Dissertations / Theses: 'Landslide assessment'

1

Abdel-Latif, M. A. "Landslide hazard assessment." The Ohio State University, 1994. http://rave.ohiolink.edu/etdc/view?acc_num=osu1371042717.

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2

Guzzetti, Fausto. "Landslide hazard and risk assessment." [S.l.] : [s.n.], 2006. http://deposit.ddb.de/cgi-bin/dokserv?idn=980716993.

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3

Karam, Karim S. (Karim Semaan) 1977. "Landslide hazards assessment and uncertainties." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/33690.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2005.
Includes bibliographical references (v. 2, p. 736-750).
Landslides are natural phenomena which are difficult to predict because their initiation depends on many factors and on the interaction between these factors. The annual number of causalities caused by landslides is in the thousands, and infrastructural damage is in the billions of dollars. To satisfy the increasingly urgent societal demand for protection against landslides, it is necessary to systematically assess and manage landslide hazard and risk. This can be done using principles of decision making under uncertainty. We develop an advanced combined hydrologic - stability model that is better capable of assessing landslide hazards than current models used in landslide analyses. This model allows one to evaluate landslide hazards deterministically. We use the model to study landslide failure mechanisms, and classify these according to the manner in which a slope gets saturated during rain. We showed that slopes with great depths to bedrock and shallow depths to the water table, tend to fail by saturation from below, resulting in deep seated landslides, and slopes with deep lying water tables tend to fail by saturation from above, resulting in shallow landslides.
(cont) Landslide hazards include, by definition, uncertainties which can be expressed probabilistically. Uncertainties arise from parameters and from models. We develop efficient techniques to formally incorporate parameter uncertainties into the combined hydrologic - stability model, and hence into the hazard assessment procedure. We then show that landslide hazards are significantly influenced by the joint probability distribution of the soil strength parameters and the strength submodel(s) used in the stability models, and by the soil characteristic curve submodel(s) used in the hydrologic models. This study leads to a better understanding of landslide mechanisms and to advanced models that assess landslide hazards more accurately than current models. The results of parameter uncertainty investigations show which parameters are most important in landslide analyses, and hence where it is worthwhile to obtain more information. The results of model uncertainty investigations show which models are most important in landslide analyses, and hence where further research needs to be undertaken.
by Karim S. Karam.
Ph.D.

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FERRETTI, ANTONIO. "Landslide hazard assessment in structurally complex soils." Doctoral thesis, Università Politecnica delle Marche, 2020. http://hdl.handle.net/11566/274557.

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Nel contesto europeo, l’Italia è il paese più incline al dissesto da frana, dove i fenomeni franosi sono i più frequenti e diffusi tra i pericoli naturali. Una stima quantitativa del pericolo da frana è perciò un importante e attuale problema e riveste un ruolo centrale nella valutazione e gestione del rischio, permettendo di individuare i migliori interventi e strategie per fronteggiare tali fenomeni. In tale contesto, questo lavoro si è concentrato sull’analisi e la comprensione dei più rilevanti fattori e processi che, alla scale del versante, regolano la stabilità dei pendii naturali. Una corretta diagnosi del meccanismo di instabilità, infatti, è di primaria importanza al fine di quantificarne il pericolo associato. Nello specifico, è stato sviluppato un processo diagnostico di una frana esistente, la quale interagisce con un tratto di un’importante arteria stradale situata in Italia centrale. Tale frana è stata opportunamente selezionata dal momento che è ben rappresentativa di una tipologia di frane ampiamente diffusa nel territorio nazionale, generalmente identificate come “frane attive a cinematica lenta”. Tali movimenti di vaste proporzioni si sviluppano in pendii dolci costituiti da depositi argillosi consistenti, molto spesso tettonizzati, che manifestano riattivazioni periodiche in relazione al regime piovoso dell’area. Dato che tali frane sono caratterizzate da velocità contenute, esse non costituiscono un pericolo diretto per le persone ma hanno un importante impatto economico sulla società, danneggiando insediamenti urbani e infrastrutture. All’interno del processo di diagnosi, il monitoraggio si è rivelato essere un prezioso strumento che ha permesso di evidenziare in maniera chiara la risposta del sistema alle azioni esterne che ne compromettono la stabilità, ossia le piogge e gli scuotimenti sismici. Per quanto riguarda lo studio degli effetti pluvioindotti, sono state condotte delle analisi idrauliche in regime transitorio attraverso una modellazione numerica agli elementi finiti che ha cercato di tener conto degli elementi più significativi che governano il processo di infiltrazione. È stato riscontrato un soddisfacente accordo tra le oscillazioni della falda simulate e quelle monitorate, evidenziando che il modello numerico è capace di riprodurre in maniera realistica la risposta idraulica del pendio in funzione del regime piovoso. Successivamente, sono state effettuate delle analisi di stabilità all’equilibrio limite considerando le oscillazioni di falda simulate in modo da quantificare il loro effetto sulla stabilità del pendio. I valori del fattore di sicurezza, ottenuti considerando che la resistenza a taglio residua sia pienamente sviluppata lungo la superficie di scorrimento, sono risultati essere generalmente bassi, confermando la condizione di precaria stabilità della frana messa in luce dal monitoraggio inclinometrico. Perciò tale modellazione ha effettivamente permesso di approfondire il meccanismo di instabilità considerato. La stabilità del pendio, inoltre, è stata valutata anche nei confronti delle azioni sismiche. Grazie alla rara disponibilità sia degli spostamenti sismici monitorati che delle registrazioni accelerometriche, è stato possibile stimare l’accelerazione critica del sistema sulla base di dati reali. A tal fine, è stata eseguita una procedura di back-analysis impiegando il ben noto metodo di Newmark. I valori così ottenuti trovano un buono accordo con altre stime riportate in letteratura e con i valori calcolati attraverso il metodo pseudostatico. Di conseguenza, è stato possibile fornire una stima attendibile dell’accelerazione critica del pendio, che è un parametro fondamentale per la valutazione della risposta del pendio alle azioni sismiche. In conclusione, sebbene questo lavoro si sia focalizzato sullo studio di uno specifico caso, la maggior parte dei risultati è di rilevante importanza per approfondire la conoscenza di così complessi fenomeni naturali e il processo interpretativo adottato può essere applicato ad altre situazioni simili.
In the European context, Italy is the most landslide prone country where landslides are the most frequent and disperse natural hazards. Therefore, the landslide hazard assessment, especially in terms of quantity, is a relevant and current problem and plays a central role within the risk assessment and management framework, allowing to find the best remedial measures and strategies to cope with such phenomena. In this context, this work has focused on the analysis and understanding of the most relevant slope factors and processes that contribute to the stability of natural slopes. In fact, a proper diagnosis of the landslide mechanism is of primary importance to the quantitative definition of the hazard posed by a given landslide. In particular, a stepwise diagnosis of a real landslide, which interacts with a segment of an important highway in central Italy, has been developed. Such landslide has been properly chosen since well representative of a class of slope failures so widespread in the national territory, generally referred to as “active slow moving landslides”. These large-scale slope movements take place in gentle slopes made of stiff clayey deposits, very often tectonically disturbed, that exhibit periodically reactivations related to the rainfall regime of the area. Since low entity velocities characterize these landslides, they are not hazardous for human lives but they have an important economic impact on society, being responsible for extensive damage to urban settlements and infrastructures. In the developed diagnostic process, monitoring turned out to be a precious instrument that allowed depicting clearly the actual response of the system to the external actions affecting its stability, i.e. rainfalls and seismic shakings. This aspect highlights the central role played by a good quality monitoring as a part of the investigation of slope stability. With regard to the rainfall-induced effects, transient hydraulic analyses have been carried out by means of finite element method modelling that tried to account for the most relevant aspects that govern the infiltration process. A good agreement between the simulated groundwater fluctuations and the monitored ones has been obtained, demonstrating that the numerical model is able to reproduce realistically the hydraulic response of the slope as a function of the rainfall regime. Subsequently, limit equilibrium stability analyses have been conducted by considering the simulated groundwater fluctuations in order to quantify their effect on the slope stability. The general low values of the factor of safety, obtained considering that the residual shear strength is fully attained along the entire slip surface, confirmed the precarious stability of the landslide, as highlighted by inclinometer monitoring. Therefore, such modelling provided a further interpretation of the analysed landslide mechanism. Moreover, the stability of the slope has been also evaluated under earthquake loadings. Thanks to the very rare availability of both monitored seismic displacements and accelerometric records, it has been possible to estimate the critical acceleration of the system based on real data. To do so, a back-analysis procedure has been carried out by the well-known Newmark’s method. The obtained values are in good agreement with other estimates reported in literature and with the ones calculated by the pseudostatic method. As a result, it has been possible to give a reliable estimate of the critical acceleration of the slope, which is an essential parameter in evaluating its performance under earthquake loadings. In conclusion, even though this work has been focused on a specific case study, most of the findings are relevant to deepen the knowledge of such complex natural phenomena and the interpretative process adopted can be applied to other similar situations.

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Postance, Benjamin F. "Indirect impact of landslide hazards on transportation infrastructure." Thesis, Loughborough University, 2017. https://dspace.lboro.ac.uk/2134/32771.

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This thesis examines the indirect impact of natural hazards on infrastructure networks. It addresses several key themes and issues for hazard assessment, network modelling and risk assessment using the case study of landslides impacting the national road network in Scotland, United Kingdom. The research follows four distinct stages. First, a landslide susceptibility model is developed using a database of landslide occurrences, spatial data sets and logistic regression. The model outputs indicate the terrain characteristics that are associated with increased landslide potential, including critical slope angles and south westerly aspects associated with increased rates of solar irradiance and precipitation. The results identify the hillslopes and road segments that are most prone to disruption by landslides and these indicate that 40 % (1,700 / 4,300 km) of Scotland s motorways and arterial roads (i.e. strategic road network) are susceptible to landslides and this is above previous assessments. Second, a novel user-equilibrium traffic model is developed using UK Census origin-destination tables. The traffic model calculates the additional travel time and cost (i.e. indirect impacts) caused by network disruptions due to landslide events. The model is applied to calculate the impact of historic scenarios and for sets of plausible landslide events generated using the landslide susceptibility model. Impact assessments for historic scenarios are 29 to 83 % greater than previous, including £1.2 million of indirect impacts over 15 days of disruption at the A83 Rest and Be Thankful landslide October 2007. The model results indicate that the average impact of landslides is £64 k per day of disruption, and up to £130 k per day on the most critical road segments in Scotland. In addition to identifying critical road segments with both high impact and high susceptibility to landslides, the study indicates that the impact of landslides is concentrated away from urban centres to the central and north-west regions of Scotland that are heavily reliant on road and haulage-based industries such as seasonal tourism, agriculture and craft distilling. The third research element is the development of landslide initiation thresholds using weather radar data. The thresholds classify the rainfall conditions that are most commonly associated with landslide occurrence in Scotland, improving knowledge of the physical initiation processes and their likelihood. The thresholds are developed using a novel optimal-point threshold selection technique, high resolution radar and new rain variables that provide spatio-temporally normalised thresholds. The thresholds highlight the role of the 12-day antecedent hydrological condition of soils as a precursory factor in controlling the rain conditions that trigger landslides. The new results also support the observation that landslides occur more frequently in the UK during the early autumn and winter seasons when sequences or clustering of multiple cyclonic-storm systems is common in periods lasting 5 to 15 days. Fourth, the three previous elements are combined to evaluate the landslide hazard of the strategic road segments and a prototype risk assessment model is produced - a catastrophe model. The catastrophe model calculates the annual average loss and aggregated exceedance probability of losses due to the indirect impact of landslides in Scotland. Beyond application to cost-benefit analyses for landslide mitigation efforts, the catastrophe model framework is applicable to the study of other natural hazards (e.g. flooding), combinations of hazards, and other infrastructure networks.

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6

Lam, Huu Quang. "DEVELOPMENT OF HAZARD ASSESSMENT TECHNOLOGY OF THE PRECURSOR STAGE OF LANDSLIDES." Kyoto University, 2018. http://hdl.handle.net/2433/232065.

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7

Protong, Shotiros. "Climate change and landslide risk assessment in Thailand." Thesis, University of Southampton, 2016. https://eprints.soton.ac.uk/401821/.

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The incidents of sudden landslides in Thailand during the past decade have occurred frequently and more severely. It is necessary to focus on the principle parameters used for analysis such as land cover/land use, rainfall values, characteristics of the soil and digital elevation model(DEM). Rainfall has increased in intensity. For example, the rainfall amount in March in 2011 was the highest in the previous 36 years (1974-2011). However,there was only one tropical cyclone that year. This situation was considered unusual compared to other years (TMD, 2011c). Landslide occurrences occur during intense rainfall especially in the rainy season in Thailand which usually starts around mid-May and ends in the middle of October. The landslide risk analysis is the focus of this research. The combination of geotechnical and hydrological data is used to determine permeability, conductivity, bedding orientation, overburden and presence of loose blocks. The regional landslide hazard mapping is developed using the Slope Stability Index SINMAP model supported by Digital Elevation Model (DEM) in 30 metres. So, the 30 metre pixel size of DEM is used to calcu late on the ground. Geological and land use data are used to define the probability of landslide occurrences in terms of geotechnical data. The geological data can indicate the shear strength and the angle of friction values for soils above given rock types, which leads to the general applicability of the approach for landslide hazard analysis. To address the research, the following methods are described in this study: the calibration and the sensitivity of the SINMAP modelfor setup, geotechnical laboratory,landslide assessment at present calibration and landslide assessment under future climate simulation scenario A2 and B2. A2 simulation scenario delineates a very heterogeneous world and continuous population and economic growth, while B2 storyline is oriented on local solution to economical, social and environmental sustainability (START, 2010). In terms of hydrological data, the millimetres/twenty-four hours of average rainfall data are used to assess the induced rainfall landslide hazard analysis in slope stability mapping. The period 1954-2012is used for the baseline of rainfall data for calibration of present-dayconditions. Future climate simulation scenarios are downscaled in the local areas. The precipitation trends are needed to predict the future climate. The Statistical Down scaling Model (SDSM), is used to assess the simulation scenario of future change for latitudes16o26’and 18o37’and between longitude 98o52’ and 103o05’,is about 117,500 km2, covering Uttaradit province in the northern part of Thailand. The research allows the mapping of landslide risk, and indicates the spatial and time periodof landslide occurrences. Thus, regional landslide hazard mapping under present-day climatic conditions from 1954 to 2012 and simulations of climate change from 2013 to 2099 related to the threshold rainfall values for the selected the study areaare presented. Finally, the zonation of landslide risk will be compared and shown by areas (km2) in both the present and the future under climate simulation scenarios A2 and B2 in Uttaradit province. The rainfall trend will increase in the future simulation. The zonation of landslide risk is nearly the same between the present and the future simulation, while the failure region will obviously increase in the future, especially in steep slope areas.

