Geophysics and Seismology Commons^™

Application Of Low-Pass Directional Filtering Techniques To Aeromagnetic Data In Order To Better Determine Relationships Between Seismicity And Deep Structure Anomalies Within Central Alaska Along The Denali Fault, Shane M. Schinagel^, Diane I. Doser*

COURI Symposium Abstracts, Spring 2012

No abstract provided.

Reservoir Potential Of Sands Formed In Glaciomarine Environments: An Analog Study Based On Cenozoic Examples From Mcmurdo Sound, Antarctica, Christopher R. Fielding, Brian A. Blackstone, Tracy D. Frank, Zi Gui

Department of Earth and Atmospheric Sciences: Faculty Publications

This paper provides documentation of unexpectedly high-reservoir-quality glaciomarine sands found in the Cenozoic succession beneath McMurdo Sound, Antarctica, as an analogue study for evaluations of hydrocarbon prospectivity in basins elsewhere. The Oligocene to Lower Miocene succession of the Victoria Land Basin, an extant portion of the West Antarctic Rift System, comprises diamictites, mudrocks, and sandstones with minor conglomerates. These lithologies are arranged in repetitive stacking patterns (cycles), interpreted to record repeated advance and retreat of glaciers into and out of the basin, with attendant eustatic and isostatic effects. Phases of ice retreat within the cycles comprise an array of mudrocks, …

Magmatic Rifting And Active Volcanism Conference, Afar Rift Consortium, Anne E. Egger, Tyrone Rooney, Donna Shillington

Geological Sciences Faculty Scholarship

The Magmatic Rifting and Active Volcanism (MRAV) Conference took place in Addis Ababa, Ethiopia January 10-13, 2012, convened by members of the Afar Rift Consortium, an international team investigating active magmatism and deformation in the Afar region. Over 200 people from around the world attended. The conference participants primarily presented the results of work on ongoing rifting processes in Afar, but work was also presented that addressed other portions of the East African Rift, comparable rift settings elsewhere, rifting processes in general, and the hazards and resources associated with the East African Rift.

The scientific program outlined the current state …

Hillslope Asymmetry Maps Reveal Widespread, Multi-Scale Organization, Michael J. Poulos, Jennifer L. Pierce, Alejandro N. Flores, Shawn G. Benner

Geosciences Faculty Publications and Presentations

Hillslope asymmetry is the condition in which oppositely-facing hillslopes within an area have differing average slope angles, and indicates aspect-related variability in hillslope evolution. As such, the presence, orientation and magnitude of asymmetry may be a useful diagnostic for understanding process dominance. We present a new method for quantifying and mapping the spatial distribution of hillslope asymmetry across large areas. Resulting maps for the American Cordillera of the Western Hemisphere and the western United States reveal that hillslope asymmetry is widespread, with distinct trends at continental to drainage scales. Spatial patterns of asymmetry correlate with latitude along the American Cordillera, …

Size And Exhumation Rate Of Ultrahigh-Pressure Terranes Linked To Orogenic Stage, Andrew R.C. Kylander-Clark, Bradley R. Hacker, Chris G. Mattinson

All Faculty Scholarship for the College of the Sciences

A growing set of data indicates a stark contrast between the evolution of two types of ultrahigh-pressure (UHP) terranes: large terranes that evolved slowly (over 10–30 Myr), and small terranes that formed and were exhumed on timescales of < 10 Myr. Here we compare the characteristics – area, thickness, formation rate, exhumation rate, age, and tectonic setting – of these two endmember types of UHP terrane worldwide. We suggest that the two UHP terrane types may form during different orogenic stages because of variations in the buoyancy and traction forces due to different proportions of subducting crust and mantle lithosphere or to different rates of subduction. The initial stages of continent collision involve the subduction of thin continental crust or microcontinents, and thus tectonic forces are dominated by the density of the oceanic slab; subduction rates are rapid and subduction angles are initially steep. However, as collision matures, thicker and larger pieces of continental material are subducted, and the positive buoyancy of the down-going slab becomes more prominent; subduction angles become gentle and convergence slows. Assessing the validity of this hypothesis is critical to understanding the physical and chemical evolution of Earth's crust and mantle.

