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Tectonics and Structure

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Articles 31 - 60 of 208

Full-Text Articles in Geophysics and Seismology

Pronounced Changes In Thermal Signals Associated With The Madoi (China) M 7.3 Earthquake From Passive Microwave And Infrared Satellite Data, Feng Jing, Lu Zhang, Ramesh P. Singh May 2022

Pronounced Changes In Thermal Signals Associated With The Madoi (China) M 7.3 Earthquake From Passive Microwave And Infrared Satellite Data, Feng Jing, Lu Zhang, Ramesh P. Singh

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Thermal variations in surface and atmosphere observed from multiple satellites prior to strong earthquakes have been widely reported ever since seismic thermal anomalies were discovered three decades ago. These thermal changes are related to stress accumulation caused by the tectonic activities in the final stage of earthquake preparation. In the present paper, we focused on the thermal changes associated with the 2021 Madoi M 7.3 earthquake in China and analyzed the temporal and spatial evolution of the Index of Microwave Radiation Anomaly (IMRA) and the Index of Longwave Radiation Anomaly (ILRA) based on 8-year microwave brightness temperature (MWBT) and 14-year …

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Processing Seismic, Gravity And Magnetic Data Over Diebold Knoll On Juan De Fuca Plate, Md Ariful Islam, Irina Filina Apr 2022

Processing Seismic, Gravity And Magnetic Data Over Diebold Knoll On Juan De Fuca Plate, Md Ariful Islam, Irina Filina

UNL Student Research Days Posters, Graduate

The Juan de Fuca plate is subducting beneath the North American plate along the Cascadia Subduction Zone. The CSZ is associated with multiple earthquakes, although compared to other subduction zones, it is less active. Many studies suggest that subduction will cause major mega thrust earthquake in near future, while others oppose this view. This project is focused on the Diebold Knoll on the JdF plate Various geophysical methods will be integrated to determine its origin and tectonic history.

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Viscous Anisotropy Of Wet Olivine Aggregates, Megan Ryan Jan 2022

Viscous Anisotropy Of Wet Olivine Aggregates, Megan Ryan

Williams Honors College, Honors Research Projects

I will deform natural olivine aggregates (Anita Bay dunite) cores in various orientations relative to a natural mineral alignment in the rock under both dry and wet conditions. Different orientations in regards to this mineral alignment will produce deformation on different slip systems. Stress measurements will be taken during the deformation of the samples in order to characterize any changes in viscous anisotropy observed due to the changes in slip system. Anita Bay dunite is a proxy for the main mineral found in the mantle wedge of subduction zones. Therefore, understanding the transformation of viscosity and slip systems in this …

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Effect Of Pre-Existing Fault Orientation On Strain Localization In A Foliated Granitic Gneiss, Geoffrey Hilliard Jan 2022

Effect Of Pre-Existing Fault Orientation On Strain Localization In A Foliated Granitic Gneiss, Geoffrey Hilliard

Williams Honors College, Honors Research Projects

The effect of fault orientation relative to the applied stress on reactivation of pre-existing brittle faults instead of forming new faults is well-explained by Mohr-Coulomb theory. However, Mohr-Coulomb theory does not explain the effect of orientation on reactivation of faults with a ductile rheology and no work has been performed to assess the effect of orientation of a pre-existing ductile fault on fault strength. In order to determine how rock strength and localization of strain into a ductile fault is affected when the orientation of the pre-existing fault (artificial fault) is changed, experiments were performed on pre-faulted cores of a …

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Dynamic Relationship Study Between The Observed Seismicity And Spatiotemporal Pattern Of Lineament Changes In Palghar, North Maharashtra (India), Biswajit Nath, Ramesh P. Singh, Vineet K. Gahalaut, Ajay P. Singh Dec 2021

Dynamic Relationship Study Between The Observed Seismicity And Spatiotemporal Pattern Of Lineament Changes In Palghar, North Maharashtra (India), Biswajit Nath, Ramesh P. Singh, Vineet K. Gahalaut, Ajay P. Singh

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

The Palghar region (north Maharashtra, India), located in the northwestern part of the stable continental region of India, experienced a low magnitude earthquake swarm, which was initiated in September 2018 and is continuing to date (as of October 2021). From December 2018 to December 2020, ~5000 earthquakes with magnitudes from M1.2 to M3.8 occurred in a small region of 20 × 10 km2. These earthquakes were probably triggered by fluid migration during seasonal rainfall. In this study, we have used multi-temporal Landsat satellite data of the year 2000, 2015, 2018, 2019, and 2020, extracted lineaments, and studied the …