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Alvarado, Bueno Mauricio. "Landslide motion assessment including thermal interaction : an MPM approach." Doctoral thesis, Universitat Politècnica de Catalunya, 2018. http://hdl.handle.net/10803/525825.

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Risk associated with landslides of natural or man-made origin depends on the prediction of the post-failure behaviour of the mobilized mass. Numerical models capable of integrating the landslide geometry and its evolution, the coupled hydro mechanical interaction and the soil properties in the context of dynamic forces and large displacements are currently under development. This thesis is a contribution to this effort. In this sense, the material point method (MPM) is especially suited for analyzing landslides with large displacements. This numerical procedure must be accompanied by tests under controlled conditions in order to accurately check and calibrate the numerical response. In this thesis the capabilities of the MPM code developed are evaluated through the modelling of scaled laboratory slope tests with large displacements. In order to achieve an adequate comparison of the experimental and numerical results, the experiments are analysed by means of the interpretation of sequential digital images of the movement of the granular medium during the test (PIV technique). A novel procedure is developed to obtain the field of deformations over time and the tracking of particle path in a manner suitable for comparison with numerical results calculated in MPM. The main objective of the thesis was the development of a comprehensive calculation tool capable of simulating the behaviour of the slides from the initial triggering to the post-failure phase including thermal effects that determine the evolution of the movement. A formulation for non-isothermal problems coupled with hydraulic and mechanical behaviour in MPM was developed and implemented. The formulation includes the dissipation of frictional work as heat, which takes place, mainly, in shear bands. The described phenomena are strongly dependent on the thickness of the shear band and this result in a strong dependence of the numerical results in MPM with the discretization mesh. A novel procedure to solve this problem is presented in this thesis. Finally, very rapid Vajont landslide (Italy 1963) is modelled. A plain strain 2D model is presented without an “a priori” definition of the sliding surface. In fact, in a generalization of previous and recent work, the mobilized materials are not restricted to rigid solids interconnected along a predefined contact surface and the heat generation is not it is limited to a single predefined surface. Thus, thermal interaction processes are developed throughout the model as a function of the location and intensity of deformations.
El riesgo asociado con deslizamientos de origen natural o artificial depende de la predicción del comportamiento posterior a la rotura de la masa movilizada. Actualmente se están desarrollando modelos numéricos capaces de integrar la geometría del deslizamiento y su evolución, la interacción hidromecánica acoplada y las propiedades del suelo en el contexto de fuerzas dinámicas y grandes desplazamientos. Esta tesis es una contribución a este esfuerzo. En este sentido, el método del punto material (MPM) es especialmente adecuado para analizar deslizamientos con grandes desplazamientos. Este procedimiento numérico debe ir acompañado de ensayos bajo condiciones controladas para poder comprobar y calibrar la respuesta numérica. En esta tesis se evalúan las capacidades del código MPM desarrollado, mediante la modelación de ensayos de laboratorio a escala con grandes desplazamientos. Para lograr una adecuada comparación de los resultados experimentales y numéricos, se analizan los experimentos mediante la interpretación de imágenes digitales secuenciales del movimiento del medio granular durante el ensayo (técnica PIV). Con este fin, se desarrolla un procedimiento novedoso para la obtención del campo de deformaciones en el tiempo y el seguimiento de la trayectoria de las partículas de forma idónea para la comparación con resultados numéricos calculados en MPM. El principal objetivo de la tesis fue el desarrollo de una herramienta potente de cálculo capaz de simular el comportamiento de los deslizamientos desde la rotura inicial hasta la fase de post-rotura incluyendo efectos térmicos que determinan la evolución del movimiento. Para esto, se desarrolla e implementa una formulación para problemas no isotérmicos acoplados con el comportamiento hidráulico y mecánico en MPM. Esta formulación incluye la disipación del trabajo friccional en forma de calor, lo cual ocurre principalmente en las bandas donde se localiza la deformación de corte. Este fenómeno descrito es fuertemente dependiente con el espesor de la banda de corte y esto se traduce en una fuerte dependencia de los resultados numéricos en MPM con la malla de discretización empleada. En esta tesis se presenta un novedoso procedimiento para solventar este problema. Por último se presenta la modelación del movimiento ocurrido en el deslizamiento rápido de Vajont (Italia 1963). Se introduce un modelo 2D en deformación plana sin una definición "a priori" de la superficie de deslizamiento. De hecho, generalizando los trabajos hechos anteriormente, los materiales movilizados no se restringen a solidos rígidos interconectados a lo largo de una superficie de contacto predefinida y la generación de calor no se limita a una única superficie predefinida. Así, los procesos de interacción térmica se desarrollan en todo el modelo en función de la localización e intensidad de las deformaciones.

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9

Mason, Philippa Jane. "Landslide hazard assessment using remote sensing and GIS techniques." Thesis, Imperial College London, 1999. http://hdl.handle.net/10044/1/8899.

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10

Hendy, Setiawan. "Landslide Hazard Assessment on the Upstream of Dam Reservoir." 京都大学 (Kyoto University), 2017. http://hdl.handle.net/2433/225565.

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付記する学位プログラム名: グローバル生存学大学院連携プログラム
Kyoto University (京都大学)
0048
新制・課程博士
博士(工学)
甲第20340号
工博第4277号
新制||工||1662(附属図書館)
京都大学大学院工学研究科社会基盤工学専攻
(主査)教授寶馨, 教授角哲也, 准教授佐山敬洋
学位規則第4条第1項該当

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11

Walstra, Jan. "Historical aerial photographs and digital photogrammetry for landslide assessment." Thesis, Loughborough University, 2006. https://dspace.lboro.ac.uk/2134/2501.

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This study demonstrates the value of historical aerial photographs as a source for monitoring long-term landslide evolution, which can be unlocked by using appropriate photogrammetric methods. The understanding of landslide mechanisms requires extensive data records; a literature review identified quantitative data on surface movements as a key element for their analysis. It is generally acknowledged that, owing to the flexibility and high degree of automation of modern digital photogrammetric techniques, it is possible to derive detailed quantitative data from aerial photographs. In spite of the relative ease of such techniques, there is only scarce research available on data quality that can be achieved using commonly available material, hence the motivation of this study. In two landslide case-studies (the Mam Tor and East Pentwyn landslides) the different types of products were explored, that can be derived from historical aerial photographs. These products comprised geomorphological maps, automatically derived elevation models (DEMs) and displacement vectors. They proved to be useful and sufficiently accurate for monitoring landslide evolution. Comparison with independent survey data showed good consistency, hence validating the techniques used. A wide range of imagery was used in terms of quality, media and format. Analysis of the combined datasets resulted in improvements to the stochastic model and establishment of a relationship between image ground resolution and data accuracy. Undetected systematic effects provided a limiting constraint to the accuracy of the derived data, but the datasets proved insufficient to quantify each factor individually. An important advancement in digital photogrammetry is image matching, which allows automation of various stages of the working chain. However, it appeared that the radiometric quality of historical images may not always assure good results, both for extracting DEMs and vectors using automatic methods. It can be concluded that the photographic archive can provide invaluable data for landslide studies, when modern photogrammetric techniques are being used. As ever, independent and appropriate checks should always be included in any photogrammetric design.

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12

Pham, Van Tien. "MECHANISMS AND HAZARD ASSESSMENT OF RAINFALL-INDUCED LANDSLIDE DAMS." Kyoto University, 2018. http://hdl.handle.net/2433/231989.

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付記する学位プログラム名: グローバル生存学大学院連携プログラム
Kyoto University (京都大学)
0048
新制・課程博士
博士(工学)
甲第21056号
工博第4420号
新制||工||1687(附属図書館)
京都大学大学院工学研究科社会基盤工学専攻
(主査)教授寶馨, 教授角哲也, 准教授佐山敬洋
学位規則第4条第1項該当

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13

Rodriguez, Pineda Carlos Eduardo. "Hazard assessment of earthquake-induced landslides on natural slopes." Boston Spa, U.K. : British Library Document Supply Centre, 2001. http://ethos.bl.uk/OrderDetails.do?did=1&uin=uk.bl.ethos.247774.

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14

Wahlstrand, Anna. "Landslide scars in the Kenyan highlands : Physical and chemical topsoil changes and landslide susceptibility assessment under tropical conditions." Licentiate thesis, Stockholms universitet, Institutionen för naturgeografi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-113346.

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Farmers living in the Kenyan highlands are exposed to the risk of being affected by landslides and they are vulnerable because of lack of resources. Vulnerability can be reduced by increasing knowledge and awareness of the risk. This thesis aims to increase knowledge of landslide-related problems. The first objective is to investigate topsoil development and to assess land cover changes in landslide scars over time (paper I). Topsoil samples were taken in previously investigated landslide scars, and analysed for chemical and physical characteristics. The results show that soil has recovered well during the 20-30 years that have passed. However, there are still higher levels of total soil organic carbon in reference topsoil than in scar topsoil. The short time for plants to produce organic material, in combination with low pH, which inhibits decomposing microorganisms, may be the explanation for this. Previous research, including photographs of the landslide scars, forms the basis for comparison over time regarding land cover changes. The results show changes in land cover where forests have been replaced by cultivated land and thereafter by plantations of Eucalyptus sp. trees or cultivation. Secondly, this study investigates the applicability of GIS-based analysis for landslide assessments in this part of the World (paper II). Commonly used data were collected and analysed in ArcGis 10.0. Documentation and field measurements from historical landslides were used as reference. The results show that (1) much information was unavailable, (2) the resolution of the Digital Elevation Model (DEM; 30 m) was too coarse to capture relevant morphometric terrain parameters and (3) land use changes were difficult to map because of low quality historical air photos, and because of lack of information about the precise timing of landslide events. Hence, landslide prone areas could not be recognised. However, we could with reasonable certainty identify sensitive conditions: landslides are most likely to occur in slopes with a gradient of 25° or more, within 80 m from roads, and during the rainy seasons.
Endogena och exogena krafter påverkar varaktigt vårt jordklot och geografiska förhållanden avgör vilken typ av förändring som kan komma att ske. Extrema naturhändelser som påverkar människor negativt kallas naturkatastrofer. I bergig terräng kan massrörelser äga rum och i den här studien behandlas en typ av massrörelse, jordskred. Jordskred sker över hela jorden och beror på försvagade mothållande krafter i förhållande till den gravitation som påverkar material i sluttningar. De vanligaste utlösande faktorerna är jordbävningar eller långvarig nederbörd som gör jorden vattenmättad, vilket leder till minskad skjuvhållfasthet. En ökad befolkning på jorden ökar kravet på matproduktion vilket har lett till att sluttningar i perifera områden har börjat utnyttjas för odling. Detta gäller i allra högsta grad i utvecklingsländer, där befolkningen i flera fall har dubblerats på kort tid. På grund av begränsade ekonomiska tillgångar, på allt från nationell till individuell nivå, påverkas människor i dessa områden hårt om en naturkatastrof inträffar. De har ofta svårt att hantera situationen, att anpassa sig till densamma eller att återhämta sig efteråt vilket gör dessa människor sårbara. Människors sårbarhet kan minskas bland annat genom ökad kunskap, eller genom att öka utsattas medvetenhet om de faror de exponeras för. Det övergripande syftet med den här studien är därför att öka kunskapen kring jordskredsrelaterade problem i ett tätbefolkat tropiskt höglandsområde. Studieområdet är beläget strax söder om ekvatorn i de centrala delarna av Kenya i den sydöstra delen av Aberdare Range. Området, som omfattar delar av Muranga och Nyeri Counties, karaktäriseras av ett undulerande landskap med korta, branta sluttningar som på grund av sina produktiva jordar dessutom är tätbefolkade. Sluttningarna i området bär spår av historiska såväl som nutida jordskredsärr. Artikel 1: För att öka kunskapen kring förändringar i marken efter att ett jordskred skett i området undersöks i den här studien hur återhämtningen i marken skett över längre tid tid, sett ur ett jordbruksperspektiv. Dessutom har marktäckningen i skreden dokumenteras. Studien skall ge svar på följande frågor (1) Hur ser återhämtningen ut i jordar i området efter att ett jordskred skett? (2) Hur har marktäckningen förändrats i skredärren över tid? För att undersöka jordens beskaffenhet togs jordprover i sju jordskredsärr och i anslutande omgivande mark. Kemiska och fysiska parametrar analyserades i laboratorium i Nairobi. Resultaten jämfördes med resultat från tidigare undersökningar i samma skredärr gjorda på 1980- och 1990-talet. Resultaten visar på en varierande positiv och negativ utveckling över tid. Jämfört med referensvärden från omgivande mark är dock skillnaderna efter > 20 år små, utom vad gäller organiskt kol som fortfarande visar lägre värden i skreden än i omgivande mark. Samtal med jordskredsdrabbade bönder i området i februari 2013, litteraturstudier och dokumentation i form av fotografier har gett en bild av hur marktäckningen och vegetationsutvecklingen i skredärren har sett ut över tid. Resultaten visar att markanvändningen har förändrats och att skogsmark ersatts av odlingsmark och därefter återigen planterats med, till stor del, eukalyptusträd. Studien bidrar med ökad kunskap om hur mark i området återhämtar sig efter att ett jordskred skett och hur marktäckningen förändrats över tid. Artikel 2: I andra delar av världen har kartor utformats för att visualisera skredkänsliga områden med hjälp av GIS. I Kenya är användningen av GIS fortfarande begränsad, då verktyget är dyrt och kräver data av hög kvalitet. I den här studien undersöks i vilken omfattning GIS är möjligt att använda för bedömning av skredrisk i ett tropiskt höglandsområde. Frågan är om relevanta data finns att tillgå och om data är av tillräckligt hög kvalité för att göra en tillförlitlig analys? Eller kan man på andra sätt identifiera de viktigaste orsakerna till jordskred och därmed medvetandegöra människor om riskabla faktorer? Parametrar som ofta använts i tidigare utförda undersökningar antogs även i denna studie. Data insamlades, dels från myndigheter i Kenya, dels genom fältarbete och dels från kommersiella företag. Vi har erhållit och arbetat med följande data; (1) en digital höjdmodell (30 m upplösning), (2) Google Earth (högupplösta bilder från Digital Globe, 2012), (3) nederbördsdata, (4) flygfoton från 1959, (5) beskrivningar från historiska jordskred från vetenskapliga artiklar, (6) fältobservationer och (7) samtal med bönder och jordbrukskunnig personal från distriktet. Datahanteringen och analyserna genomfördes i ArcGis 10.0. Beräkning av morfometriska faktorer som sluttningsvinklar, sluttningsriktningar, sluttningars konvexitet och konkavitet utfördes med hjälp av höjdmodellen. Markanvändning, vägar och vattendrag karterades i Google Earth och satellitbilder från 2012. Dessutom karterades skog i ett begränsat område utifrån flygbilder från 1959. Avstånden mellan befintliga skredärr och vägar och vattendrag uppmättes i satellitbilden, varvid en bedömning också gjordes av huruvida skreden troligen var orsakade av väg- eller vattendragsrelaterade faktorer. Analyserna jämfördes med uppmätta värden från 36 tidigare dokumenterade skred i området. Jämförelsen visade att höjdmodellen inte var tillräckligt noggrann för att fånga de branta sluttningar, sluttningsriktningar och konkaviteter som de flesta gamla skred utbildats i. Avsaknaden av information om när avskogningen skett och när de gamla skreden ägt rum gör att det inte heller går att använda markanvändningsförändringar som en parameter i vidare analyser av känsliga områden. Utifrån parametrar som kunde karteras i satellitbilder och med hjälp av information som samlades in under fältarbetet kan vi visa att jordskred i undersökningsområdet mest sannolikt sker under regnperioderna på sluttningar med en lutning på ≥ 25°, och som ligger nära en väg. Resultaten ökar dels medvetenheten kring datakvalitet vid analys av jordskredskänsliga områden i tropiska högländer, dels kunskapen om under vilka förhållanden skred kan ske.

