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Cross, Guy Matthew. "Radar imaging glacio-volcanic stratigraphy : Mt. Wrangell, Alaska." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26195.
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An airborne radar survey was conducted over the ice-filled volcanic caldera at Mt. Wrangell, Alaska. Research reported here involves computer processing and interpretation of radio-reflection data acquired over 21 traverses of the summit. In addition to describing useful data enhancement techniques, a dynamic programming approach is introduced for topographically controlled data positioning and spatial correction. Interpretation focusses upon a well defined radio-stratigraphy attributed to high acidity horizons deposited at the ice surface during periods of elevated volcanic activity. A comparative analysis of layer character indicates that echoes from the caldera floor are not continuously detected because of anomalously high signal absorption. Consequently,
results impose a lower limit upon maximum ice thickness. A numerical interpretation scheme, incorporating both glaciological measurements and empirical relations governing the behaviour of firn and ice, is developed to aid interpretation of the glacio-volcanic stratigraphy. Preliminary modelling yields a speculative volcanic record that roughly matches the known eruption sequence at Mt. Wrangell and suggests a significant extension of the volcanic history.Science, Faculty of
Earth, Ocean and Atmospheric Sciences, Department of
Graduate
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Woods, Brian Keith. "Development of an active pulsed radar receiver for a mono-static borehole-radar tool." Thesis, Stellenbosch : University of Stellenbosch, 2003. http://hdl.handle.net/10019.1/2512.
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Via, Michelle Frances. "Atmospheric Effects on Radar/Ladar Detection of Seismic Activity." Wright State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=wright1440979742.
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Dena, Ornelas Oscar S. "Fast approximate migration of ground penetrating radar using Kalman estimators and determination of the lithospheric structure of Lake Baikal, Russia." To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2008. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.
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Van, Gestel Jean-Paul. "Structure and tectonics of the Puerto Rico-Virgin Islands platform and multi-confirguration ground penetrating radar data /." Digital version accessible at:, 2000. http://wwwlib.umi.com/cr/utexas/main.
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Voytenko, Denis. "Glaciological Applications of Terrestrial Radar Interferometry." Scholar Commons, 2015. http://scholarcommons.usf.edu/etd/5856.
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Terrestrial Radar Interferometry (TRI) is a relatively new ground-based technique that combines the precision and spatial resolution of satellite interferometry with the temporal resolution of GPS. Although TRI has been applied to a variety of fields including bridge and landslide monitoring, it is ideal for studies of the highly-dynamic terminal zones of marine-terminating glaciers, some of which are known to have variable velocities related to calving and/or ocean-forced melting. My TRI instrument is the Gamma Portable Radar Interferometer, which operates at 17.2 GHz (1.74 cm wavelength), has two receiving antennas for DEM (digital elevation model) generation, and images the scenes at minute-scale sampling rates. Most of this TRI work has focused on two glaciers: Breiðamerkurjökull in Iceland and Helheim in Greenland. Monitoring the displacement of stationary points suggests velocity measurement uncertainties related to the instrument and atmosphere of less than 0.05 m/d. I show that the rapid sampling rate of the TRI can be used to observe velocity variations at the glacier terminus and assess the impact and spatial distribution of tidal forcing. Additionally, iceberg tracking in the amplitude imagery may provide insight about ocean currents near the terminus.
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Manjunath, Deepak Gomez Francisco Gustavo. "Earthquake interaction along the Sultandagi-Aksehir fault based on InSar and coulomb stress modeling." Diss., Columbia, Mo. : University of Missouri-Columbia, 2008. http://hdl.handle.net/10355/5788.
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Thesis (M.S.)--University of Missouri-Columbia, 2008.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on July 8, 2009) Includes bibliographical references.
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Jung, Hahn Chul. "Wetland Hydrodynamics Using Interferometric Synthetic Aperture Radar, Remote Sensing, and Modeling." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1291661296.
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Northrup, Dustin Shawn. "A Geomorphological Study of Yardangs in China, the Altiplano/Puna of Argentina, and Iran as Analogs for Yardangs on Titan." BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/6781.
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Collections of straight, RADAR-bright, linear features, or BLFs, on Saturn's moon Titan are revealed in Cassini SAR (Synthetic Aperture RADAR) images. Most are widely distributed across the northern midlatitudes SAR on SAR swaths T18, T23, T30, T64, and T83 and in swath T56 in the southern midlatitudes. To understand the origin of these features, we compare them with terrestrial yardangs in Dunhuang, China, the Altiplano/Puna of Argentina, and the Lut Desert of Iran and with a similar morphological landform, linear dunes in the Namib Sand Sea, Namibia and on Titan. We apply a statistical classification model developed through random forests, a type of decision tree classification system, grown with terrestrial and titanian training data to the BLFs. To develop the classification, we measured sinuosity, width, spacing, and length for all of the BLFs and their possible terrestrial analogs. We interpret the features in T18, T64-1, and T83 as yardangs based upon morphological similarities between them and features in Iran and Argentina, such as overall SAR brightness, straightness, and lack of branching. Similarities exist between the BLFs and terrestrial yardangs in sinuosity and spacing—sinuosity values range from 1.00 to 1.04 for all the BLFs, and terrestrial yardangs in Iran range from 1.00 to 1.001. A generated statistical model classified a large number of yardangs in T18 and T64-1. In contrast, we interpret the BLFs in T23 and T30 as stabilized linear dunes due to similarities in sinuosity, spacing, and scale with linear dunes in the Namib Sand Sea and Titan swath T3. Stabilized linear dunes may be slightly brighter than the SAR-dark dunes due a change in dielectric constant from introduction of liquids and subsequent stabilization or from the formation of a crust over the top the feature. Sinuosities range from 1.00 to 1.37 in T23 and T30 whereas dunes in the Namib and in T3 range from 1.01 to 1.05. Branching behavior similar to dunes are also observed in BLFs in swaths T23 and T30. The BLF features in T56 in the southern hemisphere we interpret to be dune-related, likely SAR-bright (rough) inter-dune areas. We base this interpretation on the presence of SAR-dark lineations between the BLFs that may be linear dunes. The statistical model classifies few yardangs in T23, T30, and T56. We conclude that statistical classification of these features can be performed. We also show that yardang orientations may aid in the development of global climate and wind models as both current and paleo wind direction indicators.
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Neumann, William John III. "The use of ground penetrating radar to determine the presence, extent, and spatial variability of fire related hydrophobic soils in fire impacted watersheds in southern California." Diss., University of Iowa, 2016. https://ir.uiowa.edu/etd/2251.
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Ground Penetrating Radar (GPR) methods have been used to evaluate the presence, extent, and spatial variability of hydrophobic soils in Southern California Watersheds. It has been shown that high frequency ground penetrating radar equipment, under certain conditions, has the ability to determine the presence, depth, and persistence of post fire hydrophobic soils. As part of this study an extensive investigation was undertaken to not only evaluate the capability of this approach but also to understand under what conditions the method can be applied successfully and what are the limitations of the approach. The investigation includes use of computer simulations and modeling, laboratory investigations in sand boxes with native soils, and multiple field trials spanning a five year time period. Of particular significance is the finding that using GPR it is possible to: locate the interface between the uppermost burnt soil layer, and soil horizons below; quantify the depth at which the hydrophobic layer forms; and quantify the spatial extent of the layer. As part of this study best practice methods for both field and lab experimentation have also been developed and are presented in the body of the thesis. Based on this study it is concluded that the use of GPR can provide a much more accurate and comprehensive method of evaluating the nature of hydrophobic layers in such environments than the current point specific manual methods. As a result the use of GPR has significantly advanced our capacity to assess the potential for increased erosion and the generation of debris flows in such environments after rainfall events.
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Savage, Christopher Jon. "Implications of Dune Pattern Analysis for Titan's Surface History." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/3077.
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Analyzing dune parameters such as dune width and spacing can be useful in determining the reaction of dunes to changes in atmospheric and sedimentary conditions currently and in the recent geologic past. Dune parameters, dune width and spacing, were measured for linear dunes in regions across Saturn's moon Titan from images T21, 23, 28, 44 and 48 collected by Synthetic Aperture RADAR aboard the Cassini spacecraft in order to reconstruct the surface history of Titan. Dunes in the five study swaths are all linear in form, but lack superimposed or flanking dunes. They have a mean width of 1.3 km and mean crest spacing of 2.7 km, wider and farther apart on average than similar terrestrial dunes in the Namib and Agneitir Sand Seas though larger linear dunes exist on Earth. Because of the lack of superimposed and flanking dunes and their size, Titan's dunes are classified as very large simple linear dunes. The large size, spacing and uniform morphology are all indicators that Titan's dunes are very mature and long-lived features. The ratio of dune width to spacing for Titan's dunes is similar to that found in terrestrial dunes in that dune spacing tends to be twice dune width. In addition to being similar in size, this is further evidence that terrestrial dunes can be used as analogues for Titan's dunes and vice versa and that the essential dune-forming processes are the same on both bodies. Dune width and spacing decrease northward, which is attributed to, but not limited to, increased maturity of dune fields to the south or increased sediment stabilization to the north. Sediment stabilization may be caused by Titan's asymmetric seasons and a net transport of moisture from south to north. The majority of dunes have spacings consistent with an upper limit of 2 to 4 km established by the atmospheric boundary layer, further evidence they are mature. Dunes are more widely spaced in the south are evidence they have been growing toward a steady state for a longer period of time than those in the north. Titan's large linear dunes have long reconstitution times. This is in part due to the fact that winds sufficient for saltation are reached only near the Titan equinox every 14 Earth years. Based on rates for similar terrestrial dunes the reconstitution time for Titan's dune is 600,000 Earth years or more, and therefore substantial changes in dune form should not be observable over Cassini's lifetime. Cumulative probability plots of dune parameters measured at different locations across Titan indicate there is a single population of dunes on Titan. This suggests that, unlike analogous dunes in the Namib and Agneitir Sand Seas, dune-forming conditions that currently exist on Titan are either the only dune-friendly conditions in the moon's history, or the current conditions have been stable and active long enough to erase any evidence of past conditions.
