Geophysics and Seismology Commons^™

A Modified Delay-Time Method For Statics Estimation With The Virtual Refraction, T. Dylan Mikesell, Kasper Van Wijk, Elmer Ruigrok, Andrew Lamb, Thomas E. Blum

CGISS Publications and Presentations

Topography and near-surface heterogeneities lead to traveltime perturbations in surface land-seismic experiments. Usually, these perturbations are estimated and removed prior to further processing of the data. A common technique to estimate these perturbations is the delay-time method. We have developed the “modified delay-time method,” wherein we isolate the arrival times of the virtual refraction and estimate receiver-side delay times. The virtual refraction is a spurious arrival found in wavefields estimated by seismic interferometry. The new method removes the source term from the delay-time equation, is more robust in the presence of noise, and extends the lateral aperture compared to the …

Geogram 2012, David J. Keeling, Wku Department Of Geography And Geology

Earth, Environmental, and Atmospheric Sciences Publications

No abstract provided.

Extension Of The Spatial Autocorrelation (Spac) Method To Mixed-Component Correlations Of Surface Waves, Matthew M. Haney, T. Dylan Mikesell, Kasper Van Wijk, Hisashi Nakahara

CGISS Publications and Presentations

Using ambient seismic noise for imaging subsurface structure dates back to the development of the spatial autocorrelation (SPAC) method in the 1950s. We present a theoretical analysis of the SPAC method for multicomponent recordings of surface waves to determine the complete 3 × 3 matrix of correlations between all pairs of three-component motions, called the correlation matrix. In the case of isotropic incidence, when either Rayleigh or Love waves arrive from all directions with equal power, the only non-zero off-diagonal terms in the matrix are the vertical–radial (ZR) and radial–vertical (RZ) correlations in the presence of Rayleigh waves. Such combinations …

Northern Thailand Geothermal Resources And Development: A Review And 2012 Update, Fongsaward Suvagondha Singharajwarapan, Spencer H. Wood, Natthaporn Prommakorn, Lara Owens

Geosciences Faculty Publications and Presentations

Northern Thailand has 16 hot spring systems with surface temperatures near or greater than 80°C with potential for binary plant power generation. Presently only Fang system generates power from wells flowing a total of 8.3 1/s of 116°C water to a 300 kW single module Ormat binary plant. Current production is 150-250 KW, which potentially can be increased by constructing new wells and increasing flow by pumping. Of the other 15 systems, 4 are in national parks and not considered for development. Several of the hot springs systems have silica geothermometry >130°C suggesting significant undeveloped resources exist in northern Thailand. …

Probing Local Wind And Temperature Structure Using Infrasound From Volcan Villarrica (Chile), Jeffrey B. Johnson, J. Anderson, O. Marcillo, S. Arrowsmith

Geosciences Faculty Publications and Presentations

We use the continuous and intense (∼10⁷ W) infrasound produced by Volcan Villarrica (Chile) to invert for the local dynamic wind and temperature structure of the atmosphere. Infrasound arrays deployed in March 2011 at the summit (2826 m) and on the NNW flank (∼8 km distant at 825 m) were used to track infrasound propagation times and signal power. We model an atmosphere with vertically varying temperature and horizontal winds and use propagation times (ranging from 23 to 24 s) to invert for horizontal slowness (2.75–2.94 s/km) and average effective sound speeds (328–346 m/s) for NNW propagating infrasound. The …

Hydrologic Data Assimilation With A Hillslope-Scale-Resolving Model And L Band Radar Observations: Synthetic Experiments With The Ensemble Kalman Filter, Alejandro N. Flores, Rafael L. Bras, Dara Entekhabi

Geosciences Faculty Publications and Presentations

Soil moisture information is critical for applications like landslide susceptibility analysis and military trafficability assessment. Existing technologies cannot observe soil moisture at spatial scales of hillslopes (e.g., 10⁰ to 10² m) and over large areas (e.g., 10² to 10⁵ km²) with sufficiently high temporal coverage (e.g., days). Physics-based hydrologic models can simulate soil moisture at the necessary spatial and temporal scales, albeit with error. We develop and test a data assimilation framework based on the ensemble Kalman filter for constraining uncertain simulated high-resolution soil moisture fields to anticipated remote sensing products, specifically NASA's Soil …

Interseismic Strain Accumulation Along The Western Boundary Of The Indian Subcontinent, Walter Szeliga, Roger Bilham, Din Mohammad Kakar, Sarosh H. Lodi