Included here is the post-print copy of this article. The final publication is available via ScienceDirect at http://www.sciencedirect.com/science/article/pii/S0012821X11007564

Mean Atlantic Meridional Overturning Circulation Across 26.5° N From Eddy-Resolving Simulations Compared To Observations, Xiaobiao Xu, William J. Schmitz Jr., Harley E. Hurlburt, Patrick J. Hogan

Faculty Publications

Observations along 26.5 degrees N are used to examine the time mean structure of the Atlantic meridional overturning circulation (AMOC) in eddy-resolving simulations with the Hybrid Coordinate Ocean Model (HYCOM). The model results yield a 5 year mean AMOC transport of 18.2 Sv, compared to 18.4 Sv based on data. The modeled northward limb of the AMOC has a vertical structure similar to observations. The southward limb is shallower than observed but deeper than other ocean general circulation models and includes a secondary transport maximum near 4000 m corresponding to Nordic Seas Overflow Water. The modeled flow through the Florida …

Georadar-Derived Estimates Of Firn Density In The Percolation Zone, Western Greenland Ice Sheet, Joel Brown, John Bradford, Joel Harper, W. Tad Pfeffer, Neil Humphrey, Ellen Mosley-Thompson

CGISS Publications and Presentations

Greater understanding of variations in firn densification is needed to distinguish between dynamic and melt-driven elevation changes on the Greenland ice sheet. This is especially true in Greenland’s percolation zone, where firn density profiles are poorly documented because few ice cores are extracted in regions with surface melt. We used georadar to investigate firn density variations with depth along a ~70 km transect through a portion of the accumulation area in western Greenland that partially melts. We estimated electromagnetic wave velocity by inverting reflection traveltimes picked from common midpoint gathers. We followed a procedure designed to find the simplest velocity …

Using Auto- And Cross-Correlations From Seismic Noise To Monitor Velocity Changes At Villarrica Volcano, Chile, Kathleen F. Mckee

Dissertations, Master's Theses and Master's Reports - Open

We used the Green's functions from auto-correlations and cross-correlations of seismic ambient noise to monitor temporal velocity changes in the subsurface at Villarrica volcano in the Southern Andes of Chile. Campaigns were conducted from March to October 2010 and February to April 2011 with 8 broadband and 6 short-period stations, respectively. We prepared the data by removing the instrument response, normalizing with a root-mean-square method, whitening the spectra, and filtering from 1 to 10 Hz. This frequency band was chosen based on the relatively high background noise level in that range. Hour-long auto- and cross-correlations were computed and the Green's …

Infrasound As Upper Atmospheric Monitor, Jelle Daniel Assink

Electronic Theses and Dissertations

Understanding and specification of the higher altitudes of the atmosphere with global coverage over all local times is hampered by the challenges of obtaining direct measurements in the upper atmosphere. Methods to measure the properties of the atmosphere above the stratopause is an active area of scientific research. In this thesis, we revisit the use of infrasound as a passive remote sensing technique for the upper atmosphere. Signals from the Tungurahua volcano in Ecuador are used to investigate the behavior of the upper atmosphere. Depending on the atmospheric conditions, stratospheric, mesospheric and thermospheric arrivals are observed during intervals of explosive …

Depositional And Tectonic Controls On Architecture Of The Carbonate Platform Of Upper Paleocene Khalifah Formation, Sirte Basin, Central Libya, Salah Abdurzak Shaniba

Masters Theses

"The Paleocene strata in Sirte Basin, Libya, contain major oil and gas accumulations in a variety of lithofacies of reef and bioherm carbonate depositional environments. The Upper Paleocene Khalifah Formation, which is one of the main reservoirs containing about 30% of the oil reserves of the Sirte Basin, is composed of shallowing-upward and carbonate platform deposits and is capped by open marine shale deposits formed during a marine transgression. Well and seismic data are used to interpret the depositional environments and identify upward shallowing and deepening trends in the formation. In the study area, Mabruk oil field in northwestern Sirte …