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Lewis, Corbin Robert. "Linear Dune Morphometrics in Titan’s Belet Sand Sea and a Comparison with the Namib Sand Sea." BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/7688.
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Despite atmospheric and compositional differences on Titan and Earth, the similarity in the shape and spacing of linear dunes of the Belet Sand Sea of Titan and the Namib Sand Sea of Earth suggests that comparisons will yield a better understanding of the dictating factors of duneforming processes. We present a methodology for the collection of dune width and spacing measurements representative of the Namib and Belet sand seas. 94,304 locations in Belet from Cassini SAR images and 5,563 locations in the Namib from IKONOS images are used for measurements. The average width and spacing of linear dunes in Belet are 1,235 m and 2,776 m, respectively, with a standard deviation of 422 and 859 respectively. In the Namib, the average linear dune width and spacing is 736 m and 2,203 m, with a standard deviation of 204 and 592. We also analyze these morphometrics according to potential dictating factors such as elevation and distance to sand sea margins. We establish significant trends according to distance to margin, which confirms that the largest and most widely spaced dunes are generally found in the center of the sand sea. We also observe increasing dune width with increasing elevation. The strongest trend we observe is distance to the western margin in the Namib Sand Sea. In Belet, none of these trends were found to be significant. Analysis of width vs. spacing is significant in both sand seas. The disparity in results of the two sand seas suggests factors such as age, sand sea size, or proximity to source may influence linear dune morphometrics.
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Chandler, Clayton K. "Superimposed and Auxiliary Dunes of the Northern Namib Sand Sea: a Ground-Penetrating Radar Study." BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/5636.
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Understanding modern features allows for their use as analogues for understanding the environments of the past and even environments on other planetary bodies. This study uses Ground-Penetrating Radar (GPR) to image the near surface sedimentary structures on a large linear dune in the northern Namib Sand Sea and image the sedimentary structure of an auxiliary dune. GPR data was collected using a 200 MHz antenna with a continuous scan method and was processed by removing direct arrival, gain balancing, migration and more which produced the highest resolution imagery from this region to date. Large dune data was analyzed to determine depositional process for different sedimentary patterns observed. Auxiliary dune data was analyzed to determine dune type and migration direction. Our results indicate five sedimentary process zones in the near surface of the large primary dune. These processes include motion of the dune crest as well as different phases of superimposed dune deposition. It is evident from our interpretation that there have been at least two phases of superimposed dune deposition separated by an erosional process boundary. These phases of deposition have produced a reversed succession of strata on opposing sides of the dune with deposits of 3D superimposed dunes beneath 2D superimposed dune deposits on the west and deposits of 2D superimposed dunes beneath 3D superimposed dune deposits on the east. This suggests a reversal of wind environment in the region in the recent past and could provide insight into the building and stability of linear dunes on Earth. Our results also indicate that the auxiliary study dune is oblique in nature with migration to the north-northeast and that it and other similar dunes in the vicinity are formed because of their proximity to Tsondab Vlei. The apparent dependence of these smaller scale features on interruptions in the dunefield like Tsondab Vlei suggest that the normal wind patterns within the dunefield are a combination of the regional wind patterns with significant influence from the large linear dunes themselves.
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Aly, Mohamed Hassan. "Radar interferometry for monitoring land subsidence and coastal change in the Nile Delta, Egypt." [College Station, Tex. : Texas A&M University, 2006. http://hdl.handle.net/1969.1/ETD-TAMU-1022.
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Bergman, Andrew William. "Searching for the Unmarked Henry Kinsey Family Graves at the VA Hospital Grounds in Dayton, Ohio, Using Magnetic, Electromagnetic, and Radar Methods." Wright State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=wright1494956391476108.
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Korte, David M. "Three Dimensional Analysis of a Proglacial Clastic Dyke Network Using Ground Penetrating Radar, Skeidararsandur, Iceland." Kent State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=kent1381872414.
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Brodie, Katherine L. "Observations of storm morphodynamics using Coastal Lidar and Radar Imaging System (CLARIS): Importance of wave refraction and dissipation over complex surf-zone morphology at a shoreline erosional hotspot." W&M ScholarWorks, 2010. https://scholarworks.wm.edu/etd/1539616582.
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Elevated water levels and large waves during storms cause beach erosion, overwash, and coastal flooding, particularly along barrier island coastlines. While predictions of storm tracks have greatly improved over the last decade, predictions of maximum water levels and variations in the extent of damage along a coastline need improvement. In particular, physics based models still cannot explain why some regions along a relatively straight coastline may experience significant erosion and overwash during a storm, while nearby locations remain seemingly unchanged. Correct predictions of both the timing of erosion and variations in the magnitude of erosion along the coast will be useful to both emergency managers and homeowners preparing for an approaching storm. Unfortunately, research on the impact of a storm to the beach has mainly been derived from "pre" and "post" storm surveys of beach topography and nearshore bathymetry during calm conditions. This has created a lack of data during storms from which to ground-truth model predictions and test hypotheses that explain variations in erosion along a coastline. We have developed Coastal Lidar and Radar Imaging System (CLARIS), a mobile system that combines a terrestrial scanning laser and an X-band marine radar system using precise motion and location information. CLARIS can operate during storms, measuring beach topography, nearshore bathymetry (from radar-derived wave speed measurements), surf-zone wave parameters, and maximum water levels remotely. In this dissertation, we present details on the development, design, and testing of CLARIS and then use CLARIS to observe a 10 km section of coastline in Kitty Hawk and Kill Devil Hills on the Outer Banks of North Carolina every 12 hours during a Nor'Easter (peak wave height in 8 m of water depth = 3.4 m). High decadal rates of shoreline change as well as heightened erosion during storms have previously been documented to occur within the field site. In addition, complex bathymetric features that traverse the surf-zone into the nearshore are present along the southern six kilometers of the field site. In addition to the CLARIS observations, we model wave propagation over the complex nearshore bathymetry for the same storm event. Data reveal that the complex nearshore bathymetry is mirrored by kilometer scale undulations in the shoreline, and that both morphologies persist during storms, contrary to common observations of shoreline and surf-zone linearization by large storm waves. We hypothesize that wave refraction over the complex nearshore bathymetry forces flow patterns which may enhance or stabilize the shoreline and surf-zone morphology during storms. In addition, our semi-daily surveys of the beach indicate that spatial and temporal patterns of erosion are strongly correlated to the steepness of the waves. Along more than half the study site, fifty percent or more of the erosion that occurred during the first 12 hours of the storm was recovered within 24 hours of the peak of the storm as waves remained large (>2.5 m), but transitioned to long period swell. In addition, spatial variations in the amount of beach volume change during the building portion of the storm were strongly correlated with observed wave dissipation within the inner surf zone, as opposed to predicted inundation elevations or alongshore variations in wave height.
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Futter, Peter W. "Advanced modelling of a borehole radar environment with the finite difference time domain method." Thesis, Stellenbosch : University of Stellenbosch, 2001. http://hdl.handle.net/10019.1/2478.
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Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2001.Over the last decade, as the mining industry of South Africa is moving to ever deeper mines, the borehole radar is becoming an increasingly important field of research. In December 2000, Burger completed his thesis on Electromagnetic Modelling of a Borehole Radar Environment with the FDTD Method. The goal of this thesis is to extend the research presented in Burger's thesis, considering how more advanced modelling techniques can be applied to the FDTD analysis of the borehole radar environment. Some of these techniques include implementation of dispersive and conductive material models, and developing Uniaxial Perfectly Matched Layer boundary conditions for matching these model. Simulations were run to measure the performance of these boundary condition for matching dispersive and conductive materials. The thesis also includes the implementation of a parallel version of the FDTD algorithm using the Message Passing Interface library. Finally several realistic borehole models where simulated to test the accuracy of the code and to show how the code can be used to model real world problems.
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Burger, Ernst H. "Electromagnetic modelling of a borehole radar environment with the finite difference time domain method." Thesis, Stellenbosch : University of Stellenbosch, 2000. http://hdl.handle.net/10019.1/3067.
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Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2000.South Africa has an immensely rich reserve of minerals which still has to be exploited. The problem with these reserves is that they exist in reefs where the mining environment is extremely hazardous, and where mining is very expensive. These are only two of the reasons why borehole radar has recently become a very important field of research in the South African mining industry. These radars have to operate in rock, which has a number of electromagnetically problematic characteristics, which greatly complicate modelling and design of suitable radars. The goal of this project is to demonstrate how the Finite Difference Time Domain (FDTD) method may be used to electromagnetically model and simulate borehole radars and subterranean environments.
