Dissertations / Theses on the topic 'Coastal landslide'
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1
Ip, Wing-sze Catherine. "Coastal landslide study a case study at Shek Kok Tsui, Lamma Island /." Click to view the E-thesis via HKUTO, 2004. http://sunzi.lib.hku.hk/hkuto/record/B42577597.
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Ip, Wing-sze Catherine, and 葉詠詩. "Coastal landslide study: a case study at ShekKok Tsui, Lamma Island." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B42577597.
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Nawawitphisit, Sasiwimol. "Groundwater and geotechnical controls on landslide mechanisms of coastal cliffs formed in glacial till." Thesis, Durham University, 2014. http://etheses.dur.ac.uk/10614/.
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Landslides behave in a complex manner especially in terms of the relationship between groundwater variation and the mechanisms of movement; a relationship that remains poorly understood. The aim of this research is to improve the understanding of landslide movement patterns for coastal cliffs. The objectives are (1) to understand controls on landslide initiation; (2) to evaluate landslide movement patterns so as to explain the development to failure and their mechanisms; and (3) to investigate the hysteresis relationship between groundwater and displacement rate. Field monitoring has been undertaken at Upgang, a cliff formed in glacial till in North Yorkshire, UK (54.29° N and 0.38° W) for 30 months between 2010 and 2012. The monitored section extends 250 m along the coast and is 30 m high. The characteristics of the cliff face and its deformation over time were monitored monthly by terrestrial laser scanning. The landslide complex displays seasonal movements, associated with rotational failures, sliding and deterioration of the failed mass into a complex of mudslides. Movement is dominated both by groundwater variations resulting from precipitation, and marine cutting of the cliff toe. Data from a reactivating landslide, situated at the upper till section of the cliff, was selected to characterise post-failure change. The high spatial and temporal resolutions of the monitoring undertaken in this research allow these processes to be better understood. Uniquely, this study combines three detailed datasets including terrestrial laser scanning, in-situ monitoring and rigorous laboratory testing to explore the controls on the nature and style of landslide movement. The results demonstrate that reactivation of the landslide occurred in phases of accelerated (0.2 – 6.27 mm/hr), slow (< 0.2 mm/hr) and negligible movements, which were found to be influenced by the fluctuation of groundwater. A complex relationship has been found at the reactive shallow landslide, where the onset of accelerated movements corresponds to an increase in groundwater at the landslide base. Two types of hysteresis patterns, both clockwise (Strain hardening) and anti-clockwise (Strain softening), relating groundwater and displacement rate, were observed. The key controlling mechanism appears to be plastic deformation. The varied velocities are dependent on the stress state controlled by both rate of change in groundwater and absolute groundwater level. The intensity of rainfall has a significant effect on the style of movement. The results have wider implications for understanding the controls on landslide movement in coastal cliffs and reactivation landslides.
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Tekin, Onur Baran. "Long Waves In Narrow Enclosed Basins." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614964/index.pdf.
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In this study, numerical modeling of landslide generated tsunami waves in closed basins and their mechanisms are presented. Historical landslide generated tsunamis are investigated and also the governing parameters affecting impulse wave parameters are studied. The numerical model is based on the solution of nonlinear form of the long wave equations with respect to related initial and boundary conditions. In order to validate the outputs of the modeling by NAMIDANCE, empirical formulation is applied to the same cases as the numerical model and the results are discussed. The numerical model is then applied to Pervari Dam artificial reservoir as a case study to investigate the effects of potential landslide into the reservoir. The outputs of the numerical model are compared with empirical formulation results for different approaches of modeling the landslide effect in water body. The critical sections are observed for
overtopping and maximum wave amplitude values and the results are discussed.
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Bray, Malcolm John. "Beach budget analysis and shingle transport dynamics in West Dorset." Thesis, London School of Economics and Political Science (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337297.
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Comprehensive sediment budgets are compiled for a series of pocket shingle beaches in West Dorset backed by massive soft cliffs that degrade in a rapid and complex manner. Studies involve the identification and quantification of sediment (primarily shingle) inputs, transfers, storage and outputs within terrestrial and marine subsystem components. Results are unified within budget and flow models and applied to tackle questions of coastal evolution and management. Research involved mapping and sampling of the ground forming materials in terms of their beach forming potential. Cliff landsliding and recession are analysed using comparisons of historical maps, aerial photos and documentary evidence. A method of quantifying the release, throughput and supply to the beaches of various sediment grades from the eroding cliffs is presented. The volumes and types of sediment at the beach and in the inshore zone are investigated by various profile, intertidal, and offshore surveys. Detailed sampling and sediment analysis of the beaches is undertaken to elucidate beach drift and for attrition assessments through comparisons with cliff inputs. Shingle tracing experiments using aluminium tracers are conducted to study transport and sorting at two contrasting sites over a full spectrum of wave energy conditions. Validated littoral drift volumes and original wave power relationships are developed. Information is compiled to produce budget models for the main beaches. Complex long established links are demonstrated between eroding cliff sources and the shingle beaches that they supply. Chesil Beach is identified as the ultimate shingle sink suggesting that it is not entirely a product of the Holocene transgression as often envisioned, but a component of a Lyme Bay process system and open periodically to inputs of shingle from the west. Adverse impacts arising from various human interventions are highlighted using the models.