Sequence Stratigraphy And Onlap History Of The Donets Basin, Ukraine: Insight Into Carboniferous Icehouse Dynamics, J. M. Eros, I. P. Montañez, D. A. Osleger, Vladimir Davydov, T. I. Nemyrovska, V. I. Poletaev, M. V. Zhykalyak

Geosciences Faculty Publications and Presentations

The degree to which Permo-Carboniferous cyclothemic successions archive evidence for long-term variations in ice volume during the Late Paleozoic Ice Age is insufficiently resolved. Here we develop the sequence stratigraphy and onlap-offlap history for a 33-my interval of the Carboniferous using the U-Pb calibrated succession of the Donets Basin, Ukraine, in order to assess the relationship between sea-level, high-latitude changes in glacial extent, and climate. Integrated subsurface and outcrop data permit meter-scale correlation of 242 biostratigraphically constrained limestones and coals, and in turn individual cyclothems, across ~250 km of the Donets Basin. Rapid uniform subsidence and basinwide continuity of marker …

Partitioning Of Rare Earth And High Field Strength Elements Between Titanite And Phonolitic Liquid, Paul H. Olin, John A. Wolff

Geosciences Faculty Publications and Presentations

We present the results of a LA–ICPMS study of titanites and associated glasses from the mixed-magma phonolitic Fasnia Member of the Diego Hernández Formation, Tenerife, Canary Islands. We employ a method of identifying equilibrium mineral–melt pairs from natural samples using REE contents and a linear form of the lattice strain model equation (Blundy and Wood, 1994), where the Young's modulus (E_M) for the 7-fold coordinated site is an output variable. For felsic magmas that contain crystals potentially derived from a variety of environments within the system, this approach is more rigorous than the use of solely textural criteria …

Near-Surface Imaging Of A Hydrogeothermal System At Mount Princeton, Colorado Using 3d Seismic, Self-Potential, And Dc Resistivity Data, Andrew P. Lamb, Lee M. Liberty, Kasper Van Wijk, André Revil, Chuck Diggins

CGISS Publications and Presentations

The Upper Arkansas Valley in the Rocky Mountains of central Colorado is the northernmost extensional basin of the Rio Grande Rift(Figure 1). The valley is a half graben bordered to the east and west by the Mosquito and Sawatch ranges,respectively. The Sawatch Range is home to the Collegiate Peaks,which include some of the highest summits in the Rocky Mountains. Some Collegiate Peaks over 4250 m (14,000 ft) from north to south include Mount Harvard, Mount Yale, Mount Princeton,and Mount Antero. The Sawatch range-front normal fault strikes north-northwest along the eastern margin of the Collegiate Peaks and is characterized by a …

Geodynamic Constraints On The Flow Of Samoan-Plume Mantle Into The Northern Lau Basin, Nathan Katsiaficas

Honors Theses

The northernmost portion of the Lau basin, South Pacific, features numerous geochemical and geophysical anomalies. These include: (1) a strong latitudinal gradient in the trace element and isotopic (Sr-Nd-Pb) enrichment of basalts erupted along the various back-arc spreading centers (BASCs) within the basin, (2) high 3He/4He (up to 28 times RA, where RA, the ratio in Earth's atmosphere, is 1.4 x 10-6) in basalts erupted along some portions of the BASCs (e.g., Rochambeau Bank), and (3) the presence of trench-parallel shear-wave splitting near the Tonga arc. The occurrence of these anomalies has been attributed to the southward flow of mantle …

Sh-Wave Refraction And Reflection Investigation Of Quaternary Geology―Central United States Seismic Observatory, Carrington L. Wright

