Geology Commons^™

Hydrogeophysical Assessment Of Groundwater And Saltwater–Freshwater Interface In A Quaternary– Neogene Coastal Aquifer, Kilwa Kisiwani Island, Southeast Tanzania, Simon R. Melchioly

Tanzania Journal of Science

This study aims to identify and explore new potential sites of groundwater resources using geophysical methods, and to demarcate the depth to the saltwater-freshwater interface. Kilwa Kisiwani Island is geologically covered mostly by Neogene and Quaternary alluvial sediments, sand and gravel. The geophysical techniques employed during the research include Vertical Electrical Sounding (VES), Electrical Resistivity Tomography (ERT), and Transient Electromagnetics (TEM). The Island has the potential for groundwater occurrences, but the layer with fresh water is shallow and thin. Out of the 18 VES sites, 2 (11%) points have shown non-potential, but the remaining 16 (89%) of the VES sites …

Evolution Of Propagator Wakes On The Kolbeinsey Ridge From An Integrated Geophysical Perspective, Ethan Stowell

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

Oceanic lithosphere is formed following the extension and rifting of a continent, with new material generated at mid-ocean ridges. While ridges generally spread in the direction of extension, individual spreading centers are offset by perpendicular transform faults that break the ridges into individual segments. Ridge propagation, in which one ridge segment grows at the expense of another’s shortening, has been identified in global investigations as a poorly understood component of axial reorganization. This process leaves propagator wake structures composed of faults and pseudofaults visible as lows in Earth’s gravitational field, and transferred lithosphere with a distorted magnetic signature. This study …

Mapping Along-Strike Changes In Shallow Subduction Zone Geometry At The Alaska Subduction Zone Using Seismic Reflection And Tectono-Geomorphic Analysis, Madelyn K. Hurd

Earth and Planetary Sciences ETDs

The Alaska subduction zone, where the oceanic Pacific plate subducts beneath the continental North American plate at a rate of 60-66 mm/yr, has hosted more >M8 earthquakes over the last century than any other subduction zone globally. The largest of these, the 1964 M9.2 Alaska earthquake, ruptured 800 km of the margin, including a high slip patch near the trench offshore Kodiak Island. The 1964 rupture area may have overlapped with the 1938 M8.3 Semidi earthquake rupture zone that lies to the west. Slip propagation near the subduction trench during large earthquakes can control tsunamigenesis, and differences in wedge geometry …

Toward The Significance Of Crevasse Orientation In Low And High Crevassed Regions On The Kennicott Glacier, Alaska, Usa, Claire A. Sturm

DePaul Discoveries

Supraglacial landforms serve as potential indicators of underlying bedrock morphology and glacier dynamics. The distribution and morphology of crevasses are closely associated with stress fields and ice-flow regimes, representing processes of stable glaciers, in contrast to their reduced occurrence in stagnant or receding ice masses. The orientation and density of crevasses influence a glacier’s ability to absorb solar energy, as they facilitate movement of meltwater down to subglacial rivers. Beyond the meltwater acting as a lubricant for basal sliding, the slope of the bedrock further impacts the local velocity and ice deformation of a glacier. The study of ice-fracturing mechanics …

Interseismic Creep Along The Enriquillo–Plantain Garden Fault, Haiti, Estimated From Insar, Rishabh Dutta, Jeremy L. Maurer, Yi Chieh Lee

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The Enriquillo–Plantain Garden fault zone (EPGFZ) is a major left-lateral strike-slip fault in southern Haiti hosting several recent destructive earthquakes, including the 2021 MW 7.1 Nippes event with primary thrust-slip. To investigate how strain is accommodated in the vicinity of the 2021 event, we analyzed Sentinel-1 interferometric synthetic aperture radar (InSAR) data from 2017 to 2021 using a PS + DS (persistent + distributed scatterers) InSAR time-series approach to overcome decorrelation in this highly vegetated region. We reveal interseismic creep along the EPGF and adjacent Grand'Anse–Sud border faults, with pure strike-slip mechanism and rates up to 9 mm/yr. We suggest …

