Geophysics and Seismology Commons^™

Petrogenetic Relationship Of The Postcaldera Eruptions Of Mount Mazama, Crater Lake, Oregon; Evolution Of A Sub-Volcanic Magma Chamber Following A Large Silicic Eruption, Michelle Leanna Tebbe

All Master's Theses

Mount Mazama is the volcanic edifice that cataclysmically erupted ~503 km of relatively homogeneous rhyodacite lava ~ 7,700 years ago, forming the caldera known as Crater Lake. Within a few hundred years, andesitic eruptions built three distinct volcanic edifices on the floor of Crater Lake; ~ 3000 years later, rhyodacite eruptions formed a dome (Bacon et al., 2002). How magmatic systems evolve following a shallow, relatively large silicic eruption is the focus of this study. In situ geochemical analysis coupled with high-resolution textural images of plagioclase crystals in the four postcaldera volcanic edifices were used to identify distinct crystal populations …

Documenting Magnatic Processes At Filicudi Island, Aeolian Arc, Italy: Integrating Quantitative Modeling And Plagioclase Textural And In Situ Compositional Data, Michelle Harris

All Master's Theses

Documenting the physiochemical processes that influence magma composition is critical for forecasting eruption styles and managing volcanic hazards. Compositional diversity of magmas develops through recharge, assimilation, and fractional crystallization (RAFC) within subvolcanic magma reservoirs. Integration of MELTS modeling, whole rock, plagioclase textural and in situ elemental and isotopic data from Filicudi Island, Italy allow documentation of the roles and relative chronology that RAFC played in the magmatic evolution and elucidates aspects of the magma plumbing system structure.

Results indicate a polybaric magma plumbing system with deeper (3.5-4 kilobars) and shallower (0.5-1.2 kilobars) storage regions. Within the deeper system, FC acted …

Three-Dimensional Deformation And Stress Models Of The Death Valley And San Andreas Fault Zones, Cecilia Del Pardo

Open Access Theses & Dissertations

Crustal deformation studies of tectonic motions have been the topic of many scientific investigations, as they can provide critical information about how tectonic structures shape and deform the Earth. While crustal deformation studies using observational data alone can provide a great deal of information about how the Earth is presently deforming, it is standard practice to implement mathematical and physics-based models to investigate the underlying causes of deformation in the crust. These models, constrained by geological, geodetic and seismic data, have successfully contributed key constraints of ongoing deformation processes and have provided predictions of past and future tectonic behavior of …

San Miguel Volcanic Seismicity And Structure In Central America: Insight Into The Physical Processes Of Volcanoes, Ezer Patlan

Open Access Theses & Dissertations

San Miguel volcano lies near the city of San Miguel, El Salvador (13.43°N, 88.26°W). An active stratovolcano, it presents a significant natural hazard for the city of San Miguel. In general, the internal state and activity of volcanoes like San Miguel remains an important component to understanding volcanic hazards. The main technology for addressing volcanic hazards and associated processes is through the analysis of data collected from the deployment of seismic sensors that record ground motion. Six seismic stations were deployed by UTEP around San Miguel volcano during the 2007-2008 the time period to define internal structure or magmatic plumbing …

Vertical Deformation Along The San Andreas Fault, Garrett Thornton

Open Access Theses & Dissertations

There have been numerous M 6+ earthquakes along the San Andreas Fault System (SAFS) (Schwartz et al., 1984) (Figure. 1.1) in the historical past. These rupture events have created millions of dollars worth of damage, and have been responsible for multiple lives lost. An improved understanding of the motions and crustal characteristics along the SAFS can lead to better hazard mitigation (Bakun et al., 2005). Horizontal crustal motions of the SAFS have been widely studied and applied to seismic hazard models (WGCEP, 2007), however vertical motions are not often utilized due to their complicated origin and sometimes large uncertainties. This …

Dynamic Earthquake Triggering In The Continental U.S., Ibrahim Cerda

Open Access Theses & Dissertations

Seismological studies have classified the changes in field stress required to trigger remote earthquakes into two basic types: static and dynamic triggering. Static triggering mainly originates from geological faults already present in certain tectonic environments and they could be originated due to continental crust, subduction zones or even from a highly seismicity zone. Dynamic triggering occurs when an event (earthquake) has been induced by the passing of seismic waves from a large main shock located at least two or more fault lengths from the epicenter of the main shock. This study investigates details of dynamic triggering not seen in previous …

Evaluating Hydrocarbon Source Rock For Unconventional Shale Oil Play From Seismic And Well Log Data; Kingak Shale, North Slope, Alaska, Sarah Elisabeth Leedberg

Open Access Theses & Dissertations

It has been proposed that Acoustic impedance (AI) responses can be used to estimate total organic carbon (TOC) within thick, clay rich shale. The purpose of this work is to evaluate the effectiveness of the AI inversion technique, and establish a methodology that can be applied to other basins. The Kingak Formation (lower Jurassic to early Cretaceous), located on the North Slope of Alaska, has been extensively evaluated for its unconventional potential. The Kingak is shale and is known to have greater than 30 percent clay. Because clay has ductile properties it makes it difficult to stimulate a well through …