Theses and Dissertations--Earth and Environmental Sciences

The Central United States Seismic Observatory (CUSSO) consists of an array of vertical strong motion accelerometers and medium period seismometers that penetrate 585 m into the Mississippi Embayment sediments and terminates into Paleozoic bedrock. The array is located in the New Madrid Seismic Zone within the upper embayment. The thick unconsolidated Quaternary sediments have the potential to influence strong motions; understanding how these sediments affect ground motion is the goal of the CUSSO array. Nine SH-wave refraction and five P-wave common midpoint reflection surveys were collected within a 1 km radius around the CUSSO borehole in order to characterize the …

Using Geophysics To Evaluate Levee Stability, Laura Mcconnell Dalton

Electronic Theses and Dissertations

Shallow slough slides have occurred along the river \side slope of Mississippi River Levees for over sixty years. Shallow slough slides also occur along smaller levees that protect tributaries of the Mississippi River. This investigation takes place along a section of the Coldwater River Levee, a tributary levee of the Mississippi River. Field observation, soil samples, and geophysical data were collected at two field sites located on the border of Tate and Tunica County, MS. The first site consists of a developed shallow slough slide that had occurred that has not yet been repaired and the second site is a …

Use Of Georphysics To Map Subsurface Features At Levee Seepage Locaitons, Thomas Chapman Brackett

Electronic Theses and Dissertations

The Great Flood of 2011 caused moderate to severe seepage and piping along the Mississippi River levees in Northwest Mississippi. The aim of this thesis was to implement geophysical techniques at two seepage locations in order to give a better understanding of the causes of underseepage and information on how to mitigate the problem. Sites near Rena Lara in Coahoma County and near Francis in Bolivar County were chosen to conduct this survey. Electrical Resistivity Tomography (ERT) and Electromagnetic Induction (EM) surveys were conducted on and adjacent to levees to identify seepage pathways and any dominant geological features at the …

Seismic Reflection Study Of The East Potrillo Fault, Southwestern Dona Ana County, New Mexico, Shane Alan Carley

Open Access Theses & Dissertations

The East Potrillo Mountains are located just north of the U.S.-Mexico border in southwestern Dona Ana County, New Mexico. Laramide and Rio Grande rift deformation has formed low-angle and high-angle Tertiary normal faults that are exposed in the area. Along the east flank of the range is the East Potrillo Fault identified on the surface as a north-striking scarp. Fault scarps associated with the East Potrillo Fault have been dated using slope degradation models and they range between 56 ka and 377 ka in age. Offset of geomorphic surfaces interpreted to be tectonic terraces records at least four earthquakes over …

Effectiveness Of Four Water-Bearing Zones Of The Glacierized Basin In Meltwater Runoff Modeling, Umesh K. Haritashya

Department of Earth, Environment and Sustainability Faculty Publications

Meltwater runoff modeling from glacierized basins needs several input data, including total meltwater contributing area. This study utilizes optical remote sensing data to assess glacierized basins in the central Himalayas where snow and glaciers contribute substantially to the water resources. Result shows that there are four main water-bearing zones in the basin: (a) dry snow, (b) wet snow, (c) exposed glacial ice, and (d) debris-covered glacial ice, and it is possible to differentiate and map these zones and their spatio-temporal variations from satellite sensor data. These zones can then be incorporated in meltwater runoff modeling as separate entities because they …

Could Satellite Altimetry Have Improved Early Detection And Warning Of The 2011 Tohoku Tsunami?, B. D. Hamlington, R. R. Leben, O. A. Godin, E. Gica, V. V. Titov, B. J. Haines, S. D. Desai

CCPO Publications

The 2011 Tohoku tsunami devastated Japan and affected coastal populations all around the Pacific Ocean. Accurate early warning of an impending tsunami requires the detection of the tsunami in the open ocean. While the lead-time was not sufficient for use in warning coastal populations in Japan, satellite altimetry observations of the tsunami could have been used to improve predictions and warnings for other affected areas. By comparing to both model results and historical satellite altimeter data, we use near-real-time satellite altimeter measurements to demonstrate the potential for detecting the 2011 Tohoku tsunami within a few hours of the tsunami being …