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Mickelson, Katherine A. "LiDAR-Based Landslide Inventory and Susceptibility Mapping, and Differential LiDAR Analysis for the Panther Creek Watershed, Coast Range, Oregon." PDXScholar, 2011. https://pdxscholar.library.pdx.edu/open_access_etds/253.
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LiDAR (Light Detection and Ranging) elevation data were collected in the Panther Creek Watershed, Yamhill County, Oregon in September and December, 2007, March, 2009 and March, 2010. LiDAR derived images from the March, 2009 dataset were used to map pre-historic, historic, and active landslides. Each mapped landslide was characterized as to type of movement, head scarp height, slope, failure depth, relative age, and direction. A total of 153 landslides were mapped and 81% were field checked in the study area. The majority of the landslide deposits (127 landslides) appear to have had movement in the past 150 years. Failures occur on slopes with a mean estimated pre-failure slope of 27° ± 8°. Depth to failure surfaces for shallow-seated landslides ranged from 0.75 m to 4.3 m, with an average of 2.9 m ± 0.8 m, and depth to failure surfaces for deep-seated landslides ranged from 5 m to 75m, with an average of 18 m ± 14 m. Earth flows are the most common slope process with 110 failures, comprising nearly three quarters (71%) of all mapped deposits. Elevation changes from two of the successive LiDAR data sets (December, 2007 and March, 2009) were examined to locate active landslides that occurred between the collections of the LiDAR imagery. The LiDAR-derived DEMs were subtracted from each other resulting in a differential dataset to examine changes in ground elevation. Areas with significant elevation changes were identified as potentially active landslides. Twenty-six landslides are considered active based upon differential LiDAR and field observations. Different models are used to estimate landslide susceptibility based upon landslide failure depth. Shallow-seated landslides are defined in this study as having a failure depth equal to less than 4.6 m (15 ft). Results of the shallow-seated susceptibility map show that the high susceptibility zone covers 35% and the moderate susceptibility zone covers 49% of the study area. Due to the high number of deep-seated landslides (58 landslides), a deep-seated susceptibility map was also created. Results of the deep-seated susceptibility map show that the high susceptibility zone covers 38% of the study area and the moderate susceptibility zone covers 43%. The results of this study include a detailed landslide inventory including pre-historic, historic, and active landslides and a set of susceptibility maps identifying areas of potential future landslides.
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Mohammed, Fahad. "Physical modeling of tsunamis generated by three-dimensional deformable granular landslides." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37152.
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Tsunamis are gravity water waves that are generated by impulsive disturbances such as submarine earthquakes, landslides, volcanic eruptions, underwater explosions or asteroid impacts. Submarine earthquakes are the primary tsunami source, but landslides may generate tsunamis exceeding tectonic tsunamis locally, in both wave and runup heights. The field data on landslide tsunami events are limited, in particular regarding submarine landslide dynamics and wave generation. Tsunamis generated by three-dimensional deformable granular landslides are physically modeled in the NEES (Network of Earthquake Engineering Simulation) 3D tsunami wave basin (TWB) at Oregon State University in Corvallis, Oregon. A novel pneumatic landslide tsunami generator is deployed to simulate natural landslide motion on a hill slope. The instrumentation consists of various underwater, above water and particle image velocimetry (PIV) cameras, numerous wave and runup gauges and a multi-transducer acoustic array (MTA). The subaerial landslide shape and kinematics on the hill slope and the surface elevation of the offshore propagating tsunami wave and runup on the hill slope are measured. The evolution of the landslide front velocity, maximum landslide thickness and width are obtained along the hill slope. The landslide surface velocity distribution is obtained from the PIV analysis of the subaerial landslide motion. The shape and the size of the submarine landslide deposit are measured with the MTA. Predictive equations are obtained for the tsunami wave amplitude, wave period and wavelength in terms of the non-dimensional landslide parameters. The generated 3D tsunami waves propagate away from the landslide source as radial wave fronts. The amplitudes of the leading tsunami waves decay away from the landslide source in radial and angular direction. The wave celerity of the leading tsunami wave may be approximated by the solitary wave speed while the trailing waves are slower due to the dispersion effects. The energy conversion rate between the landslide and the generated wave is estimated. The observed waves are weakly non-linear in nature and span from shallow water to deep water depth regime. The unique experimental data serves the validation and advancement of numerical models of tsunamis generated by landslides. The obtained predictive equations facilitate initial rapid tsunami hazard assessment and mitigation.
