Дисертації з теми "Earthquake-Induced landslides"
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1
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.
Анотація:
Earthquake-induced slope instability is one of the major sources of earthquake hazards in near fault regions. Simplified tools, such as Newmark&rsquos 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.
2
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.
3
Parker, Robert Neville. "Hillslope memory and spatial and temporal distributions of earthquake-induced landslides." Thesis, Durham University, 2013. http://etheses.dur.ac.uk/7761/.
Анотація:
Large earthquakes commonly trigger widespread and destructive landsliding. However, current approaches to modeling regional-scale landslide activity do not account for the temporal evolution of progressive failure in brittle hillslope materials. Progressive failure allows hillslopes to possess a memory of previous earthquakes, which has the potential to influence landslide activity in future earthquakes. The original contribution of this thesis is to address the influence of hillslope memory on spatial and temporal patterns of earthquake-triggered landslide activity, through a combination of landslide inventory analysis and numerical modeling. An understanding of spatial distributions of earthquake-triggered landslides is first established, through analysis of inventories of landslides triggered by five large (M_w > 6.7) earthquakes. The results show how current landscape conditions at the time of earthquakes influence hillslope failure probability. By identifying factors exhibiting a common influence on landslides triggered by all five earthquakes, general spatial models of landslide probability are developed, which are transferrable between different earthquakes and regions. Analysis of model performance for landslide distributions triggered by two sequential earthquakes is then used to establish where this spatial approach breaks down. Errors in the landslide distribution predicted for the second earthquake suggest that the legacy of damage to hillslope materials accrued from the first earthquake is an important control on landslide occurrence. Given the infrequent recurrence of large earthquakes and limited temporal coverage of landslide data, a new modelling approach is developed to understand how hillslope memory influences long-term patterns of earthquake-triggered landslide activity. The model integrates the site-scale evolution of hillslope progressive failure into modeling regional-scale earthquake-triggered landslide activity, in response to sequences of earthquakes. The model results suggest that the sensitivity of landscapes to landslide-triggering increases following large earthquakes, due to damage accumulated in hillslopes that do not reach the point of failure, and decays as these hillslopes fail in response to subsequent, lower-magnitude events. Prolonged elevated levels of rainfall-triggered landslide activity observed following large earthquakes appear to reflect this result. Using the model outputs, a methodology is proposed for predicting temporal variability in landslide activity using records of seismic data. The model results also suggest that, when hillslopes undergo progressive failure, relationships between seismic forcing and landslides are influenced by the magnitude-frequency distribution of earthquakes. As a result, current approaches that use these relationships to predict levels of long-term landslide hazard and erosion rates, but do not account for regional differences in earthquake distributions, may suffer from systematic under- or over-prediction. These significant implications for predicting the geomorphological and human impact of landslides highlight the need for detailed multi-temporal datasets recording the evolution of landslide activity following major earthquakes, in order to quantitatively investigate the influence of hillslope memory in real landscape settings.
4
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.
5
Trandafir, Aurelian Catalin. "Dynamic displacement analysis of earthquake-induced catastrophic landslides in saturated cohesionless soils." 京都大学 (Kyoto University), 2004. http://hdl.handle.net/2433/147830.
6
Pineda, Carlos Eduardo Rodriguez Pineda. "Hazard assessment of earthquake-induced landslides on natural slopes : modelling growth and maturation in primate and human evolution." Thesis, Imperial College London, 2001. http://hdl.handle.net/10044/1/8872.
7
Lam, Huu Quang. "DEVELOPMENT OF HAZARD ASSESSMENT TECHNOLOGY OF THE PRECURSOR STAGE OF LANDSLIDES." Kyoto University, 2018. http://hdl.handle.net/2433/232065.
8
Büch, Florian. "Seismic response of Little Red Hill - towards an understanding of topographic effects on ground motion and rock slope failure." Thesis, University of Canterbury. Geological Sciences, 2008. http://hdl.handle.net/10092/1251.
Анотація:
A field experiment was conducted at near Lake Coleridge in the Southern Alps of New Zealand, focusing on the kinematic response of bedrock-dominated mountain edifices to seismic shaking. The role of topographic amplification of seismic waves causing degradation and possible failure of rock masses was examined. To study site effects of topography on seismic ground motion in a field situation, a small, elongated, and bedrock-dominated mountain ridge (Little Red Hill) was chosen and equipped with a seismic array. In total seven EARSS instruments (Mark L-4-3D seismometers) were installed on the crest, the flank and the base of the 210 m high, 500 m wide, and 800 m long mountain edifice from February to July 2006. Seismic records of local and regional earthquakes, as well as seismic signals generated by an explosive source nearby, were recorded and are used to provide information on the modes of vibration as well as amplification and deamplification effects on different parts of the edifice. The ground motion records were analyzed using three different methods:comparisons of peak ground accelerations (PGA), power spectral density analysis (PSD), and standard spectral ratio analysis (SSR). Time and frequency domain analyses show that site amplification is concentrated along the elongated crest of the edifice where amplifications of up to 1100 % were measured relative to the motion at the flat base. Theoretical calculations and frequency analyses of field data indicate a maximum response along the ridge crest of Little Red Hill for frequencies of about 5 Hz, which correlate to wavelengths approximately equal to the half-width or height of the edifice (~240 m). The consequence of amplification effects on the stability and degradation of rock masses can be seen: areas showing high amplification effects overlap with the spatial distribution of seismogenic block fields at Little Red Hill. Additionally, a laboratory-scale (1:1,000) physical model was constructed to investigate the effect of topographic amplification of ground motion across a mountain edifice by simulating the situation of the Little Red Hill field experiment in a smallscale laboratory environment. The laboratory results show the maximum response of the model correlates to the fundamental mode of vibration of Little Red Hill at approximately 2.2 Hz. It is concluded that topography, geometry and distance to the seismic source, play a key role causing amplification effects of seismic ground motion and degradation of rock mass across bedrock-dominated mountain edifices.
9
Saponaro, Annamaria [Verfasser], Stefano [Akademischer Betreuer] Parolai, Franz [Gutachter] Rackwitz, Fausto [Gutachter] Guzzetti, and Stefano [Gutachter] Parolai. "Cross-border risk assessment of earthquake-induced landslides in Central Asia / Annamaria Saponaro ; Gutachter: Franz Rackwitz, Fausto Guzzetti, Stefano Parolai ; Betreuer: Stefano Parolai." Berlin : Technische Universität Berlin, 2018. http://d-nb.info/1156335132/34.
