Other Earth Sciences Commons^™

Beach Erosion And Recovery Since Hurricane Ivan In 2004 Along A Headland-Bay Coast In Treasure Beach, Jamaica, Elandé Engelbrecht

Graduate Theses/Dissertations

Anthropogenic climate change is causing sea-level rise and shoreline changes that threaten the environment and economy of coastal communities in Caribbean Island nations. To assess this risk, this study quantifies shoreline changes at Treasure Beach in St. Elizabeth Parish on the south coast of Jamaica from 2001 to 2023. The effects of storm events on erosion were also assessed. Over 10 km of shoreline are assessed with about half being sandy pocket beaches ranging from 300 to 900 m in length, separated by rocky headlands and beach rock outcrops. Sand beach erosion trends since 2001 are assessed for seven sandy …

Earthquakes And Seismic Waves: Solutions For Fermi Questions, March 2024, John Adam

Mathematics & Statistics Faculty Publications

Solution to Question 1: To estimate h, we take the geometric mean of 1 km and 70 km, or ~8 km, and take ρ ≈ 2500 kg/m³.

Hence, δl ≈ 4 × 0.05 × (2.5 × 10³ kg/m³) × (10 m/s²) × (8 × 10³ m) × (2 × 10⁴ m) × 0.1 ÷ (3 × 10¹⁰ kg · m⁻¹ · s⁻²) ≈ 1.3 m. (Note that this is not meant to be an estimate of the width of the Icelandic rock fracture in the photograph, though it appears to be of the right order …

Earthquakes And Seismic Waves, John Adam

Mathematics & Statistics Faculty Publications

This article discusses earthquakes and seismic waves. It explains that earthquakes occur in the crust or upper mantle, with "shallow" earthquakes happening above a depth of 70 km in the crust. The article also introduces the slider-block model, which is a simple model used to understand earthquake behavior. It provides equations to calculate the displacement and maximum slip velocity of the fault based on various factors. The article then presents two questions related to earthquake calculations. Additionally, it mentions Fermi Questions, which are brief questions with estimation techniques.

Examining Downshear Reformation In Tropical Cyclones, Nathalie Rivera Torres

Electronic Theses & Dissertations (2024 - present)

The development of a new low-level circulation center in tropical cyclones, known as downshear reformation, can lead to sudden changes in storm structure and intensity, representing a challenge in forecasting tropical cyclones. This phenomenon is commonly observed in weak tropical cyclones (e.g., tropical depressions, tropical storms) experiencing moderate to strong vertical wind shear (> 5 m s-1), when the vertical wind shear organizes convection in the downshear region of the tropical cyclone, and lower-tropospheric vorticity is generated within the intense convection. Downshear reformation has been proposed as a mechanism for intensification, sometimes rapidly, in tropical cyclones under unfavorable environmental wind …

Simulation Of Wave Propagation In Granular Particles Using A Discrete Element Model, Syed Tahmid Hussan

College of Graduate Studies: Theses & Dissertations

The understanding of Bender Element mechanism and utilization of Particle Flow Code (PFC) to simulate the seismic wave behavior is important to test the dynamic behavior of soil particles. Both discrete and finite element methods can be used to simulate wave behavior. However, Discrete Element Method (DEM) is mostly suitable, as the micro scaled soil particle cannot be fully considered as continuous specimen like a piece of rod or aluminum. Recently DEM has been widely used to study mechanical properties of soils at particle level considering the particles as balls. This study represents a comparative analysis of Voigt and Best …

Dust-Driven Mechanism For Marine Particle Aggregation: Interactions Between Clay Minerals, Heterotrophic Bacteria And Organic Matter Influences Aggregation In Marine Systems, Vignesh Gokuladas Menon