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Moore, Roger. "The clay mineralogy, weathering and mudslide behaviour of coastal cliffs." Thesis, King's College London (University of London), 1988. https://kclpure.kcl.ac.uk/portal/en/theses/the-clay-mineralogy-weathering-and-mudslide-behaviour-of-coastal-cliffs(ff869fdb-598b-40c7-8af6-f21f6ee3c2f7).html.
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Allison, Robert John. "Mass movement and coastal cliff development of the Isle of Purbeck, Dorset." Thesis, King's College London (University of London), 1986. https://kclpure.kcl.ac.uk/portal/en/theses/mass-movement-and-coastal-cliff-development-of-the-isle-of-purbeck-dorset(63f02422-0608-4a2e-9e76-648f350d8376).html.
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England, Kevin. "A GIS approach to landslide hazard management for the West Coast region, New Zealand." Thesis, University of Canterbury. Geological Sciences, 2011. http://hdl.handle.net/10092/5337.
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Landslides, in their various forms, are a common hazard in mountainous terrain, especially in seismically active areas and regions of high rainfall. The West Coast region of New Zealand is dissected by many active faults, experiences frequent earthquakes and in many locations annual rainfall exceeds ten meters. Consequently, landslides are widespread in the region and since European settlement began, have been responsible for 27 deaths, along with frequent damages to road and rail infrastructure, settlements and agricultural land.
This study identifies areas that are susceptible to rainfall triggered landslides in the West Coast region. To achieve this, a landslide susceptibility map was produced using bivariate statistics and the analytical hierarchy process. It has an accuracy that predicts 80% of all the landslides in the top 40% of the susceptibility scores on the map. As part of this process, 3221 rainfall triggered landslides and 522 earthquake (or other trigger) triggered landslides have been mapped and digitised into a Geographic Information System. In parallel with this, a descriptive historical catalogue of 1987 landslides has been compiled from the available sources.
These new tools provide decision-makers with an enhanced means of managing landslide hazards in the West Coast region. In order to avoid misinterpretation the study has been carried out in compliance with the “Guidelines for landslide susceptibility, hazard and risk zoning for land use planning”, which was published in 2008 by the Joint Technical Committee on Landslides and Engineered Slopes. The tools developed in this thesis represent a fundamental step in land-use planning and set-up of landslide hazard management in the West Coast region.
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Dixon, Neil. "The mechanics of coastal landslides in London clay at Warden Point, Isle of Sheppey." Thesis, Kingston University, 1986. http://eprints.kingston.ac.uk/20505/.
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Marshall, Michael Scott. "Slope Failure Detection through Multi-temporal Lidar Data and Geotechnical Soils Analysis of the Deep-Seated Madrone Landslide, Coast Range, Oregon." PDXScholar, 2016. https://pdxscholar.library.pdx.edu/open_access_etds/2656.
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Landslide hazard assessment of densely forested, remote, and difficult to access areas can be rapidly accomplished with airborne light detection and ranging (lidar) data. An evaluation of geomorphic change by lidar-derived digital elevation models (DEMs) coupled with geotechnical soils analysis, aerial photographs, ground measurements, precipitation data, and numerical modeling can provide valuable insight to the reactivation process of unstable landslides. A landslide was selected based on previous work by Mickleson (2011) and Burns et al. (2010) that identified the Madrone Landslide with significant volumetric changes. This study expands on previous work though an evaluation of the timing and causation of slope failure of the Madrone Landslide. The purpose of this study was to evaluate landslide morphology, precipitation data, historical aerial photographs, ground crack measurements, geotechnical properties of soil, numerical modeling, and elevation data (with multi-temporal lidar data), to determine the conditions associated with failure of the Madrone Landslide. To evaluate the processes involved and timing of slope failure events, a deep seated potentially unstable landslide, situated near the contact of Eocene sedimentary and volcanic rocks, was selected for a detailed analysis. The Madrone Landslide (45.298383/-123.338796) is located in Yamhill County, about 12 kilometers west of Carlton, Oregon. Site elevation ranges from 206 meters (m) North American Vertical Datum (NAVD-88) near the head scarp to 152 m at the toe. The landslide is composed of two parts, an upper more recent rotational slump landslide and a lower much older earth flow landslide. The upper slide has an area of 2,700 m2 with a head scarp of 5-7 m and a volume of 15,700 m3. The lower earth flow has an area of 2300 m2, a head scarp of 15 m, and a volume of 287,500 m3. Analysis of aerial photographs indicates the lower slide probably originated between 1956 and 1963. The landslide is located at a geologic unit contact of Eocene deep marine sedimentary rock and intrusive volcanic rock. The landslide was instrumented with 20 crack monitors established across ground cracks and measured periodically. Field measurements did not detect ground crack displacement over a 15 month period. Soil samples indicate the soil is an MH soil with a unit weight of 12 kN/m3 and residual friction angle of 28φ'r which were both used as input for slope stability modeling. Differential DEMs from lidar data were calculated to generate a DEM of Difference (DoD) raster to identify and quantify elevation changes. Historical aerial photograph review, differential lidar analysis, and precipitation data suggest the upper portion of the landslide failed as a result of the December 2007 storm.