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Gauthier, Eric L. "The potential of airborne synthetic aperture radar (SAR) imagery as a basic tool for stratigraphic investigations in forested areas: The Ordovician-Silurian carbonate succession of Anticosti Island, Gulf of St Lawrence, eastern Canada." Thesis, University of Ottawa (Canada), 2003. http://hdl.handle.net/10393/26373.
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Anticosti Island, located in the Gulf of St. Lawrence in eastern Canada, is one of the few places in the world where the Ordovician/Silurian boundary is well preserved and exposed. Its relatively undeformed shallow-water carbonate sequence of approximately 900 m in thickness is rich in fossils and is known to contain traces of hydrocarbons. The island has been for decades the subject of several geological studies, but its stratigraphic succession was never successfully mapped precisely because of its dense forest cover present over almost 95% of its vast territory.
This study provides new mapping tools and techniques to support the geological representation of the island stratigraphic succession. Airborne SAR (Synthetic Aperture Radar) data acquired with the active radar system onboard of the former CCRS (Canada Centre for Remote Sensing) Convair-580 aircraft, in single and fully polarimetric modes and with different viewing geometry, were qualitatively and quantitatively evaluated by means of image interpretation and polarimetric analysis for their mapping potential over the densely forested study area.
The airborne SAR data, supported with ancillary geoscience data sets and derivative topographic related products, have resulted in the availability of valuable and accurate terrain information such as topographic variations associated with the gently inclined recessive and resistant strata of the island succession. It also provided with information on the polarimetric scattering mechanism of the vegetation cover overlying the surface deposits and bedrock geology, suggesting a possible preferential distribution.
With almost 50% of the Canadian territory covered by forest, radar remote sensing, as demonstrated by this study, is a cost-effective tool to produce more accurate regional structural and geological map in areas where traditional mapping campaigns failed due to the presence of an extensive vegetation cover.
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Manjunath, Deepak Rosenblad Brent L. "Point target interferometry as applied to the characterization of localized deformation features." Diss., Columbia, Mo. : University of Missouri--Columbia, 2008. http://hdl.handle.net/10355/7118.
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Title from PDF of title page (University of Missouri--Columbia, viewed on Feb. 23, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Dr. Brent Rosenblad, Dissertation Supervisor. Vita. Includes bibliographical references.
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Quick, Annika M. "Physical and chemical properties of ice in a main valley glacier and a tributary glacier, Gornergletscher, Canton Valais, Switzerland." BYU ScholarsArchive, 2010. https://scholarsarchive.byu.edu/etd/2227.
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Glacier models often fail to incorporate the geometry and/or physical properties of tributaries included in complex glaciers. Tributary glaciers have different source areas and flow conditions than the adjacent main valley glacier. Ice cores (~3m depth) and surface samples (<0.5m depth) were collected from Grenzgletscher (main valley glacier) and Zwillingsgletscher (tributary glacier) in the Gornergletscher system of the Swiss Alps. Stable water isotopes indicate seasonal variation, showing 1-2 annual layers. The mean d18O for Grenzgletscher is ~4.8‰ lower than for Zwillingsgletscher. This difference may be accounted for in part by elevation differences between the accumulation areas (~1.1‰ δ18O), increased avalanching in Grenzgletscher (~1.8 ‰ δ18O), and by varying climatic conditions at the time of precipitation (~0.9-1.4‰ variation in δ18O). Using a kinematic ice flow model, core ages were estimated using effective annual layer thickness (based on seasonal variations), annual accumulation rate and ice thickness. The Grenzgletscher core is ~4 years older than the Zwillingsgletscher core. Based on ages and flow distances, the tributary has a lower flow velocity (63-87 m/yr) compared to Grenzgletscher (61-134 m/yr). To understand thermal properties of the tributary, a 775 m GPR survey (200 MHz) was conducted along a flow line of Zwillingsgletscher. Topographic waves (ogives) observed on the surface are mimicked by the onset of reflectivity 10-20 m below the surface. Reflective regions are interpreted as warmer ice at the pressure melting point, overlain by colder ice. This thermal structure is likely related to acceleration through an ice fall. Since most tributary glaciers include ice falls, thermal properties of tributary glaciers may be different from those of the main valley glacier. The properties and geometry of tributary glaciers are significantly different from main valley glaciers and should therefore be incorporated into glacier models in the future.
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Fugate, Joseph M. "Measurements of Land Subsidence Rates on the North-western Portion of the Nile Delta Using Radar Interferometry Techniques." University of Toledo / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1407516924.
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Sucre, Eric Brandon. "Soil resource heterogeneity and site quality in Southern Appalachian hardwood forests: Impact of decomposing stumps, geology and salamander abundance." Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/29470.
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The Southern Appalachian hardwood forests contain a wide diversity of flora and fauna. Understanding processes that affect nutrient availability in these forests is essential for sound forest management. Three interconnected research projects regarding soil resource heterogeneity were designed to increase our understanding of this ecosystem. The objective of these projects were as follows: 1) to examine and quantify the role of decaying stumps in regards to total carbon (C) and nitrogen (N) pools and fine-root dynamics, 2) compare and contrast the use of ground-penetrating radar (GPR) vs. a soil auger for estimating soil depth and site quality and 3) to evaluate how eastern red-backed salamanders (Plethodon cinereus) affect N-availability.
For the stump study, results show that decomposing stumps occupy approximately 1.2% of the total soil volume and constitute 4% and 10% of total soil N and C pools. Significant differences in N (p = 0.0114), C (p = 0.0172), microbial biomass C (p = 0.0004), potentially mineralizable N (p = 0.0042), and extractable NH4+ (p = 0.0312) concentrations were observed when compared to mineral soil horizons. In particular, potentially mineralizable N was 2.5 times greater in stump soil than the A-horizon (103 vs. 39 mg kg-1), 2.7 times greater for extractable NH4+ (16 vs. 6 mg kg-1) and almost 4 times greater for MBC (1528 vs. 397 mg kg-1). These measured properties suggest higher N-availability, organic matter turnover and N uptake in stump soil versus the bulk soil. 19% of the total fine root length and 14% of fine root surface area also occurred in the stump soil. The increased fine root length suggests higher concentrations of labile nutrient in the stumps since roots often proliferate in areas with higher nutrient availability. Significant differences occurred in N and C concentrations between all four decay classes and the A-horizon, which validated the use of this system and the need to calculate weighted averages based on the frequency and soil volume influenced by each decay class.
In the GPR Study, depth estimations were shallower using a soil auger compared to estimates obtained using GPR across all plots (p = 0.0002; Figure 3.4). On a soil volume basis, this was equivalent to about 3500 m3 of soil per hectare unaccounted for using traditional methods. In regards to using soil depth as a predictor for site quality, no significant relationships were observed with soil depth estimations obtained from the auger (Table 3.3). On the other hand, depth measurements from GPR explained significant amounts of variation across all sites and by physiographic region. Across all sites, soil depth estimates from GPR explained 45.5% of the residual variation (p = 0.001; Table 3.3). When the data were stratified by physiographic region, a higher amount of variation was explained by the regression equations; 85% for the Cumberland Plateau (p = 0.009), 86.7% for the Allegheny Plateau (0.007) and 66.7% for the Ridge and Valley (p = 0.013), respectively (Table 4.2). Results from this study demonstrate how inaccurate current methods can be for estimating soil depth rocky forests soils. Furthermore, depth estimations from GPR can be used to increase the accuracy of site quality in the southern Appalachians.
In the salamander study, no significant salamander density treatment or treatment by time effects were observed over the entire study period (p < 0.05). However, when the data were separated by individual sampling periods a few significant treatment by time interactions occurred: 1) during August 2006 for available NH4+ under the forest floor (i.e. horizontal cation membranes; p = 0.001), 2) August and 3) September 2006 for available NH4+ in the A-horizon (p = 0.026), and 4) May 2007 for available NO3- under the forest floor (p = 0.011). As a result of these trends, an index of cumulative N-availability (i.e. NH4+ and NO3-) under the forest floor and in the A-horizon was examined through the entire study period. Cumulative N-availability under the forest floor was consistently higher in the low- and medium-density salamander treatments compared to the high-density treatment. For cumulative N-availability in the A-horizon, a gradient of high to low N-availability existed as salamander density increased. Factors such as a prolonged drought in 2007 may have affected our ability to accurately assess the effects of salamanders on N-availability. We concluded that higher salamander densities do not increase N-availability.
Implementing methodologies that accurately account for soil nutrient pools such as stump soil, physical properties such as depth and fauna such as salamanders, increase our understanding of factors that regulate site productivity in these ecosystems. As a result, landscape-level and stand-level management decisions can be conducted more effectively.Ph. D.
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Arnold, Karl D. "Sand Sea Extents and Sediment Volumes on Titan from Dune Parameters." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/4112.