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Spatial Variations Of Stochastic Noise Properties In Gps Time Series, Xiaoxing He, Michael Simon Bos, Jean-Philippe Montillet, Rui Fernandes, Timothy I. Melbourne, Weiping Jiang, Wudong Li Nov 2021

Spatial Variations Of Stochastic Noise Properties In Gps Time Series, Xiaoxing He, Michael Simon Bos, Jean-Philippe Montillet, Rui Fernandes, Timothy I. Melbourne, Weiping Jiang, Wudong Li

Geological Sciences Faculty Scholarship

The noise in position time series of 568 GPS (Global Position System) stations across North America with an observation span of ten years has been investigated using solutions from two processing centers, namely, the Pacific Northwest Geodetic Array (PANGA) and New Mexico Tech (NMT). It is well known that in the frequency domain, the noise exhibits a power-law behavior with a spectral index of around −1. By fitting various noise models to the observations and selecting the most likely one, we demonstrate that the spectral index in some regions flattens to zero at long periods while in other regions it …

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Timescales Of Magma Transport In The Columbia River Flood Basalts, Determined By Paleomagnetic Data, Joseph Biasi, Leif Karlstrom Oct 2021

Timescales Of Magma Transport In The Columbia River Flood Basalts, Determined By Paleomagnetic Data, Joseph Biasi, Leif Karlstrom

Other Staff Materials

Flood basalts represent major events in Earth History, in part because they are linked to large climate perturbations and mass extinctions. However, the durations of individual flood basalt eruptions, which directly impact potential environmental crises, are poorly constrained. Here we use a combination of paleomagnetic data and thermal modeling to create a magnetic geothermometer (MGT) that can constrain the active transport lifetime of magmatic conduits and intrusions. We apply the MGT technique to eight feeder dike segments of the Columbia River basalts (CRB), demonstrating that some dike segments were actively heating host rocks for less than one month, while other …

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Prevention And Preparedness Of The Messina-Reggio Calabria Strait: An Earthquake Forecasting And Didactic Project, Francesco Di Stefano, Gioacchino Giampaolo Giuliani, Dimitar Ouzounov, Daniele Cataldi, Cristiano Fidani, Angelo D'Errico, Giulia Fioravanti Sep 2021

Prevention And Preparedness Of The Messina-Reggio Calabria Strait: An Earthquake Forecasting And Didactic Project, Francesco Di Stefano, Gioacchino Giampaolo Giuliani, Dimitar Ouzounov, Daniele Cataldi, Cristiano Fidani, Angelo D'Errico, Giulia Fioravanti

Mathematics, Physics, and Computer Science Faculty Articles and Research

This contribution is addressed to an introductive university course on the correlation existing between radon emission and earthquakes processes held following a flipped-class approach where students receive didactic materials prior to face-to-face lessons. This research was initially started to investigate the real correlation between Radon emission from the Earth and the occurrence of strong earthquakes by using measurements of hourly Radon flow variation. During quiet seismogenic conditions, we observe an unvarying level of Radon emission in the air. Before a strong earthquake, substantial variations of Radon (222Rn) concentration have been observed in the air, probably because of the …

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Stratigraphic Evidence Of Two Historical Tsunamis On The Semi-Arid Coast Of North-Central Chile, Jessica M. Depaolis, Tina Dura, Breanyn Macinnes, Lisa L. Ely, Marco Cisternas, Matías Carvajal, Hui Tang, Hermann M. Fritz, Cyntia Mizobe, Robert L. Wesson, Gino Figueroa, Nicole Brennan, Benjamin P. Horton, Jessica E. Pilarczyk, D. Reide Corbett, Benjamin C. Gill, Robert Weiss Aug 2021

Stratigraphic Evidence Of Two Historical Tsunamis On The Semi-Arid Coast Of North-Central Chile, Jessica M. Depaolis, Tina Dura, Breanyn Macinnes, Lisa L. Ely, Marco Cisternas, Matías Carvajal, Hui Tang, Hermann M. Fritz, Cyntia Mizobe, Robert L. Wesson, Gino Figueroa, Nicole Brennan, Benjamin P. Horton, Jessica E. Pilarczyk, D. Reide Corbett, Benjamin C. Gill, Robert Weiss

Geological Sciences Faculty Scholarship

On September 16, 2015, a Mw 8.3 earthquake struck the north-central Chile coast, triggering a tsunami observed along 500 km of coastline, between Huasco (28.5°S) and San Antonio (33.5°S). This tsunami provided a unique opportunity to examine the nature of tsunami deposits in a semi-arid, siliciclastic environment where stratigraphic and sedimentological records of past tsunamis are difficult to distinguish. To improve our ability to identify such evidence, we targeted one of the few low-energy, organic-rich depositional environments in north-central Chile: Pachingo marsh in Tongoy Bay (30.3°S).