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15

Schlögel, Romy. "Quantitative landslide hazard assessment with remote sensing observations and statistical modelling." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAH009/document.

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La création d’inventaires de glissements de terrain sert de base à l’évaluation quantitative de l’aléa et à la gestion du risque. Les cartes d’inventaires de mouvements gravitaires sont produites en utilisant des méthodes conventionnelles (campagnes de mesures de terrain, interprétation visuelle de photographies aériennes) et par des techniques de télédétection plus innovantes. Une des techniques les plus prometteuses pour la détection et la cartographie des glissements de terrain fait appel à la mesure de la déformation du sol par interférométrie radar satellitaire (InSAR). Cette thèse est consacrée à la constitution d’un inventaire multi-dates à partir de données multi-sources (incluant les données InSAR) en vue d’évaluer de façon quantitative l’aléa glissement de terrain. Les méthodes associent l’analyse de produits d’Observation de la Terre et des modélisations statistiques pour la caractérisation de l’aléa dans la vallée de l’Ubaye, une région rurale et montagneuse des Alpes du Sud. Elles ont été développées à l’échelle du versant (1:5.000-1:2.000) et à l’échelle régionale (1:25.000- 1:10.000). Pour la création des inventaires, cette étude propose une interprétation combinée de séries temporelles d’images SAR, de photographies aériennes, de cartes géomorphologiques, de rapports historiques et de campagnes de terrain. A l’échelle locale, une méthodologie d'interprétation guidée par la géomorphologie et utilisant l’InSAR a été proposée pour identifier les champs de déplacement des glissements de terrain et mesurer leur évolution. A l’échelle régionale, la distribution spatio-temporelle des glissements de terrain a été caractérisée et l’aléa a été calculé à partir des probabilités d’occurrence spatiale et temporelle pour une intensité donnée des phénomènes. L’occurrence spatiale est estimée grâce à un modèle multivarié (régression logistique). L’occurrence temporelle des mouvements gravitaires est évaluée grâce à un modèle de probabilité de Poisson permettant de calculer la probabilité de dépassement (incluant ou non un seuil de surface) pour plusieurs périodes de retour. Plusieurs unités d'analyse spatiale ont été utilisées pour la modélisation ; les résultats démontrent clairement leur influence sur les résultats. L’analyse de l’aléa a été réalisée sur quelques cas spécifiques. Des relations entre les (ré)activations de glissements de terrain et les facteurs déclenchants sont proposées
The analysis of landslide inventories is the basis for quantitative hazard assessment. Landslide inventory maps are prepared using conventional methods (field surveys, visual interpretation of aerial photographs) and new remote sensing techniques. One of the most promising techniques for landslide detection and mapping is related to the measurement of the ground deformation by satellite radar interferometry (InSAR).This doctoral thesis is dedicated to the preparation of a multi-date inventory, from multi-source data, including InSAR, for a quantitative assessment of landslide hazard. The methods associate the analysis of Earth Observation products and statistical modelling for the characterization of landslide hazard in a rural and mountainous region of the South French Alps. They have been developed at the slope (1:5000-1:2000) and the regional (1:25.000-1:10.000) scales. For the creation of a multi-date inventory, this study developed a combined interpretation of time series of SAR images, aerial photographs, geomorphological maps, historical reports and field surveys. At the slope-scale, a geomorphologically-guided methodology using InSAR was proposed to identify landslide displacement patterns and measure their kinematic evolution. At regional scale, spatio-temporal distribution of landslides is characterised and hazard is assessed by computing spatial and temporal probabilities of occurrence for a given intensity of the phenomena. The spatial occurrence is evaluated using a multivariate model (logistic regression). The temporal occurrence of landslide is estimated with a Poisson probability model to compute exceedance probabilities for several return periods. Different mapping units were used in the modelling, and their influence on the results is discussed. Analysis of landslide hazard is then proposed for some particular hotspots. Relationships between landslide (re)activations and triggering factors are envisaged

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16

Motamedi, Manouchehr. "Quantitative Landslide Hazard Assessment in Regional Scale Using Statistical Modeling Techniques." University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1374074469.

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17

Fourniadis, Ioannis. "Regional assessment of landslide impact in the Three Gorges, China, using remote sensing." Thesis, Imperial College London, 2007. http://hdl.handle.net/10044/1/7908.

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18

Paudel, Bhuwani Prasad. "GIS-based Assessment of Debris Flow Susceptibility and Hazard in Mountainous Regions of Nepal." Thesis, Université d'Ottawa / University of Ottawa, 2019. http://hdl.handle.net/10393/38817.

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Rainfall-induced landslides that change into debris flows and travel large distances are one of the treacherous natural calamities that can occur in mountainous areas, particularly in Nepal’s mountains. Debris flow was the second highest cause of human death in Nepal after epidemics between 1971 and 2016. Because debris flow is common in mountainous regions, its prediction and remedial measures through land use plans are important factors to consider for saving lives and properties. The spatial distribution of the initial landslides that change into debris flow, on a watershed scale, is still an important area of study in this mountainous region to develop essential land use plan. In this research, hydrologic, slope stability and Flow-R models are applied in GIS modeling to locate potential landslide and debris flow areas for a given threshold rainfall in a mountainous watershed-Kulekhani, Nepal. Soil samples from 73 locations within the watershed and a geotechnical investigation on one old landslide area were considered to determine the Soil Water Characteristics Curve (SWCC), friction angle, cohesion, and infiltration characteristics of the subsurface soils in the study area. This information is applied in an unsaturated slope stability model to find unstable locations in the study watershed in a GIS environment. The model is tested on a recorded 24-hour rainfall of 540 mm in the watershed, and potential landslide locations are obtained. The validation results show that there is a good agreement between the predicted and mapped landslides. For debris flow run out, Flow-R model, which has the capability to analyze debris flow inundation with limited input information, and the model software is readily available in the public domain, was chosen for further analysis. Two recent debris flow events and the study watershed are taken as case studies to identify the appropriate algorithms of Flow-R for runout analysis of the study areas. Landslide-triggering threshold rainfall frequency is related to the frequency of landslides and the debris flow hazard in these mountains. The above validated models are applied in a GIS environment to locate potential debris flow areas in expected threshold rainfall. Rainfall records from 1980 to 2013 are computed for one- to seven-day cumulative annual maximum rainfall. The probable rainfalls for 1 in 10 to 1 in 200 years return periods are identified. The anticipated probable rainfalls are modeled in the GIS environment to identify the factor of safety of mountain slopes for landslide susceptibility in the study watershed. The Flow-R model with user-defined landslide-susceptible areas was chosen for debris flow runout analysis. A relation between the frequency of rainfall and landslide-induced debris flow hazard area is derived for return periods of 25, 50, 100, and 200 years. Also, the debris flow hazard results from the analysis are compared with a known event in the watershed and found to agree. This developed method can be applied to anticipated landslide and landslide-induced debris flow from the live rainfall record to warn hazard-prone communities for saving lives and regulating hazardous transportation corridors in these mountains. In addition to this, this methodology will be a useful tool to help policy makers create appropriate land use plans.

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19

Al-Umar, Mohammad. "GIS Based Assessment of Climate-induced Landslide Susceptibility of Sensitive Marine Clays in the Ottawa Region, Canada." Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/37218.

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Landslides are relatively frequent in Ottawa due to the presence of sensitive marine clays (Leda clay or Champlain Sea clay), and the presence of natural or climatic triggers such as rainfall or snowmelt. A geographic information system (GIS) based modeling tool has been developed to assess and predict climate (rainfall and snowmelt)-induced landslides in the sensitive marine clays of the Ottawa region. The Transient Rainfall Infiltration and Grid-based Regional Slope-Stability (TRIGRS) model is used in a GIS framework to investigate the influence of rainfall and snowmelt on shallow landslides through the Ottawa region, with respect to time and location. First, the GIS and TRIGRS models are combined to assess landslide susceptibility with respect to rainfall. The GIS-TRIGRS approach requires topographic, geologic, hydrologic, and geotechnical information of the study area. In addition to this technical information (input data), rainfall intensity data for different durations (5 minutes, and 6, 12, 18, and 24 hours), and historical data of the regional landslides is required. This data is used to verify the locations of predicted landslide-susceptible areas with respect to historical landslide maps in the area. The generated results from the GIS-TRIGRS model were verified by comparing the predicted and historical locations of shallow landslides induced by rainfall throughout the Ottawa region. The comparison results showed a high correlation between the predicted areas of landslides and the previously reported landslides. In addition, the results also indicated that not all previous landslides in Leda clays were triggered by rainfall. The second application of the developed GIS-TRIGRS approach was used to assess and predict snowmelt-induced landslides in areas of sensitive marine clay in the Ottawa region. Similar to the first analysis, the approach requires the following input data: topographic, geologic, hydrologic, geotechnical, snowmelt intensity data for various periods (6–48 hours, 3–15 days, 25 days, and 30 days), This approach also requires data indicating the location of historical landslides in the study area. Using this data, we examine both the timing and location of shallow landslides due to snowmelt in a GIS-based framework. The developed model was validated by comparing the predicted landslide-susceptible areas to historical landslide maps in the study area. A high correlation between predicted and historical landslide location trends was obtained, confirming that the developed GIS-TRIGRS model can predict the snowmelt-induced landslide susceptibility in the sensitive marine clays relatively well. The model results reinforced the conclusion that areas with high slopes and sensitive marine clays were more prone to snowmelt-induced landslides. Finally, in a Geographic Information System (GIS) the landslide occurrence susceptibility in the Ottawa area was modeled. Results of such models are presented as maps showing landslide susceptibility in Champlain Sea clays (Leda clays) in the Ottawa area due to both rainfall and snowmelt. Various input data was collected and entered into a GIS and TRIGRS model. The main categories of such inputs are climate, topography, geology, hydrology, and geotechnical data. The rainfall and snowmelt intensity data was extracted for 24 to 48 hour periods from Environment and Climate Change Canada historical climate records. Thereafter, the factor of safety was calculated in order to determine the stability of slopes across the study area. The model assesses the effects of rainfall and snowmelt on landslide occurrence, and based on the calculated factor of safety at each pixel of the study area, the model calculates the landslide susceptibility. The results presented in this thesis will provide a geotechnical basis for making appropriate engineering decisions during slope management and land use planning in the Ottawa region.

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20

Balal, Onur. "Probabilistic Seismic Hazard Assessment For Earthquake Induced Landslides." Master's thesis, METU, 2013. http://etd.lib.metu.edu.tr/upload/12615453/index.pdf.