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Linear dunes are one of the most abundant and important features on the surface of Titan. We present a model for estimating the volume of dune sediment using the area coverage of Titan's sand seas along with dune widths, spacings, and heights. This helps to reveal local sediment transport and deposition. We refine global dune area estimates from Cassini SAR (Synthetic Aperture RADAR) of 20 million km2 or 24 ± 3% of Titan's surface based on ~50% Cassini RADAR global coverage. Additionally, the global area of sand seas is estimated from a joint analysis of Cassini SAR and ISS (Imaging Science Subsystem) images of 12.8 ± 2 million km2 or 15.4 ± 2.4% of Titan's surface. Also, we provide the first area measurements by sand sea, then describe a new method for estimation of the volume of dune sands across the sand seas based on imagery and measured dune characteristics (i.e., width, spacing, profile, and height) on Titan and in Earth's Namib Sand Sea. Our volume thickness map shows sand sea volumes of 3.8--7.9 x 104 km3 in Senkyo, 6.1--12.7 x 104 km3 in Belet, 5.3--11.0 x 104 km3 in Shangri-La, and also 5.3--11.0 x 104 km3 in Fensal and Aztlan Sand Seas. Our estimate for global dune sand volume is 206,000 km3 - 427,000 km3. The volume map identifies regional changes in sediment thickness implying local variations in transport and deposition and spatial variations in wind strength and direction. We show that dunes might be isolated to equatorial regions because of wind strength, topography, sediment supply, and humidity. Our preliminary map can be used as a tool to understand sediment transport and deposition to explain spatial variations in eolian sediment volume on Titan.
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Smith, Katelynn Marie. "A Geophysical and Geological Analysis of a Regressive-Phase Lake Bonneville Deposit, Pilot Valley, NV." BYU ScholarsArchive, 2018. https://scholarsarchive.byu.edu/etd/6737.
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Pilot Valley, located in the eastern Basin and Range, north of Wendover, UT, contains numerous shorelines and depositional remnants of late Pleistocene Lake Bonneville. These remnants present classic ground penetrating radar (GPR) targets due to their coherent stratification, low clay, low salinity, and low moisture content. Three-dimensional (3D) GPR imaging can resolve fine-scale stratigraphy of these deposits down to a few centimeters. While lake levels fluctuated due to flooding events, climatic changes were the dominant factor in controlling lake levels. In Pilot Valley, the paleowind entered from the northwest, with storms coming from the south, and circulated clockwise around the basin, forming offshore sand bars. On the western side of the valley, a uniquely well-preserved interpreted regressive phase beach deposit, dated late Pleistocene, is hypothesized to have been a point bar shortly after the Provo Shoreline period. 3D GPR data, measured stratigraphic sections, cores, mineralogical analysis, and the collection of gastropod samples for radiocarbon dating constrain a reconstruction of the deposit's depositional environment and local paleoclimate for Lake Bonneville. The GPR images, visualized with state-of-the-art petroleum industry tools, reveal fine-scale stratigraphic detail that can be analyzed using seismic stratigraphy concepts. Our study provides a comprehensive model for ancient pluvial lake-shore depositional environments in a Basin and Range setting using an integration of geological and geophysical data.
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McGraw, Timothy Joseph. "Assessment of Ground-Penetrating Radar and Comparison with Resistivity for Detecting Subsurface Cavities within Karst Topography in North-Central Ohio." Bowling Green State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1277148202.
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Kilgore, Susan Marlena. "The use of multi-channel ground penetrating radar and stream monitoring to investigate the seasonal evolution of englacial and subglacial drainage aystems at the terminus of Exit Glacier, Alaska." Diss., University of Iowa, 2013. https://ir.uiowa.edu/etd/4864.
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Concerns regarding the issue of climate change and, in particular, the rapid retreat of glaciers around the world, have placed great importance on glacial monitoring. Some of the methods most commonly used to observe glacial change--direct mass balance measurements and remote sensing--provide valuable information about glacier change. However, these methods do not address the englacial and subglacial environments.
Surface meltwater that enters englacial and subglacial hydrological networks can contribute to acceleration of ice flow, increased calving on marine-terminating glaciers, surges or outburst floods, and greater overall ablation rates. Because subsurface drainage systems often freeze during the winter and re-form each summer, examining the seasonal evolution of these networks is crucial for assessing the impact that internal drainage may have on the behavior of a glacier each year.
The goal of this study is to determine the role englacial and subglacial drainage system evolution plays in influencing summer ablation and discharge at the terminus of Exit Glacier, a small valley glacier located in South-central Alaska. During the summers of 2010 and 2011, we used ground-penetrating radar (GPR) to locate internal drainage features on the lower 100 meters of the glacier. GPR surveys were conducted in June and August of each year in an effort to observe the evolution of the drainage systems over the course of an ablation season. Three antenna frequencies--250, 500, and 800 MHz--were used on a dual frequency GPR so that various resolutions and depths in the ice could be viewed simultaneously.
Stream monitoring was conducted to document discharge in the proglacial stream throughout the 2011 season. These data were compared with weather records to differentiate noticeable meltwater releases from precipitation events. Additionally, morphological changes in the glacier were observed through photographic documentation.
Throughout the observation period, significant subglacial tunnels appeared, followed by the collapse of terminal ice above the tunnels. This phenomenon was most noticeable in 2011. These observations indicate that the internal drainage systems near the terminus of Exit Glacier became very well-developed each summer, and contributed approximately 75 meters of ice loss between June, 2010 and August, 2011.
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Pitman, Lacey. "GROUND-PENETRATING RADAR IMAGES OF A DYE TRACER TEST WITHIN THE UNSATURATED ZONE AT THE SUSQUEHANNA-SHALE HILLS CZO." Master's thesis, Temple University Libraries, 2014. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/306057.
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GeologyM.S.
Dye tracer and time-lapse ground-penetrating radar (GPR) were used to image preferential flow paths in the shallow, unsaturated zone on hillslopes in two adjacent watersheds within the Susquehanna-Shale Hills Critical Zone Observatory (CZO). At each site we injected about 50 L of water mixed with brilliant blue dye (4 g/L) into a trench cut perpendicular to the slope (~1.0 m long by ~0.20 m wide by ~0.20 m deep) to create a line of infiltration. GPR (800 MHz antennae with constant offset) was used to monitor the movement of the dye tracer downslope on a 1.0 m x 2.0 m grid with a 0.05 m line spacing. The site was then excavated and the stained pathways photographed to document the dye movement. We saw a considerable difference in the pattern of shallow preferential flow between the two sites despite similar soil characteristics and slope position. Both sites showed dye penetrating down to saprolite (~0.40 m); however, lateral flow migration between the two sites was different. At the Missed Grouse field site, the lateral migration was ~0.55 m as an evenly dispersed plume, but at distance of 0.70 m a finger of dye was observed. At the Shale Hills field site, the total lateral flow was ~0.40 m, dye was barely visible until the excavation reached ~0.10 m, and there was more evidence of distinct fingering in the vertical direction. Based on laboratory and field experiments as well as processing of the radargrams, the following conclusions were drawn: 1) time-lapse GPR successfully delineated the extent of lateral flow, but the GPR resolution was insufficient to detect small fingers of dye; 2) there was not a distinct GPR reflection at the regolith-saprock boundary, but this interface could be estimated from the extent of signal attenuation; 3) the preliminary soil moisture conditions may explain differences in the extent of infiltration at the two sites; 4) rapid infiltration into the underlying saprock limited the extent of shallow lateral flow at both sites and can be seen using the mass balance calculation and the lateral extent of dye within the radargrams; and 5) variations in flow patterns were observed between sites with similar settings at Susquehanna-Shale Hills CZO.
Temple University--Theses
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Arnold, Billie J. "A Comparitive Analysis of Glacial Landforms: Skeidararsandur Iceland and Northwestern Pennsylvania." Kent State University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=kent1389103411.
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Rosa, Maria Luiza Correa da Camara. "Geomorfologia, estratigrafia de sequências e potencial de preservação dos sistemas Laguna Barreira do Quaternário Costeiro do Rio Grande do Sul." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2012. http://hdl.handle.net/10183/66367.
