Geophysics and Seismology Commons^™

A Framework For Pore‐Scale Simulation Of Effective Electrical Conductivity And Permittivity Of Porous Media In The Frequency Range From 1 Mhz To 1 Ghz, Qifei Niu, Chi Zhang, Manika Prasad

Geosciences Faculty Publications and Presentations

Geoelectrical methods are broadly used in earth sciences for various purposes. To correctly interpret field geoelectrical data, it is essential to have a mechanistic understanding of the effective electrical conductivity and permittivity of geological materials over a broad frequency range. Recently, the pore‐scale numerical simulation, which utilizes the digital microstructural images of the material, has become a powerful tool in studying the effective electrical properties of geological media. However, it is still difficult to incorporate surface‐related electrochemical processes in a pore‐scale simulation. In this study, we develop a general framework to consider these electrochemical processes in pore‐scale simulations, which enable …

Within‐Stand Boundary Effects On Snow Water Equivalent Distribution In Forested Areas, H.P. Marshall

Geosciences Faculty Publications and Presentations

Forested areas exhibit high spatial variability in the distribution of snow water equivalent (SWE). Previous work has focused on forested areas with respect to snow accumulation in adjacent clearings. There is generally less snow in forested areas with greater variability relative to open areas due to the influence of tree canopies. However, the length scale of the transition from open areas to forested conditions is uncertain. Hence, the goal of this paper is to determine the length scales associated with forest boundary effects on SWE accumulation distribution patterns within forest stands. To accomplish this, we utilize a unique ground‐penetrating radar …

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 E_Index 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 …

Rainfall Triggers More Deep-Seated Landslides Than Cascadia Earthquakes In The Oregon Coast Range, Usa, Sean R. Lahusen, Alison R. Duvall, Adam M. Booth, A. Grant, Ben A. Mishkin, David R. Montgomery, Will Struble, Joshua J. Roering, J. Wartman

Geology Faculty Publications and Presentations

The coastal Pacific Northwest USA hosts thousands of deep-seated landslides. Historic landslides have primarily been triggered by rainfall, but the region is also prone to large earthquakes on the 1100-km-long Cascadia Subduction Zone megathrust. Little is known about the number of landslides triggered by these earthquakes because the last magnitude 9 rupture occurred in 1700 CE. Here, we map 9938 deep-seated bedrock landslides in the Oregon Coast Range and use surface roughness dating to estimate that past earthquakes triggered fewer than half of the landslides in the past 1000 years. We find landslide frequency increases with mean annual precipitation but …

Volcano Video Data Characterized And Classified Using Computer Vision And Machine Learning Algorithms, Alex J. C. Witsil, Jeffrey B. Johnson

Geosciences Faculty Publications and Presentations

Video cameras are common at volcano observatories, but their utility is often limited during periods of crisis due to the large data volume from continuous acquisition and time requirements for manual analysis. For cameras to serve as effective monitoring tools, video frames must be synthesized into relevant time series signals and further analyzed to classify and characterize observable activity. In this study, we use computer vision and machine learning algorithms to identify periods of volcanic activity and quantify plume rise velocities from video observations. Data were collected at Villarrica Volcano, Chile from two visible band cameras located ~17 km from …

Patagonian Aridification At The Onset Of The Mid‐Miocene Climatic Optimum, Robin B. Trayler, Matthew J. Kohn, M. Susana Bargo, José I. Cuitiño, Richard F. Kay, Caroline A. E. Strömberg, Sergio F. Vizcaíno

Geosciences Faculty Publications and Presentations

Fossil‐rich sediments of the Santa Cruz Formation, Patagonia, Argentina, span the initiation of the Miocene Climatic Optimum (MCO), the most recent period of warm and wet conditions in the Cenozoic. These conditions drove the expansion of tropical and subtropical ecosystems to much higher latitudes, with the fossiliferous Santa Cruz Formation recording one of the southernmost examples. We collected new carbon and oxygen isotope compositions of herbivore tooth enamel from fossils ~17.4 to 16.4 Ma in age to investigate ecological and climatic changes across the initiation of the MCO. Enamel δ¹³C values are consistent with a C₃‐dominated …

Assessment Of Switchgrass-Based Bioenergy Supply Using Gis-Based Fuzzy Logic And Network Optimization In Missouri (U.S.A.), Gia Nguyen, Erik Lyttek, Pankaj Lal, Taylor Wieczerak, Pralhad Burli

