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1
Ali, Gebril Motawil. „Water erosion on the northern slope of Al-Jabal Al-Akhdar of Libya“. Thesis, Durham University, 1995. http://etheses.dur.ac.uk/1035/.
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2
Nelis, Simon Brett. „Modelling rock slope behaviour and evolution with reference to Northern Spain and Southern Jordan“. Thesis, Durham University, 2004. http://etheses.dur.ac.uk/2206/.
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The geomorphological behaviour of steep jointed rock slopes has been studied using distinct element computer models. In order to model steep slopes effectively, methodologies need to be combined from the studies of environmental modellers, geomorphologists and engineers. The distinct element method is ideal for the study of the development of jointed rock masses, where the failure is controlled by the nature of the discontinuities. Theoretical modelling identified that block size is a key control affecting the deformation of rock masses. Deformation of rock masses with smaller block assemblages is greater than for rock masses composed of larger block sizes. This is due to the increased magnitude of joint normal closure. Catastrophic failure is less likely in slopes with smaller block sizes because the shear strength is greater in a closely jointed rock mass. These slopes are more likely to undergo gradual deformations. Block-size effects are also responsible for influencing the failure mechanism of rock masses. As block size decreases, the magnitude of block rotation increases and the failure mechanism changes from sliding to toppling. The effect of slope scale on the deformation properties of the rock masses has also been investigated. Two field locations, the Picos de Europa mountains, northern Spain and Wadi Rum, southern Jordan, have been chosen to provide a link between the theoretical modelling and classic rock landforms which are controlled by the discontinuity geometry. Given the sporadic and infrequent occurrence of failure events at the field sites, a computer modelling approach has been adopted to analyse slope behaviour. In the Picos de Europa, slope deformations are deep-seated, with sliding and toppling being the dominant modes of failure. Much of the slope deformation in these mountains is a result of post-glacial rock-slope deformation. The sandstone inselbergs of Jordan show a range of morphologies from rounded hills to vertical cliffs. The morphology of the inselbergs is related to the intact rock strength; stronger Red lshrin sandstone forms vertical slopes, whereas the weaker Disi sandstone forms rounded domes. Jointing in the area is sub-vertical with horizontal bedding and computer simulations have shown that toppling is the dominant mode of failure in these inselbergs. Comparison of computer model output suggests that different failure mechanisms have distinct failure signatures. Catastrophic, deep-seated failures are characterised by a long period of acceleration as the failure propagates through the rock mass and infinite velocity is reached. Non-catastrophic slope movements, such as self-stabilising topples, are characterised by short periods of acceleration followed by small creep movements at a constant velocity. Computer modelling has indicated that scale effects do exist in the modelled rock masses from the Picos de Europa and particularly Wadi Rum. In areas where jointing is constant, the relative block size of the rock mass decreases as slope scale increases. The greater numbers of blocks along with greater in situ stresses influence the failure of the slope. Cosmogenic dating was used to temporally constrain UDEC model output and provide a better understanding of rock slope failure mechanisms in the Picos de Europa and Wadi Rum. Dating indicated delayed paraglacial adjustment was the triggering mechanism for slope failure in the Picos de Europa, whereas failures in Wadi Rum appeared to be closely linked with wetter climatic conditions.
3
Bullard, Reuben G. Jr. „Estimation of Slope Erosion Rates from 10Be Nuclide Accumulation: A Northern Kentucky Example“. University of Cincinnati / OhioLINK, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=ucin990706816.
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4
McLernon, M. „Climate driven pore water pressure dynamics and slope stability within glacial till drumlins in Northern Ireland“. Thesis, Queen's University Belfast, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.679266.
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'Large cut slopes (excavations) in glacial tillare a common occurrence along road and rail networks in Northern Ireland, due to unique drumlin topography in the province. Despite observed occurrences of delayed slope failures within till cuttings, their long-term performance is not well understood. Decreases in the stability of overconsolidated clay till slopes with time have been shown to be in response to pore water pressure (PWP) cycles induced by soil-climate interactions. This research has developed and presented an understanding of the mechanisms controlling PWP fluctuations within till slopes in response to climatic factors. Three cut slopes in till were instrumented to measure PWP variations, surface soil water content, suction, and shallow water table fluctuations. Field and laboratory tests were carried out to characterise the geotechnical and hydraulic properties of the till. The field instrumentation facilitated the identification of a number of characteristic controls on PWP variations, including the seasonal soil water balance and more rapid PWP responses due to gravity driven recharge and stress changes. A numerical soil water storage model was used to estimate the temporal variability in recharge to the till. This water balance accounts for PWP variation, in-situ hydraulic conductivity and fracture porosity within the till. The outputs from the water balance model were subsequently used as a boundary condition in a transient seepage model. This is coupled with a limit equilibrium analyses to assess variability in the factor of safety of the cuttings. Furthermore, a generic model was used to explore how variations in climatic and hydrogeologic conditions will affect long-term slope stability. The research highlights the control of the hydrogeologic setting and climatic conditions on PWP dynamics, and makes suggestions for how this understanding can be used in design, management and remediation measures of cut slopes to protect these assets in the future.
5
Thomas, Ryan Douglas. „3-D multichannel seismic reflection study of variable-flux hydrocarbon seeps, continental slope, northern Gulf of Mexico“. Texas A&M University, 2003. http://hdl.handle.net/1969.1/1176.
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In the northern Gulf of Mexico, seafloor hydrocarbon fluid and gas seepage is an ubiquitous process on the continental margin. Although seafloor seepage and seep-related features (mud volcanoes, carbonate formation) have been studied for many years, little is known about their mechanisms of formation and the relationship of sub-surface structure to current seep activity. In this study, we examined three seafloor seeps in the Garden Banks and Mississippi Canyon areas using exploration and reprocessed 3D multi-channel seismic (MCS) data augmented with side-scan sonar (Garden Banks site) to characterize hydrocarbon seep activity and develop an understanding of the processes that led to their formation. Side-scan sonar data provided high resolution coverage of the seafloor while the exploration seismic data were used to image near and deep sub-surface features. Additionally, the 3D amplitude extraction maps were useful in delineating amplitude anomalies often associated with seep related activity. The reprocessed 3D seismic data were used to map in greater detail near seafloor features and amplitude anomalies.
Using remote sensing geophysical data, we were effectively able to map sub-surface features such as salt topography, seep-related faults and geophysical indicators of hydrocarbons and correlate them with seafloor amplitude anomalies and fault traces in order to characterize seep activity level. The southern mud volcano in the Garden Banks site is characterized as an established high flux seep vent owing to signs of active seepage and sediment flows as well as the build-up of hard grounds. The northern mud volcano in the area, with greater hard ground build-up and fewer signs of active seepage represents an established low flux seep vent. In the Mississippi Canyon area, the data suggest that the seep mound can be characterized as a mature high flux vent due to the extensive build-up of hard ground, evidence of gas hydrates and signs of active seepage and sediment flows.