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No registro estratigráfico da Planície Costeira do Rio Grande do Sul estão presentes quatro sequências deposicionais de alta frequência, correspondentes a quatro sistemas do tipo laguna-barreira (I a IV). Estas sequências possuem idades pleistocênicas e holocênica e se desenvolveram em resposta a ciclos glacioeustáticos da ordem de 100 ka. O sistema costeiro holocênico, relacionado à sequência mais jovem (IV), possui setores contemporâneos com padrões de empilhamento opostos. Partindo desta observação duas hipóteses foram formuladas e investigadas. A primeira hipótese refere-se à existência de padrões de empilhamento opostos também nas sequências deposicionais mais antigas (I, II e III) e a segunda é a de que estes padrões estejam expressos na morfologia das barreiras costeiras. Uma análise geomorfológica e estratigráfica foi realizada através das geotecnologias, com o emprego do sensoriamento remoto, do geoprocessamento, de sistemas de posicionamento e do método geofísico do georradar. Os dados foram obtidos em diferentes setores da planície costeira, com enfoque na região sul, entre a fronteira com o Uruguai (Chuí) e a desembocadura da Lagoa dos Patos (Rio Grande). Nesta região, estão presentes os sistemas laguna-barreira II, III e IV, portanto estes contaram com um maior detalhamento. As interpretações realizadas permitiram estabelecer um arcabouço estratigráfico, com a definição das principais superfícies chave e tratos de sistemas, além de um modelo de evolução paleogeográfica para a região sul. A existência dos padrões de empilhamento retrogradacional, progradacional e degradacional foi constatada nas sequências deposicionais mais antigas. Ainda que estas não tenham sido datadas foi possível inferir que comportamentos distintos tenham ocorrido simultaneamente ao longo das linhas de costa relacionadas a estas sequências deposicionais. A variabilidade do comportamento dos sistemas costeiros foi verificada também através das suas características morfológicas, as quais possuem grande influência em seu potencial de preservação. Contudo, alterações posteriores, de origem erosiva e/ou deposicional, modificaram significativamente as feições originais. A aplicação das geotecnologias referidas acima, através da perspectiva da estratigrafia moderna, permitiu ampliar o conhecimento acerca dos sistemas deposicionais costeiros, especialmente das sequências relacionadas aos sistemas laguna-barreira II e III.The stratigraphic record of Rio Grande do Sul Coastal Plain embraces four high-frequency depositional sequences corresponding to four barrier-lagoon systems (I to IV). These sequences have been developed during the Pleistocene and Holocene, in response to glacioeustatic cycles of 100 ka. The Holocene coastal system, related to the younger sequence (IV), exhibits contemporaneous sectors with opposites stacking patterns. From this observation, two hypotheses were formulated and investigated. The first hypothesis was that the opposite stacking patterns also exist in the older depositional sequences (I, II and III), and the second was that these patterns are expressed, today, in the morphology of the coastal barriers. A geomorphologic and stratigraphic analysis was performed applying various geotechnologies, like remote sensing, geoprocessing, positioning systems and the geophysical method of ground penetrating radar (GPR). The data were obtained in different sectors of the coastal plain, with a focus on the southern region between the border with Uruguay (Chui) and the inlet of Lagoa dos Patos lagoon (Rio Grande). In this region the barrier-lagoon systems II, III and IV were identified and studied in greater detail. The interpretations allowed establishing a stratigraphic framework, setting out the main key surfaces and systems tracts, and a paleogeographic model of the evolution of the southern coastal plain. The existence of retrogradational, progradational and degradacional stacking patterns was found in the older sequences. Although the absolute age of these units has not been determined, it was possible to infer that different behaviors have occurred simultaneously along the shorelines related to these depositional sequences. The variability on the behavior of the coastal systems was also verified by their morphological characteristics, which have great influence on their preservation potential. However, subsequent changes due to erosive and/or depositional events may have significantly modified the original features. The application of geotechnologies from the perspective of modern stratigraphy improved the knowledge of coastal depositional systems, especially of the sequences related to barrier-lagoon systems II and III.
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Courtland, Leah Michelle. "Deciphering Deposits: Using Ground Penetrating Radar and Numerical Modeling to Characterize the Emplacement Mechanisms and Associated Energetics of Scoria Cone Eruption and Construction." Scholar Commons, 2013. http://scholarcommons.usf.edu/etd/4460.
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Our understanding of tephra depositional processes is significantly improved by high-resolution ground-penetrating radar (GPR) data collected at Cerro Negro volcano, Nicaragua. The data reveal three depositional regimes: (1) a near-vent region on the cone itself, where 10 GPR radargrams collected on the western flank show quantifiable differences between facies formed from low energy normal Strombolian and higher energy violent Strombolian processes, indicating imaging of scoria cone deposits may be useful in distinguishing eruptive style in older cones where the proximal to distal tephra blanket has eroded away; (2) a proximal zone in which horizons identified in crosswind profiles collected at distances of 700 and 1,000 m from the vent exhibit Gaussian distributions with a high degree of statistical confidence, with tephra thickness decreasing exponentially downwind from the cone base (350 m) to ~ 1,200 m from the vent, and where particles fall from a height of less than ~2 km; and (3) a medial zone, in which particles fall from ~4 to 7 km and the deposit is thicker than expected based on thinning trends observed in the proximal zone of the deposit, indicating a transition from sedimentation dominated by fallout from plume margins to that dominated by fallout from the buoyant eruption cloud. Horizons identified in a crosswind profile at 1600 m from vent exhibit Gaussian distributions, again with high degrees of statistical confidence.
True diffusion coefficients are calculated from Gaussian fits of crosswind profiles and do not show any statistical variation between zones (2) and (3). Data display thinning trends that agree with the morphology predicted by the advection-diffusion equation to a high degree of statistical confidence, validating the use of this class of models in tephra forecasting.
One such model, the Tephra2 model, is reformulated for student use. A strategy is presented for utilizing this research-caliber model to introduce university undergraduates to key concepts in model literacy, encouraging students to develop a deeper understanding of the applicability and limitations of hazard models generally. For this purpose, the Tephra2 numerical model is implemented on the VHub.org website, a venture in cyberinfrastructure that brings together volcanological models and educational materials, and provides students with the ability to explore and execute sophisticated numerical models like Tephra2.
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Estrada, Hector. "Importance of the subsurface limestome and pockets of soil as sources of water for tree species in Yucatan, Mexico." Diss., UC access only, 2009. http://proquest.umi.com/pqdweb?index=84&did=1914305761&SrchMode=1&sid=1&Fmt=7&retrieveGroup=0&VType=PQD&VInst=PROD&RQT=309&VName=PQD&TS=1270233485&clientId=48051.
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Hubbard, Jackson Durain. "3D Cave and Ice Block Morphology from Integrated Geophysical Methods: A Case Study at Scărişoara Ice Cave, Romania." Scholar Commons, 2017. http://scholarcommons.usf.edu/etd/6712.
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Scărişoara Ice Cave has been a catalyst of scientific intrigue and effort for over 150 years. These efforts have revealed and described countless natural phenomena – and in the process have made it one of the most studied caves in the world.
Of especial interest is the massive ice block located within its Great Hall and scientific reservations. The ice block, which is the oldest and largest known to exist in a cave, has been the focus of multiple surveying and mapping efforts, typically ones utilizing traditional equipment. In this study, the goals were to reconstruct the ice block/cave floor interface and to estimate the volume of the ice block. Once the models were constructed, we aimed to study the relationships between the cave and ice block morphologies.
In order to accomplish this goal, three (3) main datasets were collected, processed, and amalgamated. Ground penetrating radar data was used to discern the floor morphology below the ice block. Over 1,500 photographs were collected in the cave and used with Structure from Motion photogrammetry software to construct a texturized 3D model of the cave and ice surfaces. And a total station survey was performed to scale, georeference, and validate each model. Once georeferenced, the data was imported into an ArcGIS geodatabase for further analysis.
The methodology described within this study provides a powerful set of instructions for producing highly valuable scientific data, especially related to caves. Here, we describe in detail the novel tools and software used to validate, inspect, manipulate, and measure morphological information while immersed in a fully 3D experience.
With this methodology, it is possible to easily and inexpensively create digital elevation models of underground rooms and galleries, to measure the differences between surfaces, to create 3D models from the combination of surfaces, and to intimately inspect a subject area without actually being there.
At the culmination of these efforts, the partial ice block volume was estimated to be 118,000 m3 with an uncertainty of ± 9.5%. The volume computed herein is significantly larger than previously thought and the total volume is likely significantly larger, since certain portions were not modeled during this study. In addition, the morphology of ceiling enlargement was linked to areas of high elevation at the base of the ice block. A counterintuitive depression was recognized at the base of the Entrance Shaft. The thickest areas of the ice were identified for future coring projects. And combining all this a new informational allowed us to propose a new theory on the formation of the ice block and to decipher particular speleogenetic aspects.
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Hazard, Colby. "Validity of Holocene Analogs for Ancient Carbonate Stratigraphic Successions: Insights from a Heterogeneous Pleistocene Carbonate Platform Deposit." BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/5496.
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Observations of modern carbonate depositional environments and their accompanying depositional models have been used for decades in the reconstruction and interpretation of ancient carbonate depositional environments and stratigraphic successions. While these Holocene models are necessary for interpreting their more ancient counterparts, they inherently exclude important factors related to the erosion, diagenesis, and ultimate preservation of sediments and sedimentary structures that are ubiquitous in shallow marine carbonate environments. Andros Island, Bahamas is an ideal location to examine the validity of Holocene conceptual models, where geologically young (Late Pleistocene) limestones can be studied immediately adjacent to their well-documented modern equivalents. For this study, two 3D ground-penetrating radar (GPR) datasets (200 MHz and 400 MHz) were collected at a schoolyard in northwest Andros. These surveys reveal the geometries and internal characteristics of a peloidal-oolitic sand wave and tidal channel in unprecedented detail. These two prominent features are underlain by low-energy lagoonal wackestones and packstones, and are bordered laterally to the northwest by wackestones-packstones intermixed with thin sheets of peloidaloolitic grainstone. A deeper radar surface is observed at approximately 6 m depth dipping gently to the west, and is interpreted to be a karstified exposure surface delineating the base of a complete depositional sequence. Interpretation of the 3D radar volumes is enhanced and constrained by data from three cores drilled through the crest and toe of the sand wave, and through the tidal channel. This study is the first of its kind to capture the complex heterogeneity of a carbonate depositional package in three dimensions, where various depositional environments, sedimentary structures, and textures (mudstone to grainstone) have been preserved within a small volume.The results from this study suggest that the degree of vertical and lateral heterogeneity in preserved carbonate successions is often more complex than what can be observed in modern depositional environments, where sediments can generally only be observed in two dimensions, at an instant in time. Data from this study demonstrate the value of using two overlapping GPR datasets at differing resolutions to image the internal characteristics of a complete carbonate depositional package in three dimensions. From these datasets, a depositional model similar to other Holocene and Pleistocene carbonate depositional models is derived.
