Geophysics and Seismology Commons^™

Geophysical Investigation Of Hot Springs In The Vicinity Of Shoshone, California, Felix Dziedzorm Ziwu

Open Access Theses & Dissertations

Magnetic and gravity surveys were conducted in the vicinity of Shoshone, California to test a hypothesis from investigating hotsprings within Tecopa and Saratoga which states that deep faults must intersect with a specific orientation relative to the regional stress field in order to create hot springs along the Amargosa River.

Three isolated basalt flows with different gravity and magnetic properties were identified near the Shoshone hot spring. Two of the flows have very low magnetic anomalies and the remaining one has a high magnetic anomaly. The high magnetic anomaly basalt flow also has a significantly higher Bouguer anomaly than the …

Seismic Reflection Exploration Of Geothermal Reservoir Atnaval Air Station (Nas) Fallon, Nevada, Alay Ghebremariam Gebregiorgis

Open Access Theses & Dissertations

The Primary objective of this study is to increase geologic and tectonic understanding of the geothermal resources at the Naval Air Station (NAS) Fallon, Nevada. The seismic reflection method is employed to study faults, fractures and other tectonic structures in the subsurface in order to identify geothermal drill targets. The efficiency of geothermal systems is strongly dependent on water circulation. Discrete faults may be permeable and provide pathways for water flow depending on the fracture density. It is therefore desirable to detect and map faults and fracture zones and characterize their physical properties when evaluating a geothermal prospect.

The seismic …

Estimating Variations In Locking Depth For The Mojave Segment Of The San Andreas Fault Over The Past 1500 Years From Paleoseismic Stress Drop, Teira Solis

Open Access Theses & Dissertations

The most fundamental model for characterizing earthquake occurrence [Reid, 1910] assumes a constant stress accumulation rate on a locked fault segment, which eventually fails at a threshold stress level. While this model provides a conceptual framework for investigating the conditions that prepare a fault for failure, there is little evidence that faults rupture periodically or at a uniform threshold stress. Moreover, this model fails to explain the large differences in earthquake recurrence intervals and paleoseismic slip for segments of major fault systems: why do some faults rupture on the order of 10's of years, while others require 100's of years …

Integrated Geological And Geophysical Studies Of The Indio Mountains And Hueco Bolson, West Texas, Pawan Budhathoki

Open Access Theses & Dissertations

This Dissertation consists of two different projects. The first project describes the results of an outcrop based sequence stratigraphic study of the Albian Cox Sandstone in the Indio Mountains of west Texas. The depositional environment of the Cox Sandstone ranges from shallow marine to the coastal plain deposited in four sequences where sequence 1 and sequence 2 consists of transgressive system tracts (TST) followed by highstand system tracts (HST). The highstand system tract (HST) is missing in sequence 3 and the transgressive systems tract is missing in sequence 4. The Cox changes in thickness from 320 m in the northern …

Software Development For A 3d Gravity Inversion And Application To Study Of The Border Ranges Fault System, South-Central Alaska, Rolando Cardenas

Open Access Theses & Dissertations

The Border Ranges Fault System (BRFS) bounds the Cook Inlet and Susitna Basins, and is an important petroleum province within south-central Alaska. A primary goal of our research is to test several plausible models of structure along the BRFS using a novel three-dimensional inversion technique utilizing gravity data, constrained with other geophysical, borehole and surface geological information. This research involves the development of 3D inversion modeling software using C++ Builder from Embarcadero's XE2 Suite. The novel inversion approach directly models known geology with a priori uncertainties assigned to the geologic model to allow researchers to compare alternative interpretations. This technique …

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. …

A Block Operator Splitting Method For Heterogeneous Multiscale Poroelasticity, Paul M. Delgado

Open Access Theses & Dissertations

Traditional models of poroelastic deformation in porous media assume relatively homogeneous material properties such that macroscopic constitutive relations lead to accurate results. Many realistic applications involve heterogeneous material properties whose oscillatory nature require multiscale methods to balance accuracy and efficiency in computation.

The current study develops a multiscale method for poroelastic deformation based on a fixed point iteration based operator splitting method and a heterogeneous multiscale method using finite volume and direct stiffness methods. To characterize the convergence

of the operator splitting method, we use a numerical root finding algorithm to determine a threshold surface in a non-dimensional parameter space …

On Different Techniques For The Calculation Of Bouguer Gravity Anomalies For Joint Inversion And Model Fusion Of Geophysical Data In The Rio Grande Rift, Azucena Zamora