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Earthquake-induced slope instability is one of the major sources of earthquake hazards in near fault regions. Simplified tools, such as Newmark&rsquo
s Sliding Block (NSB) Analysis are widely used to represent the stability of a slope under earthquake shaking. The outcome of this analogy is the slope displacement where larger displacement values indicate higher seismic slope instability risk. Recent studies in the literature propose empirical models between the slope displacement and single or multiple ground motion intensity measures such as peak ground acceleration or Arias intensity. These correlations are based on the analysis of large datasets from global ground motion recording database (PEER NGA-W1 Database). Ground motions from earthquakes occurred in Turkey are poorly represented in NGA-W1 database since corrected and processed data from Turkey was not available until recently. The objective of this study is to evaluate the compatibility of available NSB displacement prediction models for the Probabilistic Seismic Hazard Assessment (PSHA) applications in Turkey using a comprehensive dataset of ground motions recorded during earthquakes occurred in Turkey. Then the application of selected NSB displacement prediction model in a vector-valued PSHA framework is demonstrated with the explanations of seismic source characterization, ground motion prediction models and ground motion intensity measure correlation coefficients. The results of the study is presented in terms of hazard curves and a comparison is made with a case history in Asarsuyu Region where seismically induced landslides (Bakacak Landslides) had taken place during 1999 Dü
zce Earthquake.

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21

Lam, Hoi-lee, and 林凱莉. "Processing of the 2010 LiDAR data at the Pos Selim landslide and assessment of the uncertainty of survey information." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B49770755.

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Contract of Simpang Pulai-Lojing Highway was commenced in 1997. Since then, the unstable hillside at a site at CH23+800 in the north-western Cameron Highlands Malaysia was cut to ridge top but instability still observed. The cutting was mainly in schist and was about 250m high. In August – September 2003, a landslide about 190m high and between 200m and 430m wide was formed at the site as the hillside was cut into for roadworks. The work reported here shows that the overall velocity of movement of the displaced mass of the landslide is declining slightly year on year and the head of landslide had moved more than 30m by August 2010 since September 2003. In 2010 the top of the main body of the landslide was moving at about 0.5m per year. Points on the landslide continue to move 2005-2010 in generally the same direction as 2003-2005. The writer was provided with survey data at the landslide and adjoining area obtained in 2003, 2005 and 2010 by different methodologies. The survey in 2003 was a composite as-built survey; 2005 was an aerial survey and 2010 was a LiDAR survey. The 2010 LiDAR data has been used as a basis to give both the 2003 as-built survey plan and 2005 orthophoto a common horizontal reference frame. Both the 2003 as-built survey plan and 2005 orthophoto have been adjusted to fit the 2010 LiDAR data, which is expressed in terms of old MRSO grid coordinates system after transformation. The adjustments are affine transformation (2003 and 2005). The 2010 LiDAR data has been reduced to the vertical datum used in both 2003 as-built survey and 2005 aerial survey. A number of recognisable points within the landslide have been identified in all three surveys. The differences in coordinates of the points on the dates of the three surveys provide two sets of movement vectors (2003-5 and 2005-10). There are 150 such vectors. Thirty-three check points have been identified in the 3 surveys outside and adjacent to the landslide at places where movements are not expected. The apparent movement of these points is an indication of the uncertainty in the displacement data. Total displacements of 12 total station survey markers within the landslide have been plotted with time. Ground points very close to these markers are plotted for comparison. The latter are greater than the former by about two metres suggesting that the landslide had started moving before the start of deformation monitoring.
published_or_final_version
Applied Geosciences
Master
Master of Science

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22

Miles, Scott B. "Participatory assessment of a comprehensive areal model of earthquake-induced landslides /." Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/5609.

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23

Nash, Timothy Richard. "Engineering geological assessment of selected landslide dams formed from the 1929 Murchison and 1968 Inangahua earthquakes." Thesis, University of Canterbury. Geological Science, 2003. http://hdl.handle.net/10092/9342.

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This study investigated the characteristics of 26 failed and non-failed landslide dams (Murchison dataset) formed in the northern part of the South Island, New Zealand, from the 1929 Murchison and 1968 Inangahua earthquakes. The dataset was compiled from a combination of engineering geological mapping, field investigations, aerial photography interpretation and a review of existing literature. Current analysis techniques have been applied to the investigated landslide dams to assess their ability to accurately predict the post-formation development (or ‘evolution’) of the dam overtime. This has allowed the recognition of a number of additional landslide dam attributes that influence long-term stability, allowing modification of the stability analysis techniques in current use. Dam, lake, catchment and landslide characteristics were collated and analysed for the Murchison dataset by distinguishing failed from non-failed landslide dams, and then assessing the parameters common to both. Parameters that influence the post-formation development of selected landslide dams in the dataset include the dam volume, catchment area above the point of blockage, average block size of material comprising the dam, slope angle of the downstream dam face, and rock mass anal material characteristics in the source area of the dam-forming landslide. The stability of the dams in the Murchison dataset was not significantly affected by rock type, landslide movement, or the state, distribution and style of the dam-forming landslide. Existing geomorphic indices were applied to selected dams in the dataset. The Impoundment, Blockage and Dimensionless Blockage Indices (Casagli and Ermini (1999); Ermini and Casagli (2003)) predicted the correct post-formation development for 58, 86, and 81% of the selected landslide dams in the Murchison dataset, respectively. Four landslide dams covering both failed and non-failed types were investigated in detail to assist with this analysis, two being stable dams impounding lakes, and two having failed ‘catastrophically’ post-formation. Detailed investigation was carried out on Lake Stanley landslide dam, which agrees with all three indices predicting post-formation development, and of Lake Matiri, Ram Creek and Rain Peak landslide dams for which the indices incorrectly predict their post formation development. This investigation has shown that the average block size (D₅₀) of the dam material strongly influences the post-formation development of the four dams studied in detail. Dams consisting of material. with larger(> 200mm) average block sizes correspond to stable dams; while those with small(< 100mm) average block size correspond to failed dams. Rainfall duration/ intensity and slope angle of the downstream dam face were also found to influence post-formation development of the dams. The recently formed and failed Poerua landslide dam on the West Coast of the South Island was included in the geomorphic index evaluation because of the excellent documentation available, together with the prediction of its long-term stability using the index approach. The D₅₀ of the material forming the landslide dam, and the landslide dam's basal (or footprint) length, were incorporated with the parameters used in the existing geomorphic indices to produce a new geomorphic index, the Modified Dimensionless Blockage Index (MDBI). This is defined as: [complicated equation here] where Ac is the catchment area (m²), At is the lake area (m²), Hd is the height of the dam (m), Lʄ is the length of the dam footprint (m), Vd is the volume of the dam (m³), and Vd is the volume of the mean block size forming the dam (cube of the D₅₀ expressed in m³). Calculated MDBI values for the two stable landslide dams (Lake Stanley and Lake Matiri) are less than 10 (8.90 and 6.94 respective]y), while those for three failed landslide dams (Rain Peak, Ram Creek and Poerua) are greater than 10 (10.75, 10.80 and 14.9, respective]y). This suggests that the MDBI can be tentative]y used as a tool in forecasting the post-formation development of a landslide dam, with MDBI values > 10 corresponding to catastrophic dam failure, and an MDBI value < 10 corresponding to probable longer-term stability. However, it is recommended that a wider landslide dam dataset be applied to the MDBI to further test its accuracy, and to refine the parameters used both for short-term stability assessment following impoundment, and for longer-term prediction of post-formation dam (and lake) development. Rainfall duration and maximum block size of the dam material also require further evaluation, and a refinement incorporating grading parameters (such as D₆₀/D₁₀) may provide a better estimation of the post-formation landslide dam development. It is clear from this study that the block size and grading of the landslide dam material (in particular matrix or block support) exert significant influence on dam longevity and evolution, and this is reflected in the substantial weighting given to D₅₀ in the MDBI.

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Walsh, Andrew Timothy. "Engineering Geomorphological Assessment and Slope Hazard Identification of the Haast Pass Highway Corridor, State Highway Six, Haast Pass New Zealand." Thesis, University of Canterbury. Geological Sciences, 2015. http://hdl.handle.net/10092/10575.

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The Haast Pass highway has had a long history of instability since it was constructed in 1960. Steep slopes and deeply incised river create an actively changing geomorphic environment making maintaining the highway corridor hazardous and difficult. This thesis study provides the first comprehensive investigation of the highway corridor between the Summit and Thunder Creek Falls using LiDAR and detailed air-photo analysis to provide the basis for geomorphic mapping. Management of slope hazards to date has been based on a reactive approach treating the immediate unstable areas around landslides after they occur. This study presents the first large-scale geomorphological assessment of the highway corridor identifying surface unit type, slope processes and slope hazards in order to facilitate the development of a long-term highway management strategy. Because dense vegetation covers nearly all the slopes above the highway in the study area as as such, it has not been possible to adequately investigate slope geomorphology until the availability of LiDAR. This study is the first to use Light direction and ranging[LiDAR] for corridor hazard mapping beneath dense vegetation in New Zealand. The LiDAR survey was flown by New Zealand Aerial Mapping in January 2014 for the New Zealand Transport Agency and was provided for use in this study. The LiDAR surface model created serves as the basis for mapping surface units and landslide features, enabling the identification of slope processes and landslide hazards. Aerial photos were also used to identify surface unit type and slope processes where vegetation was absent and enabled the activity of slopes to be evaluated. Interpretations made using LiDAR were validated using aerial photography and targeted ground truthing with all ground truthing sites confirming the interpretations made. Large scale geomorphology mapping was undertaken on slopes above the highway on the western side of the valley and showed that there were distinct differences between the southern and northern parts of the highway corridor. Between The Haast Pass Summit and Pipson Creek the slopes are dominated by schist bedrock with regolith confined to small deposits next to the highway and larger deposits in tributary valleys. The slope hazards affecting the highway in this zone are confined to debris sliding and rockfall from regolith deposits and bedrock cliffs next to the highway between Robinson and Pipson Creeks. The slopes between Pipson Creek and the Gates of Haast, in contrast, consist of deep regolith deposits and regolith veneered slopes. Evidence of active and recently active slope processes on the slopes facing the highway confirm the instability is associated with slope hazards including debris flows, debris slides, rock fall and highway collapse. Small-scale detailed evaluations were undertaken at Diana Falls, Ford Creek, The Hinge and the Gates of Haast with the sites selected based on their history of instability and/or their particu- larly hazardous appearance during the large-scale geomorphology and hazard identification. Using the LiDAR surface model surface units and landslide features were identified and mapped with small-scale engineering geomorphology maps. This information was then used to interpret the subsurface geometry and the failure mode/slope processes acting on the slope enabling an assessment of the current stability and future slope development to be made. Diana Falls was found to have scarps and tension cracks running across the regolith covered slope indicating that future landslides from this site will be an ongoing problem. At Ford Creek the landslide was identified as a rock compound slide, but assessments of its current stability and future development were unable to be made. Detailed investigations at The Hinge revealed evidence of a large creeping debris slide and the existence smaller debris slides below the highway through the entire investigation area; the debris slides identified show signs of activity and continued debris sliding will continue to affect the highway in the future. The investigation of the Gates of Haast revealed that the slope instability is not as extensive as it has been in the past, however, recent rock slides and debris flows have continued affect the highway and will continue to pose a hazard in the future. This thesis provides fundamental information required to develop a comprehensive management plan for the Haast Pass highway corridor between the Haast Pass summit and the Gates of Haast. A new landslide management plan has been developed outlining immediate, short-term and long- term options and programmes that should be implemented. Immediate options are steps that can be taken to quickly increase the safety of road users and include moving of highway closure gates and installation of warning signage. Short-term options aim to mitigate landslide hazards where feasible including the installation of rockfall barriers and debris flow attenuators, and lay the groundwork for future avoidance of hazards by undertaking investigations of highway realignment and developing highway closure rainfall thresholds. Long-term options are recommended where landslides will continue to impact the same section of the highway repeatedly and focus on hazard avoidance by building landslide shelters or major highway realignments. The adoption of a management plan ensures security of the highway, protects against loss of life and provides the most cost effective long-term solution to manage the landsliding hazards.

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Khampilang, Namphon. "Landslide assessment in a remote mountain region : a case study from the Toktogul region of Kyrgyzstan, Central Asia." Thesis, University of Portsmouth, 2015. https://researchportal.port.ac.uk/portal/en/theses/landslide-assessment-in-a-remote-mountain-region(037d93c1-8d2d-49b4-bd85-8afd08d3f98e).html.

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Slope instability is a significant natural hazard in the Tien Shan mountain range, some landslide studies were carried out in small areas in the Tien Shan Mountain but no landslide susceptibility mapping has been carried out for the region. This thesis describes the creation of a digital landslide inventory and the use of a Geographical Information System (GIS) to create the first landslide susceptibility models for the area. This research has resulted in the landslide inventory of the Toktogul region. This was accomplished through a combination of SPOT image interpretation with the validation of Google Earth image and field mapping. 2,776 landslides were mapped with the area of approximately 202 km2 in total. This area is about 1.6% of the total study area (12,280 km2). The landslide frequency-area distribution using inverse gamma distribution was carried out using all landslides. A quantitative landslide susceptibility assessment was conducted. Parameter maps including slope, elevation, aspect, lithology, land cover, distance from faults and distance from drainage, normalised difference vegetation index and stream power index were constructed and compiled into a database with the landslide inventory. The bivariate (frequency ratio and weight of evidence) and multivariate (logistic regression) statistical analysis were used to establish landslide susceptibility maps. The susceptibility maps were validated using landslide inventory. Success rate curve and cumulative area under the curve were created. All susceptibility maps resulted in very similar prediction rate curves and cumulative area under the curves. Logistic regression gave the best result in cumulative area followed by frequency ratio and weight of evidence (79.51%, 77.86%, and 78.21%, respectively). The combining of landslide susceptibility using logistic regression method was performed. The result shows a good predictive accuracy (78.72% cumulative area). Based on the validation, the susceptibility map derived using logistic regression was determined to be the best.

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Nillorm, Mallika. "Landslide inventories for risk assessment in a World Heritage Site : a case study of Lulworth Cove, UK." Thesis, University of Portsmouth, 2016. https://researchportal.port.ac.uk/portal/en/theses/landslide-inventories-for-risk-assessment-in-a-world-heritage-site(360a9666-07bf-4991-84a3-59dcd275b830).html.