The mechanisms of formation are similar between the two study sites. Upwelling salt appears to have fractured the sub-surface leading to the formation of fault induced depressions. Mapping of geophysical indicators of hydrocarbons implies that hydrocarbon migration is occurring along bedding planes to the fault systems underlying the depressions. Here they appear to migrate vertically to the seafloor creating the topographic features and seafloor amplitude anomalies that characterize the seeps
6
Grimshaw, John M. „Aspects of the ecology and biogeography of the forest of the northern slope of Mt. Kilimanjaro, Tanzania“. Thesis, University of Oxford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360396.
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7
Avsar, Ozgur. „Landslide Stabilization In Weathered Tuffite, Northern Turkey“. Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/2/12605580/index.pdf.
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A landslide occurred during the construction of the Giresun &ndashEspiye road between Km: 1+030 &ndash
1+170 in April 2003. Investigating the causes and mechanism of this slope failure along with suggesting a proper stabilization technique is aimed in this study. For that purpose, a detailed site investigation study, including engineering geological mapping, drilling work, in situ and laboratory tests, was performed. Weathered tuffite, tuffite, flysch and dacitic tuffite, from top to bottom, are the major units in the study area. A &ldquo
translational slide&rdquo
occurred in completely weathered tuffite owing to the disturbance of the stability of the slope by the excavations performed at the toe of the slope
particularly the foundation excavation for the restaurant building and for the road cut for the Giresun &ndash
Espiye road. After establishing the model of the landslide in detail, shear strength parameters of the failure surface were determined by the back analysis method as "
cohesion"
=2.5 kN/m2 and "
friction angle"
=9°
. Toe buttressing, ground water and surface water drainage options were considered for stabilizing the slope. For the back analysis calculations, the Morgenstern-Price and Spencer methods were used with the aid of the SLOPE/W computer program.
8
De, Beukelaer Sophie Magdalena. „Remote sensing analysis of natural oil and gas seeps on the continental slope of the northern Gulf of Mexico“. Thesis, Texas A&M University, 2003. http://hdl.handle.net/1969.1/1164.
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Natural hydrocarbon seeps harbor distinctive geological, chemical, and biological features in the marine environment. This thesis verified remote sensing signatures of seeps using in-situ observation and repeated collections of satellite imagery. Bubble streams in the Gulf of Mexico water column from four natural seep sites on the upper continental slope were imaged by a side-scan sonar, which was operated from a submarine near the seafloor, and by acoustic profilers, which were operated from surface ships. These data were correlated with sea surface slicks imaged by Synthetic Aperture Radar (SAR) on the RADARSAT satellite. Comparing non-oily bubble streams from rapidly venting mud volcanoes with oily bubble streams from shallow deposits of gas hydrate showed that they produced notably different signatures. Non-oily bubbles produced high backscatter on the side-scan sonar records, but were difficult to detect with the acoustic profilers. Oily bubbles from hydrate deposits produced acoustic shadows on the side-scan sonar records. The oily bubbles generated clear signatures extending from the seafloor to the near surface on the acoustic profile records. RADARSAT SAR images verified the presence of surface oil slicks over the hydrate deposits, but not over the mud volcanoes. This indicates that SAR imagery will not be able to capture every oil and gas seep in a region because non-oily bubble streams do not create surface oil slicks. A total of 113 natural oily seep sources were identified based on surface slicks in eleven SAR images collected over the northern continental slope. A persistence analysis verified that SAR is a dependable tool for capturing oil slicks because 93.5% of the slick sources identified in the 2001 images were corroborated with slicks in the 2002 images. The sources ranged in depth from 100 to 2000 m and 79% of the sources were in 900 meters or greater of water. Seventy-six percent of the seep sources were associated with salt less than 1500 m below the seafloor and none of the sources were located in the bottom of salt withdrawal basins. Geographical Information Systems (GIS) proved to be a useful tool in these analyses.
9
Henderson, Susan Jane. „Analysis of the long-term slope stability of waste-rock dumps /“. Title page, table of contents and abstract only, 1992. http://web4.library.adelaide.edu.au/theses/09PH/09phh4972.pdf.
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10
O'Brien, Sean P. „Sedimentology of a Lower Middle Pleistocene Reservoir in Garden Banks Area, Northern Gulf of Mexico: Integration of 3D Seismic, Cores, and Well Logs“. ScholarWorks@UNO, 2010. http://scholarworks.uno.edu/td/1140.
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Garden Banks field 236, known as Pimento, is part of a lower middle Pleistocene submarine-fan deposit in the north central Gulf of Mexico. Pimento field represents a classic example of a prograding fan across the continental shelf continuing across the continental slope filling and spilling minibasins. Channel complexes cut through the field as sediment migrated across the shelf and slope to the basin floor. This thesis consists of two papers which utilized donated 3D seismic data on six of the blocks in Pimento field. Public domain data was incorporated with these data to explore the producing reservoir sand in the field. Mapped horizons revealed the overall structural elements of the field including the fill and spill facies of the minibasin that directly influences the deposition of the field. In these papers, channel complexes have been resolved using seismic geomorphological techniques and cross sections. Two potential drilling targets have also been discovered and one has been initially investigated as a drilling target.
11
Chiaravalloti, Rosario. „Numerical modelling and back analysis of a rock slope failure occurred in 2005 at Scascoli (Bologna, Italy)“. Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017.
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The rock slope failure object of this study occurred on the 12th of March, 2005, within the Scascoli Gorges in the Savena Valley, 25 km south of Bologna, in the Northern Apennines, Italy. The failure involved a volume of rock of nearly 30000 m3 that detached from an 80 m high cliff and fell on the river bed and onto the adjacent road, denoted as “Strada Provinciale – Fondovalle Savena”, damming the first and destroying the latter. The conformation of the cliff, known as “Mammellone 1”, was rather convex, overhanging and undercut at the base where in contact with the river bed. The event is the last of a series of mass movements which occurred in a 15-year span in the area. With integration of past analyses and surveys, possible causes and mechanism of failure have been investigated by means of two and three-dimensional kinematic analysis (using the software DIPS and SWEDGE by Rocscience, 2016), photogrammetry and terrestrial laser scanning comparison (Cloud Compare, Daniel Girardeau-Montaut, 2016; Autocad, Autodesk, 2016) and two-dimensional finite element numerical modelling (RS2, Rocscience, 2016). The use of a finite element method to model a predominantly blocky structure has shown to be effective and to produce good results if data integration, boundary conditions and geometry of the site are well correlated between each other to best fit the resulting scenario. The design of the numerical model considered the relative position of crown and scarp to the discontinuity families and to the geometry of the cross section, to better costrain the failure surface. Furthermore, the process of formation of the valley was taken into account in order to consider also stress-strain conditions prior to the road construction and river erosion. This was carried out by multi-staging the modelling process considering the natural erosion and the advancement of the landslide on the hydrogeological left side of the Savena steam before the last rockfall event.