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Pathier, Erwan. "Apports de l'interférométrie radar différentielle à l'étude de la tectonique active de Taiwan." Phd thesis, Université de Marne la Vallée, 2003. http://tel.archives-ouvertes.fr/tel-00007464.
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L'île de Taiwan est le résultat de la collision, toujours active, des plaques Philippines et Eurasie. Ce travail a pour objet de mieux comprendre les processus tectoniques qui accompagnent la croissance actuelle de l'orogène, en utilisant l'interférométrie radar différentielle satellitaire en complément des autres méthodes d'investigation existantes. Cette technique fournit des cartes de déformation instantanée du sol (de quelques années à quelques jours) étendues, précises et denses. Après avoir détaillé les principes et les limites de cette mesure, ainsi que son potentiel à Taiwan, la technique est appliquée, avec des données issues des satellites ERS, à deux phénomènes tectoniques caractéristiques du développement de cette chaîne de collision. (1) Le séisme de Chi-Chi (1999, Mw = 7.6) sur la frontière Ouest de l'orogène, correspond à la réactivation de la faille chevauchante majeure de Chelungpu. L'interférométrie radar et le GPS permettent de quantifier avec une précision centimétrique les déformations cosismiques métriques affectant le bloc chevauché et d'y détecter les réactivations, induites par le choc principal, des failles de Changhua et de Tuntzuchiao. La comparaison avec les déplacements prédits par les modèles publiés de distribution de glissement sur la faille montre les limites de ces modèles. (2) Au SW de l'île, l'interférométrie radar permet la quantification de la croissance rapide (1,5 cm/an de 1993 à 2000) d'un anticlinal d'axe N-S, traduisant la propagation du front de déformation sur la marge continentale chinoise à l'Ouest. Ce phénomène tectonique est modélisé par une structure en "pop-up" limitée au nord par une rampe latérale, orientée E-W.
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Guha, Swagata. "Variable-Density Flow Models of Saltwater Intrusion in Coastal Landforms in Response to Climate Change Induced Sea Level Rise and a Chapter on Time-Frequency Analysis of Ground Penetrating Radar Signals." Scholar Commons, 2010. http://scholarcommons.usf.edu/etd/3490.
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Populations residing on and near the world’s coasts have become increasingly dependent on coastal groundwater for their supply of freshwater. Under the conditions of predicted climate changes, the expected rise in global sea level can adversely affect the quality and quantity of freshwater resources in coastal areas as a result of saltwater intrusion.
In this study, a suite of two- and three-dimensional variable-density groundwater flow models of major coastal landforms (e.g. deltas, estuaries and small islands) has been constructed to assess the effects of sea level rise (SLR), using different SLR rates of 0.5 m, 1m and 1.5 m over the next 90 years, from 2010-2100. The model results indicate that in natural coastal systems the extent of saltwater intrusion is significantly controlled by the stratigraphy of the depositional environments. Among deltaic aquifers, wave-dominated deltas are more prone to saltwater intrusion than river- and tide-dominated deltas. In case of a partially mixed, microtidal estuary, SLR can cause extensive porewater salinity increases, especially within estuarine sand deposits. Simulations of atoll and barrier islands reveal that carbonate atoll islands with high conductivity units, are severely affected by SLR, resulting in significant reduction of the volume of freshwater lens. In contrast, migrating sandy barrier islands could retain their freshwater resources with rising sea level under conditions of increased recharge, assuming the barriers can migrate in response to SLR. The freshwater lens of barrier island aquifers would reduce in size due to increased evapotranspiration caused by change in vegetation pattern.
When examined for anthropogenic impacts of groundwater withdrawal through pumping, all the coastal aquifers show evidence of saltwater intrusion, with varying degrees of impact. Wave-dominated deltas are more affected by groundwater withdrawal than river- and tide-dominated deltaic aquifers. Saltwater intrusion in atoll islands is further enhanced by pumping withdrawal. It is evident from the results of the simulations that, the potential effects on coastal aquifers of groundwater withdrawals for potable water can easily exceed the adverse effects of SLR in terms of salinity increase.
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Tinard, Pierre. "Caractérisation et modélisation des déplacements du sol associés à l'activité volcanique du Piton de la Fournaise, île de La Réunion, à partir de données interférométriques.Août 2003 – Avril 2007." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2007. http://tel.archives-ouvertes.fr/tel-00271539.
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Le Piton de la Fournaise est l'un des volcans les plus actifs au monde. Depuis mi-2003, 14 éruptions sont survenues. Une surveillance en continu de cette période d'intense activité a été réalisée à partir de données ASAR-ENVISAT. Les interférogrammes calculés fournissent un enregistrement précis des déplacements de l'édifice. L'étude a permis de démontrer le fort potentiel de l'InSAR comme outil de surveillance opérationnelle de l'activité du Piton de la Fournaise. De plus, les données InSAR ont été utilisées afin de caractériser les sources des déplacements afin de mieux comprendre la géométrie des systèmes de stockage et les modalités de transfert de magma dans l'édifice. L'analyse des données en utilisant une méthode 3D-MBEM mixtes combinée à une inversion de type Monte-Carlo a été réalisée. La plupart des déplacements co-éruptifs peut être expliquée par l'injection de dykes à pendage 45° à 70° vers l'Est ou sub-verticaux s'enracinant sous le cône sommital vers 1500 m d'altitude.
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Liu, Yung-Chun. "Tectonics of Saturn's Moon Titan AND Tsunami Modeling of the 1629 Mega-thrust Earthquake in Eastern Indonesia." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/5731.
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Chapter 1-2:The Cassini RADAR mapper has imaged elevated blocks and mountains on Titan we term ‘ridges’. Two unresolved problems regarding Titan's surface are still debated: what is the origin of its ridges and was there tectonic activity on Titan? To understand the processes that produced the ridges, in this study, (1) we analyze the distribution and orientation of ridges through systematic geomorphologic mapping and (2) we compare the location of the ridges to a new global topographic map to explore the correlation between elevation and ridges and the implications for Titan's surface evolution. Globally, the orientation of ridges is nearly E-W and the ridges are more common near the equator than at the poles, which suggests a tectonic origin for most of the ridges on Titan. In addition, the ridges are found to preferentially lie at higher-than-average elevations near the equator. We conclude the most reasonable formation scenario for Titan's ridges is that contractional tectonism built the ridges and thickened the icy lithosphere, causing regional uplift. The combination of global and regional tectonic events, likely contractional in nature, plus enhanced fluvial erosion and sedimentation near the poles, would have contributed to shaping Titan's tectonic landforms and surface morphology to what we see today. However, contractional structures (i.e. thrusts and folds) require large stresses (8~10 MPa), the sources of which probably do not exist on Titan. Liquid hydrocarbons in Titan's near subsurface must play a role similar to that of water on Earth and lead to fluid overpressures, which enable contractional deformation at smaller stresses (< 1MPa) by significantly reducing the shear strength of materials. We show that crustal conditions with enhanced pore fluid pressures on Titan favor the formation of thrust faults and related folds, in a contractional stress field. The production of folds, as on Earth, is facilitated by the presence of crustal liquids to weaken the crust. These hydrocarbon fluids have played a key role in Titan's tectonic evolutionary history, leaving it the only icy body on which strong evidence for contractional tectonism exists. Chapter 3: Arthur Wichmann's ‘Earthquakes of the Indian Archipelago’ documents several large earthquakes and tsunami throughout the Banda Arc region that can be interpreted as mega-thrust events. However, the source regions of these events are not known. One of the largest and well-documented events in the catalog is the great earthquake and tsunami affecting the Banda islands on 1 August 1629. It caused severe damage from a 15-meter tsunami that arrived at the Banda Islands about a half hour after violent shaking stopped. The earthquake was also recorded 230 km away in Ambon, but no tsunami is mentioned. This event was followed by at least 9 years of uncommonly frequent seismic activity in the region that tapered off with time, which can be interpreted as aftershocks. The combination of these observations indicates that the earthquake was most likely a mega-thrust event. We use an inverse modeling approach to numerically reconstruct the tsunami, which constrains the likely location and magnitude of the 1629 earthquake. Only linear numerical models are applied due to the low-resolution of bathymetry in the Banda Islands and Ambon. Therefore, we apply various wave amplification factors (1.5 to 4) derived from simulations of recent, well-constrained tsunami to bracket the upper and lower limits of earthquake moment magnitudes for the event. The closest major earthquake sources to the Banda Islands are the Tanimbar and Seram Troughs of the Banda subduction/collision zone. Other source regions are too far away for such a short arrival time of the tsunami after shaking. Moment magnitudes predicted by the models in order to produce a 15 m tsunami are Mw of 9.8 to 9.2 on the Tanimbar Trough and Mw 8.8 to 8.2 on the Seram Trough. The arrival times of these waves are 58 minutes for Tanimbar Trough and 30 minutes for Seram Trough. The model also predicts 5 meters run-up for Ambon from a Tanimbar Trough source, which is inconsistent with the historical records. Ambon is mostly shielded from a wave generated by a Seram Trough Source.We conclude that the most likely source of the 1629 mega-thrust earthquake is the Seram Trough. Only one earthquake > Mw 8.0 is recorded instrumentally from the eastern Indonesia region although high rates of strain (50-80 mm/a) are measured across the Seram section of the Banda subduction zone. Enough strain has already accumulated since the last major historical event to produce an earthquake of similar size to the 1629 event. Due to the rapid population growth in coastal areas in this region, it is imperative that the most vulnerable coastal areas prepare accordingly.
