Open Access. Powered by Scholars. Published by Universities.®

Geophysics and Seismology Commons™

Open Access. Powered by Scholars. Published by Universities.®

2,451 Full-Text Articles 4,270 Authors 1,223,994 Downloads 108 Institutions

All Articles in Geophysics and Seismology

Faceted Search

2,451 full-text articles. Page 30 of 82.

Plate Boundary Trench Retreat And Dextral Shear Drive Intracontinental Fault-Slip Histories: Neogene Dextral Faulting Across The Gabbs Valley And Gillis Ranges, Central Walker Lane, Nevada, Jeffrey Lee, Andrew K. R. Hoxey, Andrew Calvert, Peter Dubyoski 2020 Central Washington University

Plate Boundary Trench Retreat And Dextral Shear Drive Intracontinental Fault-Slip Histories: Neogene Dextral Faulting Across The Gabbs Valley And Gillis Ranges, Central Walker Lane, Nevada, Jeffrey Lee, Andrew K. R. Hoxey, Andrew Calvert, Peter Dubyoski

All Faculty Scholarship for the College of the Sciences

The spatial-temporal evolution of intracontinental faults and the forces that drive their style, orientation, and timing are central to understanding tectonic processes. Intracontinental NW-striking dextral faults in the Gabbs Valley–Gillis Ranges (hereafter referred to as the GVGR), Nevada, define a structural domain known as the eastern Central Walker Lane located east of the western margin of the North American plate. To consider how changes in boundary type along the western margin of the North American plate influenced both the initiation and continued dextral fault slip to the present day in the GVGR, we combine our new detailed geologic mapping, structural …


Role Of Fluid Injection On Earthquake Size In Dynamic Rupture Simulations On Rough Faults, Jeremy Maurer, Eric M. Dunham, Paul Segall 2020 Missouri University of Science and Technology

Role Of Fluid Injection On Earthquake Size In Dynamic Rupture Simulations On Rough Faults, Jeremy Maurer, Eric M. Dunham, Paul Segall

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

An outstanding question for induced seismicity is whether the volume of injected fluid and/or the spatial extent of the resulting pore pressure and stress perturbations limit rupture size. We simulate ruptures with and without injection‐induced pore pressure perturbations, using 2‐D dynamic rupture simulations on rough faults. Ruptures are not necessarily limited by pressure perturbations when (1) background shear stress is above a critical value, or (2) pore pressure is high. Both conditions depend on fault roughness. Stress heterogeneity from fault roughness primarily determines where ruptures stop; pore pressure has a secondary effect. Ruptures may be limited by fluid volume or …


Monitoring The 2018 Eruption Of Kīlauea Volcano Using Various Remote Sensing Techniques, Ninad Bhagwat 2020 Montana Tech

Monitoring The 2018 Eruption Of Kīlauea Volcano Using Various Remote Sensing Techniques, Ninad Bhagwat

Graduate Theses & Non-Theses

Monitoring the regions that are prone to natural hazards is essential in disaster management to provide early warnings. Airborne and space-borne remote sensing techniques are cost-effective in accomplishing this task. Interferometric Synthetic Aperture Radar (InSAR) is an advanced remote sensing technique used to detect and measure the changes in the Earth’s topography over time. Spaceborne InSAR is a precise (~mm accuracy) way to measure the land surface altitudinal changes. Persistent Scatterer Interferometry (PSI) is a powerful method of differential SAR interferometry that processes the InSAR data by automatically selecting the persistent scatterers in the region. In this thesis, I developed …


Geospatial Analyses Of Seismic Hazards And Risk Perception In Libya, Somaia Suwihli 2020 University of Arkansas, Fayetteville

Geospatial Analyses Of Seismic Hazards And Risk Perception In Libya, Somaia Suwihli

Graduate Theses and Dissertations

Libya is not considered a highly active seismic region. However, several earthquakes of magnitude >5.0 have occurred there. This dissertation analyzes the seismicity of Libya in order to better understand earthquake hazards, related geomorphic features, and the current evolution of Libyan perceptions of seismic risk. The first article developed a baseline of past and current seismic inventory in Libya, which represented an assessment of Libya seismic hazard by translating, analyzing, and compiling historical sources and archaeological data. This study shows that Libya has experienced earthquakes in varying degrees since ancient times. Through the spatial and temporal distribution of earthquakes from …


Geophysical Survey Near Center, North Dakota, University of North Dakota. Energy and Environmental Research Center 2020 University of North Dakota

Geophysical Survey Near Center, North Dakota, University Of North Dakota. Energy And Environmental Research Center

EERC Brochures and Fact Sheets

Fact sheet about an intended geophysical survey near Center, North Dakota. Data gathering is part of Project Tundra and North Dakota CarbonSAFE. [This item is an outdated or superseded version and retained for historical purposes only. It may no longer reflect current information, policies, or practices.]


