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The earth was shown in the last century to have a surface layer composed of large plates. Plate tectonics is the study of the movement and stresses in the individual plates that make up the complete surface of the world's sphere. Two types of earthquakes are observed in the surface plates, interplate and intraplate earthquakes, which are classified, based on the location of the origin of an earthquake either between two plates or within the plate respectively. Limited work has been completed on the definition of the boundary region between the plates from which interplate earthquakes originate, other than the recent work on the Mid Atlantic Ridge, defined at two degrees and the subsequent work to look at the applicability of this degree based definition. Others suggested an alternative view of a constant width for the interplate region in recent work at Texas A&M University. The objective of the paper is to determine whether the assumption of a linear width of the region along the tectonic plate boundaries to classify earthquakes as interplate and intraplate earthquakes using accepted statistical criteria provides a better fit to the data than the constant degree definition. There are three types of interplate boundaries defined by the relative movement of the two plates to each other, which further complicates this study. The study used a nonrandom analysis of regions of the different types of boundary to compare the rate and decay of the intraplate earthquakes from a notional centerline for the known boundaries. The study used GIS software and EXCEL for the statistical analysis component of the research work. The results show that a constant width definition provides a number of advantages in determining the relative definition of interplate and intraplate earthquakes when compared to the constant degree definition developed for work on the Mid Atlantic Ridge. Further research is suggested on a randomly selected set of study sites to improve the reliability and quality of the statistical work for each type of the boundary of the tectonic plates.

The Curve Number (CN) method of estimating the direct runoff response to rainfall events was originally developed in the 1950's primarily for agricultural purposes in the mid-western United States. The accuracy of the CN method is greatly affected by variation of the soil type and land use of the region. Curve Numbers developed for a given region are not appropriate for application in other regions. In order to produce reliable, consistent results, Curve Numbers must be calibrated for the area in which the CN method is to be applied. Calibration is ideally accomplished by direct measurement using several rain and stream gauges within a watershed. Gauged data, however, is not always available or easily obtained. A more feasible method of calibration is therefore necessary for broad application of the CN method. The purpose of this study is to develop a method of CN calibration that can be easily applied to regions where no gauged data is available using the United States Geological Survey (USGS) regression equations. In this study, the peak flow values estimated using the regression equations were used in conjunction with a dimensionless hydrograph to compute runoff volume. The National Oceanic and Atmospheric Administration (NOAA) rainfall grids were used to estimate precipitation. Given the rainfall and runoff, a Curve Number can then calibrated through back-calculation. The method of CN calibration using the USGS regression equations was applied to nearly 60 watersheds in the state of Utah for this research. The calibration results obtained using the regression equations were compared to other CN calibrations developed using gauged data. Calibrations performed through the use of the regression equations were quite consistent with calibrations obtained using measured data. To ensure the validity of the application of this method in other regions, more comparisons to results obtained using measured data should be further pursued.

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Multiple linear regression models were developed to calculate lake fluctuation that occurs between 10 percent, 50 percent, and 90 percent of the time lake surface elevation is exceeded. A total of 48 lakes were selected from Hillsborough, Pasco, Highlands and Polk counties, which were identified as natural lakes through the study the Southwest Florida Water Management District (SWFWMD) conducted in 1999 and 2002 to develop the models. "Natural lake" refers to lakes that were not impacted by ground water pumping. Among these 48 lakes, 22 lakes from Hillsborough and Pasco counties sit in the coastal lowlands area. 26 lakes from Highlands and Polk counties are located in the Upland and Highlands Ridge area. In developing multiple regression models, the 48 lakes were divided into two groups, the same group of lakes that SWFWMD used to develop the Reference Lake Water Regime, the method that is used to set the minimum lake levels in the region. Further, these two groups of data were subdivided into four categories based on their physical characteristics. 22 lakes were divided into surface water flow through lakes (SWF) and surface water drainage lakes (SWD). 26 lakes used their county line as the divider to separate them into Highlands County lakes and Polk County lakes. A total of six sets of multiple regression models were developed to predict the lake stage fluctuation for lakes that have no or limited lake stage data. The Polk County date set provides the best model with R2 at 0.9. However, due to the lack of available information on lake basin characteristics, the models that were developed for Hillsborough and Pasco counties do not provide a good prediction.