10
Mita, Mara. "Assessment of seismic displacements of existing landslides through numerical modelling and simplified methods." Electronic Thesis or Diss., Université Gustave Eiffel, 2023. http://www.theses.fr/2023UEFL2075.
Анотація:
Les glissements de terrain sismo-induits sont des effets secondaires fréquents des séismes qui peuvent provoquer des dommages plus importants que les séismes eux-mêmes. Prévoir ces phénomènes est donc essentiel pour la gestion des risques dans les régions sismiques. Les déplacements co-sismiques sont généralement évalués par la méthode « bloc rigide » de Newmark (1965). Malgré ses limites, cette méthode a deux avantages: i) des temps de calcul relativement courts, ii) une compatibilité avec les logiciels SIG pour des analyses à l'échelle régionale. Les modélisations numériques complexes permettent quant à elles de simuler la propagation des ondes sismiques dans les versants et les effets associés. Cependant, elles sont caractérisées par des temps de calcul longs, ce qui limite leur utilisation à l'échelle des versants. L'objectif de cette étude est de mieux comprendre dans quel cas les méthodes analytiques et numériques prédisent des valeurs de déplacements différentes. 216 prototypes de glissements de terrain ont été définis en 2D en combinant des paramètres géométriques et géotechniques déduits de la littérature. Ces modèles ont été soumis à 17 signaux sismiques d'Intensité Arias constante (IA~ 0,1 m/s) et de période moyenne variable. Les résultats ont permis de définir un modèle « Random Forest » préliminaire pour prédire a priori la différence entre les valeurs de déplacements des deux méthodes. Les résultats ont ainsi permis : i) d'identifier les paramètres qui contrôlent les déplacements dans les deux méthodes, ii) de conclure que les différences entre les valeurs de déplacements sont négligeables dans la plupart des cas pour cette valeur de IALandslides are common secondary effects related to earthquakes which can be responsible for greater damages than the ground shaking alone. Predicting these phenomena is therefore essential for risk management in seismic regions. Nowadays, landslides permanent co-seismic displacements are assessed by the traditional « rigid-sliding block » method proposed by Newmark (1965). Despite its limitations, this method has two advantages: i) relatively short computation times, ii) compatibility with GIS software for regional-scale analyses. Alternatively, more complex numerical analyses can be performed to simulate seismic waves propagation into slopes and related effects. However, due to their longer computation times, their use is usually limited to slope-scale analyses. This study aims at better understanding in which conditions (i.e. combinations of introduced relevant parameters), analytical and numerical methods predict different landslides earthquake-induced displacements. At this regard, 216 2D landslide prototypes were designed by combining geometrical and geotechnical parameters inferred by statistical analysis on data collected by literature review. Landslide prototypes were forced by 17 signals with constant Arias Intensity (AI ~ 0.1 m/s) and variable mean period. Results allowed defining a preliminary Random Forest model to predict a priori, the expected difference between displacements by the two methods. Analysis of results allowed: i) identifying parameters affecting displacement variation according to the two methods, ii) concluding that in here considered AI level, computed displacements differences are negligible in most of the cases
11
Strenk, Patrick Murphy Wartman Joseph. "Evaluation of analytical procedures for estimating seismically induced permanent deformations in slopes /." Philadelphia, Pa. : Drexel University, 2010. http://hdl.handle.net/1860/3324.
12
Bou, Nassif Aline. "Mouvements sismiques forts dans les régions montagneuses et mouvements de terrain induits." Electronic Thesis or Diss., Université Grenoble Alpes, 2023. http://www.theses.fr/2023GRALU039.
Анотація:
Après un séisme en zone de montagne, on observe fréquemment dans les zones proches de l'épicentre une grande variabilité dans la répartition spatiale des dommages, englobant à la fois les dommages structurels et les mouvements de terrain co-sismiques. Parmi d'autres facteurs, cette variabilité spatiale peut être en partie attribuée à l'amplification du mouvement sismique provoquée par la topographie. Bien que l'effet de la topographie ait été documenté depuis longtemps, il reste mal compris et est rarement considéré dans les normes de construction parasismique. Ma thèse est dédiée à la prédiction de l'amplification topographique du mouvement du sol à courte distance du séisme, et à l'étude de son impact sur les schémas de distribution spatiale des mouvements de terrain co-sismiques.Pour atteindre cet objectif, mon travail repose en premier lieu sur l'analyse par réseau neuronal de données synthétiques obtenues précédemment à partir de simulations 3D en différences finies de la propagation des ondes sismiques. Cette analyse vise à dériver un estimateur physique des effets de site topographique dans les zones proches de la source sismique. Ce proxy, que j’appelle i-FSC (illuminated Frequency Scaled Curvature), dépend de la longueur d'onde S, de la courbure de la surface topographique et d'un nouveau paramètre appelé « angle d'éclairage sismique normalisé », qui permet de quantifier l'exposition des pentes au champ d'onde sismique incident. Cet outil simple ne nécessite pas de ressources informatiques élevées ; il utilise seulement une carte numérique d'élévation de la surface et la position de la source sismique pour prédire les facteurs d'amplification en tout point de la surface topographique. Le proxy i-FSC permet d'explorer les variabilités dans l'amplification topographique des sites, causée par des sources sismiques proches. Cette avancée dans la prédiction de l'amplification topographique est particulièrement significative, car les zones les plus proches de la faille sont généralement les plus touchées pendant les séismes.Dans un second lieu, le proxy i-FSC est utilisé pour étudier la corrélation potentielle entre l'amplification topographique du mouvement sismique et la distribution spatiale des mouvements de terrain induits par des séismes tels que le séisme de Gorkha de 2015 (MW 7.8), le séisme de Kumamoto de 2016 (MW 7.1) et le séisme de Kaikōura de 2016 (MW 7.8). Les résultats montrent que les mouvements de terrain ont tendance à se localiser dans les zones amplifiées. Différents facteurs influençant le déclenchement des mouvements de terrain co-sismiques à différentes fréquences ont été identifiés. Aux basses fréquences, les mouvements de terrain ont tendance à se concentrer sur les pentes orientées en sens opposé à la source sismique (ayant des angles d'éclairage sismique plus élevés). À petite échelle spatiale, les localisations des mouvements de terrain correspondent aux zones d'amplification topographique à hautes fréquences, qui sont contrôlées par la courbure topographique. De plus, les mouvements de terrain ont tendance à se concentrer aux interfaces entre les pentes éclairées et non éclairées, ce qui peut indiquer des zones où la déformation de la pente est plus importante. Les résultats mettent également en évidence l'importance fondamentale de prendre en compte l'effet de l'amplification topographique, simplement dérivé par le proxy i-FSC, en conjonction avec d'autres facteurs classiques tels que la raideur des pentes, pour une meilleure compréhension des mécanismes complexes qui régissent la distribution spatiale des mouvements de terrain co-sismiques aux échelles locales et régionales.Les résultats de cette étude revêtent une grande importance, car ils pourraient orienter des recherches futures visant à élaborer des stratégies plus efficaces d'évaluation et de réduction des risques dans les régions montagneusesDuring an earthquake, a high degree of variability in damage distribution, encompassing both structural damage and co-seismic landslides, is commonly observed in mountainous regions near the seismic source. Among other factors, this spatial variability can be partly attributed to the amplification of seismic waves caused by surface topography. While