Numerical Modeling Of Tectonics And Fault Activity Of Icy Satellites, John Olgin

Open Access Theses & Dissertations

Enceladus, one of the satellites of Saturn, exhibits evidence of recent fault activity, which may be due to gravitational fluctuations, or tidal stresses, generated by its orbit around Saturn. Recent Cassini spacecraft observations of Enceladus reveal water-ice plume activity at the south polar region, originating from locations that correlate with four geologically young, linear fracture-like features, named the "tiger stripes". It is the goal of this investigation to determine the ideal geophysical and geological factors (e.g., fault depths, frictional coefficients, ice layer thickness, ocean layer thickness, tidal stress sources) that support fault activity on Enceladus. The core of this work …

Propagation Of Interval And Probabilistic Uncertainty In Cyberinfrastructure-Related Data Processing And Data Fusion, Christian Servin

Open Access Theses & Dissertations

Data uncertainty affects the results of data processing. So, it is necessary to find out how the data uncertainty propagates into the uncertainty of the results of data processing.

This problem is especially important when cyberinfrastructure enables us to process large amounts of heterogeneous data.

In the ideal world, we should have an accurate description of data

uncertainty, and well-justified efficient algorithms to propagate this uncertainty. In practice, we are often not yet in this ideal situation:

the description of uncertainty is often only approximate, and the algorithms for uncertainty propagation are often not well-justified and not very computationally efficient. …

Constrained Optimization Schemes For Geophysical Inversion Of Seismic Data, Uram Anibal Sosa Aguirre

Open Access Theses & Dissertations

Many experimental techniques in geophysics advance the understanding of Earth processes by estimating and interpreting Earth structure (e.g., velocity and/or density structure). These techniques use dierent types of geophysical data which can be collected and analyzed separately, sometimes resulting in inconsistent models of the Earth depending on data quality, methods and assumptions made. This dissertation presents two approaches for geophysical inversion of seismic data based on constrained optimization. In one approach we expand a one dimensional (1-D) joint inversion least-squares (LSQ) algorithm by introducing a constrained optimization methodology. Then we use the 1-D inversion results to produce 3-D Earth velocity …

Geophysical And Geological Analysis Of The Collingwood Member Of The Trenton Formation, Ryan M. Banas

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

The Collingwood Member is a mid to late Ordovician self-sourced reservoir deposited across the northern Michigan Basin and parts of Ontario, Canada. Although it had been previously studied in Canada, there has been relatively little data available from the Michigan subsurface. Recent commercial interest in the Collingwood has resulted in the drilling and production of several wells in the state of Michigan.

An analysis of core samples, measured laboratory data, and petrophysical logs has yielded both a quantitative and qualitative understanding of the formation in the Michigan Basin. The Collingwood is a low permeability and low porosity carbonate package that …

The Reduction Of Storm Surge By Vegetation Canopies: Three-Dimensional Simulations, Y. Peter Sheng, Andrew Lapetina, Gangfeng Ma

Civil & Environmental Engineering Faculty Publications

Significant buffering of storm surges by vegetation canopies has been suggested by limited observations and simple numerical studies, particularly following recent Hurricanes Katrina, Rita, and Wilma. Here we simulate storm surge and inundation over idealized topographies using a three-dimensional vegetation-resolving storm surge model coupled to a shallow water wave model and show that a sufficiently wide and tall vegetation canopy reduces inundation on land by 5 to 40 percent, depending upon various storm and canopy parameters. Effectiveness of the vegetation in dissipating storm surge and inundation depends on the intensity and forward speed of the hurricane, as well as the …

Mantle Flow And Lithosphere-Asthenosphere Coupling Beneath The Southwestern Edge Of The North American Craton: Constraints From Shear-Wave Splitting Measurements, Hesham A. Refayee

Doctoral Dissertations

"High-quality broadband seismic data recorded by the USArray and other stations in the southwestern United States provide a unique opportunity to test different models of anisotropy-forming mechanisms in the vicinity of a cratonic edge. Systematic spatial variations of anisotropic characteristics are revealed by 3027 pairs of splitting parameters measured at 547 broadband seismic stations. The western and southern edges of the North American craton show edge-parallel fast directions with larger-than-normal splitting times, and the continental interior is characterized by smaller splitting times spatially consistent fast directions that are mostly parallel to the absolute plate motion direction of North America. Except …

Plate Kinematics Of The Afro-Arabian Rift System With An Emphasis On The Afar Depression, Helen Carrie Bottenberg

Doctoral Dissertations

This work utilizes the Four-Dimensional Plates (4DPlates) software, and Differential Interferometric Synthetic Aperture Radar (DInSAR) to examine plate-scale, regional-scale and local-scale kinematics of the Afro-Arabian Rift System with emphasis on the Afar Depression in Ethiopia. First, the 4DPlates is used to restore the Red Sea, the Gulf of Aden, the Afar Depression and the Main Ethiopian Rift to development of a new model that adopts two poles of rotation for Arabia. Second, the 4DPlates is used to model regional-scale and local-scale kinematics within the Afar Depression. Most plate reconstruction models of the Afro-Arabian Rift System relies on considering the Afar …

