, Robert A. Bindschadler, Matt A. King

All Faculty Scholarship for the College of the Sciences

The downstream portion of Whillans Ice Stream, West Antarctica, moves primarily by stick-slip motion. The observation of stick-slip motion suggests that the bed is governed by velocity-weakening physics and that the basal physics is more unstable than suggested by laboratory studies. The stick-slip cycle of Whillans Ice Plain exhibits substantial variability in both the duration of sticky periods and in slip magnitude. To understand this variability, we modeled the forces acting on the ice stream during the stick phase of the stick-slip cycle. The ocean tides introduce changes in the rate at which stress is applied to the ice plain. …

Paleomagnetic Behavior Of Volcanic Rocks From Isla Socorro, Mexico, Elise Sbarbori, Lisa Tauxe, Avto Goguitchaichvili, Jaime Urrutia-Fucugauchi, Wendy A. Bohrson

All Faculty Scholarship for the College of the Sciences

The direction and magnitude of the geomagnetic field vary both spatially and temporally and undergo significant departures from that of a geocentric axial dipole. In order to properly characterize persistent behaviors, time-averaged field models must be based on the highest quality data. Here we present full-vector paleomagnetic data for volcanic units exposed in the southeast quadrant of the island of Socorro, Mexico. We carried out a joint expedition between the Scripps Institution of Oceanography and the Universidad Nacional Autónoma México to Isla Socorro in January of 2005 during which we collected oriented paleomagnetic samples from 21 sites, representing as many …

Peary's Explorations, Ray Bradley

IPY STEM Polar Connections

How did he do it?

Stable Isotopes And Climate Change, Ray Bradley, Rob Snyder

IPY STEM Polar Connections

The following description of the role of the study of stable isotopes in water and carbon dioxide molecules when constructing a record of Earth’s pattern of climate change is an excerpt from:

Climate Change and Society by Raymond S. Bradley & Norman E. Law (2001) Nelson Thornes, Cheltenham, UK (ISBN: 0 7487 5823 2)

The Arctic Solar Challenge, Rob Snyder

IPY STEM Polar Connections

Design, build, and evaluate the performance of a portable, temporary, passive solar structure that can be used as a shelter for researchers who will be in Kotzebue, Alaska around the time of a summer solstice.

The Antarctic: Going To Extremes, Morton Sternheim

IPY STEM Polar Connections

No abstract provided.

The Problem Of Venice - Sea Level Rise, Ray Bradley

IPY STEM Polar Connections

The problem of Venice ... We are all Venetians now.

Two-Dimensional Gravity Modeling Of The Rattlesnake Springs Watershed, Carlsbad Caverns National Park, New Mexico, Nikolay D. Boykov

Open Access Theses & Dissertations

A series of non-invasive geophysical investigations at the Rattlesnake Springs part of Carlsbad Caverns National Park, New Mexico, were performed in an effort to better delineate the watershed of the springs. The goal of this project is to determine possible locations of fractures and faults that may control the distribution of groundwater that feeds Rattlesnake Springs. Once the water flow paths are identified, the park will be able to better protect Rattlesnake Springs from environmental hazards, such as oil and gas drilling, as well as from upstream water development. As part of this effort I conducted a precision gravity survey …

Insight Into The Physics Of Rupture: Dynamic Triggering Seismicity, Hector Gonzalez-Huizar

Open Access Theses & Dissertations

Seismic waves can trigger earthquakes and tremor at large distances from the causable event. Dynamic triggering occurs when the surface waves from large earthquakes change the stresses conditions on previously overstressed faults, promoting failure. To understand the causative stresses and environments behind dynamic triggering, we model the change in the stress field that the passing of Rayleigh and Love waves cause on a fault plane of arbitrary orientation relative to the direction of propagation of the waves, and apply a Coulomb failure criterion to calculate the potential of these stress changes to trigger seismicity. We apply our model to three …

Characterizing The Deformation Of Reservoirs Using Interferometry, Gravity, And Seismic Analyses, Cara Schiek

Open Access Theses & Dissertations

In this Dissertation, I characterize how reservoirs deform using surface and subsurface techniques. The surface technique I employ is radar interferometry, also known as InSAR (Interferometric Synthetic Aperture Radar). The subsurface analyses I explore include gravity modeling and seismic techniques consisting of determining earthquake locations from a small-temporary seismic network of six seismometers. These techniques were used in two different projects to determine how reservoirs deform in the subsurface and how this deformation relates to its remotely sensed surface deformation.