12
Zhu, Mangzheng. „Offshore Red River fault and slope sediments in northern South China Sea : implications for paleoceanography and uplift of the tibet plateau /“. May be available electronically:, 2007. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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13
Flexas, Sbert Maria del Mar. „Mesoscale variability of the northern current in the gulf of lions and the role of bottom topography“. Doctoral thesis, Universitat Politècnica de Catalunya, 2003. http://hdl.handle.net/10803/6386.
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The Northern Current flows cyclonically contouring the continental slope in the NW Mediterranean. At the entrance of the Gulf of Lions this current is about 20 -- 30 km wide and flows along the deepest half of the continental slope, i.e. over the 1000 to 2000 m isobaths approximately. Surface speeds are of 30 -- 50 cm s^{-1}. In the MATER HFF experiment (March -- May 1997) mesoscale variability of the Northern Current is observed from current meter records, SST images and hydrographic data. The HFF experimental box is 20 x 40 km, covering the upper half of the slope (i.e. covering from 250 m to 1250 m depth isobaths). Current meter and satellite data show that the site is embedded in a region of significant Northern Current meandering and eddy activity. From SST images, meander wavelengths are estimated larger than 60 km, embracing smaller structures. These flow patterns affect upper-layer waters down to at least 650 m depth. Current meter data distinguish two narrow energetic bands centred at 3.5 days and 7.5 days, respectively, in agreement with previous studies.Baroclinic instability is viewed as a possible mechanism to explain the generation of the Northern Current meanders. The analytical model of Tang (1975) predicts the development of unstable waves of wavelength (> 60 km) and periods compatible with the 7.5 day band recorded with current meter devices. The higher frequency band of 3.5 days is out of the frequency range predicted by the classical baroclinic instability theory and it is discussed as a restriction of quasi-geostrophic theory.
Barotropic instability is studied using a laboratory model of a -westward' jet flowing over the lower half of the continental slope, which considers dynamic similarity with the Northern Current. The laboratory model is cross-validated with a corresponding numerical model. Jet instabilities of currents similar to the Northern Current (i.e. westward jets) occur at the edges of the jet, showing a clear meandering tendency over the mid-slope. Westward currents of Ro = 0.1 -- 0.2 develop instabilities of wavelengths (50 -- 75 km) similar to those observed from SST images, with periods (3.3 -- 3.8 days) compatible with the 3.5 days period band recorded with HFFE current meters.
The laboratory and numerical experiments have reproduced westward jets (as the Northern Current), but also eastward jets, in order to have a full approach to better understand the role of the bottom topography on barotropic instabilities. The slope current instabilities are successfully explained by the Marcus and Lee theory (1998) of jets on a beta plane. This theory is valid for westward flows with Ro > 0.1 and for eastward flows with Ro > 0.2 (jets of the so-called Regime II flows in this thesis), and it states that the instabilities of each shear layer of the barotropic jet take the appearance of a Kelvin-Helmholtz-like pattern, associated with a Rossby wave (of topographic origin in our case). According to this theory, the differences between eastward and westward jets rely on the disposition of the Rossby waves --at the centre of the current in eastward flows and at the edges of the jet in westward currents. Jets over a sloping bottom with small Rossby numbers (Ro < 0.1 for westward jets; Ro < 0.2 for eastward jets) show a flow pattern (the so-called Regime I in this thesis) that has common characteristics for eastward and westward flows. In these -small'-Ro flows, Kelvin-Helmholtz-like instabilities dominate, whereas Rossby waves are too weak to produce any major difference between jets flowing in eastward or westward direction. This occurs when the topographic influence, assumed proportional to the Ro number of the jet, is small.
The differences between eastward and westward slope currents observed in this work (and similar observations of jets on a beta-plane from previous works) are explained in this thesis by a simple scheme based on conservation of potential vorticity, considering there are two main components in balance: the shear-induced vorticity and the topographically induced vorticity. The signs of these two components are determined by the relative direction of the flow with respect to the inclination of the bottom topography. Once the critical Rossby number is overpassed so that the topographic effects are important (Ro > 0.1 for westward jets; Ro > 0.2 for eastward jets), conservation of potential vorticity tends to enhance vortices at the centre of eastward jets --eastward jets show meandering at the jet core. In westward jets, potential vorticity conservation is responsible of enhancing vortices at each edge of the jet. Thus, westward jets (as the Northern Current) are broad and meandering occurs at the jet edges.
In Ro > 0.1 westward flows (i.e. Regime II westward jets) a topographic Rossby wave appears over the shelf break. This result is likely observed because of the specific topography used in this work --a continental slope and a continental shelf separated by a shelf break, producing a strong change in ambient potential vorticity. Numerical simulations reveal that this Rossby wave is triggered by the slope current. This topographic Rossby wave is a robust pattern, since it is independent of the position of the current over the slope, the shape of the velocity shear profile of the jet, and the jet width. Although this type of wave could not be inferred from the HFFE field data, it could be a focus of study in further field experiments. It also needs further analytical consideration.
The general conclusion extracted from this thesis that tries to explain the mesoscale variability associated to the Northern Current is that both baroclinic and barotropic instability could explain part of the oceanic observations. As a consequence, mixed barotropic-baroclinic instability (which occurs at wavelengths which are between those corresponding to pure barotropic and pure baroclinic instability) is thought to play an important role on the observed mesoscale variability. The resulting wavelength would depend on the relative strength of both mechanisms.
14
Huppertz, Tammo Jan [Verfasser], Rüdiger [Akademischer Betreuer] Henrich und David [Akademischer Betreuer] Piper. „Styles of continental margin sedimentation: comparing glaciated and non-glaciated slope systems using case studies on the southeast Canadian and northern Argentine and Uruguay continental slope / Tammo Jan Huppertz. Gutachter: Rüdiger Henrich ; David Piper. Betreuer: Rüdiger Henrich“. Bremen : Staats- und Universitätsbibliothek Bremen, 2011. http://d-nb.info/1071898426/34.
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15
Robinson, Rusty Wade. „Post-Den Emergence Behavior and Den Detection of Polar Bears (Ursus maritimus) in Northern Alaska and the Southern Beaufort Sea“. BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/4403.