All Faculty Scholarship for the College of the Sciences

Despite an overall sinistral slip rate of ≈3 cm/yr, few major earthquakes have occurred in the past 200 years along the Chaman fault system, the western boundary of the India Plate with the Eurasia Plate. GPS and InSAR data reported here indicate sinistral shear velocities of 8–17 mm/yr across the westernmost branches of the fault system, suggesting that a significant fraction of the plate boundary slip is distributed in the fold and fault belt to the east. At its southernmost on‐land segment (≈26°N), near the triple junction between the Arabia, Eurasia, and India Plates, we find the velocity across the …

Exploration Of Charge Carriers In Obsidian, Ryan Nordvik, Friedemann Freund

STAR Program Research Presentations

This research effort is part of an ongoing investigation into stress-activated positive hole charge carriers in common igneous and high-grade metamorphic rocks. The findings have already revealed potential early earthquake detection mechanisms and caused a re-think on the processes that could conceivably contribute to the formation of and evolution of life. Positive holes are defect electrons in the oxygen anion sub-lattice of silicate minerals that have demonstrated some intriguing capabilities: flowing out of a stressed rock volume; causing oxidation reactions at the rock-water interface and ionization at the rock-air interface; and traveling great distances. This research seeks to determine if …

Subsurface Planetary Investigation Techniques And Their Role For Assessing Subsurface Planetary Composition, Ahmed Elshafie

Graduate Theses and Dissertations

Subsurface planetary investigation techniques are of high interest and importance for the scientific community. Not only they can enhance our knowledge of the history of planetary formation but also can lead to information about its future. Whether the investigation is being conducted remotely using imagers, radars or physically using penetrometers or drills, a pre-existed knowledge of the mechanical and electrical properties of the subsurface regolith should be acquired for better data interpretation and analysis. Therefore, the main objective of this work is to investigate the mechanical and electrical properties of planetary analogs, understand their role for assessing the subsurface structure …

Statistical Clustering Of Microseismic Event Spectra To Identify Subsurface Structure, Deborah Kay Fagan

Boise State University Theses and Dissertations

Understanding subsurface structure by studying microseismicity influences a wide range of activities, including energy extraction, aquifer storage, carbon sequestration, and seismic hazard assessment. Identifying individual fractures in a larger fault system is key to characterizing, understanding, and potentially mitigating risks of natural or induced seismicity.

A year-long study associated with a carbon dioxide (CO₂) sequestration project was conducted at the Aneth oil field in southeast Utah to record microseismicity at a single downhole geophone array. A previous analysis located events by first identifying event multiplets consisting of highly correlated time-domain waveforms on receivers shallower than the depth of …

Monitoring Co2 Sequestration In Basalt With Elastic Waves, Larry Thomas Otheim

Boise State University Theses and Dissertations

The continued burning of fossil fuels as a source of energy is contributing to greater concentrations of carbon dioxide (CO₂) in the atmosphere. Increased levels of CO₂ in the atmosphere have been linked to an increase of global mean surface temperature. To mitigate the continued release of CO₂, projects to capture this gas at large point sources and sequester it in geologic formations are in place. Carbon dioxide sequestration in basalts promises permanent trapping of the fluid as these rocks react with carbonic acid and precipitate carbonate minerals. It is important to monitor the injection …

Paleoseismic Study Of The Stewart Valley And Northern Pahrump Segments Of The Stateline Fault System, Nevada, Jonathan Carter

UNLV Theses, Dissertations, Professional Papers, and Capstones

The Stateline fault system (SFS) is a ~200 km long zone of dextral faults running NW along the NV/CA border from Primm, Nevada to Amargosa Valley in the western Central Basin and Range province (CBR). Because of size and proximity, the SFS poses a hazard to the 2.5 million people, most of who live within 10 km, in Pahrump, Nevada and within 40 km, in Las Vegas, Nevada. The goals of this thesis are to (1) understand if the SFS is accommodating faulting slip change in the CBR; (2) test the along strike continuity of the SFS in Pahrump and …

Determining The Motion And Location Of The Frenchman Mountain Fault, Las Vegas, Nevada: A Paired Basin Analysis And Structural Analysis, Laura Margaret Eaton

UNLV Theses, Dissertations, Professional Papers, and Capstones

Understanding the evolution of large-scale fault systems remains a challenge to geologists and is of critical importance in understanding the dynamics of larger plate tectonic interactions. I mapped the southwestern Frenchman Mountain Fault (FMF), conducted a basin analysis of units in the footwall of the fault, and measured kinematic indicators along the fault zone in order to constrain fault offset, magnitude, and timing in an attempt to further our understanding of these systems.