Dartmouth College Master’s Theses

Atmospheric dust deposition plays a crucial role in marine biogeochemical cycles, yet mechanisms underlying its impact on particle dynamics remain unclear. This study investigates the synergistic interactions between marine heterotrophic bacteria and clay minerals in seawater, focusing on their effect on Transparent Exopolymer Particles (TEP) production and organoclay aggregation. Field experiments in the Gulf of Maine and laboratory roller tank studies were conducted using natural microbial communities and model heterotrophic bacterial strains (Alteromonas sp. EZ55, Marinobacter adhaerens HP15, and Sulfitobacter sp. NAS-14.1). Results demonstrate that clay exposure significantly enhances TEP production by bloom-associated heterotrophic bacteria, with increases up to …

From Creek To Ditch And Back Again: The History And Future Of Pattee Creek, Missoula, Montana, Carver Edward Butterfield

Graduate Student Theses, Dissertations, & Professional Papers

Pattee Creek was once a free-flowing stream that meandered across the Missoula Valley, but has been channelized, piped, and degraded by logging, mining, agriculture, and urbanization. This thesis used a mixed-method approach to examine the impact of human activities on the Pattee Creek watershed. Beginning with a historical overview, the story of how the creek has been utilized and why it was buried was told. An analysis of historical photos from 1937 to 2019 revealed drastic changes in the land cover of the watershed and the channel of lower Pattee Creek. Developed land increased dramatically, while open land decreased and …

Reducing Food Scarcity: The Benefits Of Urban Farming, S.A. Claudell, Emilio Mejia

Journal of Nonprofit Innovation

Urban farming can enhance the lives of communities and help reduce food scarcity. This paper presents a conceptual prototype of an efficient urban farming community that can be scaled for a single apartment building or an entire community across all global geoeconomics regions, including densely populated cities and rural, developing towns and communities. When deployed in coordination with smart crop choices, local farm support, and efficient transportation then the result isn’t just sustainability, but also increasing fresh produce accessibility, optimizing nutritional value, eliminating the use of ‘forever chemicals’, reducing transportation costs, and fostering global environmental benefits.

Imagine Doris, who is …

Comparative Lineament And Geomorphic Analysis Of Chaotic Terrains And Noctis Labyrinthus, Mars, Sarah A. Walton

Electronic Theses and Dissertations

Noctis Labyrinthus (NL) is an extensional trough network connecting the Tharsis rise and Valles Marineris on Mars. Chaotic terrains are a group of polygonally-fractured surface features commonly associated with subsidence due to rapid fluid loss within the subsurface. Polygonal surface patterns are seen at both sites, where geometric topographic highs are bounded by low troughs. Lineaments, topography, and geomorphology of NL and chaotic terrains were analyzed to determine tectonics and fluid influence in the formation and evolution of both sites. NL shows preferential fracture patterns associated with regional extension. Lineaments within chaotic terrains do not show cumulative preferential trends but …

Investigating The Effects Of A Southward Flow In The Southeastern Florida Shelf Using Robotic Instruments, Alfredo Quezada

All HCAS Student Capstones, Theses, and Dissertations

We deployed a Slocum G3 glider fitted with an acoustic Doppler current profiler (ADCP), a Conductivity-Temperature-Depth sensor (CTD), optics sensor channels, and a propeller on the Southeastern Florida shelf. The ADCP and CTD provide continuous measurements of Northern and Eastern current velocity components, salinity, temperature, and density, throughout the water column in a high-current environment. The optics sensor channels are able to provide measurements of chlorophyll concentrations, colored dissolved organic matter (CDOM), and backscatter particle counts. Additionally, for one of the glider deployments, we deployed a Wirewalker wave-powered profiling platform system also fitted with an ADCP and a CTD in …

Prevalence, Faunal Composition, And Vertical Distribution Of Bioluminescence In The Pelagic Gulf Of Mexico: Fishes, Crustaceans, Cephalopods And Gelatinous Megaplankton, Devynne M. Brown