Large topographical map of the northeast Tennessee region around Johnson City published in 1955. Prepared by the Army Map Service, Corps of Engineers, U.S. Army, Washington D.C. Compiled in 1951 from United States Quadrangles, U.S. Geological Survey, and county highway maps. Planimetric detail partially revised by photo-planimetric methods. Control by USC & GS, TVA, and CE. Roads, railroad and aeronautical data verified by state authorities, 1954. Legend denotes populated places, types of roads, and railroads. Topography, names of roads, communities, and waterways can be found on the map itself. Physical copy resides in the Government Information, Law and Maps Department of East Tennessee State University’s Sherrod Library. Scale - 1: 250,000 / https://dc.etsu.edu/rare-maps/1043/thumbnail.jpg

The political history of U.S. commercial remote sensing began in 1984 when the U.S. government first attempted to commercialize its civil earth observation satellite system " Landsat. Since then, the high technology of earth imaging satellite systems has generated intense debates and policy conflicts, primarily centered on U.S. government concerns over the national security and foreign policy implications of high-resolution commercial satellite systems. Conversely, proponents of commercial observation satellites have urged U.S. policymakers to recognize the scientific and socio-economic utility of commercial remote sensing and thus craft and implement regulatory regimes that allow for a greater degree of information openness and transparency in using earth observation satellite imagery. This dissertation traces and analyzes that tumultuous political history and examines the policy issues and social construction of commercial remote sensing to determine the role of knowledge in the effective crafting and execution of commercial remote sensing laws and policies. Although individual and organizational perspectives, interests, missions, and cultures play a significant role in the social construction of commercial observation satellite systems and programs, the problem of insufficient knowledge of the myriad dimensions and complex nature of commercial remote sensing is a little studied but important component of this social construction process. Knowledge gaps concerning commercial remote sensing extend to various dimensions of the subject matter, such as the global, economic, technical, and legal/policy aspects. Numerous examples of knowledge voids are examined to suggest a connection between deficient knowledge and divergent policy perceptions as they relate to commercial remote sensing. Relevant knowledge voids are then structurally categorized to demonstrate the vastness and complexity of commercial remote sensing policy issues and to offer recommendations on how to fill such knowledge gaps to effect increased collaboration between the US government and the U.S. commercial remote sensing industry. Finally, the dissertation offers suggestions for future STS studies on policy issues, particularly those that focus on the global dimensions of commercial remote sensing or on applying the knowledge gap concept advanced by this dissertation to other areas of science and technology policymaking. / Ph. D.

Alluvial river channels are self-formed by the sediment-laden flow that is supplied to them from upstream and the interactions between this flow and the materials forming the channel bed and banks. Thus, any changes in the volumes of solid and liquid discharge or the resistance of the boundary materials can produce adjustments in the form of river channels over time. These shifts may increase or decrease the capacity of a channel to contain flood flows. However, despite a wealth of studies on the average geometry of river channels across different scales and climatic regimes, there has not yet been a systematic assessment of the rates and controls of trends in channel form. Using a combination of USGS data, including manual field measurements and mean daily streamflow data at hundreds of stream gages, this work is the first attempt to quantify how trends in channel geometry develop over decadal timescales and how they contribute to shifts in flood hazard, in comparison with trends in streamflow. Findings reveal that two-thirds of all channel cross-sections studied exhibit significant trends in channel geometry. The majority of the investigated US river channels are eroding, with widening and deepening trends partially offset by decreases in average flow velocity. Rates of change are principally controlled by the channel size. Although large channels develop larger trends, changes are proportionally greater in small channels in percentage terms. A secondary major control is hydrology: rates of change in channel geometry are heightened by the variability and flashiness of flow regimes. Finally, results show that changing flood frequencies can only be accurately quantified when both hydrologic and geomorphic trends are accounted for, and that flood hazard is significantly increasing across the studied sites. These documented trends in channel geometry, hydraulics, and flood hazard have important implications for the management of alluvial channels, navigation, and riverside infrastructure.