The Case For Ice Rises At Ross Bank Since The Middle Miocene, William Weber

LSU Master's Theses

Many tens of ice rises exist at the marine margins of the Antarctic Ice Sheet. Isle-type ice rises in particular are those where an ice shelf is pinned to an underlying submarine bank. Recent and ongoing studies show that Ross Bank, on the middle continental shelf of central Ross Sea, was the former site of an important Ross Ice Shelf ice rise during the advance and retreat of the West Antarctic Ice Sheet (WAIS) in the last glacial cycle. Ross Bank is a broad and anomalously shallow water platform whose crest rises to 170 m water depth. Despite their importance …

A Fiftieth Year Retrospective On The 1976 Mw 7.5 Motagua Earthquake In Guatemala, Grant Clark, Trenton Mcenaney, Jeremy Maurer, Andreas Eckert, Stephen S. Gao, Omar G. Flores, Robin Yani, Tina Niemi, Christoph Grützner, Francisco Gomez, Jonathan Obrist-Farner

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

On 4 February 1976, an Mw > 7:5 earthquake ruptured ∼240 km of the Motagua fault in Guatemala, causing ∼23,000 fatalities. This event provided evidence for the fault's role as a major transform boundary between the North American and Caribbean plates. Field observations, seismological analyses, and postseismic studies helped constrain fundamental aspects of the 1976 earthquake mechanics and the spatial complexity of the rupture. This event opened a window for studies documenting past deformation along this plate boundary across multiple spatial and temporal scales. Five decades of research have established this earthquake as an important event for understanding strike-slip ruptures along …

Somatic Prosthetics For Planetary Resonance, Disha Dharesh Kumar R

Masters Theses

This thesis investigates how industrial design can transcend extractive technological paradigms in favor of relational interfaces that foster planetary attunement. Framing the climate crisis as a 'crisis of imagination', the research challenges the Western bifurcation of nature and culture by drawing on Indic cosmologies- which recognize stones, plants, and ecosystems as conscious at different levels and participants in a shared cosmic field. By synthesizing research in Biosemiotics, Quantum Information Pansycishm, and Neuroscience, the project redefines intelligence as a distributed, more-than-human phenomenon.

The research materializes as a speculative design artifact: a device that functions as a somatic prosthetic for planetary resonance. …

Marine Geophysical Studies Of Coupled Tectonic And Sedimentary Processes At Active Plate Boundaries, Sarah R. Rysanek

Earth and Planetary Sciences ETDs

Deep-sea and convergent margin sedimentary systems preserve critical records of tectonic and climatic processes that shape Earth’s surface. This dissertation investigates source-to-sink sediment routing and forearc deformation to better constrain the interplay between sedimentary and tectonic processes, through investigations of a deep-sea fan system, and the forearc geomorphology offshore Nicaragua. In the Gulf of Alaska, we integrate ultra-long-offset and regional multi-channel seismic reflection data, multi-resolution bathymetry, and plate reconstructions to remap the Baranof Fan system. Results show that the fan is larger than previously recognized and constructed by two primary depocenters linked to distinct glacial sediment pathways, with accommodation space …

Phase Equilibria Modeling Constraints On Seismic Velocity And Density For Mafic Granulites In The Athabasca Granulite Terrane, Western Canadian Shield, Olivia Wyllie

Geosciences Undergraduate Honors Theses

Samples of mafic granulite and eclogite from the Athabasca granulite terrane, thought to be representative of the lower continental crust, were analyzed via bulk geochemistry analysis and seismically modelled with Perple_X v.7.1.6. Modeled P-wave speeds, S-wave speeds, and densities for the samples were graphed by region and calculated for wet (1.00 wt.% H2O) versus dry (0.01 wt.% H2O) conditions at 460 °C and 648 °C. The samples were found to have higher median P-wave values than those determined by Rudnick and Fountain (1995; 7.4 km/s to 7.8 km/s, as compared to 6.9 km/s to 7.2 km/s). This indicates both a …

Mapping Of Petroleum-Prospective Structures In The Jurassic Complex Of The Western Aral Uplift Based On Seismic Attributes, Yuliya Leonidovna Salaydinova, Marina Georgievna Yuldasheva