Geophysical Survey Near Milton R. Young Station, University of North Dakota. Energy and Environmental Research Center 2020 University of North Dakota

Geophysical Survey Near Milton R. Young Station, University Of North Dakota. Energy And Environmental Research Center

EERC Brochures and Fact Sheets

Fact sheet about an intended geophysical survey near Milton R. Young Station. Data gathering is part of Project Tundra and North Dakota CarbonSAFE. [This item is an outdated or superseded version and retained for historical purposes only. It may no longer reflect current information, policies, or practices.]


Groundwater Storage Loss Associated With Land Subsidence In Western United States Mapped Using Machine Learning, Ryan G. Smith, Sayantan Majumdar 2020 Missouri University of Science and Technology

Groundwater Storage Loss Associated With Land Subsidence In Western United States Mapped Using Machine Learning, Ryan G. Smith, Sayantan Majumdar

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Land subsidence caused by groundwater extraction has numerous negative consequences, such as loss of groundwater storage and damage to infrastructure. Understanding the magnitude, timing, and locations of land subsidence, as well as the mechanisms driving it, is crucial to implementing mitigation strategies, yet the complex, nonlinear processes causing subsidence are difficult to quantify. Physical models relating groundwater flux to aquifer compaction exist but require substantial hydrological data sets and are time consuming to calibrate. Land deformation can be measured using interferometric synthetic aperture radar (InSAR) and GPS, but the former is computationally expensive to estimate at scale and is subject …


Improved Characterization Of Thin Bed And Low-Resistivity/Low-Contrast Hydrocarbon Reservoirs, Hasnan Hijaz Kamal 2020 Universiti Malaya

Improved Characterization Of Thin Bed And Low-Resistivity/Low-Contrast Hydrocarbon Reservoirs, Hasnan Hijaz Kamal

Student Works (2020-2029)

Thin-bed and low-resistivity/low-contrast (LRLC) reservoirs such tidal heterolithic deposits contain a significant amount of the global hydrocarbon reserves. However, due to millimetre-to-centimetre thin sandstone, forecasting hydrocarbon reserves and production are challenging. Producing hydrocarbon economically from heterolithic deposits in thin-bed reservoirs requires the characterisation of flow properties in thin beds for improved hydrocarbon reserves and production estimates. Sedimentology interpretation of the study area and reservoir in Malaysia shows that heterolithic deposits are part of tidal bars in a shallow marine environment with a large areal extent that suggests the substantial volume of heterolithic deposits which represent potential hydrocarbon reserves. Conventional Well …


Janus: A Python Package For Agent-Based Modeling Of Land Use And Land Cover Change, K. E. Kaiser, A. N. Flores, C. R. Vernon 2020 Boise State University

Janus: A Python Package For Agent-Based Modeling Of Land Use And Land Cover Change, K. E. Kaiser, A. N. Flores, C. R. Vernon

Geosciences Faculty Publications and Presentations

Janus is an open source Python package for agent-based modeling (ABM) of land use and land cover change (LULCC). Many ABMs of LULCC have been created across platforms, some of which are not ideal for large scale, high resolution scenarios. This model provides a simple object-oriented framework for creating ABMs specific to LULCC. The organizational philosophy of the modeling framework is to create software objects (agents) that are associated with specific and contextual attributes which are isolated from where those agents exist in the spatial setting of the model, and still provide clear linkages between the agent, their environment, and …


Using Geophysical And Geodetic Data To Improve Natural And Human-Induced Hazard Assessments, Fanghui Deng 2020 University of South Florida

Using Geophysical And Geodetic Data To Improve Natural And Human-Induced Hazard Assessments, Fanghui Deng

USF Tampa Graduate Theses and Dissertations

I use geophysical and geodetic data to study dynamics of the Earth System, including volcanoes and induced seismicity, aiming to improve related hazard assessment at different time and space scales. My dissertation consists of the following three projects: 1) Geophysical model for the origin of volcano vent clusters (Deng et al., 2017). We developed a conceptual model to simulate long-term magma transport to explain the origin of volcanic vent clusters in Quaternary Colorado Plateau volcanic fields. We used density contrast inverted from gravity data to constrain the magma transport model. The development of vent clusters appears to be influenced by …


Changing Mantle Sources And The Effects Of Crustal Passage On The Steens Basalt, Se Oregon: Chemical And Isotopic Constraints, Nicole E. Moore, A. L. Grunder, Wendy A. Bohrson, Richard W. Carlson, I. N. Bindeman 2020 Oregon State University