this effect has long been documented, it remains poorly understood and is rarely incorporated into building specification codes. My thesis is dedicated to predicting the amplification of ground motion caused by surface topography in close distances to an earthquake, and studying its potential impact on co-seismic landslides distribution patterns.To achieve this goal, my work initially relies on neural network analysis of previously-available synthetic data obtained from 3D finite-differences simulations of seismic wave propagation. This analysis aims to derive a physics-based estimator of topographic site effects in close distances to the source. This proxy, which I refer to as the i-FSC proxy (illuminated Frequency Scaled Curvature), depends on the S-wavelength, the curvature of the topographic surface, and a new parameter called the “normalized seismic illumination angle” which quantifies the slope's exposure to the incoming wavefield. This user-friendly tool does not require high computational resources; it only uses a digital elevation map and the position of the seismic source to predict amplification factors at any point of the surface topography. The i-FSC allows exploring the variations in topographic amplification influenced by nearby seismic sources. This advancement is particularly significant as the areas closest to the fault are typically the ones most severely affected during earthquakes.Subsequently, the i-FSC proxy is employed to investigate the correlation between ground motion amplification and the spatial distribution of earthquake-induced landslides triggered by events such as the 2015 Gorkha earthquake (MW 7.8), the 2016 Kumamoto earthquake (MW 7.1), and the 2016 Kaikōura earthquake (MW 7.8). The results indicate that co-seismic landslides tend to be localized in amplified areas. Different controls on the landslide triggering at different frequencies have been identified. At lower frequencies, landslides tend to concentrate on slopes facing away from the seismic source (with higher seismic illumination angles). At smaller scales, the location of landslides mimics the amplification maps at higher frequencies, which are primarily influenced by surface topography curvature. Furthermore, landslides appear to also cluster at the interfaces between illuminated and non-illuminated slopes, which may indicate areas where slope deformation is the greatest. The results also highlight the crucial importance of considering the effect of topographic amplification, simply derived by the i-FSC proxy, together with other classic factors such as slope steepness, for a better understanding of the complex mechanisms governing the spatial distribution of earthquake-induced landslides at local and regional scales.The results of this study hold significant importance, as they could guide future research efforts aimed at developing more effective risk assessment and mitigation strategies in mountainous regions
13
Dreyfus, Daniel Kenoyer. "A comparison of methodologies used to predict earthquake-induced landslides." Thesis, 2011. http://hdl.handle.net/2152/ETD-UT-2011-05-3042.
Анотація:
The rigid sliding-block analysis introduced by Newmark in 1965 has become a popular method for assessing the stability of slopes during earthquakes. Estimates of sliding displacement calculated using this methodology serve as an index of seismic performance and are used for mapping seismic landslide hazard potential. The original approach of rigorously integrating ground acceleration time-histories to compute estimates of sliding displacement has been replaced by the use of simple, empirical models that predict displacement as a function of a slope's yield acceleration and one or more measures of ground shaking. To be useful the results of these models must be compared with observations of landslides from previous earthquakes.
Seven different empirical models were evaluated by comparing predicted displacements with an inventory of observed landslides from the 1994 Northridge, California earthquake. Using a comprehensive set of ground motion data and shear strength properties from the Northridge earthquake, sliding displacements were calculated within a geographic information system (GIS) and the accuracy of each model was computed. The influence of factors such as landslide size, geologic unit, slope angle, and material strength on the prediction of landslides was also evaluated. The results were used to show that the accuracy of the predictive models depends less on the model used and more on the uncertainty in the model parameters, specifically the assigned shear strength values. Because current approaches do not take into account the spatial variability of strength within individual geologic units, the accuracy of the predictive models is controlled by the distribution of slope angles within observed and predicted landslide cells. Assigning overly conservative (low) shear strength values results in a higher percentage of landslides accurately identified, but also results in a large over-estimation of the seismic landslide hazard.text
14
Saygili, Gokhan 1980. "A probabilistic approach for evaluating earthquake-induced landslides." 2008. http://hdl.handle.net/2152/18115.
Анотація:
Earthquake-induced sliding displacements are commonly used to assess the seismic performance of slopes. These displacements represent the cumulative, downslope movement of a sliding block due to earthquake shaking. While the sliding block model is a simplified representation of the field conditions, the displacements predicted from this model have been shown to be a useful index of seismic performance of slopes. Current evaluation procedures that use sliding block displacements to evaluate the potential for slope instability typically are based on a deterministic approach or a pseudo-probabilistic approach, in which the variabilities in the expected ground motion and predicted displacement are either ignored or not treated rigorously. Thus, there is no concept of the actual hazard (i.e., the annual probability of exceedance) associated with the computed displacement. This dissertation focuses on quantifying the risk for earthquake-induced landslides. The basic approach involves a probabilistic framework for computing the annual rate of exceedance of different levels of sliding displacement for a slope such that a hazard curve for sliding displacement can be developed. The framework incorporates the uncertainties in the prediction of earthquake ground shaking, in the prediction of sliding displacement, and in the assessment of soil properties. The framework considers two procedures that will yield a displacement hazard curve: the scalar hazard approach that utilizes a single ground motion parameter and its associated hazard curve to compute permanent sliding displacements; and a vector hazard approach that predicts displacements based on two (or more) ground motion parameters and the correlation between these parameters. Current predictive models for sliding displacement provide the expected level of displacement as a function of the characteristics of the slope (e.g., geometry, strength, yield acceleration) and the characteristics of earthquake shaking (e.g., peak ground acceleration, peak ground velocity). However, current models contain significant aleatory variability such that the range of predicted displacements is large. To reduce the variability in the sliding displacement prediction and to provide models appropriate for the presented probabilistic framework, sliding displacement predictive equations are developed that utilize single and multiple ground motion parameters. The developed framework is implemented to the Mint Canyon 7.5-minute quadrangle in California to generate a map of earthquake-induced landslide hazard. Application of the probabilistic procedure to a 7-1/2 minute quadrangle of California is an important exercise to identify potential difficulties in California Geological Survey’s (CGS) current application for hazard mapping, and for the eventual adoption by CGS and USGS.text
15
Lin, Yam-chih, and 林彥志. "Earthquake-induced Landslides Behavior Simulation Using Numerical Model." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/63928323791560038853.