MSc (Chemistry / Department of Chemistry / In this study, three sampling sites (Tshipise thermal spring, Mphephu thermal spring and Siloam borehole) in Limpopo Province South Africa were considered for an investigation into the mineral composition of their water and soil samples. Tshipise and Mphephu thermal springs are well developed and located within tourist resorts. On the other hand, Siloam is a borehole on the grounds of a private household. The water is used for various domestic purposes such as laundry, general cleaning of the household and bathing. Water and soil samples from the three sites were collected once per week every week in February 2018. The sampling bottles were spiked with 1M HNO3 before sampling to keep any metal ions present in the water samples in solution. The soil and water samples were analysed for their chemical composition using X-ray fluorescence (XRF) and inductively coupled plasma mass spectrometry (ICP-MS) respectively. XRF analysis of the soil samples found many major oxides of which SiO2 made up 63.67%, 85.37% and 46.28% by mass of Tshipise, Mphephu and Siloam soil samples respectively. XRF analysis also showed the presence of dangerous levels of heavy metals such as As, Tl, Pb and V. The analysis of the water samples by ICP-MS found that Tshipise, Mphephu and Siloam mineral water were soft, soft-moderately hard and soft-hard respectively with regards to the water hardness scale according to the United States Geological Survey (USGS) and the Water Quality Association (WQA). Analysis of water samples also found the presence of As, Cd, Cr and V. Arsenic was found to occur at concentrations above the Maximum Allowable Concentration (MAC) set by the World Health Organisation (WHO) (10 μg L-1) for Tshipise, Mphephu and Siloam mineral water (13.63 μg L-1, 15.83 μg L-1 and 20.97 μg L-1 respectively). Water temperatures for the three sites ranged from 38°C (Siloam borehole) to 64°C (Tshipise thermal spring). The pH values were 7.25 (Siloam borehole), 7.40 (Mphephu thermal spring) and 8.67 (Tshipise thermal spring). Due to the presence of As, Tl, Pb, V, Cd and Cr, the mineral water from all three thermal springs is unsafe to consume as it would lead to serious negative health effects some of which are outlined in this study. / NRF

The need to consider groundwater and surface water as a single resource has fostered the interest of the scientific community on the interactions between surface water and groundwater. The region below and alongside rivers where surface hydrology and subsurface hydrology concur is the hyporheic zone. This is the region where water exchange determines many biogeochemical and ecological processes of great impact on the functioning of rivers. However, the complex processes taking place in the hyporheic zone require a multidisciplinary approach. The combination of innovative point and distributed techniques originally developed in separated disciplines is of great advantage for the indirect identification of water exchange in the hyporheic zone. Distributed techniques using temperature as a tracer such as fiber-optic distributed temperature sensing can identify the different components of groundwater-surface water interactions based on their spatial and temporal thermal patterns at the sediment-water interface. In particular, groundwater, interflow discharge and local hyporheic exchange flows can be differentiated based on the distinct size, duration and sign of the temperature anomalies. The scale range and resolution of fiber-optic distributed temperature sensing are well complemented by geophysics providing subsurface structures with a similar resolution and scale. Thus, the use of fiber-optic distributed temperature sensing to trace flux patterns supported by the exploration of subsurface structures with geophysics enables spatial and temporal investigation of groundwater-surface water interactions with an unprecedented level of accuracy and resolution. In contrast to the aforementioned methods that can be used for pattern identification at the interface, other methods such as point techniques are required to quantify hyporheic exchange fluxes. In the present PhD thesis, point methods based on hydraulic gradients and thermal profiles are used to quantify hyporheic exchange flows. However, both methods are one-dimensional methods and assume that only vertical flow occurs while the reality is much more complex. The study evaluates the accuracy of the available methods and the factors that impact their reliability. The applied methods allow not only to quantify hyporheic exchange flows but they are also the basis for an interpretation of the sediment layering in the hyporheic zone. For upscaling of the previous results three-dimensional modelling of flow and heat transport in the hyporheic zone combines pattern identification and quantification of fluxes into a single framework. Modelling can evaluate the influence of factors governing groundwater-surface water interactions as well as assess the impact of multiple aspects of model design and calibration of high impact on the reliability of the simulations. But more importantly, this modelling approach enables accurate estimation of water exchange at any location of the domain with unparalleled resolution. Despite the challenges in 3D modelling of the hyporheic zone and in the integration of point and distributed data in models, the benefits should encourage the hyporheic community to adopt an integrative approach comprising from the measurement to the upscaling of hyporheic processes.