Changing Mantle Sources And The Effects Of Crustal Passage On The Steens Basalt, Se Oregon: Chemical And Isotopic Constraints, Nicole E. Moore, A. L. Grunder, Wendy A. Bohrson, Richard W. Carlson, I. N. Bindeman

Geological Sciences Faculty Scholarship

Continental flood basalts are more prone to compositional modification from passage through thicker and (or) more felsic crust in comparison to their oceanic counterparts. The Steens Basalt in southeast Oregon (~17 Ma) is among the oldest and most mafic members of the Columbia River Basalt Group and provides a record of the early stages of flood basalt volcanism. We evaluate the balance of mantle sources in time during the onset of Columbia River Basalt Group magmatism and assess the effect of crustal passage using stratigraphically controlled Sr, Nd, Pb, Hf, Os, and O isotopic compositions, as well as whole rock …


Sediment Transport And Geomorphological Evolution In The Transgressive Ship Shoal, Louisiana: Insights From Geophysical Observation, Modeling, And Machine Learning Studies, Haoran Liu 2020 Louisiana State University

Sediment Transport And Geomorphological Evolution In The Transgressive Ship Shoal, Louisiana: Insights From Geophysical Observation, Modeling, And Machine Learning Studies, Haoran Liu

LSU Doctoral Dissertations

Ship Shoal has been a high-priority target sand resource for dredging activities to restore the eroding barrier islands in Louisiana, USA. Many studies have been performed in Ship Shoal in recent decades, but our knowledge of temporal and spatial variations of sediment transport and post-dredge morphology is still limited. The objectives of this dissertation are to explore the sediment infilling process, the spatial and temporal evolution of the morphology of dredge pits near and on Ship Shoal by using multiple methods. Scientific methods used in this study include (a) geophysical observation using bathymetry, side-scan and subbottom technique, (b) sediment transport …


Noise Characteristics Of Operational Real‐Time High‐Rate Gnss Positions In A Large Aperture Network, Diego Melgar, Brendan W. Crowell, Timothy I. Melbourne, Walter Szeliga, Marcelo Santillan, Craig Scivner 2020 University of Oregon

Noise Characteristics Of Operational Real‐Time High‐Rate Gnss Positions In A Large Aperture Network, Diego Melgar, Brendan W. Crowell, Timothy I. Melbourne, Walter Szeliga, Marcelo Santillan, Craig Scivner

Geological Sciences Faculty Scholarship

Large earthquakes are difficult to model in real‐time with traditional inertial seismic measurements. Several algorithms that leverage high‐rate real‐time Global Navigation Satellite Systems (HR‐GNSS) positions have been proposed, and it has been shown that they can supplement the earthquake monitoring effort. However, analyses of the long‐term noise behavior of high‐rate real‐time GNSS positions, which are important to understand how the data can be used operationally by monitoring agencies, have been limited to just a few sites and to short time spans. Here, we show results from an analysis of the noise characteristics of 1 year of positions at 213 GNSS …


Does Updating Natural Hazard Maps To Reflect Best Practices Increase Viewer Comprehension Of Risk?, Carson C. MacPherson-Krutsky, Brittany D. Brand, Michael K. Lindell 2020 Boise State University

Does Updating Natural Hazard Maps To Reflect Best Practices Increase Viewer Comprehension Of Risk?, Carson C. Macpherson-Krutsky, Brittany D. Brand, Michael K. Lindell

Geosciences Faculty Publications and Presentations

In this study, we examine whether updating an interactive hazard map using recommendations from the literature improves user map comprehension. Analyses of experimental data collected from 75 university students revealed that map comprehension scores were not significantly better for those who viewed a “best practices” map compared to those who viewed an existing version. This may be because the existing map was itself better than most other interactive maps. Additionally, we found map comprehension levels to have significant positive relationships with objective tests, but not self-reported measures of spatial ability. Moreover, self-reported spatial ability had statistically significant, but only moderately …


Neural Network Models For Nuclear Treaty Monitoring: Enhancing The Seismic Signal Pipeline With Deep Temporal Convolution, Joshua T. Dickey 2020 Air Force Institute of Technology

Neural Network Models For Nuclear Treaty Monitoring: Enhancing The Seismic Signal Pipeline With Deep Temporal Convolution, Joshua T. Dickey

Theses and Dissertations

Seismic signal processing at the IDC is critical to global security, facilitating the detection and identification of covert nuclear tests in near-real time. This dissertation details three research studies providing substantial enhancements to this pipeline. Study 1 focuses on signal detection, employing a TCN architecture directly against raw real-time data streams and effecting a 4 dB increase in detector sensitivity over the latest operational methods. Study 2 focuses on both event association and source discrimination, utilizing a TCN-based triplet network to extract source-specific features from three-component seismograms, and providing both a complimentary validation measure for event association and a one-shot …