Open Access Theses & Dissertations

Density variations in the Earth result from different material properties, which reflect the tectonic processes attributed to a region. Density variations can be identified through measurable material properties, such as seismic velocities, gravity field, magnetic field, etc. Gravity anomaly inversions are particularly sensitive to density variations but suffer from significant non-uniqueness. However, using inverse models with gravity Bouguer anomalies and other geophysical data, we can determine three dimensional structural and geological properties of the given area. We explore different techniques for the calculation of Bouguer gravity anomalies for their use in joint inversion of multiple geophysical data sets and a …

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 …

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 …

Software Development For A Three-Dimensional Gravity Inversion And Application To Study Of The Border Ranges Fault System, South-Central Alaska, Rolando Cardenas

Open Access Theses & Dissertations

The Border Ranges Fault System (BRFS) bounds the Cook Inlet and Susitna Basins, an important petroleum province within south-central Alaska. A primary goal in the research is to test several plausible models of structure along the Border Ranges Fault System using a novel three-dimensional inversion utilizing gravity and magnetic data, constrained with other geophysical, borehole and surface geological information. This research involves the development of inversion modeling software using a Borland C++ compiler as part of the Rapid Application Development (RAD) Studio. The novel inversion approach directly models known geology, and "a priori" uncertainties on the geologic model to allow …

The East Jhomolari Fault System And The Timing Of East-West Extension In Northwest Bhutan, John Matthew Cannon

Open Access Theses & Dissertations

This investigation documents a little known, regionally significant, high angle, southeast dipping, system of normal faults in northwest Bhutan, the East Jhomolari Fault System (EJFS). The EJFS trends parallel to the Yadong Gulu rift (YG) and can be traced from Mt. Jhomolari to the northern border with Tibet. This fault zone has been demonstrably active since the last glacial maximum and there is geomorphic evidence of Holocene activity on some fault segments. The structurally lowest EJFS fault, the Lingshi fault appears on some published maps, but the full geographic extent, displacement, onset of faulting, and most recent activity have not …

Gpu Based Parallel Smoothing Of Seismic Tomography Models, Ivan Gris

Open Access Theses & Dissertations

Three-dimensional models of the velocity structure of the Earth's crust are an important and relevant factor for several types of analyses across disciplines. Crustal velocity models are also commonly used to analyze and search for different materials of interest or to determine and differentiate many aspects of life on Earth during different eras.

Seismic tomography techniques, both in two and three dimensions, perform image reconstruction of the crust of the Earth. Seismic tomography algorithms can calculate crustal velocity structure through inversion of traveltimes of seismic waves produced by natural events, such as earthquakes, or controlled source experiments, such as explosions. …

Evidence Of Ancient Rifts Beneath Texas, Keisuke Irie

Open Access Theses & Dissertations

Continental rifts are defined as geological features where Earth's lithosphere is pulled away by surface expansion of the Earth. Their physiographic features include linear rift valleys associated with active volcanism. Many rifts fail to split a continent and ancient rifts that failed to split can be found by using seismic waves to image these ancient structures. Using seismic data collected by EarthScope USArray stations in Texas, teleseismic receiver functions was calculated and utilized surface wave dispersion curves to simultaneously invert for the 2D velocity structure beneath each seismic station. EarthScope is a scientific program funded by NSF that provides geophysical …

An Integrated Geological And Geophysical Study Of The Fresh And Brackish Water Boundary In The Hueco Bolson, West Texas, Sandy Stephanie Marrufo

Open Access Theses & Dissertations

The Hueco Bolson in West Texas is located in the Rio Grande rift basin and provides water to El Paso County, Texas and Juarez, Mexico. El Paso Water Utilities (EPWU) drilled many wells up to 1000 ft (305) m into this aquifer, which provide 40% of El Paso's water supply. Stratigraphy and sedimentation in active extensional basins have received little study because they are usually buried and this research helped document these processes. The study area within the West Texas region of the Hueco Bolson Aquifer (HBA) lies within a transition zone between the fresh and brackish water sections of …

Joint Geophysical Data Analysis For Geothermal Energy Exploration, Antony Munika Wamalwa

Open Access Theses & Dissertations

Geophysical data modelling often yields non-unique results and hence the interpretation of the resulting models in terms of underlying geological units and structures is not a straightforward problem. However, if multiple datasets are available for a region of study, an integrated interpretation of models for each of the geophysical data may results to a more realistic geological description. This study not only demonstrates the strength of resistivity analysis for geothermal fields but also the gains from interpreting resistivity data together with other geophysical data such as gravity and seismic data. Various geothermal fields have been examined in this study which …

Evaluating Suspended Dust Particulate Matter From Anthropogenically - Altered Lands, Roberto Velarde