Анотація:
碩士臺灣大學
土木工程學研究所
98
Taiwan lies in the interjunction of Eurasia and Philippines sea plates, the platescollide with each other causing the rugged landscape. However, massive rainfall andearthquake often trigger landslides, which may lead to serious casualties and loss of properties. If the run-out of landslides could be simulated, then we can take some precautions against the hazard, so its applications are quite extensive. This study is based on the continuous mechanics and sliding-block analysis, two numerical methods in this study, Newmark method and FEM, numerical models were established to simulate the earthquake-induced landslides behavior, including run-out distance, critical acceleration, and initiation time. The data of large scale-shaking table test by Wang and Lin (2009) were used for simulation and results were compared with the results of experiment. The plastic zone is considered the location of failure plane,and parameter studies were also performed to find out the effects of each factor on the run-out distance. The numerical model was applied to the field case at Hoya village in Nantou County, the 921 earthquake acceleration record was applied to the bottom of the model,and estimated sliding surface to simulate the crack development and the run-out distance. The result shows that the continuous mechanics numerical model can simulate well with both cases, and the run-out distance and starting time fit the experiment results; Therefore, numerical model can simulate the earthquake-induced landslides well.
16
Cheng, Chieh-Ming, and 鄭傑銘. "The Application of GIS to Rain-induced and Earthquake-induced Landslides Susceptibility Zonation." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/02317158266024233853.
Анотація:
碩士國立臺灣大學
土木工程學研究所
91
Zonation on slope failure caused by rainfall and earthquakes is an important task for mitigating disaster due to landslide. The aim of this work is to assess slope instability zonation caused by heavy rainfall or earthquakes through physically based single-variable analysis on the basis of GIS technology. The analysis in static and pseudo-static conditions, using the infinite slope analysis and Newmark’s displacement method which is proposed by Jibson et al.(2000), is carried out and the values of Fs and Dn (Newmark’s displacement) are evaluated. Nevertheless, it is difficult to estimate Data requirements for the hazard analysis, especially for geotechnical parameters. Thus, the sensitivity analysis of parameters and the variability of data requirements for the hazard analysis will be discussed. Besides, an implementation of the inverse analysis to derive geotechnical parameters is described in this work. The study area is located in the east and west parts of the Fenghuang mountain ridge of the Experimental Forest of NTU, and the west parts of the Fenghuang mountain ridge is the Chi-Tou Forest Recreation Area. The landslide susceptibility of the study area after the Chi-Chi earthquake (1999) and the Toraji typhoon (2001) were verified in using the landslide location data. The result of the sensitivity analysis of parameters reveals that the slope, failure surface depth and effective cohesion are high, and that the unit weight and groundwater depth factors are relatively low. In addition, the geotechnical parameters which were evaluated by the inverse analysis are satisfactory consistence between the east and west parts of the Fenghuang mountain ridge. If data sets describing the topography, geology, shear strength, rainfall and seismic shaking of an area or region can be procured, maps produced by using the method in this work can be useful in emergency preparedness planning, lifeline siting and maintenance, critical-facility siting, long-term land-use planning, and a variety of other applications.
17
Yang, Ling-Shiang, and 楊凌翔. "Conditional probability prediction model for landslides induced by Chi-Chi earthquake." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/20195995026775436983.
Анотація:
碩士國立臺灣大學
土木工程學研究所
93
Taiwan locates in the circum-pacific seismic zone with frequent earthquake activities, which could induce the hazardous landslides. An effective landslide prediction map could provide an important reference for policymaking for land use regulation and drafting of mitigation measures of potential disastrous area. The geographic information system database of the research area was constructed by colleting geology and geomorphology data and the landslide scars triggered by Chi-Chi earthquake of research area. Furthermore, the Conditional Probability method was utilized to construct landslide potential model and prediction model. Based on the results of landslide potential analysis, the best factor combination for landslide prediction analysis was determined. Verification of results from the landslide potential and prediction analysis was performed using landslide scars of research area, and success rate of analysis could be quantified. The results of landslide prediction analysis indicate that using the aspect, slope and geology factors, could properly build up a distinguishing landslide prediction model. The landslide scars in the landslide prediction map coincide well with the high landslide probability area. Furthermore, the results of comparisons also prove the suitability of verification method used in this research.
18
Ering, Pinom. "Methodologies for Risk Assessment of Landslides Induced by Rainfall and Earthquake." Thesis, 2019. https://etd.iisc.ac.in/handle/2005/4944.
Анотація:
Landslide is one of the greatest natural catastrophes and poses a major threat to lives and property worldwide. As development expands into unstable hill areas under the pressure of increasing population and urbanisation, the risk of landslide has been growing all over the world during the last decades. The present work aims at risk analysis of landslides in an effort to reduce the socio-economic impact of landslides and to mitigate the landslide risk effectively. The risk analysis of landslides is neither simple nor straightforward as the effects of different triggering factors have to be analyzed individually and managed separately. In this view, landslide risk analysis requires a detailed understanding of the physical process of landslides and the development of different methodologies to relate landslide occurrences with the characteristics of triggering factors.
Rainfall and earthquakes are considered as the most common triggering factors for landslides. Due to the contrast in the characteristics of rainfall and earthquake loads, and their subsequent effects on the landslide movements, the evaluation of landslide risk by a single methodology becomes difficult, if not impossible. The present study introduces methods for risk analysis of landslides due to rainfall as well as earthquake events. These methods recognize the conditions that caused the slope to become unstable and the processes that triggered the landslide movement. Often landslides occur due to the combination of rainfall and earthquake events as the probability of concurrent rainfall and earthquake event in any area is not rare. Consequently, it is essential to evaluate the landslide risk by considering the unfortunate combination of independent events such as rainfalls and earthquakes, and the effects of their mutual interactions on landslide movements. Therefore, for regions prone to both earthquake and heavy rainfall events, risk analysis should take into consideration multiple processes rather than one single event to avoid underestimation of the threats caused by their potential interaction. Understanding the interaction of these events can form the basis and provide a rational approach for multi-hazard risk assessment. The methodologies developed in the present work aims to provide systematic and rigorous processes to formalize slope engineering practice and enhance slope management.