Technical science and innovation

To solve the problems of identifying and mapping prospective structures, comprehensive analysis of 3D seismic attributes is widely used at the present stage of geological research; it was applied to assess the petroleum potential of the Jurassic rock complex in the Aral Sea offshore area of the Ustyurt region. The study integrates structural mapping on the tops of Permo-Triassic and Jurassic horizons, attribute volumes (Variance/Coherence, Sweetness, root-mean-square (RMS) amplitude, Envelope) and generalized spectral decomposition (GSD, 19-41 Hz), combined with well-log and well-test data from the Western Aral, Meros, Dengiz and Karakum areas. Variance attributes were used to delineate fault zones …

Towards Physics-Informed Neural Networks For Simulating Multiphase Geothermal Convection​*, Daniel C. Patton, Andrew Harrison Eno

Campus Research Month

Water and steam flow through porous rock, transferring heat via conduction and buoyancy-driven convection caused by density differences. Traditional numerical methods (finite-volume/finite-element) model this well but can become memory-intensive and unstable for long, high-detail simulations. This work demonstrates a Physics-Informed Neural Network (PINN) using a finite-difference approach within the NVIDIA PhysicsNeMo framework to simulate magma chambers in 2D. Tested on the Rio Pisco pluton in Peru, results are compared with the USGS HYDROTHERM model. PINNs learn from physical laws, offering accurate, flexible solutions with less data and development effort.

Empirical-Based Model Of Spatio-Temporal Errors, Godwin Naaba Ndaa

Masters Theses

This research develops an empirical model to characterize spatial-temporal InSAR errors and improve the accuracy of deformation time-series analysis. Using standardized Sentinel-1 HyP3 products and MintPy, the study quantifies how correlated noise affects velocity precision and validates the results against continuous GNSS velocities.

Residual velocities are near-Gaussian, with σ ~0.92–2.04 cm/yr and ~1 cm/yr on average. Variograms show power-law spatial structure with a non-zero nugget implicating troposphere and decorrelation while errors drop exponentially with more acquisitions; spatial uncertainty is strongly affected by unwrapping errors, coherence, and tropospheric noise, not simply troposphere.

A comparative assessment of on-demand cloud processing with other …

The Effects Of A Microplate On Plume-Ridge Interactions: Constraints From Comparing Easter And Juan Fernandez Microplates In The Eastern Pacific Ocean, Katherine Ames, Jennifer Georgen

OES Faculty Publications

This study investigates the nature of plume-ridge interactions near a tectonic microplate using mantle Bouguer anomaly (MBA) gravity calculations. The focus of this investigation is a comparison of the Easter and Juan Fernandez microplates, which are located in the eastern Pacific Ocean along the Pacific, Nazca, and Antarctic plate boundaries. The microplates have several similar characteristics, including general size, time of formation, and clockwise rotation within the larger bounding mid-ocean ridge systems. Unlike the Juan Fernandez microplate, however, the Easter microplate is located near a mantle plume (Easter/Salas y Gomez). Previously published geochemical data suggest that material from this plume …

Applied Machine Learning In Mineral Prospectivity Mapping In The South Pass-Granite Mountains Of Wyoming, Carl D. York

Graduate Theses/Dissertations

The South Pass-Granite Mountains, comprised of Archean to Tertiary rocks embedded with an Archean greenstone belt in Central Wyoming, have historically been mined for gold, iron, steel, and silver. Rare earth elements have been of increasing interest in the region and thus, several datasets have become available. Knowledge driven and data driven models are used in mineral prospectivity mapping with input data including geological mapping, geochemical data, geophysical (USGS Critical Mineral magnetic and gravity data), radiometric (U, Th, K) data and multispectral remote sensing data. Mineral prospectivity has seen a rapid improvement in recent years using advancements in machine learning …

Aquifer Distribution In Lukobe Ward, Morogoro Municipality, Tanzania: Mapped Resources For Sustainable Water Access, Kelvin K. Kayuni