The first project uses InSAR to determine land subsidence in the Mimbres basin near Deming, NM. The land subsidence measurements …

Crustal Modification By Tectonic Events And Upper Mantle Anisotropy Beneath The Midcontinent Rift And New Madrid Seismic Zone: Insights From Receiver Function Studies And Teleseismic Shear Wave Splitting, Moikwathai Moidaki

Doctoral Dissertations

"The earth's crust and upper mantle have been continually modified by tectonic processes such as rifting, earthquake activity. In this dissertation, shear wave splitting and receiver function techniques were employed to study the extent of crustal and upper mantle modifications beneath the New Madrid Seismic Zone (NMSZ) and the Midcontinent Rift (MCR). Shear wave splitting analysis in the MCR reveals the presence of fossilised anisotropy along the rift axis...In the NMSZ, anticipated rift-parallel fast directions associated with vertical magmatic dikes or along-rift flow, rift-orthogonal fast directions from small-scale convection, or reduction in splitting times as a result of vertical asthenospheric …

Environmental Geochemistry Of Metal Contaminated Sediments From The Big River System Of Southeastern Missouri, Helen Carrie Bender

Masters Theses

"Geochemical analysis of stream sediments from the Big River Watershed of southeastern Missouri indicates that they contain elevated concentrations of contaminant metals such as Pb. Zn, Cu. Co, Ni and Cd. The elevated concentrations are derived from natural exposures of metal enriched strata and the numerous mine tailings piles and water seeps created as a result of about 300 years of lead-zinc mining in the “Old Lead Belt”. Galena (PbS), sphalerite (ZnS), and pyrite (FeS₂) are the primary sulfides found in the tailings piles and Scanning Electron Microscopy analysis of individual metallic sediment particles collected at intervals downstream …

The Cretaceous-Paleogene Transition In The Northern Mississippi Embayment, S.E. Missouri: Palynology, Micropaleontology, And Evidence Of A Mega-Tsunami Deposit, Tambra L. Eifert

Doctoral Dissertations

"Upper Cretaceous to lower Paleogene sedimentary rocks in Southeastern Missouri record the northwest extension of the Mississippi Embayment, yet very little information exists about them due to lack of exposures. Access to borehole and trench material and well logs provided an opportunity to study the sedimentology, palynology and micropaleontology of the three formations spanning the Cretaceous-Paleogene (K-Pg) boundary interval: Owl Creek (Cretaceous) and Clayton and Porters Creek (Paleocene). Lithologic features, palynomorphs (mainly spores, pollen, dinoflagellate cysts), dispersed organic matter, and foraminifera were used to interpret biostratigraphy, paleovegetation, paleoclimatic and depositional conditions, thereby creating a framework upon which further questions involving …

Investigating The Impact Of Microbial Interactions With Geologic Media On Geophysical Properties, Caroline A. Davis

Doctoral Dissertations

"The goals of this study were to investigate the effect of: (1) microbial metabolic byproducts, microbial growth, and biofilm formation on the low frequency electrical properties of porous media, (2) biofilm formation on acoustic wave properties, and (3) the natural electrical (self-potential) signatures associated with an in-situ biological permeable reactive barrier (PRB). The results suggest: (1) increases in electrolytic conductivity are consistent with increased concentrations of organic acids and biosurfactants; (2) mineral weathering promoted by organic acids causes increases in electrolytic conductivity, concomitant with increases in major cation concentrations; (3) interfacial conductivity generally parallels microbial cell concentrations and biofilm formation; …

Geoelectrical Response Of Surfactant Solutions In A Quartzitic Sand Analog Aquifer, Meghan Therese Magill

UNLV Theses, Dissertations, Professional Papers, and Capstones

In this project, the resistivity and phase shift of ten surfactant aqueous solutions in a sand matrix were measured using spectral induced polarization (SIP). In addition, specific conductivity, pH, dissolved oxygen, and dielectric constant measurements of the solutions were also evaluated. The frequency range assessed was 0.091-12000Hz. The surfactants, which are typically used in the remediation of tetrachloroethylene, were Aerosol MA 80-I, Dowfax 8390, and Steol CS-330. The surfactants were mixed into solutions of both deionized and tap water at varying concentrations and injected into a closed system of silica sand. The surfactant treatments altered resistivity, specific conductivity, and pH …

Slip Heterogeneity On A Corrugated Fault, Phillip G. Resor, Vanessa E. Meer

Phillip G Resor

Slip heterogeneity reflects the fundamental physics of earthquake rupture and has been attributed to strong fault patches termed asperities or barriers. We propose that variations in fault-surface orientation due to slip-parallel corrugations may act as geometric asperities and barriers, generating variations in incremental (i.e. due to a single earthquake) slip across a fault surface. We evaluate this hypothesis using observations from the Arkitsa normal fault exposure in central Greece. A scan of the Arkitsa fault surface with 1-m spatial resolution and mm-scale precision reveals corrugations made up of 1–5 m wide synforms, antiforms, and nearly planar fault sections with long …