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Quinn, Joseph David. "The landslides and recession of the holderness coast, Yorkshire Uk." Thesis, University of Leeds, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.511175.
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Beeson, Helen. "The Influence of Deep-Seated Landslides on Topographic Variability and Salmon Habitat in the Oregon Coast Range, USA." Thesis, University of Oregon, 2014. http://hdl.handle.net/1794/18421.
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A well-accepted idea in geomorphology is that landforms control the type and distribution of biological habitat. However, the linkages between geomorphology and ecology remain poorly understood. In rivers, the geomorphic template controls the hydraulic environment, partly shaping the river ecosystem. But what processes shape the geomorphic template? Here, I examine how two hillslope processes dominant in the Oregon Coast Range, debris flows and deep-seated landslides, affect valley floor width and channel slope, key components of the geomorphic template in riverine ecosystems. I then investigate how patterns in potential salmon habitat differ between streams dominated by deep-seated landslides and streams dominated by debris flows. I show that terrain influenced by deep-seated landslides exhibits (1) valley widths that are more variable throughout the network but less locally variable, (2) more variable channel slopes, and (3) more potential salmon habitat as well as significantly more connectivity between habitat types.
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Dirringer, Sebastian. "LANDSLIDE INVENTORY MAPPING OF THE DRIFT CREEK WATERSHED, LINCOLN COUNTY, OREGON, USING LIDAR DATA." Kent State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=kent1445452392.
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Kluger, Max Oke [Verfasser], Tobias [Akademischer Betreuer] [Gutachter] Mörz, and Vicki G. [Gutachter] Moon. "Failure mechanisms and mobilization processes of coastal landslides in sensitive soils / Max Oke Kluger ; Gutachter: Tobias Mörz, Vicki G. Moon ; Betreuer: Tobias Mörz." Bremen : Staats- und Universitätsbibliothek Bremen, 2017. http://d-nb.info/1143765583/34.
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Cerovski-Darriau, Corina. "Landslides and Landscape Evolution over Decades to Millennia—Using Tephrochronology, Air Photos, Lidar, and Geophysical Investigations to Reconstruct Past Landscapes." Thesis, University of Oregon, 2016. http://hdl.handle.net/1794/20405.
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Landscapes respond to external perturbations over a variety of timescales, including million-year tectonic forcing, millennial to decadal climate fluctuations, and minutes-long high intensity storms or large magnitude earthquakes. In mountainous regions, understanding the role of landslides in driving the hillslope response to these perturbations is paramount for understanding landscape evolution over geologic timescales and hazards over human timescales. Here I analyze the landslide-driven hillslope response over millennial to decadal timescales using a variety of tools and techniques (e.g. tephrochronology, lidar and air photo analysis, field and subsurface investigations, and seismic refraction) in the Waipaoa Basin (New Zealand) and Oregon Coast Range (USA). For the Waipaoa study catchment, pervasive landslides have been sculpting >99% of the hillslopes in response to >50 m of fluvial incision following the shift to a warmer, wetter climate after the Last Glacial Maximum (LGM) (~18 ka). Then, starting in the late 1800s, European settlement resulted in deforestation and conversion of >90% of the landscape to pastureland—spurring a rapid increase in landslide-driven erosion. To quantify the landscape response, I first reconstruct LGM and younger paleosurfaces using tephrochronology and lidar-derived surface roughness to estimate the volume, timing, and distribution of hillslope destabilization. From these reconstructions, I calculate the post-LGM catchment-averaged erosion rate (1.6 mm/yr) and determine that the timing of the initial hillslope adjustment was rapid and occurred by ~10 ka. Second, I quantify the rate and volume of historic hillslope degradation using a 1956-2010 sequence of aerial photographs, lidar, and field reconnaissance to map the spatial extent of active landslides, create a ‘turf index’ based on the extent and style of pastoral ground disruption, correlate that with downslope velocity, and calculate the average annual sediment flux. From the sediment flux, I calculate an erosion rate over the past ~50 years (~20 mm/yr) that is 10x greater than post-LGM. Lastly, in Western Oregon, I confirm that seismic refraction can determine the size (e.g. depth) and failure style of landslides in western Oregon—data needed to incorporate these poorly studied landslides into future landscape evolution or hazard models.