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The historical record of landslide occurrence is by far the most important data for assessing landslide risk. The objective of this study is to utilise archive imagery for assessing the probability of landslide occurrence and provide a quantitative landslide risk framework for geo tourism destination in Dorset. Within this study, risk analysis focuses on the risk to loss of life and injury. To calculate landslide risk, landslide inventories were prepared using the analysis of different archive imagery, the spatial and temporal probabilities of potentially damaging events, as well as the visitor exposure, considering also vulnerabilities, were determined. As risk is context-dependant and socially constructed, visitors’ risk perception was also investigated in this study. Results from risk analysis allow for establishing how well the landslides are recorded in the archive sources, to what extent the landslide inventories can be used to determine the frequency of landslide occurrence, and the significance of landslide inventories as a preliminary step for landslide risk assessment.

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Yates, Katherine. "Post-disaster geotechnical response for hilly terrain: a case study from the Canterbury Earthquake Sequence." Thesis, University of Canterbury. Geological Sciences, 2014. http://hdl.handle.net/10092/9345.

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Case study analysis of the 2010-2011 Canterbury Earthquake Sequence (CES), which particularly impacted Christchurch City, New Zealand, has highlighted the value of practical, standardised and coordinated post-earthquake geotechnical response guidelines for earthquake-induced landslides in urban areas. The 22nd February 2011 earthquake, the second largest magnitude event in the CES, initiated a series of rockfall, cliff collapse and loess failures around the Port Hills which severely impacted the south-eastern part of Christchurch. The extensive slope failure induced by the 22nd February 200 earthquake was unprecedented; and ground motions experienced significantly exceeded the probabilistic seismic hazard model for Canterbury. Earthquake-induced landslides initiated by the 22nd February 2011 earthquake posed risk to life safety, and caused widespread damage to dwellings and critical infrastructure. In the immediate aftermath of the 22nd February 2011 earthquake, the geotechnical community responded by deploying into the Port Hills to conduct assessment of slope failure hazards and life safety risk. Coordination within the voluntary geotechnical response group evolved rapidly within the first week post-earthquake. The lack of pre-event planning to guide coordinated geotechnical response hindered the execution of timely and transparent management of life safety risk from coseismic landslides in the initial week after the earthquake. Semi-structured interviews were conducted with municipal, management and operational organisations involved in the geotechnical response during the CES. Analysis of interview dialogue highlighted the temporal evolution of priorities and tasks during emergency response to coseismic slope failure, which was further developed into a phased conceptual model to inform future geotechnical response. Review of geotechnical responses to selected historical earthquakes (Northridge, 1994; Chi-Chi, 1999; Wenchuan, 2008) has enabled comparison between international practice and local response strategies, and has emphasised the value of pre-earthquake preparation, indicating the importance of integration of geotechnical response within national emergency management plans. Furthermore, analysis of the CES and international earthquakes has informed pragmatic recommendations for future response to coseismic slope failure. Recommendations for future response to earthquake-induced landslides presented in this thesis include: the integration of post-earthquake geotechnical response with national Civil Defence and Emergency Management; pre-earthquake development of an adaptive management structure and standard slope assessment format for geotechnical response; and emergency management training for geotechnical professionals. Post-earthquake response recommendations include the development of geographic sectors within the area impacted by coseismic slope failure, and the development of a GIS database for analysis and management of data collected during ground reconnaissance. Recommendations provided in this thesis aim to inform development of national guidelines for geotechnical response to earthquake-induced landslides in New Zealand, and prompt debate concerning international best practice.

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Cardozo, Claudia Paola. "A spatially integrated modelling approach to landslide risk assessment: a case study of the Nova Friburgo disaster - RJ, Brazil." Instituto Nacional de Pesquisas Espaciais (INPE), 2018. http://urlib.net/sid.inpe.br/mtc-m21c/2018/03.12.14.01.

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Landslides cause enormous economic damage and fatalities worldwide. The 2011 Mega disaster in the Rio de Janeiro mountainous region is considered the worst landslide disaster in Brazilian history. Traditionally, risk topic has been analyzed from a purely engineering-based perspective, which has proved to have an ineffective response to face the challenges posed by physical and social factors, especially in low-income countries. This thesis introduces a conceptual framework for an integrated risk assessment and undertakes the proposal in a practical way in the Nova Friburgo municipality, as a case study. In the first part of this research, an assessment of the physical component of risk was addressed. Three scenarios of landslide susceptibility were performed using a 10m-resolution DEM, geotechnical data and a landslide inventory. Findings suggest that the scenario with a wide range of cohesion parameter values was able to predict almost 70% of the inventoried landslides and about 50% of the territory with landslide-prone areas. In the second part of this thesis, a deep analysis of human component of risk is performed. A social vulnerability assessment- using the SoVI methodand data collection disaggregated by age, sex and race/ethnicity of the 2011 landslide-related fatalities were conducted. Results reveal differential social vulnerability among census tracts. Most of them were classified as moderately vulnerable. Although highly social vulnerable areas were not widely distributed in the territory, they are important because of their location and implications for the municipality economic matrix. Regarding the 2011 landslide-related fatalities, 434 casualties were registered. Spatial analysis indicates that the highest mortality was located at the northwest and central municipality zones. Landslide disaster affected males and females differently. In most age groups, landslides have killed more men and boys than women and girls. Fifty percent of those who lost their lives were the youngest and the elderly. The black population had a slightly higher mortality rate than either the brown (Pardos) and white ones. Data did not reveal a discernible trend in the association between social vulnerability and casualties. It seems that the landslide quantity and magnitude was so great that all of Nova Friburgo inhabitants were equally reached, beyond the inequalities expressed by their social vulnerability. In the third part of this inquiry, to predict landslide risk probability, the social vulnerability and the landslide susceptibility predictors were combined using the Generalized Additive Model (GAM). Findings suggest that in instable terrains, is enough a moderate social vulnerability level to increase the probability of landslide risk. Results also highlight model capacity to uncover hidden patterns in the dataset, capturing a nonlinear effect of social vulnerability predictor and a linear effect of terrain stability predictor. In conclusion, the proposed conceptual framework is generic and flexible, so can be applied to other areas, analysis scales and natural hazard types although some adaptation would be necessary depending on available data. Furthermore, the integrated approach performed in this thesis highlights that it is feasible and necessary linking data from different science domains to better understand disaster risk complexity, reducing risk and curbing losses of both human lives and economic assets through knowledge-based actions. It should be noted that this thesis research complies with guidelines given at the first priority area for action of the Sendai Framework for Disaster Risk Reduction 2015-2030, which outlines the importance of Understanding disaster risk. Finally, resulting knowledge provides Nova Friburgo community, organizations and governments with a basis to comprehend the risk related to a specific natural hazard: the landslides which can be leveraged to achieve an effective preparation and response to future disasters and also to promote disaster-resilient societies.
Os deslizamentos de terra causam enormes prejuízos econômicos e mortes em todo o mundo. O Mega desastre 2011 na região montanhosa do Rio de Janeiro é considerado o pior desastre na história do Brasil. Tradicionalmente, o tópico de risco foi analisado a partir de uma perspectiva puramente baseada na engenharia que provou ter uma resposta ineficaz para enfrentar os desafios impostos por fatores físicos e sociais, especialmente em países de baixa renda. Esta tese apresenta um marco conceitual para uma avaliação integrada do risco e realiza a proposta de maneira prática no município de Nova Friburgo, como um estudo de caso. Na primeira parte desta pesquisa, uma avaliação do componente físico do risco foi abordada. Três cenários de suscetibilidade a escorregamentos foram realizados usando um DEM de 10m de resolução espacial, dados geotécnicos e um inventário de deslizamentos. Os resultados sugerem que o cenário que utilizou uma ampla gama de valores de coesão foi capaz de prever quase 70% dos deslizamentos de terra inventariados e cerca de 50% do território com áreas propensas a deslizamentos. Na segunda parte desta tese, se analisou o componente humano de risco. Uma avaliação de vulnerabilidade social - usando o método SoVI - e a coleta de dados desagregados por idade, sexo e raça/etnia dos óbitos provocados pelos deslizamentos de 2011 foram realizados. Os resultados revelam uma vulnerabilidade social diferenciada entre os setores censitários. A maioria deles foi classificada como moderadamente vulnerável. Embora as áreas altamente vulneráveis não sejam amplamente distribuídas no território, elas são importantes devido à sua localização e implicações para a matriz econômica do município. Em relação aos óbitos por deslizamentos de terra, foram registradas434 vítimas. A análise espacial indica que a maior mortalidade se localizou nas zonas do noroeste e centro do município. O desastre provocado pelos deslizamentos de terra afetou aos homens e mulheres de maneira diferente. Na maioria das faixas etárias, morreram mais homens e meninos do que mulheres e meninas. Cinquenta por cento daqueles que perderam suas vidas eram os mais jovens e os idosos. A população negra teve uma taxa de mortalidade ligeiramente maior do que os Pardos e brancos. Os dados não revelaram uma tendência discernível na associação entre vulnerabilidade social e óbitos. Parece que a magnitude dos deslizamentos foi tão grande que todos os habitantes de Nova Friburgo foram igualmente atingidos, além das desigualdades expressas por sua vulnerabilidade social. Na terceira parte desta investigação, determinou-se a probabilidade de risco de deslizamento, para isso a vulnerabilidade social e a susceptibilidade aos deslizamentos de terra foram combinados usando o Modelo Aditivo Generalizado (GAM). Os resultados sugerem que, em terrenos instáveis, basta um nível moderado de vulnerabilidade social para aumentar a probabilidade de risco de deslizamento. Os resultados também destacam a capacidade do modelo de descobrir padrões oculto no conjunto de dados, capturando um efeito não linear da variável vulnerabilidade social e um efeito linear da variável estabilidade do terreno. Em conclusão, o marco conceptual proposto é genérico e flexível pelo que pode ser aplicado a outras áreas, escalas de análise e tipos de perigos naturais, embora seja necessária alguma adaptação, dependendo dos dados disponíveis. Além disso, a abordagem integrada desta tese destaca que é viável e necessário vincular dados de diferentes domínios científicos para melhor compreender o risco de desastres, reduzir riscos e reduzir perdas de vidas humanas e ativos econômicos por meio de ações baseadas em conhecimento. Deve-se notar que esta pesquisa está em conformidade com as diretrizes dadas na primeira área prioritária para a ação do Marco de Sendai para a Redução de Riscos de Desastres 2015-2030, que descreve a importância de "Compreender o risco de desastres". Finalmente, o conhecimento resultante desta pesquisa fornece à comunidade, às organizações e ao governo de Nova Friburgo uma base para compreender o risco relacionado a um perigo natural específico: "os deslizamentos" que podem ser aproveitados para obter uma preparação melhor e respostas eficazes a desastres futuros e também para promover sociedades resilientes aos desastres.

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Grahn, Tonje. "Risk assessment of natural hazards : Data availability and applicability for loss quantification." Doctoral thesis, Karlstads universitet, Institutionen för miljö- och livsvetenskaper, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-48324.

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Quantitative risk assessments are a fundamental part of economic analysis and natural hazard risk management models. It increases the objectivity and the transparency of risk assessments and guides policymakers in making efficient decisions when spending public resources on risk reduction. Managing hazard risks calls for an understanding of the relationships between hazard exposure and vulnerability of humans and assets. The purpose of this thesis is to identify and estimate causal relationships between hazards, exposure and vulnerability, and to evaluate the applicability of systematically collected data sets to produce reliable and generalizable quantitative information for decision support. Several causal relationships have been established. For example, the extent of lake flood damage to residential buildings depends on the duration of floods, distance to waterfront, the age of the house and in some cases the water level. Results also show that homeowners private initiative to reduce risk, prior to or during a flood, reduced their probability of suffering building damage with as much as 40 percent. Further, a causal relationship has been established between the number of people exposed to quick clay landslides and landslide fatalities. Even though several relationships were identified between flood exposure and vulnerability, the effects can only explain small parts of the total variation in damages, especially at object level. The availability of damage data in Sweden is generally low. The most comprehensive damage data sets in Sweden are held by private insurance companies and are not publicly available. Data scarcity is a barrier to quantitative natural hazard risk assessment in Sweden. More efforts should therefore be made to collect data systematically for modelling and validating standardized approaches to quantitative damage estimation.
Natural hazard damages have increased worldwide. Impacts caused by hydrological and meteorological hazards have increased the most. An analysis of insurance payments in Sweden showed that flood damages have been increasing in Sweden as well. With climate change and increasing populations we can expect this trend to continue unless efforts are made to reduce risk and adapt communities to the threats. Economic analysis and quantitative risk assessments of natural hazards are fundamental parts of a risk management process that can support policymakers' decisions on efficient risk reduction. However, in order to develop reliable damage estimation models knowledge is needed of the relationships between hazard exposure and the vulnerability of exposed objects and persons. This thesis has established causal relationships between residential exposure and flood damage on the basis of insurance data. I also found that private damage-reducing actions decreased the probability of damage to buildings with almost 40 percent. Further, a causal relationship has been established between the number of people exposed to quick clay landslides and fatalities. Even though several relationships have been identified between flood exposure and vulnerability, the effects can explain only small parts of the total variation in damages, especially at object level, and more effort is needed to develop quantitative models for risk assessment purposes.

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Erener, Arzu. "An Approach For Landslide Risk Assesment By Using Geographic Information Systems (gis) And Remote Sensing (rs)." Phd thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/3/12611314/index.pdf.