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

Bioenergy has been globally recognized as one of the sustainable alternatives to fossil fuels. An assured supply of biomass feedstocks is a crucial bottleneck for the bioenergy industry emanating from uncertainties in land-use changes and future prices. Analytical approaches deriving from geographical information systems (GIS)-based analysis, mathematical modeling, optimization analyses, and empirical techniques have been widely used to evaluate the potential for bioenergy feedstock. In this study, we propose a three-phase methodology integrating fuzzy logic, network optimization, and ecosystem services assessment to estimate potential bioenergy supply. The fuzzy logic analysis uses multiple spatial criteria to identify suitable biomass cultivating regions. …

Slab Dehydration And Mantle Upwelling In The Vicinity Of The Sumatra Subduction Zone: Evidence From Receiver Function Imaging Of Mantle Transition Zone Discontinuities, Fansheng Kong, Stephen S. Gao, Kelly H. Liu, Weiwei Ding, Jiabiao Li

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

A total of 10,586 P-to-S radial receiver functions recorded by 64 broadband seismic stations were utilized to image the 410 and 660 km discontinuities (d410 and d660, respectively) bordering the mantle transition zone (MTZ) beneath the Sumatra Island, the Malay Peninsula, and the western margin of the South China Sea. The d410 and d660 were imaged by stacking receiver functions in successive circular bins with a radius of 1°, after moveout corrections based on the 1-D IASP91 Earth model. The resulting apparent depths of the discontinuities exhibit significant and spatially systematic variations. The apparent depths of the d410 and d660 …

Topography Of The 410 And 660 Km Discontinuities Beneath The Cenozoic Okavango Rift Zone And Adjacent Precambrian Provinces, Youqiang Yu, Stephen S. Gao, Kelly H. Liu

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

By taking advantage of the recent availability of a broadband seismic data set from Networks NR and BX covering the entire country of Botswana, we conduct a systematic receiver function investigation of the topography of the 410 and 660 km discontinuities beneath the incipient Okavango rift zone (ORZ) in northern Botswana and its adjacent Archean-Proterozoic tectonic provinces in southern Africa. Similar to a previous mantle transition zone (MTZ) discontinuity study using data from a 1-D profile traversing the ORZ, a normal MTZ thickness is observed in most parts of the study area. This is inconsistent with the existence of widespread …

Evaluating Performance Of Openmp Tasks In A Seismic Stencil Application, Eric Raut, Jie Meng, Mauricio Araya-Polo, Barbara Chapman

Department of Applied Mathematics & Statistics Faculty Publications

Simulations based on stencil computations (widely used in geosciences) have been dominated by the MPI+OpenMP programming model paradigm. Little effort has been devoted to experimenting with task-based parallelism in this context. We address this by introducing OpenMP task parallelism into the kernel of an industrial seismic modeling code, Minimod. We observe that even for these highly regular stencil computations, taskified kernels are competitive with traditional OpenMP-augmented loops, and in some experiments tasks even outperform loop parallelism.

This promising result sets the stage for more complex computational patterns. Simulations involve more than just the stencil calculation: a collection of kernels is …

Evolution Of The Magnolia Growth Fault: An Evaluation Of Cenozoic Activity, Plaquemines Parish, Southeastern Louisiana, Jared S. Bullock

LSU New Orleans Theses and Dissertations

A geologic investigation of the Lake Hermitage area west of the Mississippi River in Plaquemines Parish, Louisiana suggests an active, regional growth fault has caused rapid local subsidence. The Magnolia growth fault is a down-to-the-south, deep-seated listric fault bounded to the west and east by two salt diapirs. Evidence from 3D seismic data, well logs, and biostratigraphy, in addition to local geomorphology, suggests the fault has been active since the Miocene and is causing submergence of wetlands on the hanging wall side. To investigate whether a correlation exists between deep-seated growth faults and subsidence at this location, near-surface data including …

Forecasting The Development Of A Natural Levee Breach And Subsequent Sediment Distribution At Mardi Gras Pass, Louisiana, Joshua Hansen

LSU New Orleans Theses and Dissertations

In 2012, a breach in a natural levee occurred on the Mississippi River near the Bohemian Spillway, forming a new distributary named Mardi Gras Pass. Since its genesis, scientists from local universities and NGOs have been regularly performing bathymetric and bank surveys to track the channel’s expansion, as well as discharge surveys throughout the receiving basin. This study developed and implemented a hindcast simulation based on this wealth of data utilizing the morpho- and hydrodynamic model, Delft3D. This model was then used to create a 20-year forecast and a 1-year simulation without tidal and subtidal forces. The results demonstrated that …

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 …

The Source Detection Of 28 September 2018 Sulawesi Tsunami By Using Ionospheric Gnss Total Electron Content Disturbance, Jann-Yenq Liu, Chi-Yen Lin, Yuh-Ing Chen, Tso-Ren Wu, Meng-Ju Chung, Tien-Chi Liu, Yu-Lin Tsai, Loren C. Chang, Chi-Kuang Chao, Dimitar Ouzounov, Katsumi Hattori