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Pregnant polar bears (Ursus maritimus) construct maternal dens out of snow in the autumn where they give birth to and raise altricial young. In recent years, there has been a decrease in polar sea ice extent and thickness, which has led to changes in denning behavior. One such change in the southern Beaufort Sea (SBS) is that polar bears are selecting maternal den sites on land, rather than on unstable sea ice. This change, coupled with expanding petroleum exploration along Alaska's North Slope, heightens the likelihood of bear-human interactions at maternal den sites. The purpose of this research was to 1) describe polar bears' post-den emergence behavior, establishing a benchmark for comparison to identify behavioral changes associated with climate change and disturbance, and 2) explore factors influencing the efficacy of a currently used den detection method, forward-looking infrared (FLIR). Maternal den sites were observed along Alaska's North Slope from March to April of 2009 and 2010. The mean length of stay at den sites post-emergence was 11.3 ± 7.5 d. The mean date of den emergence was 14 March; abandonment 26 March. Adult females were generally inactive (58.4% out-of-den time) with standing being the most prevalent activity (49.9%). Cubs were generally active (76.7%), playing more than any other activity (45.3%). Bears spent the majority of their time in the den (97.3% for adult females and 99% for cubs) with short bouts of intermittent activity (× = 7 min 42 s). We documented the death of one member of a triplet polar bear litter at its den site. All three cubs showed low activity levels relative to other cubs observed, and one died within one week of den emergence. Necropsy confirmed that the dead cub had a low body weight and was malnourished. Capture later confirmed that the two surviving cubs were also undersized. Triplet litters are often smaller and suffer higher mortality rates than singletons and twins. This cub was not only a triplet but also born following 2 y of record minimum sea ice extent, both of which may have played a role in this cub's death. Concurrent with the den emergence portion of this work, we conducted a separate study to identify limitations and optimal conditions for locating dens using FLIR. We took handheld FLIR images of three artificial dens under varied conditions. We tested variables hypothesized to influence detectability with linear models using a zero-inflated negative binomial distribution. Solar radiation, wind speed, and den wall thickness reduced the likelihood of detecting dens. The negative effect of wind speed on detectability increased with increasing distance. To maximize the efficacy of hand-held FLIR, den surveys should be conducted when solar radiation is <16 w/m2 (night) and when wind speed is <10 km/h (6 mph). Adherence to these guidelines will maximize the protection FLIR can afford to denning bears.
16
Beazley, Melanie J. „The significance of organic carbon and sediment surface area to the benthic biogeochemistry of the slope and deep water environments of the northern Gulf of Mexico“. Thesis, Texas A&M University, 2003. http://hdl.handle.net/1969/534.
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17
Pedley, Katherine Louise. „Modelling Submarine Landscape Evolution in Response to Subduction Processes, Northern Hikurangi Margin, New Zealand“. Thesis, University of Canterbury. Geological Sciences, 2010. http://hdl.handle.net/10092/4648.
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The steep forearc slope along the northern sector of the obliquely convergent Hikurangi subduction zone is characteristic of non-accretionary and tectonically eroding continental margins, with reduced sediment supply in the trench relative to further south, and the presence of seamount relief on the Hikurangi Plateau. These seamounts influence the subduction process and the structurally-driven geomorphic development of the over-riding margin of the Australian Plate frontal wedge.
The Poverty Indentation represents an unusual, especially challenging and therefore exciting location to investigate the tectonic and eustatic effects on this sedimentary system because of: (i) the geometry and obliquity of the subducting seamounts; (ii) the influence of multiple repeated seamount impacts; (iii) the effects of structurally-driven over-steeping and associated widespread occurrence of gravitational collapse and mass movements; and (iv) the development of a large canyon system down the axis of the indentation. High quality bathymetric and backscatter images of the Poverty Indentation submarine re-entrant across the northern part of the Hikurangi margin were obtained by scientists from the National Institute of Water and Atmospheric Research (NIWA) (Lewis, 2001) using a SIMRAD EM300 multibeam swath-mapping system, hull-mounted on NIWA’s research vessel Tangaroa. The entire accretionary slope of the re-entrant was mapped, at depths ranging from 100 to 3500 metres. The level of seafloor morphologic resolution is comparable with some of the most detailed Digital Elevation Maps (DEM) onshore. The detailed digital swath images are complemented by the availability of excellent high-quality processed multi-channel seismic reflection data, single channel high-resolution 3.5 kHz seismic reflection data, as well as core samples. Combined, these data support this study of the complex interactions of tectonic deformation with slope sedimentary processes and slope submarine geomorphic evolution at a convergent margin.
The origin of the Poverty Indentation, on the inboard trench-slope at the transition from the northern to central sectors of the Hikurangi margin, is attributed to multiple seamount impacts over the last c. 2 Myr period. This has been accompanied by canyon incision, thrust fault propagation into the trench fill, and numerous large-scale gravitational collapse structures with multiple debris flow and avalanche deposits ranging in down-slope length from a few hundred metres to more than 40 km. The indentation is directly offshore of the Waipaoa River which is currently estimated to have a high sediment yield into the marine system. The indentation is recognised as the “Sink” for sediments derived from the Waipaoa River catchment, one of two target river systems chosen for the US National Science Foundation (NSF)-funded MARGINS “Source-to-Sink” initiative. The Poverty Canyon stretches 70 km from the continental shelf edge directly offshore from the Waipaoa to the trench floor, incising into the axis of the indentation. The sediment delivered to the margin from the Waipaoa catchment and elsewhere during sea-level high-stands, including the Holocene, has remained largely trapped in a large depocentre on the Poverty shelf, while during low-stand cycles, sediment bypassed the shelf to develop a prograding clinoform sequence out onto the upper slope. The formation of the indentation and the development of the upper branches of the Poverty Canyon system have led to the progressive removal of a substantial part of this prograding wedge by mass movements and gully incision. Sediment has also accumulated in the head of the Poverty Canyon and episodic mass flows contribute significantly to continued modification of the indentation by driving canyon incision and triggering instability in the adjacent slopes.
Prograding clinoforms lying seaward of active faults beneath the shelf, and overlying a buried inactive thrust system beneath the upper slope, reveal a history of deformation accompanied by the creation of accommodation space. There is some more recent activity on shelf faults (i.e. Lachlan Fault) and at the transition into the lower margin, but reduced (~2 %) or no evidence of recent deformation for the majority of the upper to mid-slope. This is in contrast to current activity (approximately 24 to 47% shortening) across the lower slope and frontal wedge regions of the indentation. The middle to lower Poverty Canyon represents a structural transition zone within the indentation coincident with the indentation axis. The lower to mid-slope south of the canyon conforms more closely to a classic accretionary slope deformation style with a series of east-facing thrust-propagated asymmetric anticlines separated by early-stage slope basins. North of the canyon system, sediment starvation and seamount impact has resulted in frontal tectonic erosion associated with the development of an over-steepened lower to mid-slope margin, fault reactivation and structural inversion and over-printing.