We found sedimentary evidence of the 2015 and one previous tsunami as tabular …

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Digital Appendix Of Masters Thesis "Constraining Deformation Mechanisms Of Damage Zones: A Case Study Of The Shallow San Andreas Fault At Elizabeth Lake, Southern California, James P. Evans, Caroline Studnicky May 2021

Digital Appendix Of Masters Thesis "Constraining Deformation Mechanisms Of Damage Zones: A Case Study Of The Shallow San Andreas Fault At Elizabeth Lake, Southern California, James P. Evans, Caroline Studnicky

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We performed macroscopic, optical petrographic, scanning electron microscopy, and geochemical analyses on rock core acquired across the San Andreas Fault at Elizabeth Lake, California, in order to understand the distribution and accommodation of fault-related slip and energy within the shallow damage zone of this continental scale strike-slip fault. We characterized the deformation structures, alteration textures, and elemental variabilities to constrain the properties of the uppermost ~2 km fault-related damage zone at this site. We identified evidence for coseismic slip in the form of pulverized rocks, injection veins, clay-clast aggregates, and pseudotachylyte, and aseismic slip through calcite twins, dilatant vein fills, …

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Characterization Of Landslide Processes From Radar Remote Sensing And Hydromechanical Modeling, Yuankun Xu May 2021

Characterization Of Landslide Processes From Radar Remote Sensing And Hydromechanical Modeling, Yuankun Xu

Earth Sciences Theses and Dissertations

Landsides are a natural geomorphic process yet a dangerous hazard which annually causes thousands of casualties and billions of property loss in a global scale. Understanding landslide motion kinematics from early initiation to final deposition is critical for monitoring, assessing, and forecasting landslide movement in order to mitigate their hazards. Landslides occur under diverse environmental settings and appear in variable types; however, all types of landslides can be mechanically attributed to shearing failure at the basal surface due to stress regime shift contributed by internal and/or external forcing. Typical internal factors include soil/rock weathering, whereas typical external triggering forces encompass …

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Microstructural Characteristics Of Deformed Quartz Under Non-Steady-State Conditions, Hamidreza Soleymani Feb 2021

Microstructural Characteristics Of Deformed Quartz Under Non-Steady-State Conditions, Hamidreza Soleymani

Dissertations, Theses, and Capstone Projects

Because of the long timescale of many geological processes (millions of years), it has been traditionally assumed that the existing forces acting on the rocks at deep crustal levels are in equilibrium (i.e., steady-state). An alternative assumption, however, suggests that rocks in the lower crust and upper mantle are continuously evolving and exchanging energy at various time scales. Under the latter assumption (i.e., non-steady-state), certain geologic systems may never attain equilibrium regardless of the length and the time scale of operating geologic events. These two “endpoint” assumptions suggest there is a wide range of geologically reasonable conditions under which rocks …

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Analyzing Slab Holes In Subduction Zones And Their Impacts Through Numerical Simulations, Taylor M. Arrowood Jan 2021

Analyzing Slab Holes In Subduction Zones And Their Impacts Through Numerical Simulations, Taylor M. Arrowood

Theses and Dissertations--Earth and Environmental Sciences

Subduction zones form as higher density oceanic lithosphere is forced beneath an over-riding, lower density, continental or oceanic plate; a process driven by contrasts in buoyancy throughout this system. We seek to explore subduction zones in which the subducting lithosphere is discontinuous after passing through the trench, forming a slab gap. The main research objective is to determine the effect of slab gaps on surface topography in a subduction-related orogen and asthenospheric flow into the mantle wedge using two and three-dimensional numerical mechanical models. We obtain results from 24+ models that suggest a connection between slab gaps/holes and the magnitude …

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Analysis Of Water Concentration Formed Within Deformed Synthetic Quartz Crystals, Andrew Steward Jan 2021