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Scaggs, Laura M. "A Geophysical Study of Subsurface Paleokarst Features and Voids at Ohio Caverns, Champaign County, Ohio." University of Akron / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1396104600.
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Heiner, Brandon D. "Multi-Scale Neotectonic Study of the Clear Lake Fault Zone in the Sevier Desert Basin (Central Utah)." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/3840.
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A multi-scale high-resolution geophysical and geological study was conducted in the Sevier Desert, central Utah, found within the Colorado Plateau-Basin and Range Transition Zone. The region is marked by with Quaternary volcanics and faulting as young as 660 yr B.P., with many fault scarps thought to have the potential for 7+ magnitude earthquakes. Three locations within the Sevier Desert which represent three different tectonic expressions of possible faulting at the surface were selected. These include a location found within surface sedimentation, a location with surface sedimentation and sub-surface basalts and a location with basalts, at the surface with very limited sedimentation. A suite of geophysical data were obtained including the use of P-wave, SH-wave, ground-penetrating radar (GPR). Auger holes, microprobe glass analysis, and mapping information were also completed in order to constrain and gain a more complete understanding of the sub-surface structure. These data were used to determine if there are sub-surface expressions of the possible surface scarps and if all the faults within the fault zone have the same structural style. The possible surface fault expressions were found to be connected to sub-surface fault expressions but with differing results within both sediments and basalts. Our data show that a multi-scale approach is needed to obtain a complete view of tectonic activity. The area faulting in the Sevier Desert penetrates at depth involving multiple complex styles that include some faulting that cuts recent lava flows and some that do not. The evidence also indicates that in at least some area faulting was episodic and others may be single events having implications on level of activity and hazard.
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Cist, David Bishop. "Ground penetrating radar characterization of geologic structure beneath the Aberjona wetland." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/53040.
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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1999.Includes bibliographical references (leaves 232-236).
Ground penetrating radar (GPR) surveys are performed to determine geologic structure and to assist in the characterization and eventual modeling of ground water flow beneath the Well-H region of the Aberjona River in Woburn, Massachusetts. Even though cone penetrometer and coring studies provide point source "ground truth" data about the stratigraphy, soil chemistry, and composition of the first seven meters of peat, sand and silt they are time-consuming and labor intensive. The advantage of GPR is its ability to extend point-source ground truth information into two and three dimensions. This dissertation provides an accurate geologic model of one section of the Aberjona wetland by improving the state of three-dimensional GPR imaging. Data fusion, target implantation, and a novel 3-D migration technique are combined to render the subsurface volume accurately to resolutions of about 30 centimeters in all directions. The technique was tested using various synthetically generated models as well as carefully constructed test pits to verify its accuracy and estimate error. For our surveys in the wetland, we verify the accuracy of our method using the large database of "ground truth" information about subsurface structure and soil properties. We use this information along with data collected for this project to assemble what 3-D geological information we can. For example, direct measurements of soil bulk properties are made at various depths in several locations. Borehole conductivity surveys not only confirm core sample measurements, but also give deep conductivity information not otherwise available. Cone penetrometer surveys provide high vertical resolution to map stratigraphic variation. A 3-D resistivity survey provides general information about the conductivity of the site. In addition to ground truth measurements, several different types of radar surveys were employed to estimate soil electrical properties. A new method of Vertical Radar Profiling (VRP) was developed to provide velocity information at different locations and various depths throughout the wetland. Morphing methods were applied as an interpolation tool for surveys with broadly spaced profiles. A fast three dimensional migration algorithm was developed specifically for GPR imaging that incorporates layered velocity information and soil electrical conductivity. Ultimately, this technique is shown to offer a means of mapping larger regions of wetland stratigraphy more accurately than was currently feasible.
by David Bishop Cist.
Ph.D.
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Smith, Courtney B. "GRAIN SIZE ANALYSIS OF A PRECURSOR TO A FLYING SPIT IN THE WESTERN MAUMEE BASIN IN NW OHIO, AND COMPARISON TO THE PRESQUE ISLE FLYING SPIT." Kent State University / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=kent1626887825114558.
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Santos, Elaine Marra dos. "Análise de imagens do satélite ALOS PALSAR (Banda L, modo polarimétrico) para discriminação de coberturas de terras no Distrito Federal." reponame:Repositório Institucional da UnB, 2009. http://repositorio.unb.br/handle/10482/4132.
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Dissertação (mestrado)—Universidade de Brasília, Instituto de Geociências, 2009.Submitted by Allan Wanick Motta (allan_wanick@hotmail.com) on 2010-03-15T17:37:18Z No. of bitstreams: 1 2009_ElaineMarradosSantos.pdf: 5054960 bytes, checksum: 05b807c07bfb99f6249d1d65c615ab4b (MD5)
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Mapas de cobertura de terras são importantes fontes de dados para monitoramentos ambientais, preservação da biodiversidade, zoneamentos sócio-econômico e ambiental e monitoramento de mudanças climáticas locais e globais, dentre outras atividades. No Distrito Federal (DF), os mapeamentos de cobertura de terras têm sido realizados com base em imagens ópticas. No entanto, imagens de radar constituem-se em uma alternativa viável às imagens ópticas, pois independem das condições de iluminação solar, podem atravessar nuvens e fumaças e podem detectar diferenças nas estruturas da vegetação. O objetivo deste estudo é analisar o potencial das imagens de radar adquiridas pelo satélite ALOS PALSAR para o mapeamento de cobertura de terras. Uma imagem de 25 de abril de 2007 (banda L, polarizações HH, HV e VV, final da estação chuvosa) de parte do DF foi convertida para coeficientes de retroespalhamento (s°) e processada por meio da técnica de segmentação por crescimento de regiões. Valores de s° foram analisados estatisticamente por meio de cluster analysis. Os segmentos foram convertidos para o formato shape e mapeados visualmente na tela do monitor de computador, com suporte de um pacote de programas de sistema de informações geográficas, em uma escala de mapeamento compatível com 1:100.000. As seguintes classes temáticas foram consideradas: Áreas Urbanas consolidadas, Áreas Urbanas em consolidação, Culturas Agrícolas, Pastagens Cultivadas, Reflorestamento, Campos, Cerrado Típico, Matas de Galeria, Matas Indiscriminadas e Reservatórios. A exatidão de mapeamento, fornecido pelo índice kappa e calculado a partir da verificação de 86 pontos em campo, foi de 0,69. _______________________________________________________________________________ ABSTRACT
Land cover maps are important source of data for environmental monitoring, biodiversity conservation, social, economic and environmental zonning, and local and global climatic changes, among other activities. In the Federal District of Brazil (FD), land cover mappings have been obtained from optical images. However, radar data are valuable alternative for the optical remote sensing since they are independent of solar illumination, can penetrate clouds and smokes and can depict differences in canopy structures. The goal of this study is to analyze the potential of ALOS PALSAR radar data for land cover mapping. A scene covering part of FD, obtained in April 25th, 2007 (L-band, HH, HV and VV polarizations, end of wet season) was converted into backscattering coefficients (s°) and processed through the image segmentation technique by growing region. Values of s° were analyzed with the support of cluster analysis. The segments were converted into shape format and mapped visually in the computer screen using a geographical information system software package, in a 1:100,000 mapping scale. The following thematic classes were considered: consolidated urban areas, urban areas in consolidation, croplands, planted pasturelands, reforestations, grasslands, shrub Cerrado, gallery forests, indiscriminated forests and reservoirs. The accuracy of the final map, provided by the kappa index and obtained from 86 field checking points, was 0.69.
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Cartwright, Richard. "Analysis of Channel Networks and the Potential for Sediment Transport in the Vicinity of the North Polar Seas of Titan." Digital Archive @ GSU, 2009. http://digitalarchive.gsu.edu/geosciences_theses/20.
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This study analyzes the available radar evidence in order to describe the morphology of channel networks around the north polar seas of Titan. Critical flow depths necessary to entrain water-ice grains, and denudation rates for a north polar channel network are discussed. The results indicate that channel networks on Titan have similar morphologies to channel networks cut by water on Earth. We also find that water-ice sediment should be readily entrained in the headwaters and downstream sections of the analyzed Titanian basin, given sufficient flow depths of liquid hydrocarbons. Also, the importance of slope and the elevated topography of the highlands surrounding the polar lakes are considered, as well as potential formation theories for the elevated highlands and low-lying maria that dominate the north polar region.
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Johnson, Jeffrey Roy. "Geologic investigations of the Venusian surface using Magellan radar imagery, altimetry, and radiometry." Diss., The University of Arizona, 1994. http://hdl.handle.net/10150/186993.