Evidence points to at least three main seamount subduction events within the Poverty Indentation, each with different margin responses:
i) older substantial seamount impact that drove the first-order perturbation in the margin, since approximately ~1-2 Ma
ii) subducted seamount(s) now beneath Pantin and Paritu Ridge complexes, initially impacting on the margin approximately ~0.5 Ma, and
iii) incipient seamount subduction of the Puke Seamount at the current deformation front.
The overall geometry and geomorphology of the wider indentation appears to conform to the geometry accompanying the structure observed in sandbox models after the seamount has passed completely through the deformation front. The main morphological features correlating with sandbox models include: i) the axial re-entrant down which the Poverty Canyon now incises; ii) the re-establishment of an accretionary wedge to the south of the indentation axis, accompanied by out-stepping, deformation front propagation into the trench fill sequence, particularly towards the mouth of the canyon; iii) the linear north margin of the indentation with respect to the more arcuate shape of the southern accretionary wedge; and, iv) the set of faults cutting obliquely across the deformation front near the mouth of the canyon. Many of the observed structural and geomorphic features of the Poverty Indentation also correlate well both with other sediment-rich convergent margins where seamount subduction is prevalent particularly the Nankai and Sumatra margins, and the sediment-starved Costa Rican margin. While submarine canyon systems are certainly present on other convergent margins undergoing seamount subduction there appears to be no other documented shelf to trench extending canyon system developing in the axis of such a re-entrant, as is dominating the Poverty Indentation.
Ongoing modification of the Indentation appears to be driven by: i) continued smaller seamount impacts at the deformation front, and currently subducting beneath the mid-lower slope, ii) low and high sea-level stands accompanied by variations on sediment flux from the continental shelf, iii) over-steepening of the deformation front and mass movement, particularly from the shelf edge and upper slope.
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Skog, Emma. „Geological factors affecting the channel type of Bjur River in Västerbotten County : A study concerning the connection between surficial geology, landforms, slope and different hydrological process domains in a stream catchment above the highest shoreline“. Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-160914.
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Process domains categorizes sections of streams according to its local dominant processes. These processes often reflect on the local ecology and the streams appearance. But the underlying reason why these different process domains are formed are still not completely certain. In this study the distribution of the process domains: lakes, rapids and slow-flowing reaches in the Bjur River catchment were compared to the geological factors of slope, surficial geology and landforms to see if any connections could be found. The possibility of using GIS (geographic information systems) and remote data to distinguish these stream types and to connect them to the different studied geological factors were also examined. The hypothesis for this study is that the geological factors of slope, surficial geology and landforms all should have an influence over the distribution of the process domains in Bjur River. The analysis was executed through map-studies in ArcGIS and statistical analysis in Excel. All process domains showed statistical significance towards the studied geological factors. The slope was generally steeper in the rapids than in slow-flowing reaches and lakes. The surficial geology displayed more fine-grained sediment (peat) in proximity to lakes and slow-flowing reaches whilst till was more abundant close to rapids. Hilly moraine landscapes were most common around lakes, while rapids displayed a high percentage of glacio-fluvially eroded area. Slow-flowing reaches also showed to have around 44% of its studied points around glacio-fluvially eroded area, and 43% at areas without any major landforms. Even if the statistical analysis and figures display a difference between the different process domains, it is still difficult to say which of these geological factors that plays the most crucial role for their development. However, by using remote data and through studies over slope, adjacent surficial geology and landforms the different process domains can be differentiated from one another.
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Montiel, A. Katty, B. Henry Maldonado und M. Edith Luz Gouveia. „Amenaza por inestabilidad de las laderas en la cuenca del río Mocoy. Andes venezolanos“. Pontificia Universidad Católica del Perú. Centro de Investigación en Geografía Aplicada, 2014. http://repositorio.pucp.edu.pe/index/handle/123456789/119889.
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In the intention to establish a geomorphologic zonation of the threat levels due to slope in-stability of the Mocoy hydrographic basin, an analysis of the biophysics conditions was made by using the heuristic method. Space variables of greater incidence in local dynamics were identified and processed in ARC/INFO, and applied methodological proposals associated to the matrix of spatial analysis of Leopold and the system of transparencies of MacHarg. It was possible to identify three levels of threat: low, moderate and high, which were correlated with the operating morphogenetic processes, the geologic structure and lithology, as well as with the land use of this important river basin in the northern flank of the Venezuelan Andes. The analysis of the implicit mechanisms in the collapse of geologic material, as well as the estimation of the future tendency and detection of the areas of greater threat, constitute the basis for a suitable mitigation problem of dangerous slope processes and the sediment contribution tothe fluvial system of the Mocoy river.Con la intención de establecer una zonificación de los niveles de amenaza geomorfológica porinestabilidad de laderas de la cuenca hidrográfica del río Mocoy, se efectuó un análisis de las condiciones biofísicas, mediante el método heurístico y se identificaron las variables espaciales de mayor incidencia en la dinámica local, tratadas en ARC/INFO y con propuestas metodológicas asociadas a la matriz de análisis espacial de Leopold y el sistema de transparencias de MacHarg. Se logró representar tres niveles de amenaza: baja, moderada y alta, las cuales fueron correlacionadas con los procesos morfogenéticos actuantes, la estructura geológica y litología, así como también con el uso de la tierra de esta importante cuenca del flanco norandino vene- zolano. El análisis de los mecanismos implícitos en el colapso de material geológico, así como la estimación sobre la tendencia futura y detección de las áreas de mayor amenaza, constituyen las bases para una adecuada mitigación del problema de procesos de ladera peligrosos y el aportede sedimentos al sistema fluvial del río Mocoy.
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Montiel, A. Katty, und H. Ricardo Seco. „Niveles de peligro de inestabilidad de las laderas de un sector del flanco norandino venezolano: Monte Carmelo, estado de Trujillo“. Pontificia Universidad Católica del Perú. Centro de Investigación en Geografía Aplicada, 2015. http://repositorio.pucp.edu.pe/index/handle/123456789/119671.
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A zonation of slope instability hazard levels of the Mount Carmelo region was carried out based on an analysis of the geographical conditions using the Van Westen (2003) heuristic method and GIS. Three levels of instability hazard were established: low hazard areas (no actual harmful phenomena is recorded, although it might occur over the next years), moderate hazard (medium probability that harmful processes might appear over next years) and high hazard (high probability of harmful processes over the next years.) Zonation maps showing hazard areas will be very useful for physical planning and population protection, taking into· consideration that these maps may reduce economic losses and human casualties due to the above mentioned natural hazards.Con la intención de establecer una zonificación de los niveles de peligro de inestabilidad de laderas de la región de Monte Carmelo, se efectuó un análisis de las condiciones geográficas mediante la aplicación del método heurístico de Van Westen (2003) y de un SIG. Los resultados obtenidos arrojaron tres niveles de peligro de inestabilidad: peligro bajo (no se presentan fenómenos dañinos, aunque se podrían presentar en los próximos años), peligro moderado (moderada probabilidad de que aparezcan fenómenos dañinos que ocasionen algún tipo de impacto negativo en los próximos años) y peligro alto (probabilidad alta de ocurrencia de un fenómeno dañino para la población en los próximos años). Los mapas de zonificación de áreas de peligro serán de gran utilidad para la planificación de los territorios y para la defensa civil, al contribuir a la reducción de pérdidas materiales y humanas que puedan producirse ante la ocurrencia de estos fenómenos.