Tanzania Journal of Science

In response to the ongoing challenges posed by the scarcity of reliable fresh-water sources in Lukobe Ward, Morogoro Municipality, Tanzania, this study applied an integrated approach that combines geospatial and geophysical datasets to identify previously undocumented aquifers. The datasets utilized include an apparent density map generated from high-resolution GGMPlus satellite gravity data, a geological map (Quarter Degree Sheet 183), a water drainage map, and a slope map created from a digital elevation model (DEM). The analysis successfully identified four unconfined, saprolitic aquifers in the study area, designated as aquifers A, B, C, and D. These aquifers span areas of 12.2 …

Seismological Investigations Of Magmatic Systems Using Dense Nodal Arrays, Wenkai Song

Earth and Planetary Sciences ETDs

Understanding the internal architecture of magmatic systems is crucial for volcanology, yet conventional geophysical techniques often lack the resolution to image their fine-scale structures. This dissertation leverages unique datasets from dense nodal arrays to investigate the upper crustal magmatic systems beneath Yellowstone Caldera, Valles Caldera, and Mount St. Helens. At Yellowstone, I processed vibroseis data to delineate the top of the modern magma reservoir and evaluate the thermal connection between the magmatic and the overlying hydrothermal systems. At Valles, 3D radial seismic anisotropy imaging reveals strong positive radial anisotropy within the reservoir, indicating an organized structure of horizontally sill-like melt …

Modeling The Greenland-Iceland-Faroe Ridge Using Integrated Geophysical Analysis, Zachary Clowdus

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

The Greenland-Iceland-Faroe Ridge (GIFR) is an area of significant geologic interest with anomalously thick crust related to enhanced melt generation from the interaction between the Mid-Atlantic Ridge and the Iceland hotspot. To the northeast of Iceland lies the Jan Mayen Microcontinent (JMMC), which is a continental fragment separated from Greenland during the opening of the Northern Atlantic. The overall extent of the JMMC, especially its southern boundary, remains poorly constrained. The crust beneath the GIFR is believed to be primarily of oceanic affinity. However, a recent discovery of felsic lavas in Iceland led to an alternative hypothesis that implies the …

Vulnerability Of Blue Carbon In Coastal Freshwater Ecosystems To Sea-Level Rise, Suvrajit Ghosh, Jonathan Obrist-Farner, Jeffery R. Stone, Marta Wojewodka-Przybyt, Ryan Smith, Mark Brenner, Jason H. Curtis, Susan R. H. Zimmerman, Alex Correa-Metrio, Paula Gabriela Echeverrio Galinda, Madeline J. Brosky, Liseth Perez

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Coastal freshwater ecosystems are economically and ecologically important and provide multiple environmental services worldwide. They sequester carbon at rates ten times faster, and store five times more carbon per unit area than do mature tropical forests. Vulnerability of these carbon sinks to marine inundation, however, is expected to increase in response to global sea-level rise (GSLR). To better understand the implications of future GSLR, we investigated the geochemical and biological consequences of episodic Holocene marine incursions into Lake Izabal, a large coastal freshwater ecosystem on the Caribbean coast of Central America. About 8300 cal yr BP, marine incursion transformed Lake …

Evaluation Of Towed Tem Potential For Rapid Characterization Of Levee Foundations, Kolawole Arowoogun, Katherine Grote, Jeremy Maurer

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Assessing the geologic conditions of levee foundation soils is a challenging task owing to the extensive length of most levees and the heterogeneity of many alluvial deposits. Traditional investigation techniques (such as boring and cone penetrometer testing [CPT]) are expensive, invasive, and provide spatially-limited information. As a result, they are restricted to pre-identified problematic zones in the levee. To overcome these challenges, geophysical instruments capable of better spatial coverage are proposed for rapid geoelectrical characterization of levees. In this study, we presented a field-based application of the towed time-domain electromagnetic method (tTEM) system in characterizing the subsurface geology adjacent to …

Integrating Satellite Observations And Modeling Approaches To Study Tectonic And Land Surface Hazards, Jeng Hann Chong