All HCAS Student Capstones, Theses, and Dissertations

Bioluminescence is the phenomenon of light emission by living organisms. It occurs through a chemical reaction within an organism and serves various purposes. The diversity of bioluminescent capabilities and occurrence in unrelated taxa suggest that bioluminescence has evolved independently numerous times amongst taxa thriving in certain environments. One such environment is the deep ocean, where little to no sunlight penetrates the water column, specifically in the mesopelagic (200-1000 m depth) and bathypelagic (> 1000 m) zones. The mesopelagic and bathypelagic zones have been extensively sampled and well documented in the Gulf of Mexico (GoM), one of the few places globally …

Wavelet Compression As An Observational Operator In Data Assimilation Systems For Sea Surface Temperature, Bradley J. Sciacca

LSU New Orleans Theses and Dissertations

The ocean remains severely under-observed, in part due to its sheer size. Containing nearly billion of water with most of the subsurface being invisible because water is extremely difficult to penetrate using electromagnetic radiation, as is typically used by satellite measuring instruments. For this reason, most observations of the ocean have very low spatial-temporal coverage to get a broad capture of the ocean’s features. However, recent “dense but patchy” data have increased the availability of high-resolution – low spatial coverage observations. These novel data sets have motivated research into multi-scale data assimilation methods. Here, we demonstrate a new assimilation approach …

Review Of Harmful Algal Bloom Effects On Birds With Implications For Avian Wildlife In The Chesapeake Bay Region, Barnett A. Rattner, Catherine E. Wazniak, Julia S. Lankton, Peter C. Mcgowan, Serguei V. Drovetski, Todd A. Egerton

United States Geological Survey: Staff Publications

The Chesapeake Bay, along the mid-Atlantic coast of North America, is the largest estuary in the United States and provides critical habitat for wildlife. In contrast to point and non-point source release of pesticides, metals, and industrial, personal care and household use chemicals on biota in this watershed, there has only been scant attention to potential exposure and effects of algal toxins on wildlife in the Chesapeake Bay region. As background, we first review the scientific literature on algal toxins and harmful algal bloom (HAB) events in various regions of the world that principally affected birds, and to a lesser …

Cross-Scale Urban Land Cover Mapping: Empowering Classification Through Transfer Learning And Deep Learning Integration, Zhe Wang, Chao Fan, Xian Min, Shoukun Sun, Xiaogang Ma, Xiang Que

I-GUIDE Forum

Urban land cover mapping is essential for effective urban planning and resource management. Thanks to its ability to extract intricate features from urban datasets, deep learning has emerged as a powerful technique for urban classification. The U-net architecture has achieved state-of-the-art land cover classification performance, highlighting its potential for mapping urban trees at different spatial scales. However, deep learning approaches often require large, labeled datasets, which are challenging to acquire for specific urban contexts. Transfer learning addresses this limitation by leveraging pre-trained deep learning models on extensive datasets and adapting them to smaller urban datasets with limited labeled samples. Transfer …

Reducing Uncertainty In Sea-Level Rise Prediction: A Spatial-Variability-Aware Approach, Subhankar Ghosh, Shuai An, Arun Sharma, Jayant Gupta, Shashi Shekhar, Aneesh Subramanian

I-GUIDE Forum

Given multi-model ensemble climate projections, the goal is to accurately and reliably predict future sea-level rise while lowering the uncertainty. This problem is important because sea-level rise affects millions of people in coastal communities and beyond due to climate change's impacts on polar ice sheets and the ocean. This problem is challenging due to spatial variability and unknowns such as possible tipping points (e.g., collapse of Greenland or West Antarctic ice-shelf), climate feedback loops (e.g., clouds, permafrost thawing), future policy decisions, and human actions. Most existing climate modeling approaches use the same set of weights globally, during either regression or …

How Is Flash Drought Understood?—Experts’ Definitions And Decision-Makers’ Perceptions, Caily Schwartz, Tonya Haigh, Mark D. Svoboda, Madeline Goebel