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Kunderová, Markéta. „Návrh udržitelné městské struktury - na bázi středověkého města - pro 21.století“. Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2021. http://www.nusl.cz/ntk/nusl-443689.
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The diploma thesis deals with the design of a sustainable urban structure of the 21st century based on a medieval town in Náměšť nad Oslavou in the Vysočina region. It is a relatively large location defined by a zoning plan for the future development of the town. The area is specific because it is located entirely on the northern slope and is directly adjacent to the railway track, which is a physical as well as noise barrier for potential construction. The aim of the thesis is to design a solution that uses the potential of the place, offers a modern and economical way of living and creates appropriate public spaces based on medieval towns. The intention is to connect the new location with the existing structure of the town and thus prevent it from becoming the city periphery.
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„Overpressure and Earthquake Initiated Slope Failure in the Ursa Region, Northern Gulf of Mexico“. Thesis, 2010. http://hdl.handle.net/1911/70969.
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We use two-dimensional fluid flow and slope stability models to study the evolution of overpressure and slope stability in the Ursa region, northern Gulf of Mexico. Our model predictions match measured overpressures from Integrated Ocean Drilling Project Expedition 308 Site U1324 above 200 mbsf, but overpredicts deeper overpressures by 0.4-1.1 MPa. Slope stability models predict a slope failure at 61 ka on the eastern end of the Ursa region. This predicted failure corresponds to a mass transport deposit (MTD) that has been interpreted as a retrogressive failure initiated by high overpressure. Overpressure alone could not drive failure of a second MTD at ~27 ka. We predict that a magnitude 5 earthquake within 140 km of the Ursa region would initiate this failure. We conclude that overpressure could drive submarine slope failures and horizontal acceleration from earthquakes can further facilitate this process.
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Bowes, A. G. „Erosion control on a steep slope pipeline crossing of the Sikanni Chief River, northern British Columbia“. 1988. http://hdl.handle.net/2429/12873.
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Chen, Yi-Chun, und 陳亦君. „The Impacts of Rainfall in Typhoon on the Slope Failure along Road of the Northern Coastal Range“. Thesis, 2004. http://ndltd.ncl.edu.tw/handle/71908133735577080893.
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碩士國立東華大學
自然資源管理研究所
92
Typhoon is the most serious natural disaster in Taiwan. It brings lots of rainfalls and creates slope failures in mountainous area. This study takes the roads in northern Coastal Range as the research object. The study collected road damage records and typhoon rainfall data during the period from 1995 to 2002. This study also analyzed the impacts of the typhoon tracks and rainfalls on slope failures. The rainfall variables were classified according to whether rainfalls create slope failures or not. Discriminant analysis was used to establish the critical line in order to provide a reference for warning. There were 26 typhoons during the period from 1995 to 2002 and twelve of them made slop failures. The study results are as follows：（1）For the roads in northern Coastal Range, the second track of typhoon caused most serious disaster, but the forth and fifth tracks of typhoon also caused disaster.（2）Accumulative rainfall and rainfall intensity were higher in second track that direct attack eastern Taiwan, but the forth and fifth tracks of typhoon also caused higher accumulative rainfall and rainfall intensity.（3）The distance away from the typhoon was in inverse proportion to the accumulative rainfall. The typhoons over accumulative 400 mm rainfall were often located within 100km of study area. Stations located near the mountainous area have higher accumulative rainfall and rainfall intensity. （4）The annual average volume of slope failures was higher in Paliwan Formation Suilien Member and Transported andesitic blocks, and this number was lower in Tuluanshan Formation and Paliwan Formation. The results in this discriminant analysis indicate that all discriminant functions reach significance level and this classification would be over 80% correct. The factors are effective accumulative rainfall and effective rainfall intensity at the study area, Tuluanshan Formation and Fanshuliao Formation. The factors are effective accumulative rainfall and duration at the Alluvium. The factors are maximum rainfall intensity in a 3 hours period and duration at Transported andesitic blocks’s. The factors are effective accumulative rainfall and maximum rainfall intensity in a 3 hours period at Paliwan Formation Suilien Member and Paliwan Formation. This research indicates that proper critical line should be established for specific regions.
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Yu, Hsing-Chien, und 游行健. „A Study on Selection of Slope Protection Methods for Roads in Northern Taiwan by Back-Propagation Network, BPN“. Thesis, 2003. http://ndltd.ncl.edu.tw/handle/37652617342624524250.
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碩士國立臺灣科技大學
營建工程系
91
Back-propagation network (BPN) method together with the PCNeuron 4.0 software are used to establish the models for selecting the slope protection methods and the model for evaluating slope failure. Cases studied here are collected from four major public roads in northern Taiwan and the northern part of the second trans-island highway. Totally, 72 not-failed slope cases and 47 failed slope cases are adopted in this study. After trained with the geologic, hydrologic, and engineering factors related to the failed and not-failed slope cases, the BPN method can reasonably identify the failed or not-failed status of slopes which are protected with certain slope stabilization methods. Due to the limitation of the case numbers, BPN method generates a better result when identifying the not-failed slopes than the failed slopes in this study. But this situation can be improved if more failed slopes are collected and used to train the BPN method. When compared with the suitability of discriminant analysis method in identifying the status of a slope, similar results can be determined from both methods. But the BPN method is more sensitive to the number of cases can be input for analysis and more time is needed to generate the parameters needed for analysis. The accuracy of BPN method can be kept improving as long as the numbers of slope cases input to BPN are increased. In comparison, the accuracy of discriminant analysis can also be increased by increasing the number of input cases. However, once the discriminant functions are determined the accuracy of discriminant analysis method is set. Finally, the failure probability of slopes can be calculated easily from the discriminant functions with a calculator. But a computer is needed when determining the status of slopes with BPN method.
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Ni, Jin-Jiang, und 倪錦江. „Sedimentary and structural characteristics of hydrate- bearing strata on a slope ridge in the northern South China Sea continental margin“. Thesis, 2012. http://ndltd.ncl.edu.tw/handle/41865315306998673529.