Uncertainty is implicit in almost every field of engineering. In geotechnical engineering, the uncertainty is mainly attributed to inherent or spatial variability of soil parameters, limited number of samples, testing and measurement errors, and the modelling techniques which relate the laboratory or in-situ properties with response characteristics in terms of stability and deformation behaviour of soil. Unless all the sources of uncertainty are clearly brought out and included in the risk analysis appropriately, it is not possible to explicitly assess the risk associated with landslides. To this end, probabilistic methods which have the potential to include the spatial and temporal variability of different components should be incorporated in the risk analysis of landslides. The need for sophisticated probabilistic methods for landslide risk analysis arises from the complex response of slopes to external loads and the uncertainties in material properties. Random field theory is employed to model the inherent spatial variability prevalent in naturally occurring soils. While the spatial variation of earthquake ground motions is modelled using the random process concepts. The probabilistic methods have the ability to identify mechanisms responsible for the occurrence of landslides while incorporating uncertainties in the analysis.
The present study also addresses the challenging issue of numerical simulation of large deformation problems in geomechanics. Material Point Method (MPM), which is a mesh-based particle method, is employed to simulate large deformations occurring in landslides. MPM simulates large displacement with Lagrangian material points moving through a fixed Eulerian mesh. MPM has been employed in the thesis to study the behaviour of saturated slopes under seismic excitation.
Documentation of the past landslide events provides the opportunity to advance the research and practice of landslide risk analysis and also in the development of techniques for slope remediation. In general, the timely collection of data from landslide sites is a challenging problem but very important for landslide risk analysis. The present study introduces a systematic framework which aims at timely and systematic collection of data from landslide affected areas. It also updates the information on strength parameters and other conditions existing in the slope after the landslide event based on an inverse analysis.
Overall, it is expected that the work reported in the thesis will furnish useful guidelines for 1) risk analysis of landslides due to rainfall, earthquake and the coalescence of rainfall and earthquake events 2) modelling the various sources of uncertainty in landslide problems 3) modelling large deformations which occur during landslide events, particularly landslides of flow types 4) collection of timely and systematic data of landslide events.
19
Liao, Chi-Wen, and 廖啟雯. "Probabilistic Hazard Analysis of Earthquake-Induced Landslides – an Example from KouHsing, Taiwan." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/40770319585442476726.
Анотація:
博士國立中央大學
地球物理研究所
93
For a comprehensive hazard assessment of earthquake-induced landslides, it is important to consider temporal effects from regional seismicity and active faults. To include the time factor into landslide hazard analysis, probabilistic seismic hazard analysis (PSHA) can be utilized. In this study, we combined the results from probabilistic seismic hazard analysis with the Newmark’s model to establish a procedure for producing regional probabilistic earthquake-induced landslide hazard map. The material properties of a slope used for calculating the factor of safety and critical acceleration were back-calculated from landslide inventory. To calculate the probabilities of different levels of seismic shaking in the time interval of interest, probabilistic seismic hazard analysis was conducted by using Arias intensity attenuation equation. The results were input into Newmark’s model to produce a probabilistic landslide hazard map. An example of this approach was applied to an area in central Taiwan and shows that the introduction of the time factor allows for the temporal evaluation of the earthquake-induced landslide hazard. The proposed approach provides a temporal assessment of the earthquake-induced landslide hazard. Slope’s material properties, estimated from back-analysis, help to conduct a more objective and physical-based assessment.
20
Yen-ChihChueh and 闕衍智. "Simulating the Earthquake-Induced Large Landslides by Three Dimensional Distinct Element Method." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/79323679292424717670.
Анотація:
碩士國立成功大學
土木工程學系碩博士班
101
Chichi earthquake of a magnitude of up to 7.3 occurred on September 21, 1999, induced many landslides, especially to TasoLing and Chiufenerhshan, are larger scale landslide. However, when we face such large-scale landslide, how to set the scope affected by collapse and the mechanism caused is a major issue. DEM (Distinct Element Method) analysis method is developed for sloving the questions of continous analysis numerical method. Therefore, in this study, to simulate the large landslides use three-dimensional distinct element code that is based on DEM theory. To discuss collapse history and deposition behavior of Tasoling and Chiufenerhshan under earthquake. More indoor tests about material, baseline correction of strong motion stations acceleration history curve and different friction angles of sensitivity analysis Then, the simulation results show that the low friction angle to accord with the material under earthquake. In simulation result can find out it is collapse history and deposition behavior in different period of time.
21
Feng, Zi-Xuan, and 馮梓琁. "Assessment of Vegetation Recovery for Earthquake-induced Landslides at the Chiufanershan Area." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/65045961448291684382.
Анотація:
碩士明道大學
環境規劃暨設計研究所
95
Massive landslides, caused by the catastrophic Chi-Chi earthquake on September 21, 1999, occurred at the Chiufanershan area in Nantou County. Multi-temporal SPOT satellite images, taken on April 1, 1999, September 27, 1999 and March 11, 2006, were chosen for landslide change analysis. First, image subtraction algorithm coupled with unsupervised classification methods such as Iterative Self-Organizing Data Analysis Technique Algorithm (ISODATA) and Self-Organizing Map (SOM) were used for landslide sites identification at different dates. Then, terrain analysis, ecological patch indices and hillslope sediment estimation was used to assess the eco-environmental impacts for the references of vegetation recovery and disaster prevention in the landslide area. The analyzed result shows SOM has higher overall accuracy. The areas decreased from 217.38 ha on September 27, 1999 to 97.15 ha on March 11, 2006, about decreasing 55.31% of area, indicating that the sites of landslide have been gradually restored. In accordance with ecological patch indices analysis, the restoration trend at landslides became obvious. From Semtember 27, 1999 through March 11, 2006, number of patch (NP) hugely decreased, mean patch size (MPS) was decreasing and ecological patch structure became fragile. Additionally, the annual erosion depth at landslides on April 1, 1999, September 27, 1999 and March 11, 2006 were 0.40 cm, 1.71 cm and 1.14 cm, respectively. The analyzed results indicate that the landslide has been recovered by native pioneer plants over six year of vegetation succession. Nature itself has quite robust vegetation restoration ability in the landslide area.