Open Access Theses & Dissertations

Substantial dust loads are transported from drylands including the Saharan, Asian, and Chihuahuan Desert deposits by localized to planetary-scale processes to nearby and distal sites. These dusts may carry harmful constituents. To evaluate dust movement patterns and characteristics relative to carried constituents, three studies are presented comprising (A) Localized displacement of uranium and progeny radionuclides from high-grade uranium ore storage piles at Peña Blanca, Chihuahua, Mexico; (B) Long-distance transport of plutonium via Saharan and Asian aeolian pathways; and (C) Dust movement patterns in military maneuvering and non-maneuvering areas at White Sands Missile Range (WSMR), New Mexico. Study (A) evaluated surface …

An Investigation Of The Seismic Hazards Of The El Paso-Juarez Region: The Nature And Extent Of The Southern East Franklin Mountains Fault Zone, Victor Manuel Avila

Open Access Theses & Dissertations

ABSTRACT

The El Paso-Ciudad Juarez Region is situated at the southern end of the active Rio Grande Rift within the Mesilla and Hueco basins. The Hueco basin is separated from the eastern Franklin Mountains by a prominent fault, the Eastern Boundary Fault. Studies of this fault have revealed fault scarps that displace Quaternary deposits (Keaton et al., 1995; Raney and Collins, 1990; Lovejoy, 1976). This fault is cataloged as an active fault in the National Seismic Hazard Map with an estimated slip rate of 0.1 mm/yr. A fault with similar characteristics as the Eastern Boundary Fault extends further to the …

Seismological Studies In South-Central Alaska And Northern Mexico, Oscar Mario Romero De La Cruz

Open Access Theses & Dissertations

The work in this study is focused on two different areas, south-central Alaska and northern Mexico. In the first study area, I calculated dynamic stress drops for moderate sized earthquakes and performed receiver function analyses. The goal of the stress drop studies was to determine if events occurring within the more strongly coupled portion of the subducting slab have higher stress drops. My results shows that higher stress drops correspond to the locked and strongly coupled region in Prince William Sound, and lower stress drops are associated with the Cook Inlet region, a zone of relaxation of the plate interface. …

On Constrained Optimization Schemes For Joint Inversion Of Geophysical Datasets, Uram Anibal Sosa Aguirre

Open Access Theses & Dissertations

In the area of geological sciences, there exist several experimental techniques used to advance in the understanding of the Earth. We implement a joint inversion least-squares (LSQ) algorithm to characterize one dimensional Earth's structure by using seismic shear wave velocities as a model parameter. We use two geophysical datasets sensitive to shear velocities, namely Receiver Function and Surface Wave dispersion velocity observations, with a choice of an optimization method: Truncated Singular Value Decomposition (TSVD) or Primal-Dual Interior-Point (PDIP). The TSVD and the PDIP methods solve a regularized unconstrained and a constrained minimization problem, respectively. Both techniques include bounds into the …

Studies Of Earthquakes Stress Drops, Seismic Scattering, And Dynamic Triggering In North America, Christian Rene Escudero Ayala

Open Access Theses & Dissertations

I use the Relative Source Time Function (RSTF) method to determine the source properties of earthquakes within southeastern Alaska-northwestern Canada in a first part of the project, and earthquakes within the Denali fault in a second part. I deconvolve a small event P-arrival signal from a larger event by the following method: select arrivals with a tapered cosine window, fast fourier transform to obtain the spectrum, apply water level deconvolution technique, and bandpass filter before inverse transforming the result to obtain the RSTF. I compare the source processes of earthquakes within the area to determine stress drop differences to determine …

Seismic Investigation Of The Southern Rio Grande Rift, Lennox Emmanuel Thompson

Open Access Theses & Dissertations

Competing models exist to explain what caused the Earth's crust to spread apart 29 million years ago to create a region known today as the Rio Grande Rift (RGR). The RGR extends from central Colorado through New Mexico to northern Mexico, near El Paso. The RGR has different geologic features that distinguish it from most other valleys (e.g., the RGR was not cut by a river nor does a river branch upstream). A growing body of evidence shows that geologic activity still occurs in the RGR, with a continuation of faulting, seismicity and widening at a small rate of about …

Bagc.M: Three Dimensional Gravity Modeling Software With An Application In Death Valley, Ca, Brian Eugene Eslick

Open Access Theses & Dissertations

Basin Anomaly Gravity Calculator (BAGC.m) is a 3D interactive gravity modeling package designed to create, edit, and calculate the gravitational attraction of basin models entirely within the MATLABTM environment. Gravity anomalies are calculated using the Rectangular Prism Method (Bott, 1960; Kane, 1962; and Plouff, 1966) which subdivides earth models into regularly spaced rectangular prisms. This approach requires large 3D matrices to store most realistic earth models. The process of model editing is simplified by storing basins as 2D gridded files which define the depth to the boundary between basement rock and sedimentary fill for each model cell. In order to …