2d And 3d Imaging Of The Metamorphic Carbonates At Omalos Plateau/Polje, Crete, Greece By Employing Independent And Joint Inversion On Resistivity And Seismic Data, Hamdan Ali Hamdan Dr, Nikos Economou, Giorgos Kritikakis, Nikos Andronikidis, Emmanuil Manoutsoglou, Antonis Vafidis, Pangratis Pangratis, Georgina Apostolidou

International Journal of Speleology

A geophysical survey carried out at Omalos plateau in Chania, Western Crete, Greece employed seismic as well as electrical tomography methods in order to image karstic structures and the metamorphic carbonates (Tripali unit and Plattenkalk group) which are covered by post-Mesozoic deposits (terra rossa, clays, sands and gravels). The geoelectrical sections image the metamorphic carbonates which exhibit a highly irregular relief. At the central part of the plateau the thickness of post-Mesozoic deposits (terra rossa, clays, sands and gravels) ranges from 40-130 m. A 3D resistivity image was generated by inverting resistivity data collected on a grid to the south …

Collisional Reactivation Of Rift Margin Fracture Zones, Taiwan And The Taconic Allochthon, David C. Mirakian

Master's Theses

Chapter I. Transverse Topographic Development due to the Reactivation of a Partially-Subducted Fracture Zone: The Southwest Hsüehshan Range, Central Taiwan

Abstract — The southwest flank of the Hsüehshan Range is defined by a topographic break which cuts across regionally mapped structures in central Taiwan. The mountain front trends ~345°, slightly oblique to the Sanyi-Puli seismic zone which has been previously interpreted as a reactivated continental margin fracture zone. Structural data collected along the length of the topographic break reveal two populations of cross-cutting faults with distinct fault-zone materials and a series of southwest-plunging folds. Paleostress axes were reconstructed using the …

3-D Transient Hydraulic Tomography In Unconfined Aquifers With Fast Drainage Response, Michael Cardiff, Warren Barrash

CGISS Publications and Presentations

We investigate, through numerical experiments, the viability of three-dimensional transient hydraulic tomography (3DTHT) for identifying the spatial distribution of groundwater flow parameters (primarily, hydraulic conductivity K) in permeable, unconfined aquifers. To invert the large amount of transient data collected from 3DTHT surveys, we utilize an iterative geostatistical inversion strategy in which outer iterations progressively increase the number of data points fitted and inner iterations solve the quasi-linear geostatistical formulas of Kitanidis. In order to base our numerical experiments around realistic scenarios, we utilize pumping rates, geometries, and test lengths similar to those attainable during 3DTHT field campaigns performed at …

Hydrological Parameter Estimations From A Conservative Tracer Test With Variable-Density Effects At The Boise Hydrogeophysical Research Site, B. Dafflon, Warren Barrash, Michael Cardiff, T. C. Johnson

CGISS Publications and Presentations

Reliable predictions of groundwater flow and solute transport require an estimation of the detailed distribution of the parameters (e.g., hydraulic conductivity, effective porosity) controlling these processes. However, such parameters are difficult to estimate because of the inaccessibility and complexity of the subsurface. In this regard, developments in parameter estimation techniques and investigations of field experiments are still challenging and necessary to improve our understanding and the prediction of hydrological processes. Here we analyze a conservative tracer test conducted at the Boise Hydrogeophysical Research Site in 2001 in a heterogeneous unconfined fluvial aquifer. Some relevant characteristics of this test include: variable-density …

Co2 Sequestration In Basalt: Carbonate Mineralization And Fluid Substitution, Thomas L. Otheim, Ludmila Adam, Kasper Van Wijk, Michael L. Batzle, Travis Mcling, Robert Podgorney

CGISS Publications and Presentations

Geologicalsequestration of carbon dioxide in deep reservoirs may provide alarge-scale option for reducing the emissions of this gas intothe atmosphere. The effectiveness of sequestration depends on the storagecapacity and stability of the reservoir and risk of leakageinto the overburden. Reservoir rocks can react with a CO₂-watermixture, potentially resulting in the precipitation of minerals in theavailable matrix pore space and within pre-existing fractures. This inducedmineralization may form internal seals that could help mitigate theleakage of CO₂ into the overburden. For basaltic host rocks,carbonic acid partially dissolves minerals in the host rock, suchas the calcium plagioclase mineral, freeing various …

Effects Of High-Impedance-Contrast Boundary Upon Multi-Modal Seismic Surface Wave Data, Prajwol Tamrakar

UNLV Theses, Dissertations, Professional Papers, and Capstones

Synthetic studies and analyses of an experimental dataset were conducted to address the use of Rayleigh-type surface waves for estimation of shear wave velocity (VS) profiles of shallow bedrock sites. The shallow bedrock presents a high impedance contrast boundary which causes surface wave energy to be partitioned to higher modes. Idealized studies of hypothetical datasets and root-mean-squared calculations of error surfaces showed that if reliable dispersion data are available over a broad frequency spectrum, the VS profile can be recovered using the fundamental mode alone. However, when dispersion data are limited to a relatively narrow frequency band representing what might …