Analysis Of Water Concentration Formed Within Deformed Synthetic Quartz Crystals, Andrew Steward

Williams Honors College, Honors Research Projects

Analyzing the strength of synthetic quartz is essential to understanding the strength of natural milky quartz, which likely controls the strength of Earth’s continental crust. Synthetic quartz is sometimes used for deformation experiments because it has a homogenous water distribution unlike natural milky quartz. The purpose of this study is to determine if annealing synthetic quartz at T = 600°C will convert the water in synthetic quartz to free water, like milky quartz, but with little water loss. Following two annealing experiments at Texas A&M University, I performed four annealing experiments to measure the water content of five synthetic quartz …

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Advancement Of Full-Vector Variable-Temperature Magnetometry For Rock-Magnetic And Paleointensity Applications, Leonid Surovitskii Jan 2021

Advancement Of Full-Vector Variable-Temperature Magnetometry For Rock-Magnetic And Paleointensity Applications, Leonid Surovitskii

Dissertations, Master's Theses and Master's Reports

Data on the variation of the direction and strength of Earth’s ancient magnetic field (absolute paleointensity) provide crucial information into the mechanisms of the geodynamo and the Earth’s thermal history. However, the use of conventional methods and instrumentation for absolute paleointensity determination has been hampered by physicochemical alteration of the samples caused by multiple high-temperature cycles and long experiment durations. The reliability and efficiency of the measurement process can be improved by the measurement of the full remanent magnetization vector simultaneously with the temperature cycling of a sample. Such as approach can also substantially expand the scope of materials available …

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Earth’S Outgoing Longwave Radiation Variability Prior To M ≥6.0 Earthquakes In The Taiwan Area During 2009–2019, Ching-Chou Fu, Lou-Chang Lee, Dimitar Ouzounov, Jyh-Cherng Jan Sep 2020

Earth’S Outgoing Longwave Radiation Variability Prior To M ≥6.0 Earthquakes In The Taiwan Area During 2009–2019, Ching-Chou Fu, Lou-Chang Lee, Dimitar Ouzounov, Jyh-Cherng Jan

Mathematics, Physics, and Computer Science Faculty Articles and Research

This paper proposes an analysis method, using the National Oceanic and Atmospheric Administration satellite data, to trace variations in outgoing longwave radiation (OLR) for finding the precursors of earthquakes. The significance of these observations is investigated using data sets of recent M ≥6.0 earthquakes around the Taiwan area from 2009 to 2019. We suggest that the precursory signal could be an EIndex anomaly (EA) in the form of substantial thermal releases distributed near the epicenter. The consecutive appearances of OLR EAs are observed as precursors 2–15 days before significant earthquakes, and we refer to this as a pre-earthquake OLR …

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Toward Near‐Field Tsunami Forecasting Along The Cascadia Subduction Zone Using Rapid Gnss Source Models, Amy L. Williamson, Diego Melgar, Brendan W. Crowell, Diego Argas, Timothy I. Melbourne, Yong Wei, Kevin Kwong Aug 2020

Toward Near‐Field Tsunami Forecasting Along The Cascadia Subduction Zone Using Rapid Gnss Source Models, Amy L. Williamson, Diego Melgar, Brendan W. Crowell, Diego Argas, Timothy I. Melbourne, Yong Wei, Kevin Kwong

Geological Sciences Faculty Scholarship

Over the past 15 years and through multiple large and devastating earthquakes, tsunami warning systems have grown considerably in their efficacy in providing timely and accurate forecasts to affected communities. However, one part of tsunami warning that still needs improvement is forecasts catered to local, near‐field communities in the time after an earthquake rupture but before coastal inundation. In this study, we test a rapid, Global Navigation Satellite Systems (GNSS)‐driven earthquake characterization model using a large data set of synthetic megathrust ruptures for its near‐field tsunami forecasting potential. We also provide a framework for tsunami forecasting that focuses on the …

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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 Jul 2020

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 …

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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 Jun 2020

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 …

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Testing A Drone-Based Magnetic Field Surveying System, Erik Jacobson, Irina Filina Apr 2020

Testing A Drone-Based Magnetic Field Surveying System, Erik Jacobson, Irina Filina