Earth and Planetary Sciences ETDs

The increasing availability of Earth observation satellites, such as SAR and optical platforms, has improved our ability to study the ground deformation processes during, after, and leading up to these natural hazards, such as earthquakes and debris flows. In this dissertation, I analyze satellite geodetic interseismic velocities across the Rakhine-Bangladesh megathrust and the influence of having realistic modeling assumptions for subduction zones to better constrain seismic hazard. I also examined changes in post-fire debris flow likelihood four years after the 2020 Lake Fire in Southern California using a suite of satellite data and field observations. Together, these studies highlight how …

Paleoseismic Evidence Of Directivity For The 1976 Mw 7.5 Motagua Earthquake, Guatemala, Jonathan Obrist-Farner, Jeremy Maurer, Derek Gibson, Trenton Mcenaney, Andreas Eckert, William F. Kenney, Jeffrey Beeson, Nigel Wattrus, Quin Stangeland, Fatima Reyes

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

On 4 February 1976, a Mw 7.5 earthquake along the Motagua fault, Guatemala, ruptured ∼230 km of the North American and Caribbean plate boundary. Today, the plate boundary remains poorly monitored, and the 1976 earthquake is still not fully understood. Here, we present seismic reflection profiles and radiometrically dated sediment core data from six lakes around the Motagua fault, together with reports of destruction and a quasi-dynamic rupture model, which show that the 1976 earthquake experienced strong directivity that impacted the distribution of shaking. The earthquake left behind a detailed record of event deposits (EDs) in five of the six …

Mantle Flow And Fault Zone Related Seismic Anisotropy Revealed By A Dense Linear Broadband Array In Southeast Tibet, Jing Wu, Yinshuang Ai, Stephen S. Gao, Peixi Huang, Fansheng Kong, Deke Xu, Jianguo Song, Xinyu Gao, Mengyi Wei, Long Li, Jien Zhang, Yanbin Zhang, Yingying Zhang

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Southeast Tibet, a key region for the southeastward extrusion of the Tibetan Plateau, remains debated in terms of its tectonic deformation in response to the ongoing collision between the Indian and Eurasian plates. In this study, we applied shear-wave splitting analysis of core-refracted phases recorded by a newly deployed dense seismic array and six permanent stations to delineate crustal and mantle deformation processes. The observed fast polarization directions are predominantly aligned NNW–SSE, while the splitting delay times vary across four sub-blocks. The anisotropy pattern suggests a dominantly asthenospheric origin, consistent with southeastward-directed mantle flow associated with the extrusion of the …

Receiver Function Imaging Of The Mantle Transition Zone Beneath The East Sayan Mountains And Adjacent Area In Central Asia: Implications For Lithospheric Drip And Intraplate Cenozoic Volcanism, Yangyang Liao, Kelly H. Liu, Stephen S. Gao

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

To provide constraints on the formation mechanisms of intracontinental volcanisms and intriguing lithospheric thickness variations in the East Sayan Mountains and surrounding areas, we stack P-to-s receiver functions to image the 410-km and 660-km discontinuities. Mantle transition zone (MTZ) thickening observed in a continuous area is attributable to ancient slab remnants, and Cenozoic volcanisms in the peripheral area can be explained by slab dehydration. The thinning of the MTZ in the Tuva-Mongolian Massif can be explained by mantle upwelling branches induced by slab subduction. Our results reveal an approximately circular area in the MTZ that is significantly thicker than usual, …

Mantle Flow And Crustal Deformation Revealed By Seismic Anisotropy In The Subduction Zone Beneath Myanmar, Enbo Fan, Mingming Jiang, Yinshuang Ai, Stephen S. Gao, Kelly H. Liu, Yumei He, Yiming Bai, Guangbing Hou, Yuan Ling, Chit Thet Mon, Myo Thant, Kyaing Sein