22
Chung, Yi-Jung, and 鍾翼戎. "he Characteristics of Landslides induced by Chi-chi Earthquake in Mt. Chiu-chiu." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/06495171697234204620.
Анотація:
碩士國立中興大學
水土保持學系
92
Abstract Lots of potential factors induce landslides due to steep terrain, particular geology, heavy rainfall and the frequently earthquakes in Mt. Chiu-chiu. Large landslides occurred after the Chi-chi earthquake and it caused serious soil disaster by large number of soil. The research emphasized the characteristics of landslides, and it included: (1)the estimation of the volume and the depth of landslide, (2)the Sediment Delivery Ratio (SDR) of landslides, (3)the trend of the profile of landslides. This study made DTM of watershed of Dry-Stream using topographical base maps with 1/5000 provided from Agricultural and Forestry Aerial Survey Institute and delineated automatically the sub-watersheds and analyzed with 5m*5m grid information by using GIS. It calculated the volume of landslides and corrected the lifting of stratum. First, the study estimated that the average depth of landslide for the whole sub-watersheds and the area of landslides was 1.74 meters and 2.7 meters in watershed of Dry-Stream and illustrated that about 29.68% and 70.32% of area is respectively deep and shallow landslides with digital picture. Furthermore, the estimate of average depth of deep landslides was 8.16 meters. Second, it analyzed that the soil produced from landslides of slope transport to the Dry-Stream with the conception of SDR. The relation of regression between SDR and the area is yielded as: Y = -15.208 ＊ ln(X) + 17.051 Y : SDR(%) X : area(km2) Finally, we selected four slopes of watersheds and extracted the information of the profile of geography from the DTM. The angle of reach is applied to describe the behavior of run-out of landslides and we figured out that the movement of landslide mass was mixed mode and the chage of angle was from 1.19゜to 2.73゜. Additionally, the shape of slope for the shallow landslides after the earthquake is trending to that before the earthquake and the shape for the deep landslides is transferred from convex slope to concave one.
23
Chung, Yu-Ying, and 鍾育櫻. "Comparison on the Characteristics of Rainfall-Induced Landslides Before and After the Chi-Chi Earthquake." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/40007769876313953645.
Анотація:
碩士國立臺灣大學
地理環境資源學研究所
93
Steep terrain and fragile geology in the mountainous area in Taiwan makes the slope susceptible to landslides during heavy rainfall and earthquakes. In 1999, the Chi-Chi Earthquake induced a great deal of landslides in central Taiwan. It is dubious if the weakening of the slope material by the earthquake still influences slope stability and changes the landslide-triggering threshold in some rainfall characteristics. Typhoon Polly in 1992, Herb in 1996, Toraji in 2001 and Mindulle in 2004 are selected for study. The former two took place before the Chi-Chi Earthquake, while the other two occurred after it. Aerial photos are interpreted to identify landslides triggered by each of the typhoons, and individual landslide is then delineated and digitized. Based on the 40 meter resolution DEM, terrain attributes such as size, slope, slope location and specific catchment area for each landslide are calculated using and the results are statistically analyzed. In addition, SINMAP is applied to back calculate the internal frictional angle of each geologic stratum during corresponding typhoon. It is concluded on the calculation results that (1) the fragile metamorphic strata are more subjected to landslides than the sedimentary strata. However, after the Chi-Chi Earthquake, landslides in the sedimentary strata have increased a lot. (2) Both before and after the Chi-Chi Earthquake, the number and area of the landslides increase with increasing rainfall intensities. (3) In all the three sub-watersheds, the estimated internal frictional angles of the slope material after the earthquake tend to be smaller than those took place before the earthquake. (4) The average specific catchment area for the landslides which took place after the earthquake also tends to be smaller than those before the quake. (5) The internal frictional angles of the metamorphic rock after the earthquake are also smaller than it was before. It is shown that the Chi-Chi Earthquake weakened slope material, but since most part of the loose materials has slipped away and vegetation has colonized the once stripped ground surface, the after effects of the Chi-Chi Earthquake have been alleviated.
24
Jiang, Shan-Hong, and 江山宏. "Monitoring and Assessment of Vegetation Recovery for Earthquake-induced Landslides at the Jou-Jou Mountain Area." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/27101503740341175166.
Анотація:
碩士明道管理學院
環境規劃暨設計研究所
94
The earthquake occurred on September 21, 1999 caused not only heavy casualties and extensive damage to buildings, but also a large number of landslides in central Taiwan. Due to scattered distribution of landslides, satellite images were used to rapidly monitor and evaluate the change of the large-scale landslides. Currently, the Jou-Jou Mountain area was proposed as a Nature Reserve Area by the Taiwan Forestry Bureau to restore the natural landscape and ecosystem. There have been over six years since earthquake occurred. It is essential to assess the change of landslide sites. The objectives of this study are to analyze multi-temporal SPOT images from 1999 to 2003 years, and monitor the change and vegetation recovery condition of landslide sites by using Normalized Difference Vegetation Index (NDVI), image change analysis and vegetation recovery rate (VRR). The analyzed results show that the sites of landslide have been gradually restored, the areas decreased from 958.359 ha on September 27, 1999 to 163.672 ha on July 20, 2003. The corresponding VRR has been restored to 70.46% on July 20, 2003 without human interference, which shows that nature itself has quite robust vegetation restoration ability. Additionally, the landslide change evaluation also shows that there are over 84.921 ha of enlarging landslide sites identified on July 20, 2003, most of which primarily concentrated on ridgelines and concave river bank. Using multi-temporal SPOT satellite images can effectively assess and monitor the landslide and its VRR for the reference of decision making and policy planning in the landslide area.
25
Chuang, Shan-Chieh, and 莊善傑. "The relationships between geological environment and landslides-induced by typhoon and earthquake along the Tachia River." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/73421900427054575057.