Mathematics, Physics, and Computer Science Faculty Articles and Research

The 28 September 2018 magnitude Mw7.8 Palu, Indonesia earthquake (0.178° S, 119.840° E, depth 13 km) occurred at 10:02 UTC. The major earthquake triggered catastrophic liquefaction, landslides, and a near-field tsunami. The ionospheric total electron content (TEC) derived from records of 5 ground-based global navigation satellite system (GNSS) receivers is employed to detect tsunami traveling ionospheric disturbances (TTIDs). In total, 15 TTIDs have been detected. The ray-tracing and beamforming techniques are then used to find the TTID source location. The bootstrap method is applied in order to further explore the possible location of the tsunami source based on results of …

Geologic Study In Central North Dakota, University Of North Dakota. Energy And Environmental Research Center

EERC Brochures and Fact Sheets

Fact sheet explaining the process of drilling a test hole to collect data for the North Dakota CarbonSAFE project. North Dakota CarbonSAFE is an Energy & Environmental Research Center project, conducted in partnership with the U.S. Department of Energy. [This item is an outdated or superseded version and retained for historical purposes only. It may no longer reflect current information, policies, or practices.]

North Dakota Carbonsafe – Permanent Co2 Storage In Central North Dakota, University Of North Dakota. Energy And Environmental Research Center

EERC Brochures and Fact Sheets

Fact sheet on North Dakota CarbonSAFE project. An Environmental & Energy Research Center-led project, under the U.S. Department of Energy’s CarbonSAFE Initiative, it seeks to safely deploy safe and permanent CO₂ storage in North Dakota. [This item is an outdated or superseded version and retained for historical purposes only. It may no longer reflect current information, policies, or practices.]

A Gis-Based Method For Archival And Visualization Of Microstructural Data From Drill Core Samples., Elliott Holmes

Electronic Theses and Dissertations

Core samples obtained from scientific drilling could provide large volumes of direct microstructural and compositional data, but generating results via the traditional treatment of such data is often time-consuming and inefficient. Unifying microstructural data within a spatially referenced Geographic Information System (GIS) environment provides an opportunity to readily locate, visualize, correlate, and explore the available microstructural data. Using 26 core billet samples from the San Andreas Fault Observatory at Depth (SAFOD), this study developed procedures for: 1. A GIS-based approach for spatially referenced visualization and storage of microstructural data from drill core billet samples; and 2. Producing 3D models of …

Assessment Of Landslide Susceptibility At Canada Hill In Miri, Sarawak, Telun Daniel Marelyn

Student Works (2020-2029)

Landslide occurrences have become a common sight in Miri, Sarawak due to the combination of unfavourable geological conditions, abundant rainfall and anthropogenic factors which leads to infrastructural damages following prolonged rainfall. Two of the major landslide events caused the demise of two lives and several damaged houses at Kampung Lereng Bukit. Events like this may recur if the landslide hazards are not effectively managed. Numerous studies on landslide susceptibility have been performed by researchers using different approaches. This study aims to evaluate the landslide susceptibility of Canada Hill area in Miri using a heuristic approach and bivariate statistical approach which …

Experimental Polycrystal Stress Mapping Using Raman Spectroscopy, Genevieve C. Kidman

UNLV Theses, Dissertations, Professional Papers, and Capstones

Stress conditions leading to rock deformation influence how a rock will ultimately deform. However, the internal distribution of stress in an elastically anisotropic rock under load, a precursor to rock deformation, is not well understood. Two models that may describe the distribution of stress in polycrystals include the Reuss bound and stress percolation. The Reuss bound, when applied to a polycrystal, describes isostress on each grain resulting in homogeneous intragranular strain and heterogeneous intergranular strain. The stress percolation model involves a network of strong contacts or force chains containing domains of high stress interwoven through areas of lower stress that …

Quaternary Shelf-Slope Development In The Northern Gulf Of Alaska From Combined Geophysical And Geomorphologic Analysis, Wesley A. Clary

Earth and Planetary Sciences ETDs

This dissertation follows the hybrid format as defined by the Office of Graduate Studies at the University of New Mexico. The three chapters defined herein were prepared as manuscripts to be submitted for publication in peer reviewed journals in the field of Earth sciences. A version of chapter 1 was published in Proceedings of the Integrated Ocean Drilling Program, 2017, Volume 41. Chapter 2 was submitted to Marine Geology in Feb 2020, and is under revision as of this date. A version of chapter 3 will be submitted to the Journal of Geophysical Research. In chapter 1, I …