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The oblique convergence of the Indian and Eurasian plates drives significant deformation in the crust and mantle beneath Myanmar. However, the crustal deformation in the Indo-Burman Ranges (IBR) and mantle flow beneath Myanmar and adjacent areas remain unclear due to limited studies. We utilized data from the newly deployed second phase of the China-Myanmar Geophysical Survey of the Myanmar Orogen array to perform shear wave splitting analysis of PKS, SKKS, and SKS (XKS) phases. Our results, together with previous findings, provide new insights into mantle flow and crustal deformation across central Myanmar. In the IBR, we observed a transition from …

Deformation And Earthquake Potential On The North America - Caribbean - Cocos Triple Junction In Guatemala, Jeremy Maurer, Andreas Eckert, Qiaoqi Sun, Jonathan Obrist-Farner

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The triple junction between the Cocos (CO), North American (NA), and Caribbean (CA) tectonic plates in Guatemala is a region of high seismic risk and includes many large faults and historic earthquakes. Previous analyses of the tectonic system have been overly simplified, resulting in discrepancies between geologically derived and geodetic models of fault slip rate. This study leverages available geodetic, seismic, and geologic data to develop new strain rate maps and faulting models for the region. We find that locking on the regional faults matches historic reports of large earthquakes and that multiple minor fault segments are active and accommodate …

Retraction: A Database Of Teleseismic Shear-Wave Splitting Measurements For The Ordos Block And Adjacent Areas(Seismological Research Letters (2022), 93, 5, (2731–2739), 10.1785/0220210310), Lin Liu, Stephen S. Gao, Kelly H. Liu, Tu Xue, Yan Jia, Sanzhong Li

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

An earlier version of this article (Liu et al., 2022) included private data from the Himalayan-III program which should not have been made public. The authors acknowledge and regret their negligence during the selection of the measurements. The impacted data represent only 2.7% of the total data published in this article, and after review, the authors and the editors agree that this unintentional error has no bearing on the work's scientific conclusions. Therefore, we are retracting the impacted data and have made corrections to remove any Himalayan-III program data from the article's text, figures, and supplemental tables.

Deciphering A Quantitative Relationship Between Rifting And Crustal Melt Fraction: Insights From The Incipient Okavango Rift Zone, Tuo Wang, Ling Chen, Stephen S. Gao, Kelly H. Liu

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Rifting and magmatism are fundamental geological processes in the evolution of the lithosphere; however, quantitative investigations of their relationship are rare. The Okavango Rift Zone (ORZ) is in the early stages of rifting and magmatic activity and thus is an ideal locale to study this relationship. We examine the relationship using two primary crustal structure parameters: crustal thickness and average Vp/Vs ratio obtained from receiver functions. Our large Vp/Vs estimates indicate the existence of melts within the crust of the ORZ. Comparing our results with those of other continental rifts, we identify a quantitative relationship between rifting and crustal melt …

Characterization Of The Quaternary Active Twin Lakes Fault, Mount Hood, Oregon, Johnathan Peterson

University Honors Theses

The High Cascades chain of volcanoes results from Cascade Arc volcanism and is responsible for the generation of the highest topography in the state of Oregon. Surrounding Mt. Hood at the crest of the Cascade chain in northern Oregon is the Mt. Hood Fault Zone, an extensional fault zone of generally north-south trending normal faults that down-drop this high volcanic topography. The Twin Lakes Fault is located just south of Mt. Hood and is one of the southernmost faults in the Mt. Hood Fault Zone, previously mapped as approximately 12-13 km in length. This study provides the first in-depth characterization …

Seismological Applications To Crustal Deformation And Explosion Discrimination, Olumide Adedeji

Earth and Planetary Sciences ETDs

There are many outstanding questions in seismology and plate tectonics that remain unresolved due to the complexity of seismic wave propagation, fault system evolution, and sedimentary-tectonic interactions. In this dissertation, I analyze seismic and acoustic data to improve event discrimination, understand strain partitioning along a transpressive plate boundary, and investigate the influence of tectonic deformation on sedimentary processes. Using seismic arrays, I assess the detectability of Ground Coupled Airwaves (GCA) generated by shallow borehole explosions and earthquakes, demonstrating that GCA detections are highly dependent on source type, environmental conditions and sensor distribution. Along the Queen Charlotte Plate Boundary, I analyze …