This dissertation includes both previously published and unpublished co-authored material.
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Sanford, Barry A. "The West Tidewater Earthflow, Northern Oregon Coast Range." PDXScholar, 2014. https://pdxscholar.library.pdx.edu/open_access_etds/2497.
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The West Tidewater earthflow, one of the largest in Oregon's history, occurred in December of 1994. The earthflow is located approximately 15 km north of Jewel, Oregon near the summit ofthe Northern Oregon Coast Range Mountains. The earthflow is 900 m long and 250 m wide, giving it a surface area of 9 ha, or 22 acres. Volume is 3.5 million m3. The earthflow occurred in low strength, well-bedded, tuffaceous, carbonaceous, micaceous, clay-rich mudstone, and very fine-grained, feldspathic, clay-rich siltstone of the lower Miocene age Northrup Creek Formation. The soil clay fractions contain up to 90% smectite with indications ofhalloysite. This earthflow is a reactivation ofa 650-year-old landslide (C-14 dating of uncovered buried trees). The failure mode is examined using a Janbu slope analysis and includes double wedge failure near the headscarp. High soil pore water pressure is one of the major causes of this slope failure. Rainfall levels for October, November, and December of 1994 were twice the previous five-year average. Present day groundwater level within the basin is less than one meter below ground surface. The earthflow is partially controlled by two faults of regional extent that dissect the basin near the headscarp in NW-SE and NE-SW directions. The Inceptisol soils in the basin remain moist below 20 cm year around. Soil in the basin may have been further weakened due to loss of root strength following timber harvest on the site in 1991. Soil liquid limits range from 42% to 95%, with PI values ranging from 2% to 77%. Soil clay content ranges between 18% and 30%. Direct shear tests on the mudstone and siltstone bedrock in both drained and undrained conditions produced internal friction angles of 14-18°, with cohesion values of 4 - 8 kPa. Back calculation of study area soil strength using the modified Bishop method results in a residual friction angle of 20.7°. The failure mode ofthe earthflow is from the headscarp downward and is modeled using Janbu methods. The study includes a detailed topographic map and a failure analysis of the earthflow basin.
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Woodruff, Malcolm. "The engineering geology of the landslides on the north coast of the Isle of Wight : their analysis and stabilisation." Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/426883/.
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The geological history of the north coast of the Isle of Wight is outlined and the published stratigraphy corrected. The engineering properties of the beds are summarised. The state of stress within the ground is discussed together with the effect that may have on the formation of shear zones and slip planes. Pore water pressure profiles in the slopes are described and the time scales involved in changing pore water profiles are discussed in terms of their effects on slope stability. Alternative methods of analysis are described and the results of several methods are compared for a slope typical of those on the north coast of the Isle of Wight. Long term movements on slides are considered and both progressive and episodic failure examined. Methods of stabilising landslides are discussed. The use of piles as stabilising elements is considered in some detail and a new method of calculating the moments and deflections on a passive pile is derived. Methods of extending the results of calculations on a single pile to rows of piles, i.e. group effects, are also summarised. The results of all the known boreholes in the Cowes, Gurnard area that penetrate the full depth of the land slipped material are plotted and a 3D model of the area presented. This is then used to draw sections which can be used to delineate the depth to the insitu geology. Finally, a number of case histories are described in both the Cowes Gurnard and Seagrove Bay areas which illustrate the problems encountered and the wide variety of methods used to overcome them. Many of the concepts discussed are illustrated by way of computer programs, written for the purpose.
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Borie, Mariane. "Les massifs rocheux crétacés supérieurs du Labourd occidental : processus d'altération et instabilités littorales." Thesis, Bordeaux 1, 2008. http://www.theses.fr/2008BOR13732/document.