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This study aims to develop a Geographic Information Systems (GIS) and Remote Sensing (RS) Based systematic quantitative landslide risk assessment methodology for regional and local scales. Each component of risk, i.e., hazard assessment, vulnerability, and consequence analysis, is quantitatively assessed for both scales. The developed landslide risk assessment methodology is tested at Kumluca watershed, which covers an area of 330 km2, in Bartin province of the Western Black Sea Region, Turkey. GIS and RS techniques are used to create landslide factor maps, to obtain susceptibility maps, hazard maps, elements at risk and risk maps, and additionally to compare the obtained maps. In this study, the effect of mapping unit and mapping method upon susceptibility mapping method, and as a result the effect upon risk map, is evaluated. Susceptibility maps are obtained by using two different mapping units, namely slope unit-based and grid-based mapping units. When analyzing the effect of susceptibility mapping method, this study attempts to extend Logistic Regression (LR) and Artificial Neural Network (ANN) by implementing Geographically-Weighted Logistic Regression (GWR) and spatial regression (SR) techniques for landslide susceptibility assessment. In addition to spatial probability of occurrence of damaging events, landslide hazard calculation requires the determination of the temporal probability. Precipitation triggers the majority of landslides in the study region. The critical rainfall thresholds were estimated by using daily and antecedent rainfalls and landslide occurrence dates based on three different approaches: Time Series, Gumble Distribution and Intensity Duration Curves. Different procedures are adopted to obtain the element at risk values and vulnerability values for local and regional scale analyses. For regional scale analysis, the elements at risk were obtained from existing digital cadastral databases and vulnerabilities are obtained by adopting some generalization approaches. On the other hand, on local scale the elements at risk are obtained by high resolution remote sensing images by the developed algorithms in an automatic way. It is found that risk maps are more similar for slope unit-based mapping unit than grid&ndash
based mapping unit.

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Risby, Olle. "Crystallization and Emplacement of the Monte Amarelo Dikes: Magma Storage Assessment on Fogo, Cape Verde Islands." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-316988.

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The volcanic island of Fogo belongs to the Cape Verde archipelago, a two-tiered chain of islands situated 500 km west of the African coast. Fogo is regarded as one of the most active volcanoes in the world with 10 eruptions during the last 250 years. The former shield volcano Monte Amarelo reached 3500 m.a.s.l. before it collapsed into the Atlantic Ocean. The massive landslide event occurred between 124 and 86 ka, forming the Bordeira cliffs and the high plateau Cha das Caldeiras on Fogo. We have collected rock samples from the Bordeira dikes, which intruded into the Bordeira wall prior to collapse. The purpose of the project is to produce a magmatic storage model for Fogo using mineral chemistry and thermobarometric methods. Additionally, I aim to determine the processes prevailing in the magmatic system, the link between the volcanic and plutonic system. Previous studies on the magma storage beneath Fogo have focused on the volcanics, which show crystallization pressures between 0.45 to 0.68 GPa using clinopyroxene-melt thermobarometry on rims. The Bordeira dikes are basanitic to nephelinitic in composition. The mineral assemblage of the 20 dike samples consist of phenocrystic clinopyroxene ± olivine ± plagioclase ± xenocrystic amphibole. Accessory minerals are titanomagnetite, apatite, nepheline, plagioclase and alkali feldspar in a microcrystalline groundmass. Clinopyroxene displays a large compositional variation, ranging from Mg#38 to Mg#85, with a mean of Mg#71±10 2s.d. (n=614). Xenocrystic amphibole varies from Mg#37 to Mg#72, with a mean of Mg#62±15 2s.d. (n=78). Interstitial feldspar forms two groups, one of An#24 to An#79, with a mean of An#66±19 2s.d., (n=125) and a second with Or#19 to 100 with a mean of Or#69±42 2s.d.(n=71). Bulk geochemistry of the 20 samples range from 1.82 to 11.5 MgO wt%. Our clinopyroxene-melt thermobarometry show crystallization pressures ranging from 0.02 to 0.85 GPa, with a mean of 0.47±0.29 2s.d. (n=502) (Putirka et al. 2003). Structural data from the intrusive dikes in the Bordeira contain three preferred orientations, N-S, NW-SE and E-W (n=371). The main process occurring in the magmatic system is fractional crystallization, however there is some evidence for phenocryst accumulation and magma recharge. Our magma storage model show that clinopyroxene crystallization initiates in the lithospheric mantle, between 15 to 28 km depth. Significant clinopyroxene rim and microcryst crystallization occur above Moho, between 9 to 12 km, implying that magma storage levels do exist in the oceanic crust. The intrusive and extrusive rocks present on Fogo show common storage levels, suggesting that they are formed in the same system but the difference being their residence time in the crustal level storage. Our structural data and 3D model suggest that the Monte Amarelo rift zone was composed of three components, being oriented NW-SE, N-NE and E-W. The flank collapse was caused by dike intrusions of N-S orientation which enabled a E-W extension of the shield volcano.
Vulkanön Fogo är en del av ögruppen Kap Verde i Atlanten. Ögruppen bildar en två delad arkipelag positionerad 500 km väster om det afrikanska fastlandet. Ön, tillika vulkanen Fogo har på senare tid varit en av de mest aktiva vulkanerna i världen med 10 utbrott under de senaste 250 åren. Ön byggdes upp av sköldvulkanen Monte Amarelo nådde 3500 m ö h innan delar av den kollapsade ned i Atlanten. Det massiva skredet som skedde mellan 86 och 124 tusen år sedan skapade högplatån Cha das Caldeiras samt den omringande klippsektionen Bordeira. Vi har samlat stenprover från de plutoniska bergarter som har trängt in sig i klippsektionen Bordeira. Målet med vår studie är att skapa en modell för hur magma lagringen fungerar under Fogo. Vi ämnar kartlägga magmalagringsdjupet med hjälp av kemiska variation i mineral som kan användas för att kartlägga kristalliseringstryck och temperatur som i t.ex. klinopyroxen. Vi är samtidigt intresserade av att veta vilka processer som sker i det magmatiska systemet och sambandet mellan vulkanska bergarter t.ex. lava och plutoniska bergarter. Tidigare studier av Fogos magmalagring har använt vulkaniska bergarter, som kristalliserar sig mellan 0.45 till 0.68 GPa när man undersökt kemin på kristallkanter av klinopyroxen. 20 prover har analyserats från Bordeiraklipporna och de innehåller låga kiselhalter, mellan 37 till 47% samt höga mängder alkaliska oxider så som kalium och natrium. Provernas mineralinnehåll består främst av större kristaller av silikatmineralen klinopyroxen ± olivin± fältspat ± främmande amfibolkristaller. De större kristallerna är omringande av en mikrokristallin grundmassa bestående av järn-titanoxider, apatit och fältspatoider. Klinopyroxen har en relativt stor kemisk variation, med Mg#37 till Mg#85, med ett medelvärde på Mg#71. Vi har även två olika sorter av fältspat, en grupp med ett kalciumrik rikt innehåll klassificeras som anortit, och en annan med ett kaliumrikt innehåll, som ortoklas. Vår analys av klinopyroxen-smälta har gett oss kristalliseringstryck som sträcker sig mellan 0.02 till 0.85 GPa med ett medelvärde på 0.47 GPa. Detta innebär att den dominerande processen i magmalagringssystemet är fraktionerad kristallisering då vi kan se ett linjärt avtagande för många ämnen när de jämförs mot magnesiumhalten. Vår magmalagringsmodell för vulkanen Fogo visar att klinopyroxenkrystallisering påbörjas i den litosfäriska manteln, mellan 15 och 28 km djup. Kristallisering av kanter på klinopyroxenkristaller samt mindre kristaller i grundmassan sker ytligare och visar på att det finns en eller flera magmalagringsnivåer i den oceaniska jordskorpan, mellan 9 till 12 km djup. Vulkaniska och plutoniska bergarter vittnar om ett delat magmasystem, vilket indikerar att skillnaden mellan de två bergarterna främst är tiden de befinner sig på respektive lagringsnivå. Vår strukturgeologiska data samt 3D modell visar att den intrusiva aktiviteten var primärt orienterad NV-SO, N-NO och O-Vriktning. Monte Amarelo-vulkanens skred och kollaps orsakades av intruderande gångar med en generell N-S orientering vilket ledde till ett skred på östsidan.

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Rose, Brett Tyler. "Tennessee Rockfall Management System." Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/29263.

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The Rockfall Management System developed for Tennessee DOT (TennRMS)integrates a customized rockfall risk rating system, web-based GIS application, and rockfall database to provide a robust single interface for interacting with rock slope information. The system should prove to be a valuable tool for the proactive management of rock slopes. The most important use of the system will be to identify and prioritizing rock slopes with the greatest potential for rockfall in order to provide decision makers with all the necessary information they need to plan remediation efforts. Over time, TennRMS can be used to track costs and effectiveness of different remediation methods used on problem rock slopes. Three papers have been developed for publication in peer reviewed journals. The papers describe the work done in support of developing Tennessee's Rockfall Management System (TennRMS) and its components. The system can be described by its conceptual framework and actual implemented components. Asset management incorporating risk & decision analysis and knowledge management makes up the conceptual framework. The system components include a field data collection system using PDA's, a rockfall database and a web-based GIS interface. The papers articulate the development and implementation of the various components and to provide a detailed review of rockfall management systems as implemented over the past 15 years.
Ph. D.

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Oztepe, Damla Gaye. "Slope Stability Assessment Along The Bursa-inegol-bozuyuk Road At Km: 72+000-72+200." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/3/12611097/index.pdf.

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The purpose of this study is to determine the most suitable remediation technique via geotechnical assessment of the landslide that occurred during the construction of Bursa-inegö
l-Bozü
yü
k Road at KM: 72+000-72+200 in an ancient landslide area. For this purpose, the geotechnical parameters of the mobilized soil along the slide surface was determined by back analyses of the landslide at four profiles by utilizing the Slope/W software. The landslide was then modeled using coupled analyses (with the Seep/W and Slope/W softwares) along the most representative profile of the study area by considering the landslide mechanism, the parameters determined from the geotechnical investigations, the size of the landslide and the location of the slip circle. In addition, since the study area is located in a second degree earthquake hazard region, pseudo-static stability analyses using the Slope/W software were performed incorporating the earthquake potential. The most suitable slope remediation technique was determined to be a combination of surface and subsurface drainage, application of rock buttress at the toe of the slide and unloading of the landslide material. A static and dynamic analyses of the landslide was also performed through utilizing finite element analyses. The static analyses were calibrated using the inclinometer readings in the field. After obtaining a good agreement with the inclinometer readings and finite element analyses results, the dynamic analyses were performed using acceleration time histories, which were determined considering the seismic characteristics of the study area.

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34

Yung-ShengChue and 邱永昇. "Rainfall-Induced Landslide Potential and Landslide Distribution Characteristics Assessment." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/3uadpd.

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35

Hsieh, Ang-tai, and 謝昂泰. "Using Slope-Unit for Landslide Fragility Curves on the Regional Landslides Assessment." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/05388677390272516906.

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碩士
逢甲大學
土木工程學系
102
On August 8th 2009, the middle Typhoon Morakot struck Taiwan, and it not only brought around 2000 mm rainfall in south-central Taiwan but also caused a wide range of landslides in eastern and southern sloping fields of Taiwan. Due to the fragile geology and precipitous landforms, plus the development of rare landslide type and barrier lake which intensified the condition of disaster in south-central Taiwan. This study adopts maximum rainfall intensity Imax as rainfall indicator, preceding rainfall R0 and cumulative rainfall R as collapsed thrust, and the collapsed area which is captured from the satellite image to calculate the probability for landslide caused by rainfall which is based on Geographical indexes (Slope Level, NDVI, and River Distance), adopting maximum likelihood method (MLE) to obtain two parameters of median μ and Log-standar deviation σ to draw the probability distribution under various physiographic conditions, namely Landslides Fragility Curves (LFC). Substituting the probability of different rainfall factors into slope unit, and take percentage of each category to weight, and Slope-Unit for Landslide Fragility Curves will be derived. The establishment of Fragility Curve for slope units, the development of reasonable description, the management capacity for landslide alert and disaster assessment method, expecting to be an important basis which can be directly applied to decrease disaster and as an emergency measure before hazard in daily life

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36

Chiou, Lin-Bin, and 邱琳濱. "Assessment of Rainfall Induced Landslide Potential." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/96275923515198497299.

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博士
臺灣大學
土木工程學研究所
98
The pore pressure increases due to rainfall infiltration, which may result in the slope instability. Thus, the rainfall-induced landslide is closely related to the hydrological response. Regarding the slope stability analysis in the mountain area, usually numerical models were developed and then case studies of disasters were performed. It lacked field testing, monitoring and analysis, and hence the actual hydrogeological parameters could not be integrated into the numerical models. The purpose of this study is to further understand the mechanism of rainfall-induced landslides, the influences of hydrogeological and rainfall characteristics on landslides are investigated. Therefore, instruments are installed, groundwater levels are observed, and field parameters are analyzed. These field data are integrated into the model. First, a series of field hydrogeological tests including the ground resistivity image profiling, the double-ring infiltration test, the borehole camera investigation and the double-packer test are performed to obtain the strata distribution, slip mode and hydrological parameters to help develop the hydrogeological conceptual model. Furthermore, the hydrogeological parameters and the long-term hydrological records are compiled with the GeoStudio software to perform the transient coupled analysis. The conceptual model and the corresponding parameters applied in the model are based on a series of in-situ investigations and laboratory experiments. A seepage analysis is conducted, and the model is calibrated and verified using the field monitoring data in order to investigate the relationship between landslides and hydrogeology and to understand the influence of hydrogeological characteristics on landslides. In order to understand the stability of landslide sites under different rainfall characteristics, three types of deign rainfall conditions including different patterns, intensity and cumulative amount are introduced into the model. The design rainfalls are obtained based on the data of a rain gauge near the landslide site. The coupled stability analysis is then conducted to establish the relationship between the rainfall characteristics and the slope stability. The advanced rainfall pattern has the least influence on the factor of safety while the delayed rainfall pattern has the greatest influence. It can be concluded that the delayed rainfall pattern threatens the slope stability the most among all the rainfall patterns. As to the influence of the rainfall intensity, the factor of safety decreases as the rainfall intensity increases. When the rainfall intensity is more than a threshold value, apparent decrease in factor of safety is found. Most noticeably, the factor of safety yields a significant drop when the rainfall intensity reaches a certain high value, and the drop slows down when the intensity is over that high value. It shows that the influence of rainfall intensity on the slope stability has an upper limit. Finally, as to the influence of cumulative rainfall, the factor of safety linearly decreases with increasing cumulative rainfall, but the decreasing trend is not significant.