UCARE: Research Products

Aeromagnetic surveys are conducted by geoscientists to study subsurface geologic structures, such as faults. This type of survey uses a magnetometer mounted upon an airborne vehicle to collect magnetic field data. Magnetic anomalies are caused by variations in subsurface geology, namely in magnetic properties of subsurface rocks. Jacobson and Filina (2019) reported on the development of a new low cost drone, based magnetic field surveying system by the UNL Geophysics Team. This drone-based magnetic system is capable of collecting high resolution data at low speeds and low altitudes. The current study focuses on testing this system by conducting two flights …

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Characterization Of Magma Storage And Dynamics At Akutan, Semisopochnoi, And Okmok Volcanoes From Analytical And Numerical Models Of Geodetic, Seismic, And Petrologic Data, Kimberly Degrandpre Apr 2020

Characterization Of Magma Storage And Dynamics At Akutan, Semisopochnoi, And Okmok Volcanoes From Analytical And Numerical Models Of Geodetic, Seismic, And Petrologic Data, Kimberly Degrandpre

Earth Sciences Theses and Dissertations

Volcanic eruptions can cause significant socioeconomic loss, but a better understanding of the processes and dynamics influencing the evolution of volcanic plumbing systems will advance the development of eruption forecasting models that will ultimately mitigate hazards and risks associated with eruptive events. Geologic and geophysical data must be integrated in 3D, finite- element, multiphysical, numerical models to define the coupled evolution of magmatic and crustal stress regimes in volcanic environments, but in data limited regions this is not always an option. The remote nature of the Aleutian Island Arc restricts ground-based monitoring and sampling efforts, and due to sparse temporal …

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Microwave Brightness Temperature Characteristics Of Three Strong Earthquakes In Sichuan Province, China, Feng Jing, Ramesh P. Singh, Yueju Cui, Ke Sun Jan 2020

Microwave Brightness Temperature Characteristics Of Three Strong Earthquakes In Sichuan Province, China, Feng Jing, Ramesh P. Singh, Yueju Cui, Ke Sun

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Passive microwave remote sensing technology is an effective means to identify the thermal anomalies associated with earthquakes due to its penetrating capability through clouds compared with infrared sensors. However, observed microwave brightness temperature is strongly influenced by soil moisture and other surface parameters. In the present article, the segmented threshold method has been proposed to detect anomalous microwave brightness temperature associated with the strong earthquakes occurred in Sichuan province, China, an earthquake-prone area with high soil moisture. The index of microwave radiation anomaly (IMRA) computed by the proposed method is found to enhance prior to the three strong earthquakes, 2008 …

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Crustal Structure Beneath The East Coast Magnetic Anomaly From Seismic Refraction Tomography, Collin C. Brandl Dec 2019

Crustal Structure Beneath The East Coast Magnetic Anomaly From Seismic Refraction Tomography, Collin C. Brandl

Earth and Planetary Sciences ETDs

Syn-rift igneous addition is necessary for successful continental breakup. Past investigations of passive margins have focused on strike perpendicular structure, but potential field anomalies indicate that significant crustal variations may be present. Data from 21 ocean bottom seismometers was acquired as part of the Eastern North American Margin Community Seismic Experiment and was used for tomographic inversion to create 2D velocity models of the margin that are representative of crustal structure. Crustal thickness varies along-strike from ~20 km to ~24 km and a high velocity (Vp > 7 km/s) layer is present at the base of the crust above the Moho. …

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Improving Earthquake Disaster Models With Post-Event Data: Insights From The 2015 Gorkha, Nepal Earthquake, Bradley Steven Wilson Dec 2019

Improving Earthquake Disaster Models With Post-Event Data: Insights From The 2015 Gorkha, Nepal Earthquake, Bradley Steven Wilson

Graduate Theses and Dissertations

Immense amounts of data are collected following earthquake disasters. Yet, it remains unclear how researchers’ might take full advantage of diverse post-disaster datasets. Using data from the 2015 Gorkha Nepal earthquake, this dissertation explores three ways in which post- disaster survey and assessment datasets can be used to inform models of seismic risk, vulnerability, and recovery processes. The first article presents an empirical analysis of scale issues in disaster vulnerability indices using a novel dataset of 750,000 households. This study finds that using aggregated household data to create social vulnerability indices can produce results that are meaningfully different from equivalent …

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Application Of 3d Salt Modeling: An Example From The Northeastern Gulf Of Mexico, Adam Mattson Oct 2019

Application Of 3d Salt Modeling: An Example From The Northeastern Gulf Of Mexico, Adam Mattson