National Drought Mitigation Center: Faculty Publications

Because flash drought is a relatively new phenomenon in drought research, defining the concept is critical for scientists and decision-makers. Having detrimental impacts on many sectors, it is important to have a consistent definition and understanding of flash drought, between experts and stakeholders, to provide early warning to the community. This study focuses on onset and progression of conditions and demonstrates the difference in flash drought identification for 15 events across six quantitative definitions of flash drought that use the U.S. Drought Monitor (USDM). Five flash drought events have been studied in the literature while 10 additional events have been …

The Patchwork Governance Of Ecologically Available Water: A Case Study In The Upper Missouri Headwaters, Montana, United States, Amanda E. Cravens, Julia B. Goolsby, Theresa Jedd, Deborah J. Bathke, Shelley Crausbay, Ashley E. Cooper, Jason Dunham, Tonya Haigh, Kimberly R. Hall, Michael J. Hayes, Jamie Mcevoy, Rebecca L. Nelson, Markéta Poděbradská, Aaron Ramirez, Elliot Wickham, Dionne Zoanni

National Drought Mitigation Center: Faculty Publications

Institutional authority and responsibility for allocating water to ecosystems (“ecologically available water” [EAW]) is spread across local, state, and federal agencies, which operate under a range of statutes, mandates, and planning processes. We use a case study of the Upper Missouri Headwaters Basin in southwestern Montana, United States, to illustrate this fragmented institutional landscape. Our goals are to (a) describe the patchwork of agencies and institutional actors whose intersecting authorities and actions influence the EAW in the study basin; (b) describe the range of governance mechanisms these agencies use, including laws, policies, administrative programs, and planning processes; and (c) assess …

Droughtscape, Summer 2023, National Drought Mitigation Center

DroughtScape: Quarterly Newsletter of the National Drought Mitigation Center (2007–2023)

DroughtScape, Summer 2023

Wildlife Ecological Risk Assessment In The 21st Century: Promising Technologies To Assess Toxicological Effects, Barnett A. Rattner, Thomas G. Bean, Val R. Beasley, Philippe Berny, Karen M. Eisenreich, John E. Elliott, Margaret L. Eng, Phyllis C. Fuchsman, Mason D. King, Rafael Mateo, Carolyn B. Meyer, Jason M. O'Brien, Christopher J. Salice

United States Geological Survey: Staff Publications

Despite advances in toxicity testing and the development of new approach methodologies (NAMs) for hazard assessment, the ecological risk assessment (ERA) framework for terrestrial wildlife (i.e., air‐breathing amphibians, reptiles, birds, and mammals) has remained unchanged for decades. While survival, growth, and reproductive endpoints derived from whole-animal toxicity tests are central to hazard assessment, nonstandard measures of biological effects at multiple levels of biological organization (e.g., molecular, cellular, tissue, organ, organism, population, community, ecosystem) have the potential to enhance the relevance of prospective and retrospective wildlife ERAs. Other factors (e.g., indirect effects of contaminants on food supplies and infectious disease processes) …

Impact Of Land Use/Cover Change And Slope Gradient On Soil Organic Carbon Stock In Anjeni Watershed, Northwest Ethiopia, Bethel Geremew, Tsegaye Tadesse, Bobe Bedadi, Hero T. Gollany, Kindie Tesfaye, Abebe Aschalew

National Drought Mitigation Center: Faculty Publications

Today’s agri-food systems face the triple challenge of addressing food security, adapting to climate change, and reducing the climate footprint by reducing the emission of greenhouse gases (GHG). In agri-food systems, changes in land use and land cover (LULC) could affect soil physicochemical properties, particularly soil organic carbon (SOC) stock. However, the impact varies depending on the physical, social, and economic conditions of a given region or watershed. Given this, a study was conducted to quantify the impact of LULC and slope gradient on SOC stock and C sequestration rate in the Anjeni watershed, which is a highly populated and …