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Ce travail est une analyse des conséquences de la présence de roches altérées, les altérites, sur les instabilités littorales du Labourd (Pays Basque). Le contexte environnemental des mouvements de terrain qui mobilisent ces matériaux méconnus est étudié afin de mieux appréhender les processus de rupture. Pour cela, d’une part, les altérites sont caractérisées d’un point de vue géologique ; d’autre part, les propriétés géotechniques et les circulations hydrogéologiques sont déterminées. Ces études permettent de mettre en évidence les différents facteurs prédisposant et déclenchant les instabilités, validés par modélisation numérique. La connaissance des processus ainsi améliorée, un outil d’estimation de l’aléa dans les altérites est proposéThis work is an analysis of the consequences of the presence of weathered rocks, called alterites, on the coastal landslides of the Labourd (Basque country). The environmental context (geological, hydrogeological and morphological) of the landslides is studied to a better understanding of the failure processes. These studies allow to highlight the main triggering factors of the landslides, which are validated by numerical modelling. The knowledge of the processes so improved, a tool to estimate landslide hazards in the alterites is proposed
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MAZZANTI, PAOLO. "Analysis and modelling of coastal landslides and induced tsunami." Doctoral thesis, 2009. http://hdl.handle.net/11573/477066.
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Sun, Wei-Fang, and 孫維芳. "A Study on the Landslide Characteristics along the Highway of the Northern Coastal Range." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/04672339258741378336.
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碩士國立東華大學
自然資源管理研究所
90
Eastern Taiwan is a landslide-prone region. Landslides induced by typhoons, heavy rain, or earthquakes not only paralyze traffic but also cause severe damage in property and threaten lives. The main objective of this study is to set up a database along the three highways (the 11th provincial highway, the 193th county highway, and the 11th-I provincial highway) of the Northern Coastal Range of the eastern Taiwan, by collecting and interpreting the corresponding information from topographic maps, geological maps, and disaster records (1995-2001) offered by the Taiwan Highway Bureau as well as field investigation. Statistic results of geological and rainfall factors influencing the slope failure were presented in this thesis. The research concludes as follows: (1) The 11th provincial highway is a dangerous road with a lot of huge landslides. (2) The most dangerous sections are 19~23k, 34~37k of the 11th provincial highway and 10~13k, 16~17k of the 11th-I provincial highway. (3) The annual slope failure volume has presented regularity change from one year to next year. (4) Landslides with a failure volume of not less than 200m3 have a cumulative frequency-size distribution with a power-law dependence on volume of failure. (5) Transported andesitic blocks (b) and Paliwan Formation Suilien Member (Pls) are landslide-prone formations. (6) Low accumulate rainfall (about 350mm) will induce landslides on the 11th provincial highway or in Transported andesitic blocks (b).
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Guthrie, Richard. "The Occurrence and Behavior of Rainfall-Triggered Landslides in Coastal British Columbia." Thesis, 2009. http://hdl.handle.net/10012/4484.
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This thesis seeks to analyze the occurrence and behavior of rainfall-triggered landslides in coastal British Columbia. In particular, it focuses on the analysis of landslide temporal and spatial distributions occurrence and their magnitudes, and considers the major factors that influence regional landslide behavior. Implicit in the research is the understanding that the landscape of coastal BC is managed, and that landslides, in addition to occurring naturally may be caused by, and certainly impact, resources that are important to humankind. Underlying each chapter is the rationale that by better understanding the causes of, and controls on landslide occurrence and magnitude, we can reduce the impacts and lower the associated risk. Statistical magnitude-frequency relationships are examined in coastal BC. Observations suggest that landslides in coastal British Columbia tend to a larger size until about 10,000 m2 in total area. At this point larger landslides are limited by landscape controls according to a power law. Probabilistic regional hazard analysis is one logical outcome of magnitude-frequency analysis and a regional mass movement hazard map for Vancouver Island is presented. Physiographic controls on statistical magnitude-frequency distributions are examined using a cellular automata based model and results compare favorably to actual landslide behavior: modeled landslides bifurcate at local elevation highs, deposit mass preferentially where the local slopes decrease, find routes in confined valley or channel networks, and, when sufficiently large, overwhelm the local topography. The magnitude-frequency distribution of both the actual landslides and the cellular automata model follow a power law for magnitudes higher than 10,000 m2 - 20,000 m2 and show a flattening of the slope for smaller magnitudes. The results provide strong corroborative evidence for physiographic limitations related to slope, slope distance and the distribution of mass within landslides. The physiographic controls on landslide magnitude, debris flow mobility and runout behavior is examined using detailed field and air photograph analysis. The role of slope on deposition and scour is investigated and a practical method for estimating both entrainment and runout in the field, as well as in the GIS environment, is presented. Further controls on landslide mobility, including the role of gullies and stream channels, roads and benches and intact forests, are considered. The role of landslides in controlling landscape physiography is also examined. In particular, it is determined that moderate-sized landslides do the most work transporting material on hillslopes, defined by a work peak, and that magnitude varies based on local physiography and climate. Landslides that form the work peak are distinct from catastrophic landslides that are themselves formative and system resetting. The persistence time for debris slides/debris flows and rock slides/rock avalanches is calculated over six orders of magnitude and an event is considered catastrophic when it persists in the landscape ten times longer than the population of landslides that form the work peak. A detailed case study examines meteorological controls on landslide occurrence and the role of extreme weather is considered. A critical onset of landslide triggering rainfall intensity is determined to be between 80 mm and 100 mm in 24 hours and wind is determined to result in increased local precipitation. The role of rain-on-snow is also evaluated and determined to be crucial to landslide occurrence. Finally, a conceptual model of landslide-induced denudation for coastal mountain watersheds spanning 10,000 years of environmental change is presented. Recent human impacts are calculated for landslide frequencies over the 20th century. The impact of logging during the last 100 years is unambiguous; logging induced landslides almost doubles the effect frequency of the wettest millennia in the last 10,000 years. This suggests that the impact of logging outpaces that of climatic change. Debris slides and debris flows are estimated to have resulted in a landscape lowering of 0.7 m across the Vancouver Island during the last 10,000 years.