Stress-State And Injection-Rate Dependent Damage Processes During The Hydraulic Fracturing Of Granite, Gayani Sasendrika Gunarathna 2020 New Jersey Institute of Technology

Stress-State And Injection-Rate Dependent Damage Processes During The Hydraulic Fracturing Of Granite, Gayani Sasendrika Gunarathna

Dissertations

Hydraulic fracturing is a well-stimulation technique that is employed in field applications, such as enhanced geothermal systems (EGS) and shale oil/gas extraction. This research experimentally investigates the effect of the state of stress and injection rate on the hydraulic fracturing processes. In addition, a displacement discontinuity method (DDM) code, FROCK, is used to model the crack initiation and propagation in a granite specimen under hydraulic fracturing conditions. In order to conduct the experimental work, a test setup capable of applying a triaxial state of stress and water pressure inside pre-fabricated flaws cut in prismatic granite specimens is developed. Additionally, the …


Uas-Based Tracking Of The Santiaguito Lava Dome, Guatemala, Edgar U. Zorn, Thomas R. Walter, Jeffrey B. Johnson, René Mania 2020 German Research Centre for Geosciences GFZ

Uas-Based Tracking Of The Santiaguito Lava Dome, Guatemala, Edgar U. Zorn, Thomas R. Walter, Jeffrey B. Johnson, René Mania

Geosciences Faculty Publications and Presentations

Imaging growing lava domes has remained a great challenge in volcanology due to their inaccessibility and the severe hazard of collapse or explosion. Changes in surface movement, temperature, or lava viscosity are considered crucial data for hazard assessments at active lava domes and thus valuable study targets. Here, we present results from a series of repeated survey flights with both optical and thermal cameras at the Caliente lava dome, part of the Santiaguito complex at Santa Maria volcano, Guatemala, using an Unoccupied Aircraft System (UAS) to create topography data and orthophotos of the lava dome. This enabled us to track …


Soil Moisture Contributions To Insar Phase And Decorrelation, Yusuf Eshqi Molan 2020 Southern Methodist University

Soil Moisture Contributions To Insar Phase And Decorrelation, Yusuf Eshqi Molan

Earth Sciences Theses and Dissertations

Interferometric synthetic aperture radar (InSAR) provides capability to detect surface deformation. Between two SAR images, in addition to ground surface deformations, changes may happen in the surface parameters such as soil moisture, vegetation layer water content, and so on. Despite deformation, the other changes may not be of interest for a common InSAR analysis and an ordinary InSAR analysis rarely takes into account their influences on InSAR phase and coherence. The effect of the changes on InSAR phase and coherence can potentially impede accurate estimation of ground surface deformation but also can open new window into soil moisture retrieval and …


Crystal Queer: Fracturing The Binaries Of Matter, Creation, And Landscape, Sarah Knight 2020 Washington University in St. Louis

Crystal Queer: Fracturing The Binaries Of Matter, Creation, And Landscape, Sarah Knight

Graduate School of Art Theses

In this thesis, I compile a series of fragments consisting an analysis of my artwork in the gendered contexts of landscape, self-identity, mythology, and philosophy. I develop my concept of a “queer mark” in my art that serves as a form of queering, a disruption of visual and conceptual cohesion. I form a picture of how our contemporary selves are influenced by our gendered understanding of the landscape through the analysis of philosophical, artistic, and mythological concepts of creation. I see my sculptures as an atlas to an alternative means of understanding identity, a queering of these historical and exclusionary …


Mesopause Airglow Disturbances Driven By Nonlinear Infrasonic Acoustic Waves Generated By Large Earthquakes, P. A. Inchin, J. B. Snively, J. Aguilar Guerrero, M. D. Zettergren, A. Williamson, D. Melgar 2020 Embry-Riddle Aeronautical University

Mesopause Airglow Disturbances Driven By Nonlinear Infrasonic Acoustic Waves Generated By Large Earthquakes, P. A. Inchin, J. B. Snively, J. Aguilar Guerrero, M. D. Zettergren, A. Williamson, D. Melgar

Publications

Near-epicentral mesopause airglow perturbations, driven by infrasonic acoustic waves (AWs) during a nighttime analog of the 2011 M9.1 Tohoku-Oki earthquake, are simulated through the direct numerical computation of the 3D nonlinear Navier-Stokes equations. Surface dynamics from a forward seismic wave propagation simulation, initialized with a kinematic slip model and performed with the SPECFEM3D_GLOBE model, are used to excite AWs into the atmosphere from ground level. Simulated mesopause airglow perturbations include steep oscillations and persistent nonlinear depletions up to 50% and 70% from the background state, respectively, for the hydroxyl OH(3,1) and oxygen O(1S) 557.7-nm emissions. Results suggest that …


Digital Commons powered by bepress