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37

McLean, Amanda. "Landslide Risk Assessment using Digital Elevation Models." 2011. http://hdl.handle.net/10222/13339.

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Regional landslide risk, as it is most commonly defined, is a product of the following: hazard, vulnerability and exposed population. The first objective of this research project is to estimate the regional landslide hazard level by calculating its probability of slope failure based on maximum slope angles, as estimated using data provided by digital elevation models (DEM). Furthermore, it addresses the impact of DEM resolution on perceived slope angles, using local averaging theory, by comparing the results predicted from DEM datasets of differing resolutions. Although the likelihood that a landslide will occur can be predicted with a hazard assessment model, the extent of the damage inflicted upon a region is a function of vulnerability. This introduces the second objective of this research project: vulnerability assessment. The third and final objective concerns the impact of urbanization and population growth on landslide risk levels.

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38

LIN, CHI-WEN, and 林琦雯. "Impact of Rainfall Characteristics on Landslide Assessment." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/40673841495690442535.

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碩士
長榮大學
土地管理與開發學系碩士班
104
About two-thirds of Taiwan’s total area is covered by mountains and hills. Coupled with the global climate change, rainfall-induced landslides often occur and lead to human causalities and properties loss. Therefore, the assessment of rainfall-induced landslides is indeed an important task. The study areas in this research are the Tsengwen and Nanhua Dam watershed in the southern Taiwan. The FORMOSAT satellite images before and after the years 2009-2013 (including 7 typhoons and rainfall events) were acquired and used. The Genetic Adaptive Neural Network (GANN) was implemented in the analysis techniques for the interpretation of satellite images and to obtain surface information and hazard log data. The scope of the impact of different rainfall stations in the study area was estimated using Thiessen's Polygon Method to explore the characteristics of rainfall. The relationship between the pattern, amount, and duration of rainfall and location and scale of landslide was also explored. The results of image classification show that the average value of coefficient of agreement is 0.75 at medium-high level. The rainfall patterns are classified into 5 types using 72-hour rainfall duration for each rainfall station: pre-peak, central-peak, post-peak, twin-peak, and tri-peak. The results also show that when the accumulated rainfall is small, rainfall pattern affect the number and scale of landslides. When the accumulated rainfall is large, there is no correlation between rainfall patterns and landslides. Furthermore, regardless rainfall patterns most landslide sites occur in slope between 20˚ and 40˚. Pre-peak and central-peak rainfall-induced landslides sites occur in slope between 20˚ and 30˚. The other rainfall-induced landslides sites occur in slope between 30˚ and 40˚. Moreover, in the case of the same accumulated rainfall, the elevations of landslides induced by pre-peak and central-peak are much higher than those induced by the others.

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39

Chang, Shuo-Fen, and 張碩芬. "Using Slope-Unit for Landslide Susceptibility Assessment." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/70140229484906370525.

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碩士
國立中央大學
應用地質研究所
101
This study uses slope unit as mapping unit for landslide susceptibility assessment. The delineation of slope unit must consider topographic meaning. In the past, most of slope units applied to landslide susceptibility assessment were delineated by combining the watershed by DEM and the watershed by reverse DEM. Further editing and merging work is usually required and it needs much manual work. The process is times consuming, and containing too much subjective comment. This study follows Chien(2011) using an object-oriented analysis method to automatically generate slope unit. I have modified the processes of slope unit delineation and checked the slope unit quality by statistical methods. In the study area, Shihmen Reservoir catchment area, we first classified the flat area, and using sub-catchment for the former limits. Finally, I use slope aspect as an important component in the object-oriented analysis software, Definiens. According to the weight and the heterogeneity index of image layer, slope units are delineated. Then we calculated standard deviation of slope aspects and normal vectors in each slope unit. I choose two of sub-catchment in the study area for comparison and discussion. The result shows that the delineation methods of our study can get a better result. Then we use the slope unit for landslide susceptibility assessment. Standard deviation of elevation, steep slope ratio, wetness index, slope roughness, the maximum rainfall intensity, and total rainfall of Aere typhoon were adopted in a logistic regression analysis. Because slope units belonging to landslide group or non-landslide group had no conclusive judgment previously, so I will choose different landslide area ratio of slope unit to determine the slope units belong to which group. It reveals that a 5% landslide area ratio of slope unit is good for the threshold. The result shows success rate of the model is fairly good with an AUC of 0.786.

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40

Huang, Shiau-Jen, and 黃筱真. "Risk Assessment of Landslide Disaster in Keelung City." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/8ed9py.

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碩士
國立臺灣海洋大學
河海工程學系
102
In recent years, there was frequently climatic anomaly due to the influence of global climate change in Taiwan. During the typhoon event on August 31, 2013, the heavy rainfall with the intensity of 92 mm/hr was observed. This heavy rainfall induced landslide disasters such as the debris flow and rockfalls in Keelung city. In order to find out high risk areas of the landslide disaster, the study was initiated. In this study, we conducted the vulnerability analysis for the landslide disaster in Keelung. According to disaster potential maps of “Metropolitan area and the periphery of the slope environmental geology atlas data” made by the Central Geological Survey, Ministry of Economic Affairs, we built a quantitative method for the vulnerability of landslide disaster and evaluated the potential areas of landslide disaster in Keelung. We considered the strength of disaster, the spatial distribution and the element of risk and used the geographic information system (GIS) to analyze low, medium and high potential area. Therefore, we classified the vulnerability of building and personnel. Furthermore, we obtained the landslide disaster risk maps. In addition, this study also adopted an unsaturated numerical model for rainfall-induced regional shallow landslides to understand the shallow landslides on the study area in different rainfall events. This numerical model was developed based on the one-dimensional Richards equation. The numerical results could be used to assort the vulnerability of building and personnel and then obtain landslide disaster risk. The results of the study are expected to provide the authority for assisting the decision making of future disaster prevention. Keywords: Landslide disaster; Vulnerability; Richards equation; Rainfall; Shallow landslides

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41

Huang, Kai-Wei, and 黃凱威. "Assessment of regional safety for Rainfall-Induce Landslide." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/70958580999755946839.

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碩士
國立暨南國際大學
土木工程學系
97
In this research region has the Taiwan 14 Guangdong fog road, the Guangdong fog road for the Renai Town foreign main road, is middle the Hengguangonglu main line, communicates Hualian and middle the important road section. However this road section actually because often the typhoon, the torrential rain, the earthquake and so on natural disaster creates the path interrupt as well as the personnel casualty, if can therefore when comes by the torrential rain, carries on the secure appraisal to the region, not can only provide the improvement work order of priority, can the effective region against even forecast that disaster's occurrence, serves the purpose which the disaster prevention reduces disaster. How therefore by carries on the wide range the landslide to dive the feeling analysis is this research main topic effectively reasonably. This article chooses in 2008 Xin Leke the typhoon is the analysis event, uses wide range side slope analysis software TRIGRS, advances together the parametric analysis, is carrying on the wide range landslide to dive the feeling analysis. In this research supposition each grid is independent, by the different grid glide depth, the subsoil water level, the rainfall carries on the analysis. And carries on the sole mesh parameter to analyze its result to demonstrate that the slope, the glide depth, the cohesive force will have the tremendous influence to TRIGRS. Therefore how does the reasonable choice need the parameter, is an important topic.

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42

Yun-ChungTsang and 臧運忠. "Study on Rapid Safety Assessment of Landslide-Dam." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/94639014661281386547.

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博士
國立成功大學
水利及海洋工程學系碩博士班
101
Natural dams could be created by landslides, debris flows, or avalanches, etc. The material that composes the dam usually is loose and heterogeneious colluvial debris with low shear strength. When the material strength cannot resist the force of the river flow from upstream, the dam could fail. The dam failure can dramatically increase the river discharge and result in loss of life. According to previous research, the life of the natural dams has forty one percent of chance to last less than a week and eighty five percent of chance to last no longer than a year. Due to this short life, the authority office needs to evaluate the risk and prepare the corresponding response plan within a short period of time after a natural dam is formed. Therefore, this study develops a rapid safety assessment method for natural dams. The geometry of a natural dam is important information for assessment of the dam. However, the geometry is not easy to obtain due to remote location and extreme weather. This study collects world-wide natural dam cases to develop a database. Based on this database, a rapid assessment method for dam geometry is developed using statistical techniques. Only information needed for the assessment is the landslide area which can be rapidly obtained from remote sensing data which is not restricted by the location of the dam site and can provide critical information about the dam. Because the characteristic parameters of the dam material are not easy to be quantitatively identified, the stability of the dam is difficult to be evaluated. Instead of drilling core sampling and in-situ experiment for accurate parameter values, this study develops a rapid estimation method for these parameters using soil mechanism theory and empirical equations. To prepare needed data, a surface sampling hole and particle size distribution analysis are used. The proposed method can be a substitute method to rapidly provide critical parameters of dam material for stability analysis and dam failure simulation model after a natural is formed. To evaluate the stability of the natural dam correlated to seepage, a full scale simulation model is usually used. However, the parameter collection and full scale simulation model run need a period of time which may not meet the time requirement for emergency response at the early stage of a natural dam event. Therefore this study develops a concept of the critical stable seepage slope ( ) for evaluation of the dam stability considering the seepage. If the dam slope angle at the downstream direction ( ) is larger than the critical stable seepage slope ( ), the dam is considered as unstable. Because the seepage water surface reaches the foot of the dam, the seepage water flow would damage the dam foot and eventually cause failure of the dam. Otherwise, the dam is considered as stable. In addition to the mathematical model, this study also uses physical hydraulic model for experiments. Based on the experiment results, the difference between dam slope angle at the downstream direction ( ) and the critical stable seepage slope ( ) is used. Larger difference while 〉 indicates higher chance for dam failure. The failure type during the seepage damage is also studied. The results show that two parameters are important: the critical stable seepage slope ( ) and the original slope of river channel ( ). If 〉 , the failure type is sudden failure. Otherwise, the damage type is progressive failure in upstream direction.

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43

Guzzetti, Fausto [Verfasser]. "Landslide hazard and risk assessment / vorgelegt von Fausto Guzzetti." 2006. http://d-nb.info/980716993/34.

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44

HONG, YI-JIA, and 洪藝家. "Assessment of Disaster Losses due to Rainfall-induced Landslide." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/40360287240966963879.

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碩士
長榮大學
土地管理與開發學系碩士班
104
Taiwan’s plain development is increasingly saturated, slope land development become a future trend. However, landslides often occur due to extreme rainfall events and earthquakes, and then affect life and property safety. Therefore, assessment of landslide potential and disaster losses is an important part of disaster prevention. The research results also provide the government to develop anti-disaster countermeasures. The study area in this research is the Nanhua Dam watershed in the southern Taiwan. The satellite images before and after the 2009 Typhoon Morakot were acquired and used. Sample regions of roads, buildings, fruit trees, farmland, green cover, bare land, rivers, and waters were selected and the Genetic Adaptive Neural Network (GANN) was implemented in the analysis techniques for the interpretation of satellite images and to obtain surface information and hazard log data. The geographic information system combined with digital elevation model and rainfall data was employed to establish database of influencing factors of landslide. This study developed an evaluation module for landslide potential according to optimum seeking theory to predict landslide probability. Disaster losses in buildings, farmland, woodland, and transport and water conservancy land were estimated according to interpretation results, field investigation, and related information published by the government. The maps associated with the probability of landslide and prediction of disaster losses were plotted using the geographic information system. The results of image classification show that the values of coefficient of agreement are at medium-high level. The results show that weights of slope disturbance and effective accumulative rainfall are the highest, followed by weights of elevation, slope roughness, and slope. The correct rate of the model is 70%. Therefore, the proposed model can be applied in practice for subsequent disaster prevention, disaster insurance, and subsidy amount.

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45

"The use of geographical information system (GIS) for inventory and assessment of natural landslides in Hong Kong." Chinese University of Hong Kong, 1995. http://library.cuhk.edu.hk/record=b5888435.