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Brardinoni, Francesco. "Identification of natural and logging-related landslide in the Capilano River basin (coastal British Columbia) : a comparison between remotely sensed survey and field survey." Thesis, 2001. http://hdl.handle.net/2429/12740.
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In the Pacific Northwest landslide inventories are routinely compiled by means of aerial
photo interpretation. When examining photo pairs the forest canopy, notably in old-growth
forest, hides a population of "not visible" landslides. The present study attempts to estimate
how important is the contribution of landslides not detectable from aerial photographs, to the
global mass of sediment production from mass failures on forested terrain of the Capilano
basin.
To achieve this, aerial photo interpretation has been coupled with intensive fieldwork
for identification and measurement of all landslides. In order to minimise bias in the
comparison and integration of field-collected and air photo-collected data it was decided to
define a 30-year time window. Incidentally, it has been possible to prove how landslide scars
that appear on a single photo set would date further back than 30 years.
Results show that "not visible" landslides can represent up to 85 percent of the total
number of failures and can account for up to 30 percent the total volume of debris mobilised.
Rates of sediment production differ greatly (one order of magnitude) between two sub-basins
of the study area, suggesting that such figures should be generalised with care within a
physiographic region. The difference in denudation rate is explained qualitatively by GISbased
analysis of slope frequency distributions, drainage density and spatial distribution of
surficial materials.
Fieldwork has demonstrated that gully-related failures have a greater importance than
one could expect from air photo interpretation. ANOVA and nonparametric tests indicate that
careful logging in East Cap Creek has produced no detectable effects on mass wasting.
Similarly, Sisters Creek, where timber harvesting stopped about 20 years before the start of
our 30-year time window, has apparently recovered from the signs of past extensive logging.
The existence of "not visible" events affected in a minor way conclusions about the
impact of logging on slope stability in terms of land use (management) effects. It had a major
impact on the nature of landslide magnitude-frequency relations and, finally is demonstrated
to have implications for British Columbia Terrain Stability Classification from the terrain
sensitivity point of view.
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Surfleet, Christopher G. "Precipitation characteristics for landslide hazard assessment for the central Oregon Coast Range /." 1997. http://hdl.handle.net/1957/9880.
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Chi-PingChen and 陳啓平. "Characteristics of Landslides on Taiwan East Coast." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/44450463214612038263.
Full textAbstract:
碩士國立成功大學
水利及海洋工程學系碩博士班
101
In this research, we use ArcGIS by NDVI (Normalized Difference Vegetation Index) to judge landslides in 4 periods of Formosa II satellite images. By using 5-meter DEM (Digital Elevation Model) which is drawn by Soil and Water Conservation Bureau in 2003 and the rock data which is established by National Cheng Kung University Disaster Prevention Research Center (DPRC) in 1995, we can get slope, aspect, elevation and rock data. Individually discussed this four factors which their effect of collapse. For researching the data of collapse during the first period (during 2009 August to 2011 Feb.) to the fourth period (during 2012 March to 2012 July). Making the first period data of collapse be the datum and make the other three periods subtract the first period. Thus, we can get the benchmarking of this three periods. By discussing this benchmarking, we get a result that slope and elevation have a tendency of direct ratio to collapse ratio. Using dangerous value method to calculate potential collapse. By the factor of geography, we can calculate collapse index and weight. Combining the collapse index and weight, we can get the empirical formula of potential collapse in research area. Input the data of research area to empirical formula, we can get potential collapse of this area. Integrating potential collapse of these three periods. Thus, we can get high potential collapse of these area. In researching, we use this method to mark higher risk of collapse in the research area and have a result: elevation bigger than 2500 meter, rock which is Pilushan Formation, slope bigger than 30 degree and aspect is south and south-west have more possibility to occur collapse.