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碩士國立臺灣大學
海洋研究所
100
This study uses a dense seismic data set to analyze the distribution and characters of hydrate-bearing strata in the northern South China Sea (SCS) continental margin. The study area is a slope ridge formed as a remnant erosional topographic high where BSRs are abundant. The dense seismic data block consists of a series of 2D seismic profiles with 400-m line spacing and covers an area of 13-by-23 km. In addition, two large offset seismic profiles which run across the study area, EW9509-34 and MGL0905-22, have been processed through prestack depth migration to provide good velocity constraints and better deep structural images of the slope ridge. Numerous cut-and-fill channel deposits, erosional truncations and sediment waves observed on seismic sections indicate that geological processes in the slope ridge are active and complicated. Our study suggests that there are different sedimentary characters in the upper ridge and in the lower ridge, respectively. BSRs are affected by local sedimentary processes and can be categorized into 3 types: Type 1 is continuous and clear BSR, usually distributed in the upper ridge. This type of BSR suggests that gas hydrate is stable. Type 2 BSR is associated with enhanced reflectors, it is commonly observed in the lower ridge where rapid sedimentation and erosion have changed local temperature and pressure, result in adjusting of gas hydrate stability zone, therefore shifting the BSR. Type 3 BSR is intra-layer BSR. It mainly exists in distal lower ridge, and hard to be identified, because the seafloor is parallel to strata. High velocity zone above BSR may indicate the existence of gas hydrate and low velocity zone below BSR are interpreted to be free gases zone.
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Huang, Qun Xiu, und 黃群修. „Studies on the forest dynamics and population structure of the kawakamii fir forest in the northern slope of Hsueh-shan“. Thesis, 1994. http://ndltd.ncl.edu.tw/handle/29780939205923399002.
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28
Chen-Hao, Hsueh, und 薛成皓. „Properties of Large-amplitude Internal Solitary Waves in the Sand-Dune Area on Upper Continental Slope of Northern South China Sea“. Thesis, 2017. http://ndltd.ncl.edu.tw/handle/9a6f6g.
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碩士國立臺灣大學
海洋研究所
106
In the northern South China Sea, the internal solitary wave (ISW) is extremely active and has the largest amplitude (> 150 m) in the world. The ISWs generate from tidal forcing on the ridges in the Luzon Strait, propagate northwestward, and traveling across the deep basin to the continental shelf. There are a few very large subaqueous sand dunes distribute on the upper continental slope and the ISWs could passage these sand dunes. According to the multi-beam bathymetry survey, the amplitude of sand dunes were about 10 m and crest-to-crest wavelength were about 300 m. These sand dunes could influenced the aspects of ISW. Five temperature and current velocity moorings deployed in the sand-wave area on the upper continental slope in June 3-19, 2014, which was contain a spring/neap tide period in order to investigate the properties of ISWs in this area. The transect of these moorings was almost parallel to the slope and the length of mooring array was about 13 km from local depth 380 m to 260 m. In traditional method, the average phase speed of ISWs could be estimated by the arrival time and the distance between different moorings. However, the directions of the ISWs were not parallel to the mooring transect, and therefore the phase speed estimated from arrival time could overestimated. Based on the DJL theory, using the temperature and current profiles observation data to estimate properties of ISWs including vertical displacement, instantaneous phase speed, direction, and energy flux. Moreover, based on Thorpe scale, the turbulence kinetic energy dissipation rates are estimated from shipboard CTD data by Thorpe scale. The total energy of ISWs reduce about 60 % and the average dissipation reach about 21.8 W/m2 and the average dissipation rate is about 6.2×〖10〗^(-5) W kg-1 in water depth from 286 m to 342 m which is relatively flat. However, the total energy of ISWs change insignificantly in water depth from 342 m to 262 m which is the steepest part of experimental area. The dissipation rate in the sand-wave continental slope is about 600 times as Dongsha plateau. It may because of the shoaling and the large subaqueous sand dunes. Moreover, the peak turbulence kinetic energy dissipation rate occur at the trailing edge of the apparent core, with the value of 6×〖10〗^(-5). Forty minutes later, the turbulence kinetic energy dissipation rate was small.
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Shu, kuo-hui, und 徐國輝. „The study of the engineering properties and the slope stability of the pyroclastic deposits at the Jin-Shen area, northern Taiwan“. Thesis, 1998. http://ndltd.ncl.edu.tw/handle/84892684337941433571.
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30
Sanchez, Carla Maria 1978. „Controls on sedimentary processes and 3D stratigraphic architecture of a mid-Miocene to recent, mixed carbonate-siliciclastic continental margin : northwest shelf of Australia“. Thesis, 2011. http://hdl.handle.net/2152/ETD-UT-2011-05-2678.
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Determining the relative importance of processes that control the generation and preservation of continental margin stratigraphy is fundamental to deciphering the history of geologic, climatic and oceanographic forcing imprinted on their sedimentary record. The Northern Carnarvon Basin (NCB) of the North West Shelf of Australia has been a site of passive margin sedimentation throughout the Neogene. Cool-water carbonate sedimentation dominated during the early-middle Miocene, quartz-rich siliciclastics prograded over the shelf during the late-middle Miocene, and carbonate sedimentation resumed in the Pliocene. Middle Miocene to Pliocene siliciclastics were deposited as clinoform sets interpreted as delta lobes primarily based on their plan-view morphology and their relief of 40-100 m. Shelf-edge trajectory analysis suggests that part of this stratigraphic succession was built during a long-term, third order, regressive phase, producing shelf-edge deltas, followed by an aggradational episode. These trends appear to correlate with third-order global eustatic cycles. Slope incisions were already conspicuous on the slope before deltas reached the shelf-break. Nevertheless, slope gullies immediately downdip from the shelf-edge deltas are wider and deeper (>1 km wide, ~100 m deep) than coeval incisions that are laterally displaced from the deltaic depocenter (~0.7 km wide, ~25 m deep). This change in gully morphology is likely the result of greater erosion by sediment gravity flows sourced from shelf-edge deltas. Total late-middle to late Miocene margin progradation increased almost three times from 13 km in the southwest to 34 km in the northeast, where shelf-edge deltas were concentrated.
Flat-topped carbonate platforms seem to have initiated on subtle antecedent topographic highs resulting from these deltaic lobes. A reduction of siliciclastic supply to the outer paleo-shelf during the Pliocene combined with the onset of a southwestward-flowing, warm-water Leeuwin Current (LC) most likely controlled the initiation of these carbonate platforms. These platforms display marked asymmetry, likely caused by an ancestral LC, which created higher-angle, upcurrent platform margins, and lower-angle, downcurrent clinoforms. The along-strike long-term migration trend of the platforms could be the result of differential subsidence. These platforms constitute the first widespread accumulation of photozoan carbonates in the Northern Carnarvon Basin. They became extinct after the mid-Pleistocene when the LC weakened or became more seasonal.text
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Chen, Chih-Hao, und 陳志豪. „A study on the Toppling Failure of Rock slopes along the Northern Cross-Island Road“. Thesis, 2001. http://ndltd.ncl.edu.tw/handle/05728119668349839887.