My findings include: 1) the presence of vertical and sub-vertical slickenlines on southwest dipping fault surfaces indicative of normal sense offset; 2) relatively little lateral variation in …

Evaluation Of Use Of Em38-Mk2 As A Tool To Understand Field Scale Changes In Soil Properties, Sudershan Gangrade

All Theses

Sustainable water resources management requires tools to help farmers identify variations in soil hydraulic characteristics so that precision irrigation schemes can be developed to optimize water use. In this study we use electromagnetic induction (EMI) to evaluate whether changes in the apparent electrical conductivity (σ_a) of agricultural fields can be related to hydrologic processes. Field work for this study was completed at three different sites - 1) in different agricultural fields located in a watershed near Salri, Madhya Pradesh, India, 2) over an agricultural field located near Clemson University, SC, and 3) at a flood plain wetland restoration site near …

A Feasibility Study Of Time-Lapse Seismic Monitoring Of Co2 Sequestration In A Layered Basalt Reservoir, Murari Khatiwada, Ludmila Adam, Michael Morrison, Kasper Van Wijk

CGISS Publications and Presentations

We investigate the potential of scattered seismic waves to remotely sense geological sequestration of CO₂ in basalt. Numerical studies in horizontally layered models suggest that strong scattering quickly complicates the wave fields, but also provides a sensitive tool to monitor physical changes in and around the reservoir. These results go hand-in-hand with recent laboratory work and rock-physics modeling that has shown significant changes in the seismic properties of a reservoir undergoing CO₂ sequestration, due to fluid substitution and mineral precipitation.

Modeling, Visualizing, And Understanding Complex Tectonic Structures On The Surface And In The Sub-Surface, Steven Wild

Physics Theses & Dissertations

Plate tectonics is a relatively new theory with many details of plate dynamics which remain to be worked out. Moving plates can interact by divergence, lateral sliding, convergence, or collision. At a convergent plate boundary, a lithospheric slab of oceanic crust and upper mantle is subducted at a trench and dips down under a magmatic arc — either oceanic or continental. Textbooks show a static view of convergent boundaries but plate dynamics require that subduction zones and magmatic arcs must migrate with time. Therefore I develop animated models to help convey this motion. Also, convergent plate boundaries cannot continue along …

The Influence Of Non-Equilibrium Pressure On Rotating Flows, Irfan Rashid Zardadkhan

Mechanical & Aerospace Engineering Theses & Dissertations

This study was undertaken to investigate the influence of pressure relaxation on steady, incompressible flows with strong streamline curvature. In the early part of this dissertation research, the significance of non-equilibrium pressure forces in controlling the structure of a steady, two dimensional axial vortex was demonstrated. In order to extend the study of pressure relaxation influences on more complex rotating flows, this dissertation has examined other rotating flow features that can be associated with hurricanes, tornadoes and dust devils. To model these flows, modified boundary layer equations were developed for a fluid column rotating near a solid plane including the …

Gravity Anomalies Along The East Scotia Ridge: Constraining The Relative Importance Of Magmatic And Tectonic Controls On Crustal Accretion, Briton Lee Nicholson

OES Theses and Dissertations

Similar to regions such as the Lau Basin and the Caribbean Sea, the eastern Scotia Sea is a geologically complex area that involves multiple plate boundary types. This study uses bathymetry and gravity data to infer upper mantle geodynamics in the eastern Scotia Sea region. Beneath this region is an intermediate-rate back-arc spreading center known as the East Scotia Ridge (ESR) that forms the boundary between the Scotia and Sandwich plates. To the east of the ESR are the South Sandwich island arc and the South Sandwich Trench. The ESR is a relatively young feature, with spreading estimated to have …

Investigation Of Stress Changes At Mount St. Helens, Washington, And Receiver Functions At The Katmai Volcanic Group, Alaska, With An Additional Section On The Assessment Of Spreadsheet-Based Modules., Heather L. Lehto

USF Tampa Graduate Theses and Dissertations

Forecasting eruptions using volcano seismology is a subject that affects the lives and property of millions of people around the world. However, there is still much to learn about the inner workings of volcanoes and how this relates to the chance of eruption. This dissertation attempts to increase the breadth of knowledge aimed at helping to understand when a volcano is likely to erupt and how large that eruption might be. Chapters 2 and 3 focus on a technique that uses changes in the local stress field beneath a volcano to determine the source of these changes and help forecast …

Plains Co2 Reduction (Pcor) Partnership Atlas, Wesley D. Peck, Tera D. Buckley, Earl P. Battle, Megan M. Grove, Joyce M. Riske, Charles D. Gorecki, Edward N. Steadman, John A. Harju

EERC Maps and Infographics

The Plains CO₂ Reduction (PCOR) Partnership Atlas provides a regional profile of CO₂ sources and potential CO₂ storage locations across the PCOR Partnership region. The fourth edition provides an update-to-date look at PCOR Partnership activities, including regional characterization and full-scale demonstration activities. Additional background information on carbon capture, utilization, and storage (CCUS) is included to give a better understanding of how CCUS addresses concerns about climate change while allowing future energy needs to be met.