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Wong, Bernard Bong-lap. "Controls on movement of selected landslides in the Coast Range and western Cascades, Oregon." Thesis, 1991. http://hdl.handle.net/1957/37271.
Full textAbstract:
The movement characteristics of five landslides are
compared and interpreted based on records of approximately
10-years duration. Condon landslide in the Oregon Coast
Range has consistently exhibited brief (1 - 8 days) movement
episodes in wet winter months, separated by long periods of
no movement. The translatory movement is probably
controlled by the orientation and structure of the
underlying sedimentary rocks. From 1981 to 1990, annual
movement averaged 109 mm, and individual events varied from
1 to 187 mm. All major movement events (> 10 mm in 4-10
days) were precipitation-induced. A non-linear relationship
exists between movement rates and Antecedent Precipitation
Index, which has a daily recession coefficient of 0.87. The
API threshold for movement initiation was estimated to be
160 mm, based on 16 documented major events between 1984 and
1990. Groundwater level at the landslide responded to
precipitation very quickly, with lag time usually less than
3 days. Movement started on days when the groundwater level
rose above 2.5 m below ground surface, and a non-linear
relationship exists between daily movement rate and
groundwater level. Based on available data, there appears
to be no change in movement characteristics of Condon
landslide after two-third of it was clearcut in 1987.
Wilhelm landslide, located near Condon landslide, has a
similar movement pattern, but smaller movement magnitude
(averaged 34 mm per year, 1985-1990). The Mid-Santiam and
Jude Creek landslides in the volcanic terrane of the western
Cascade Range move at much faster rates, averaging 3.8 and
7.8 m per year from 1982 to 1990, respectively. Unlike the
Condon and Wilhelm landslides, where individual movement
events correspond with individual storms, these two western
Cascades landslides exhibit prolonged movement. The Mid-Santiam
landslide moves all year, and annual movement shows
little variation over the year. The other studied
landslides all have large intra- and interannual variation
in movement rates, and movement generally stops in the
summer dry period. The Lookout Creek landslide (average
annual movement = 79 mm, 1981-1990) has slowed in the past
four years, and has exhibited movement patterns similar to
the storm-dominated Coast Range slides.
Geology and climatic patterns are the two most
important factors contributing to the observed differences
in timing and style of movement in the landslides studied.
Climatic patterns trigger movement events, and geology
influences movement patterns through control on geotechnical
properties of landslide materials. These factors can be
used to classify landslide movement patterns on a regional
scale.Graduation date: 1992
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Dent, Elizabeth F. "Influence of hillslope and instream processes on channel morphology of Esmond Creek in the Oregon Coast Range /." 1993. http://hdl.handle.net/1957/9491.
Full text
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English, Russell Richard. "Lineament control on drainage basin development, large rock landslides and mountain slope deformation in the southwest coast mountains, British Columbia, Canada." Thesis, 1998. http://hdl.handle.net/2429/8077.
Full textAbstract:
This research describes lineaments in the southwestern Coast mountains of British Columbia
and their effect on landscape evolution and contemporary geomorphic processes.
Lineaments mapped on air photographs are reflective of bedrock structure. Three regional
trends are evidenced: a Cretaceous, northwest trend; a Tertiary norhteast trend; and an east-west
trend which may represent recent crustal convergence between the North American and Juan de Fuca
plates. Field and air photo evidence suggests lineaments should be interpreted primarily as either
faults or large-scale regional joints.
Lineament control of basin axial position is demonstrated. The spatial correlation between
stream segments and lineaments is determined using the IDRISI GIS. On average 66% of the stream
network overlies lineaments and 51% of lineaments in a basin are overlain by streams.
The relationship of lineament length to basin morphometry is assessed by linear regression
and compared to the relation between stream length and basin morphometry, Stream length is a
better predictor of basin morphometry but lineament length is a good predictor of many parameters
and becomes more important as basin area increases. It is speculated that lineaments become more
important than streams in determining mean topography as landscape scale increases.
20 sites of large rock landslides and mountain slope deformation are identified in the study
area. Rock avalanches and mountain slope deformation are the most common features, other failure
types include rockfalls and landslides in surficial materials adjacent to rivers. Lineaments influence
these features in three ways: 1) forming landslide headscarps; 2) providing locations about which
slope deformation occurs; 3) forming rockfaces capable of shedding large rockfalls.
Debris flow and avalanche initiation points are examined in the Seymour watershed north of
Vancouver, British Columbia. These are almost twice as likely to occur where streams and
lineaments intersect as where a stream only is present.
This study suggests that the morphometry of drainage basins in the southwest Coast
Mountains and some of the processes operating within them are a consequence of the underlying,
tectonically emplaced bedrock structure. It is argued that processes operating at tectonic scales
influence, and are reflected in, the landscape patterns around us.