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by Wong, Tak-yee Tammy.
Thesis (M.Phil.)--Chinese University of Hong Kong, 1995.
Includes bibliographical references (leaves 170-178).
ABSTRACT --- p.i-iii
ACKNOWLEDGEMENTS --- p.iv-v
TABLE OF CONTENTS --- p.vi-x
LIST OF FIGURES --- p.xi-xii -
LIST OF PLATES --- p.xiii-ix
LIST OF TABLES --- p.x-xii
Chapter CHAPTER I: --- INTRODUCTION --- p.1
Chapter 1.1 --- Introduction --- p.1
Chapter 1.2 --- Research Questions --- p.5
Chapter 1.3 --- Study Significance --- p.7
Chapter 1.4 --- Organization of the Thesis --- p.8
Chapter CHAPTER II: --- LITERATURE REVIEW --- p.10
Chapter 2.1 --- Introduction --- p.10
Chapter 2.2 --- Nature of Landslides --- p.10
Chapter 2.2.1 --- Landslide Classification --- p.10
Chapter 2.2.2 --- Morphometry of Landslides --- p.12
Chapter 2.2.3 --- Factors Affecting Landslide Occurrence --- p.16
Chapter 2.2.3.1 --- Gradient --- p.19
Chapter 2.2.3.2 --- Slope Shape --- p.21
Chapter 2.2.3.3 --- Aspect --- p.22
Chapter 2.2.3.4 --- Vegetation --- p.24
Chapter 2.2.3.5 --- Drainage --- p.26
Chapter 2.2.3.6 --- Precipitation/Seismicity --- p.26
Chapter 2.2.3.7 --- Lithology and Geological Influences --- p.28
Chapter 2.2.3.8 --- Regolith --- p.29
Chapter 2.2.3.8.1 --- Hydrological Properties of Soils --- p.29
Chapter 2.2.3.8.2 --- Engineering Properties of Soils --- p.30
Chapter 2.3 --- Data Sources for Landslide Studies --- p.31
Chapter 2.3.1 --- Aerial Photo Interpretation (API) --- p.32
Chapter 2.3.2 --- Remote Sensing --- p.34
Chapter 2.3.3 --- Field Survey --- p.35
Chapter 2.3.4 --- Subsurface Investigation --- p.36
Chapter 2.4 --- Landslide Studies in Hong Kong --- p.36
Chapter 2.5 --- Applications of GIS on Landslide Studies --- p.38
Chapter 2.5.1 --- Major Data in GIS for Landslide Studies --- p.39
Chapter 2.5.1.1 --- Triangulated Irregular Network (TIN) as a Representation of Surface --- p.39
Chapter 2.5.2 --- Applications --- p.42
Chapter 2.5.2.1 --- Inventory --- p.43
Chapter 2.5.2.2 --- Landslide Hazard Assessment --- p.43
Chapter 2.5.2.2.1 --- Statistical Modeling --- p.46
Chapter 2.5.2.2.2 --- Physical Processes or Three- Dimensional Modeling --- p.50
Chapter 2.6 --- Suggestions for Future Research Directions --- p.51
Chapter CHAPTER III: --- STUDY AREA --- p.54
Chapter 3.1 --- Location and Choice of Study Area --- p.54
Chapter 3.2 --- Climatic Aspects --- p.56
Chapter 3.3 --- Geological Aspects --- p.62
Chapter 3.3.1 --- General Information of GASP V --- p.62
Chapter 3.3.2 --- Rock Types Specific to the Two Sites Chosen --- p.63
Chapter 3.3.2.1 --- Volcanic Units - Repulse Bay Formation --- p.65
Chapter 3.3.2.2 --- Sedimentary Units - Port Island Formation (PI) --- p.65
Chapter 3.4 --- Geomorphological Aspects --- p.66
Chapter 3.4.1 --- General Information of GASP V --- p.66
Chapter 3.5 --- Erosion and Stability --- p.67
Chapter 3.6 --- Vegetation --- p.67
Chapter 3.7 --- Summary --- p.70
Chapter CHAPTER IV: --- DATABASE CONSTRUCTION AND MANIPULATION --- p.71
Chapter 4.1 --- Data Collection --- p.73
Chapter 4.1.1 --- Aerial Photo Interpretation (API) --- p.73
Chapter 4.1.1.1 --- Landslip Inventory --- p.75
Chapter 4.1.2 --- Field Techniques --- p.78
Chapter 4.1.2.1 --- Slope Failure/Deposit Field Survey sheet --- p.78
Chapter 4.1.2.2 --- Collection of Landslide Data --- p.79
Chapter 4.1.3 --- Collection of Existing Data --- p.80
Chapter 4.1.3.1 --- 1:5000 Topographic Maps --- p.80
Chapter 4.1.3.2 --- Terrain Classification --- p.81
Chapter 4.1.3.3 --- WWF Vegetation Database --- p.85
Chapter 4.2 --- Data Input and Conversion --- p.86
Chapter 4.2.1 --- Digitizing of Data --- p.87
Chapter 4.2.1.1 --- Landslip Capture in Stereocord --- p.87
Chapter 4.2.1.2 --- Data Conversion --- p.94
Chapter 4.2.1.2.1 --- Topographic Maps - Scanning and Vectorization --- p.94
Chapter 4.3 --- Data Editing --- p.94
Chapter 4.3.1 --- Line Cleaning for Landslide Coverage --- p.96
Chapter 4.3.2 --- Line Cleaning and Height Tagging for Topographic Map --- p.96
Chapter 4.3.3 --- Editing on Terrain Classification Map --- p.97
Chapter 4.4 --- Database Construction --- p.97
Chapter 4.4.1 --- Data Base Design --- p.97
Chapter 4.4.1.1 --- Graphical Data Base --- p.98
Chapter 4.4.1.2 --- Attribute Data Base --- p.99
Chapter 4.4.2 --- Creation of a Triangulated Irregular Network (TIN) --- p.104
Chapter 4.5 --- Data Preparation and Pre-analysis Manipulation --- p.105
Chapter 4.5.1 --- Extraction of Terrain Variables from TIN --- p.105
Chapter 4.5.1.1 --- TIN'S Derived Variable - Elevation --- p.105
Chapter 4.5.1.2 --- TIN'S Derived Variable - Gradient --- p.107
Chapter 4.5.1.3 --- TIN'S Derived Variable - Orientation --- p.109
Chapter 4.5.1.4 --- TIN's Derived Variable - Dimensions (surface distance) of Landslides --- p.109
Chapter 4.5.1.5 --- Micro-DEM and Profile --- p.109
Chapter 4.5.1.6 --- Weighting Method Adopted in Calculating the Gradient and Orientation of Primary Depletion Scar --- p.110
Chapter 4.5.2 --- Data Preprocessing --- p.110
Chapter 4.6 --- Summary --- p.114
Chapter CHAPTER V: --- STATISTICAL ANALYSIS OF LANDSLIDE DISTRIBUTION --- p.115
Chapter 5.1 --- Sampling --- p.116
Chapter 5.1.1 --- Sampling Frame --- p.116
Chapter 5.1.1.1 --- Simple Random Point Sampling --- p.117
Chapter 5.1.1.2 --- Stratified Random Point Sampling --- p.117
Chapter 5.2 --- Comparison of the Two Study Areas --- p.119
Chapter 5.3 --- Statistical Analyses of Landslip Variables --- p.123
Chapter 5.3.1 --- Gradient (TIN) and Elevation --- p.124
Chapter 5.3.2 --- "Aspect, Geological Materials, Gradient, Terrain Component, Erosion & Instability, and Vegetation" --- p.126
Chapter 5.3.2.1 --- Aspect --- p.127
Chapter 5.3.2.2 --- Geological Materials --- p.130
Chapter 5.3.2.3 --- Gradient --- p.132
Chapter 5.3.2.4 --- Terrain Component --- p.137
Chapter 5.3.2.5 --- Erosion and Instability --- p.140
Chapter 5.3.2.6 --- WWF Vegetation --- p.140
Chapter 5.3.3 --- Result of the Partial Model --- p.145
Chapter 5.4 --- Logistic Regression Model --- p.147
Chapter 5.4.1 --- Landslide Probability Mapping --- p.154
Chapter 5.4.2 --- Testing the Model Output --- p.157
Chapter 5.5 --- Summary --- p.161
Chapter CHAPTER VI: --- CONCLUSIONS --- p.162
Chapter 6.1 --- Summary of Findings --- p.162
Chapter 6.2 --- Limitations of the Study --- p.163
Chapter 6.3 --- Recommendations for Further Studies --- p.166
BIBLOGRAPHY --- p.167
APPENDICES
"APPENDIX I Draft 3.3 slope failure/deposit field survey sheet (King, 1994a)"
"APPENDIX II Landslide/deposit field description sheet (King, 1994b)"
"APPENDIX III Hourly rainfall (mm) record at N05 in September 26-27，1993 (Source: Special Projects Division, Geotechnical Engineering Office, Civil Engineering Department)"
"APPENDIX IV Hourly rainfall (mm) record at R23 in September 1993 (Source: Hydrometeorology Section, Royal Observatory, Hong Kong,1993)"
"APPENDIX V Hourly rainfall (mm) record at R31 in September 1993 (Source: Hydrometeorology Section, Royal Observatory, Hong Kong,1993)"

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46

HUANG, JYUN-TAI, and 黃均臺. "Establish Susceptibility and Risk Assessment Models for Rainfall-induced Landslide." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/m732zu.

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碩士
逢甲大學
水利工程與資源保育學系
105
Most of the landslide cases in Taiwan were triggered by rainfall or earthquake events. The heavy rainfall in the typhoon seasons, from June to October, causes the landslide hazard more serious. Renai Township is the most of large landslide cases after 2009 Typhoon Morakot (from Aug. 5 to Aug. 10, 2009) in Taiwan. Around 2,744 landslide cases with the total landslide area of 21.5 km2 (landslide ratio =1.8%), including 26 large landslide cases, induced after 2009 Typhoon Morakot in Renai Township. Three methods, including frequency ratio method (abbreviated as FR), weight of evidence method (abbreviated as WOE), and logistic regression method (abbreviated as LR), are used in this study to establish the landslide susceptibility in the Renai Township, Nantou County, Taiwan. Eight landslide related-factors, including elevation, slope, aspect, geology, land use, distance to drainage, distance to fault, accumulated rainfall during 2009 Typhoon Morakot, are used to establish the landslide susceptibility models in this study. The range of original susceptibility values established by three methods are 4.0 to 20.9 for FR, -33.8 to -16.1 for WOE, and 0 to 1 for LR, and the mean landslide susceptibility value are 8.0, -24.6 and 0.38, respectively. The AUC values are 0.815 for FR, 0.816 for WOE, and 0.823 for LR. And the correct ratio is 65.5% for FR, 61.9% for WOE, 74.5% for LR. The study adopted 14 rainfall stations with more than 20 years rainfall data in Renai Township to estimate the 24-hours duration rainfall with different RPYs. Landslide susceptibility map under 24-hours duration rainfall distribution with different RPYs is used to estimate the landslide disaster location and scale. The landslide risk under different RPYs in Renai Township is calculated as 0.45 billion for 5 RPYs, 0.55 billion for 10 RPYs, 0.77 billion for 25 RPYs, 0.12 billion for 50 RPYs, 2.40 billion for 100 RPYs, and 3.87 billion for 200 RPYs, respectively.

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47

Wu, Cheng-Fang, and 吳政芳. "Assessment on Land Development Suitability in Landslide Disaster Potential Area." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/06838761063729704991.

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碩士
長榮大學
土地管理與開發學系碩士班
99
In recent years, the vulnerable area with low economical value has been considered to develop due to the population growing pressure in urban area and the development of technology and economy. In general, natural environmental characteristics and potential and limitation of development must be considered in the sloping land use. In this research, the land development suitability in Fonglin of Hualien was evaluated. Most of land in eastern Taiwan is hillside. After typhoons, rainstorms and earthquakes, large-scale sediment disasters such as landslides, debris flow, etc., threaten lives and properties of local residents. Geographic information system was employed to establish environmental and essential map database. Some affecting factors of sloping land development suitability were selected and correlation matrix was used to explore the potential and limitation of the development in research area. Finally, the development suitability in research area was configured according to the evaluated levels of potential and limitation of the development. The sloping land development suitability was classified to three levels by using criteria for the analysis of the land development suitability. Then, with corresponding ordinances, current land use and transportation situation, the classification of land development suitability was proposed. The area with high land development suitability is mainly distributed in urban planning district, the western half of the research area. The area with medium-high land development suitability scatters in the research area and around the urban planning district. The area with medium-low land development suitability occupies the most part of the research area. The rest area with low land development suitability is not supposed to be developed. The time saving level classification in sloping land development process constructed in this research can be applied in practice as a guide before real land development.

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48

Tsai, Pei-Shan, and 蔡培珊. "Landslide Susceptibility and Conservation Benefit Assessment for Chi-Sun watershed." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/72146439752574861895.

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碩士
國立中興大學
水土保持學系所
103
In this study a multivariate analysis method, Logistic regression, was used for landslide susceptibility analysis of Chi-Sun watershed. After the extraction and selection of environmental factors, the elevation, slope, terrain roughness, slope roughness, NDVI, wentness index, and accumulated rainfall were selected as causal factors of initiating landslides. By inspecting the distributions of landslides resulted from Typhoon Morakot, it is found that the landslides are located in medium-high and high susceptibility area of the midstream and upstream watershed. And the overall accuracy in this event is 72.4%. The predicted susceptibility values show a good agreement with the observed landslides. It indicates that the model and factors used in this model are valid and the simulation results match the Typhoon Morakot event. In addition, the information on the past NDVI values obtained by the analysis of SPOT-4 images suggests a good vegetation recovery in the watershed landslides except the midstream and upstream areas. Therefore, this study focuses on providing suitable conservation and planning strategies around the small catchment of midstream watershed. Landslide hazardous areas are analyzed and mapped resulting from vegetation recovery for different situations. The result is that vegetation recovery to landslide susceptibility values greater impact in the study area when the return period from 50 to 100 years.

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49

Chiu, Hui-Ching, and 邱惠靖. "The Assessment Model of Fluidizing Landslide Slope in the Catchment." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/20459744171178525013.

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碩士
國立屏東科技大學
水土保持系所
103
The assessment model of fluidizing landslide was developed in this study since the debris flow was frequently related to the fluidized landslides from gullies or slopes in the catchment. Three debris flow streams which occurred in Typhoon Morakot in Kaoping river basin were studied to develop the assessment model. The process of the analysis unit delineation has established based on the micro topography through the tool of GIS, aero photos, the DEM of morphology, and the field verification. The criterion, the basin area larger than 1.5 hectares with the same outlet of a zero-order basin or slope, was applied to the delineation of analysis unit. A total of 198 analysis units were achieved from three debris flow catchments. Eight factors, including A,B, and C, of discriminant model on fluidizing landslide developed by Yang (2014) was selected in this study. Assessed by discriminant model, three catchments have achieved with 50 potential fluidizing landslide units and 148 slope units. Verified with the 21 real fluidized landslide and 40 general landslide events occurred within three catchments in Typhoon Maroka, the good match rate of 82% was achieved. Three verification catchment, one debris flow event and two no debris flow events, have been also conducted through the same delineation procedure to explore the relationship between the among of potential fluidizing landslides to the occurrence of debris flow of a catchment. After total of 6 catchments study, 4 occurred and 2 did not occurred, found that the high occurrence probability to the catchment as the area ratio of potential fluidizing landslide larger than 30%.

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50

El-Fengour, Abdelhak. "Landslide susceptibility assessment in the Amzaz Valley, Central Rif, Morocco." Master's thesis, 2016. https://repositorio-aberto.up.pt/handle/10216/84379.

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