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碩士中原大學
土木工程研究所
89
Because of its inferior geological conditions and environmental factors, intense geological hazards like slope failure have been a serious issue in Taiwan. Among several modes of slope failure, toppling always happens in the anaclinal rock slopes composed of one single steeply-dipping discontinuity set. According to rock characteristics and discontinuity spacing, toppling failure can be classified further as block, flexural, and block-flexural types. Failure of this kind often initiates at the toe of a slope, and gradually propagates upslope, causing a progressive type of failure. The main objective of this thesis is to establish a comprehensive methodology of analyzing the stability of rock slopes mainly involving the block-toppling mode, by taking the cases along the Northern Cross-Island (NCI) Road for example. Three different kinds of stability analyses are used in this thesis, i.e., kinematics analysis (KA), limit equilibrium method (LEM), discontinuous deformation analysis (DDA). KA is conducted merely based on the three-dimensional orientation data of rock slope and discontinuity, and it is a simple tool to identify the toppling potential spots over large areas. The LEM used is the TOP code, in which a rock slope is idealized as a system of rigid columnar blocks formed by one discontinuity set, and it can be utilized to quickly determine the safety factor (FS) of a slope as well as the support force at the toe (P0). DDA is otherwise a sophisticate discrete analysis which deals with the complex interactions of multiple deformable blocks, and it can yield more precise estimates of FS and P0 based on the computed displacement history of selected control points. According to the methodology proposed in this thesis, KA, TOP, and DDA are adopted to prescreen a number of sites of interest, to calculate the FS values of these prescreened sites, and to determine the P0 values and disturbed zone of some critical sites, respectively. The NCI Road chosen for illustrative purpose is located in the northern part of Shen-Shan Geologic Region, and its route is mainly covered by inter-bedded sandstone and shale. By reviewing previous geological records and performing KA, ten sites were selected along the road, followed by field data collected including the corresponding idealized profiles of rock slopes. The analysis results of TOP code show that the FS values of these sites vary from 1.00 to 1.15, and three sites with the lowest FS values match their field observations, i.e., continuous toppled mass near their toes. DDA simulation results indicate that the P0 values of these sites for a FS of 1.20 are in the magnitude of 10ton/m, and no further horizontal excavation at the toe is allowed for every site under investigation.
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Aubuchon, Elizabeth Anne. „Soil Moisture Profiles and Root growth of Hardwood Trees Planted in Different Groundcovers on the Steep Slopes of Reclaimed Mine Sites“. 2010. http://trace.tennessee.edu/utk_gradthes/772.
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Surface mining is a major industry in eastern Tennessee that removes much of the native forest. To restore the forest, reclamation practices are used. These include planting a ground cover species with native hardwoods. Competition between the ground cover and tree species for soil resources could hinder growth and decrease survival of the trees. Northern red oak (Quercus rubra) was used for this study to examine the possible effects of this competition and the relationships between root growth and soil moisture through a field and a greenhouse experiment.
A field experiment was designed using four different ground cover treatments (Soldiago nemoralis, Medicago sativa, Panicum virgatum, and bare ground) with four different hardwood species. Northern red oak was measured for this study. The results showed that the site physical factors (slope position, soil temperature, and soil moisture) were not related to each other. Soil moisture varied by depth with the lower depths (46 cm to 76 cm) was much higher than the upper depths (0 to 46 cm). Root growth did not differ by treatment or percent cover. Both soil temperature and ground cover percentage increased over the growing season. Root growth showed a relationship with depth with the upper depths of soil having more roots than the lower depths. Annual rye was used as well as switchgrass, alfalfa, and bare ground treatments for a green house study. Two-year-old Northern red oak seedlings were first planted in pots and then ground covers were established and grown for 9 weeks. Then water stress was imposed over two dry down periods during which transpiration and soil moisture were measured. Root growth was measured after harvest. The results showed a relationship between transpiration and soil moisture. Soil moisture was highest in the bare ground treatment and lowest in the annual rye treatment. Fine root development of trees was greatest in the bare and alfalfa and lowest in the annual rye. Switchgrass had the second highest soil moisture and third highest fine root development. Root growth was related to both soil moisture and transpiration.
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Chou, Hyrum, und 周賢德. „Identification and Potential Evaluation of Cataclinal and Anaclinal Slopes over a Large Area Using GIS — Northern Cross-island Road for Example“. Thesis, 2002. http://ndltd.ncl.edu.tw/handle/02858865661783376364.
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碩士國立中央大學
應用地質研究所
90
Because of huge population over a relatively-small plain area in Taiwan, the continuous reclamation of slope-lands is a general trend. The west-side corridor of Taiwan is located in a fairly-folded terrain of numerous bedding planes, in which cataclinal and anaclinal slopes are populated, both leading to geological hazards. Locating the probable cataclinal and anaclinal slopes is greatly valuable for siting such reclamation in the preliminary stage. However, a detailed site investigation and precise mechanical analysis is not affordable for performing this task over a large area. The objective of this thesis is to establish a preliminary framework of quantitatively rating cataclinal and anaclinal slopes over a wide region using the geographic information system (GIS) technique. The preliminary rating system of cataclinal and anaclinal slopes in this thesis is based on the National water-soil preservation code and the kinematics analysis by comparing the attitude data of a surface slope and those of the closest outcropping bedding plane (as a only discontinuity), neglecting the contribution of others. And the adequacy of this system will be justified through the accumulative field observations and model test results. The attitude data of a surface slope were determined by GIS with input of DTM, while those of the bedding plane at any point were estimated by a polynomial interpolation method (up to an order of n) with input of real attitude measurements. A hypothesized case of one symmetrical continuous slope surface and smoothly-varied bedding planes was used to testify the above proposed framework, and it is found that the rating maps produced are very reasonable. The target field site under investigation is the area between Fu-hsin and Ba-lin along the Northern Cross-Island Road. The grid size of DTM map used is 40m□40m. The attitude data of weak planes were collected through various sources, whose correctness were unknown; the total number of these data was much less than that of slope surfaces computed by the DTM map, and its spacial distribution was not uniform over the target area. By comparing the rating map produced with the limited number of field observations, it is found that good match appears in most sites of smoothly-changing bedding attitude, but large deviation occurs in the Zong-hwa damsite with considerable variation in bedding attitude. In the latter case, an additional effort was made in which the Kriging method was used to replace the polynomial interpolation method for estimating the bedding attitude. Subsequently, it is concluded that the proposed scheme is very useful for rating that the upper-left quarter of the study area, in which bedding attitude varies quite smoothly. In summary, the rating framework established in this thesis is a automatic, quick and objective tool for quantitatively locating cataclinal and anaclinal slopes with a sufficient number of reliable input data, and it will provide a sound reference of preliminary siting and planning in the slope-lands of Taiwan in the near future.