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A comprehensive study of Magellan multiple-Cycle synthetic aperture radar (SAR) data from Venus reveals morphological, surface roughness, and dielectric variations valuable in understanding emplacement mechanisms of fluidized ejecta blanket (FEB) craters, nearby plains and lava flows. FEB deposits develop variable channel morphologies related to parameters such as crater diameter and flow length. This study develops new procedures of digital unit mapping and polygon-filling algorithms using Magellan SAR, altimetry, and radiometry data. These techniques allow the extraction of radiophysical information for geologic materials such as: (1) specific backscatter (σₒ) behavior; (2) average calculated values of emissivity, rms slopes, corrected reflectivity, and the diffuse component of reflectivity; and (3) variations in radar properties along longitudinal traverses that are best explained by surface roughness trends at several spatial scales and/or dielectric variations. Backscatter curve slopes of the FEBs studied here are consistent with surface textures that are either transitional between a'a and pahoehoe-like or more pahoehoe-like. Increasing FEB roughnesses downflow are interpreted to be associated with more lava-like flows, while decreasing roughnesses are more similar to trends typical of gravity (pyroclastic-like or debris-like) flows. Most commonly, FEB crater flow materials exhibit either gravity flow-like styles or transitions from proximal, lava/melt-like flow styles to distal, gravity flow-like styles. Some FEBs show more complicated behavior, however, or appear to be more dominated by dielectric differences downflow, as inferred from correlations between the data sets. Such transitions may result from changes in local topography or from overlapping of flow lobes during FEB emplacement. Computer modeling of FEB flows over topography was performed using modified programs previously applied to Mt. St. Helens' flows. These models demonstrate for the three FEB craters studied that the flows require relatively low initial velocities as well as low values of yield strength and viscosity. Geologic mapping of USGS quadrangle Barrymore (V59) shows evidence of an extensive plains formation event obscuring older local tectonic and volcanic structures, followed by regional and localized compression, forming wrinkle ridges and ridge belts. Application of terrestrial ERS-1 SAR data of the Channeled Scabland region shows backscatter values indicative of surfaces somewhat rougher than terrestrial a'a flows.
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Yeboah-Forson, Albert. "Hydrogeophysical Characterization of Anisotropy in the Biscayne Aquifer Using Geophysical Methods." FIU Digital Commons, 2013. http://digitalcommons.fiu.edu/etd/919.
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The anisotropy of the Biscayne Aquifer which serves as the source of potable water for Miami-Dade County was investigated by applying geophysical methods. Electrical resistivity imaging, self potential and ground penetration radar techniques were employed in both regional and site specific studies. In the regional study, electrical anisotropy and resistivity variation with depth were investigated with azimuthal square array measurements at 13 sites. The observed coefficient of electrical anisotropy ranged from 1.01 to 1.36. The general direction of measured anisotropy is uniform for most sites and trends W-E or SE-NW irrespective of depth. Measured electrical properties were used to estimate anisotropic component of the secondary porosity and hydraulic anisotropy which ranged from 1 to 11% and 1.18 to 2.83 respectively. 1-D sounding analysis was used to models the variation of formation resistivity with depth. Resistivities decreased from NW (close to the margins of the everglades) to SE on the shores of Biscayne Bay. Porosity calculated from Archie's law, ranged from 18 to 61% with higher values found along the ridge. Higher anisotropy, porosities and hydraulic conductivities were on the Atlantic Coastal Ridge and lower values at low lying areas west of the ridge. The cause of higher anisotropy and porosity is attributed to higher dissolution rates of the oolitic facies of the Miami Formation composing the ridge. The direction of minimum resistivity from this study is similar to the predevelopment groundwater flow direction indicated in published modeling studies. Detailed investigations were carried out to evaluate higher anisotropy at West Perrine Park located on the ridge and Snapper Creek Municipal well field where the anisotropy trend changes with depth. The higher anisotropy is attributed to the presence of solution cavities oriented in the E-SE direction on the ridge. Similarly, the change in hydraulic anisotropy at the well field might be related to solution cavities, the surface canal and groundwater extraction wells.
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Durand, Philippe. "Traitement des donnees radar varan et estimation de qualites en geologie, geomorphologie et occupation des sols." Paris 7, 1988. http://www.theses.fr/1988PA077183.
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Ce travail porte sur l'exploitation thematique des donnees radar varan en geologie et l'occupation des sols. Les deux premieres parties passent en revue les pretraitements subis par l'image: elimination du bruit et corrections geometriques. Ces chapitres suivants exploitent l'analyse multisources, ainsi que les methodes issus de la morphologie mathematique et de l'analyse de texture
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Villi, Filippo. "Analisi dei fenomeni franosi lenti nell'abitato di Gaggio Montano mediante interferometria radar." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amslaurea.unibo.it/10134/.
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I movimenti lenti delle colate in terra sono una caratteristica geomorfologica comune nell’Appennino settentrionale e sono uno dei principali agenti di modellazione del paesaggio. Spesso case e piccoli centri abitati sorgono in zone affette da questo tipo di movimento franoso e di conseguenza subiscono danni causati da piccoli spostamenti.
In questo lavoro di Tesi vengono presentati i risultati ottenuti dall’interferometria radar ad apertura sintetica (InSAR) mediante elaborazione tramite StaMPS (Stanford Method of Persistent Scatterers), utilizzando la tecnica avanzata Small Baseline Subset (Berardino et al., 2002). Questo metodo informatico è applicato alle acquisizioni rilevate dai satelliti Envisat e COSMO-SkyMed in orbita ascendente e discendente, ottenendo una copertura di dati che va dal 2004 al 2015, oltre ad un rilevamento geologico-geomorfologico in dettaglio eseguito nell’area di studio.
Questa tecnica di telerilevamento è estremamente efficace per il monitoraggio dei fenomeni di deformazione millimetrica che persistono sulla superficie terrestre, basata sull'impiego di serie temporali d’immagini radar satellitari (Ferretti et al., 2000). Lo studio è stato realizzato nel paese di Gaggio Montano nell’Appennino bolognese. In questa zona sono stati identificati diversi corpi di frana che si muovono con deformazioni costanti durante il tempo di investigazione e grazie ai risultati ottenuti dai satelliti è possibile confrontare tale risultato. Gli spostamenti misurati con il metodo InSAR sono dello stesso ordine di grandezza dei movimenti registrati dai sondaggi inclinometrici. Le probabili cause dell’instabilità di versante a Gaggio Montano sono di natura antropica, in quanto alti tassi di deformazione sono presenti nelle zone dove sorgono case di recente costruzione e complessi industriali. Un’altra plausibile spiegazione potrebbe essere data dalla ricarica costante d’acqua, proveniente dagli strati dei Flysch verso l’interno del complesso caotico sottostante, tale dinamica causa un aumento della pressione dell’acqua nelle argille e di conseguenza genera condizioni d’instabilità sul versante. Inoltre, i depositi franosi rilevati nell’area di studio non mostrano nessun tipo di variazione dovuta ad influenze idrologiche. Per questo motivo le serie temporali analizzare tendo ad essere abbastanza lineari e costanti nel tempo, non essendo influenzate da cicli stagionali.
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Portabella, Arnús Marcos. "Wind Field Retrieval from Satellite Radar Systems." Doctoral thesis, Universitat de Barcelona, 2002. http://hdl.handle.net/10803/734.
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Wind observations are essential for determining the atmospheric flow. In particular, sea-surface wind observations are very useful for many meteorological and oceanographic applications. In this respect, most of the satellite remote-sensing radar systems can provide sea-surface wind information. This thesis reviews the current wind retrieval procedures for such systems, identifies the most significant unresolved problems, and proposes new methods to overcome such problems.In order to invert the geophysical model function (GMF), which relates the radar backscatter measurement with the wind speed and direction (unknowns), two independent measurements over the same scene (wind cell) are at least needed. The degree of independence of such measurements is given by the azimuth (view) angle separation among them. This thesis is focused on improving the wind retrieval for determined systems (two or more measurements) with poor azimuth diversity and for underdetermined systems (one single measurement). For such purpose, observations from two different radar systems, i.e., SeaWinds and SAR (Synthetic Aperture Radar), are used.
The wind retrieval methods proposed in this book for determined (Multiple Solution Scheme, denoted MSS) and underdetermined (SAR Wind Retrieval Algorithm, denoted SWRA) systems are based on Bayesian methodology, that is, on maximizing the probability of obtaining the "true" wind given the radar measurements and the a priori wind information (often provided by numerical weather prediction models), assuming that all wind information sources contain errors. In contrast with the standard procedure for determined systems, the MSS fully uses the information obtained from inversion, which turns out to positively impact the wind retrieval when poor azimuth diversity. On the other hand, in contrast with the various algorithms used nowadays to resolve the wind vector for underdetermined systems, the SWRA assumes not only that the system can not be solved without additional information (underdetermination assumption) but also that both the algorithms and the additional information (which are combined to retrieved the wind vector) contain errors and these should be well characterized. The MSS and the SWRA give promising results, improving the wind retrieval quality as compared to the methods used up to now.
Finally, a generic quality control is proposed for determined systems. In general, high-quality retrieved wind fields can be obtained from scatterometer (determined systems) measurements. However, geophysical conditions other than wind (e.g., rain, confused sea state or sea ice) can distort the radar signal and, in turn, substantially decrease the wind retrieval quality. The quality control method uses the inversion residual (which is sensitive to inconsistencies between observations and the geophysical model function that are mainly produced when conditions other than wind dominate the radar backscatter signal) to detect and reject the poor-quality retrievals. The method gives good results, minimizing the rejection of good-quality data and maximizing the rejection of poor-quality data, including rain contamination.