Masters Theses & Specialist Projects

Salt tectonics has important implications for hydrocarbon exploration in saltbearing basins since salt deformation can directly or indirectly form hydrocarbon traps, influence hydrocarbon migration, and can control deepwater depositional systems. In various basins around the globe, extensive research has been conducted on initiation of salt mobilization, subsequent deformation, and eventual cessation, mostly from subsurface two-dimensional (2D) sections. However, 3D seismic data has dominated the petroleum industry for the last 30 years. Despite the plethora of 3D seismic data acquired in salt-bearing basins, there has been hardly any published work on the 3D geometries of complex salt bodies. 3D salt mapping …

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Orientation Of Paleostress Of Raplee Ridge Anticline, Loren Randall Holyoak, John S. Maclean Sep 2019

Orientation Of Paleostress Of Raplee Ridge Anticline, Loren Randall Holyoak, John S. Maclean

The Compass: Earth Science Journal of Sigma Gamma Epsilon

During the Laramide Orogeny several major folds were formed in Southern Utah, one of those being the Raplee Ridge anticline. Raplee Ridge is approximately eight miles from Mexican Hat, Utah. The San Juan River cuts through the anticline, exposing the Honaker Trail Formation’s beds of shale and limestone with chert nodules. Accompanying the mountain-scale ductile deformation of the Raplee Ridge anticline are decimeter-scale brittle conjugate fractures in the limestone’s chert nodules. The objective of this study is to compare the orientation of paleostress that formed the Raplee Ridge anticline with the conjugate fractures within the chert nodules to see if …

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Machine Learning Predicts Aperiodic Laboratory Earthquakes, Olha Tanyuk, Daniel Davieau, Charles South, Daniel W. Engels Aug 2019

Machine Learning Predicts Aperiodic Laboratory Earthquakes, Olha Tanyuk, Daniel Davieau, Charles South, Daniel W. Engels

SMU Data Science Review

In this paper we find a pattern of aperiodic seismic signals that precede earthquakes at any time in a laboratory earthquake’s cycle using a small window of time. We use a data set that comes from a classic laboratory experiment having several stick-slip displacements (earthquakes), a type of experiment which has been studied as a simulation of seismologic faults for decades. This data exhibits similar behavior to natural earthquakes, so the same approach may work in predicting the timing of them. Here we show that by applying random forest machine learning technique to the acoustic signal emitted by a laboratory …

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A Bayesian Framework For Estimating Seismic Wave Arrival Time, Hua Zhong May 2019

A Bayesian Framework For Estimating Seismic Wave Arrival Time, Hua Zhong

Graduate Theses and Dissertations

Because earthquakes have a large impact on human society, statistical methods for better studying earthquakes are required. One characteristic of earthquakes is the arrival time of seismic waves at a seismic signal sensor. Once we can estimate the earthquake arrival time accurately, the earthquake location can be triangulated, and assistance can be sent to that area correctly. This study presents a Bayesian framework to predict the arrival time of seismic waves with associated uncertainty. We use a change point framework to model the different conditions before and after the seismic wave arrives. To evaluate the performance of the model, we …

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Geophysical Analysis Of The Midcontinent Rift’S Subsurface Structure In Southeastern Nebraska, Patrick Szopinski Mar 2019

Geophysical Analysis Of The Midcontinent Rift’S Subsurface Structure In Southeastern Nebraska, Patrick Szopinski

Honors Program: Senior Projects (Public)

The Midcontinent Rift System (MCRS) is a 1.1 billion-year-old failed rift system that spans much of the North American continental interior. The MCRS is exposed at Lake Superior and is buried in the subsurface along its southwest-extending arm through southeastern Nebraska. Due to the presence of buried volcanic rocks, the MCRS has characteristic highly-pronounced potential field anomalies (gravity and magnetic). Despite these large anomalies, not much is known about the subsurface faulting associated with the rift zone in the Midwest. The goal of this project is to attempt to use integrated analysis of collected geophysical data from multiple methods to …

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Engaging The Greater Lafayette Community In A Journey Through The Earth Sciences: Purdue’S Eaps Earth Science Passport Day Event, Dara Laczniak, Bradley Garczynski Mar 2019

Engaging The Greater Lafayette Community In A Journey Through The Earth Sciences: Purdue’S Eaps Earth Science Passport Day Event, Dara Laczniak, Bradley Garczynski

Engagement & Service-Learning Summit

No abstract provided.

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