Анотація:
碩士國立臺灣大學
地質科學研究所
93
This study focused on the effects of four events including typhoon Herb in 1996, 921-earthquake in 1999, typhoon Toraji in 2001, and typhoon Mindulle in 2004 along the catchments of Tachia River between Techi Dam and Ma-an Dam. We used SPOT satellite images and air photos to map landslide and analyzed the landslide data with GIS program. The measurement data of suspended-sediment load was conducted to estimate the annual sediment discharge and comparison of the unit sediment discharge before and after 921-earthquake. The result of rock strength test was used to discuss the relationships between geological environment and landslides-induced by typhoon and earthquake along the Tachia River. From the result of landslide mapping, we found the newborn landslide rate was 88% in 921-earthquake, 47% in typhoon Toraji, and 49% in typhoon Mindulle. The newborn landslide areas were 14 and 19 square kilometers in typhoon Toraji and Mindulle, respectively. It indicated that the completeness of formation was destroyed by 921-earthquake, so the landslide areas were increased. Besides, the reactive landslide rates were 51% in 921-earthquake, 59% in typhoon Toraji, and 66% in typhoon Mindulle. And the reactive landslide areas were 15 and 19 square kilometers in typhoon Toraji and Mindulle, respectively. It implied that the landslide induced by 921-earthquake was reacted more easily in consequent torrential rain events. According to rock strength test, the average uniaxial compressive strength of the Paileng Formatiom, Chiayang Formatiom and Tachien Sandstone were 107, 129 and 137 MPa. The average volumetric joint counts were 11.6, 10.9 and 12, respectively. The 48 % landslides induced by 921-earthquake in the Paileng Formation was higher than others. The landslide rate of the Chiayang Formation and the Tachien Sandstone were increased 5 and 11 times than that in typhoon Herb, respectively. It indicated that the high rock strength of formation with dense discontinuities was especially easily collapsed during the earthquake event. According to the data of the sediment discharge in typhoon Herb and Toraji, we found that the rainfall and total water discharge during typhoon Herb were 1.8 times than that during typhoon Toraji, but the sediment discharge during typhoon Herb was less 50% than that during typhoon Toraji. If we compared the data of suspended-sediment load, we found that the unit sediment discharge ratio was all greater than 1 before and after 921-earthquake. This result indicated that unit sediment discharge in the post-earthquake was greater than that in the pre-earthquake, so the ratio of unit sediment discharge raised in multiple times with the increasing of water discharge.
26
Shou-HengLiu and 劉守恆. "A Statistical Model for the Impact of the 1999 Chi-Chi Earthquake on the Subsequent Rainfall-induced Landslides." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/87947964808203115173.
Анотація:
博士國立成功大學
地球科學系碩博士班
101
A statistical model is proposed for the temporal influence of the 1999 Chi-Chi earthquake on the subsequent rainfall-induced new landslides in the Jhuoshuei River Watershed of Central Taiwan. Based on the landslide inventory via satellite image classifications and daily precipitation records from 1996 to 2008, the parameters of the model functions were obtained by genetic algorithm. The proposed model gives estimation from daily precipitation with an average error of 13.91% of new landslide density to the variation analysis result from landslide inventory over 15 image dates. The results of the model estimation reveal a continuously decaying pattern of earthquake influence on the subsequent rainfall-induced new landslides, an average daily 0.004‰ background new-landslide density, and a 4.97‰ new-landslide density caused by the earthquake directly within the study area. Also, the estimations of the models suggest that there are influences and latency of antecedent rainfall among the occurrence of new landslides. Estimations from time-decay earthquake-impact-factor models show consistent results on the decay constant of 0.0012, which is equivalent to a 578-day (1.58-year) half-life for the influence of an earthquake. Model validations show more representative estimations on short-term (i.e., days) precipitation records and decreasing function for the impact factor of antecedent rainfall. However, constant-impact model of antecedent rainfall is recommended if there is no sufficient observations.
27
Chia-Han, Tseng. "Non-Catastrophic Landslides Induced by the Mw 7.6 Chi-Chi Earthquake in Central Taiwan Revealed by the PIV Analysis." 2006. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-2607200622584900.
28
Tseng, Chia-Han, and 曾佳漢. "Non-Catastrophic Landslides Induced by the Mw 7.6 Chi-Chi Earthquake in Central Taiwan Revealed by the PIV Analysis." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/77357010998640312926.
Анотація:
碩士國立臺灣大學
地質科學研究所
94
Phenomena of natural disasters, such as landslide and debris flow torrents, are very common in Taiwan due to the rugged mountains and large precipitation during the typhoon season every year. After the 1999 Mw 7.6 Chi-Chi earthquake, the catastrophic landslides and debris flow torrents occur more frequently. However, the non-catastrophic Hongtsaiping landslide triggered by the Chi-Chi earthquake in Central Taiwan is less reported and documented. To understand the characteristics of the non-catastrophic Hongtsaiping landslide, several pairs of gray-scale aerial photographs of the study area are compared and analyzed. They are first precisely orthorectified in order to correct geometric distortion of the aerial photographs. These images are then analyzed by cross-correlation using the Particle Image Velocimetry (PIV) technique. And the directions, magnitude as well as the boundary of the non-catastrophic Hongtsaiping landslide are revealed. The calculated results reveal that the maximum horizontal displacement is about 24 m, and directions of displacement lie between north and west. Specific boundary of the landslide can be confirmed, and the dimension of the Hongtsaiping landslide area is measured about 1.2 km2. In addition to the main landslide area, a minor landslide area east of the main landslide area is also detected. The small landslide moved toward the west and the magnitude of displacement is measured about 10 m. According to the results, it is inferred that there are two different sliding blocks in the northern and southern parts of the Hongtaiping landslide area. Based on the patterns of topography within the Hongtsaiping area, the non-catastrophic Hongtsaiping landslide appears to fit the type of circular failure. However, the detailed mechanism of the Hongtsaiping landslide needs more geological survey and data to be understood.
29
Chen, Ying-Jing, and 陳盈靜. "The relationship between rainfall and the occurrence rate of induced landslides and vegetation recovery after Chi-Chi earthquake in Taiwan." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/48158145979124067031.
Анотація:
碩士國立中央大學
應用地質研究所
102
Based on the previous studies, this study re-examined the previous data and added more data of rainfall events before 1999 and after 2010. This large data set was used to analysis the relationship between rainfall and the occurrence rate of induced landslides. We investigate the trend of landslide ratio with rainfall value and observe the rainfall threshold of landsliding. We find out the relationship between landslide ration and a rainfall factor and the combination of rainfall factors. Rainfall factors used in this study include maximum hourly rainfall, total rainfall, average rainfall intensity and maximum 3, 6, 9, 12, 24 hour rainfalls. The results of univariate regression analysis and multivariate regression analysis showed that maximum hourly rainfall, total rainfall and maximum 3, 24 hour rainfalls are fitting with the landslide ratio well and are more effective in explaining landslides. A residual after regression is defined as the difference between observed value and predicted value for the landslide ratio. We plot the residuals against the time and observe the change of residuals with time. The results showed that the areas affected by Chi-Chi earthquake (central Taiwan) have gradually restored in the last decade.
30
Huei-SianSyu and 徐慧嫺. "Earthquake-Induced Landslide: Analysis of the Initiation-Time and Failure Surfaces." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/rz7q5e.
Анотація:
碩士國立成功大學
土木工程學系
104
A catastrophic earthquake can easily result in destructive disasters. It is well-known that earthquakes are one of the causes of landslides. On April 16, 2016, the main-shock of the Kumamoto earthquakes (Mw7.3) struck beneath the Kumamoto City and generated large-scale landslides around the Aso area. Among the landslides, the Aso-bridge landslide is the largest one. According to topographical scanning of Digital Elevation Models (DEMs), the collapse of the Aso-bridge could suffer from two mechanisms. To analyze the initiation-time and failure behavior of the Aso-bridge landslide, this study utilizes two approaches: the Newmark’s sliding block method and a finite element analysis (FEA) program-PLAXIS-2D. In order to ensure our research methods are practicable, this study makes use of a famous case – the Tsaoling landslide induced by the Chi-Chi earthquake, for verification. The results of this study show the landslide time is t=37.5~40 sec, and the obtained failure surface is close to the actual observed surface. Therefore, the results fit-well with previous studies and are thus the verified approaches for the study. Furthermore, this study also uses the data of the 1999 Chi-Chi earthquake and the 2016 Meinong earthquake to conduct further verification of the approaches to analyze landslide behavior and potential failure surface of the Tsaoling landslide. Upon the verifications, this study applies the verified approaches to analyze the landslide initiation-time and landslide failure surface of the Aso-bridge landslide. The results show that (i). The initiation-time of the Aso-bridge landslide is between 18.45~21sec. (ii). The geometrical strength parameters are ϕ=35° and c=80kPa, and the failure surface is close to the actual observed surface predicted by DEMs. (iii). The geology of Aso-bridge is Igneous. The soil strength is slightly less than the peak value of 95 kPa reported, suggesting that the strength of the soil layers was reduced likely due to weathering. (iv). The Aso-bridge landslide was excited immediately from the ridge of the slope when the main-shock of the Kumamoto earthquake struck. The study demonstrates that the Newmark’s sliding method and the finite element analysis (FEA) can be applied to analyze the landslide initiation-time and the landslide failure surface with a reasonable agreement. Finally, since the vertical acceleration is not taken into account in the FEA, a pseudo-static analysis is used to evaluate the effect of the landslide considering the vertical acceleration as to verify the errors in predicting the failure surfaces of the landslide. A MATLAB GUI, a user-friendly Apps, which is convenient for rapidly predict the landslide initiation-time, has also been developed to facilitate subsequent research and application.
31
Huang, De-Sheng, and 黃得勝. "A study of dip-slope landslide induced by earthquake and rainfall." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/39281516406903254768.
Анотація:
碩士國立中興大學
水土保持學系所
97
This study uses programs and field tests to discuss the dip-slope landslide induced by earthquake and rainfall. The result by using FLAC program shows that the landslide occurs at the toe of slope when the earthquake happened, and then makes the huge dip-slope landslide of entire slope. The result by GeoStudio program shows that infiltration by the rainfall during the Sinlaku typhoon caused surface landslide and deformation of retaining wall possibly. For applying the electrical resistivity imagine profile method, this study shows that Resistivity Image Profile (RIP) results can be used to roughly estimate the distribution of the strata and location of groundwater surface with borehole test result. This study also used GeoStudio program to analyze the engineered dip-slope after the Sinlaku typhoon. It is concluded that the new lateral drain can block the rainfall on top of slope, but the residual water still affects the stability of slope.
32
Lee, Shing-Tzu, and 李馨慈. "Applications of Cumulative Displacement Method on Earthquake-induced Landslide Hazard Analysis." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/20322701004780570447.
Анотація:
碩士國立成功大學
資源工程學系碩博士班
92
A mountainous area of 48 km2 of Taiwan is selected for earthquake triggered landslide hazard analysis. The Chi-Chi earthquake induced cumulative deformation of this area was calculated based on Newmark’s slide-block method. The larger displacements are supposed to have a higher probability of landslide failure. Then the distribution of the displacement is compared with the digital inventory of landslides triggered by the Chi-Chi earthquake to construct a probability curve relating predicted displacement to probability of failure. The degree of agreement between these two distribution maps is considered as a degree of success of this method. Since only one strong-motion station is located in this research area. Since only one station is located in the research area, the detailed variation of ground motion was not sufficient to represent, and the few station information cannot display the surface topography effects of the complicated topography of the research area. It has been reported that buildings located on the hilltops suffer much more intensive damage then those located at the base of hills. This study includes the complex amplification and deamplification effect causing by surface topography to predict the earthquake triggered landslide hazard. The geotechnic parameters of the area were calculated, performing a back-analysis based on the pseudo-static model. The past study advocated the use of a seismic coefficient of 0.5. The earthquake-induced landslide hazard analysis includes topographic effect have resulted in the higher accuracy rate, but it have resulted in the lower probability of failure.
33
Rana, Himanshu. "Regional and Local-scale Analysis of Landslides Induced by Rainfall and Earthquakes." Thesis, 2022. https://etd.iisc.ac.in/handle/2005/5803.
Анотація:
Landslides are major natural disasters which pose a significant risk to lives and infrastructure globally. As urbanization is increasing due to the increasing population in mountainous regions, the risk due to landslides draws grave concern owing to the damage and disruption since the last decade. Hence, regional-scale and local-scale landslide analyses are necessary to reduce the impact of landslides on lives and infrastructure; and efficiently prevent the landslide risk. The landslide analysis must be conducted separately for different triggering factors as the slope materials follow different failure mechanisms under various triggering factors. In this thesis, efficient models for landslide analysis at regional-scale as well as local-scale are developed, focusing mainly on understanding the relationship between actuating factors and slope failure events; and the slope failure mechanism. These models are developed for different causal factors, including rainfall and earthquakes.
For regional scale analysis of landslides, a methodology is introduced for landslide mapping, which aims at the accurate and faster demarcation of slope areas affected by landslides. Fast and accurate landslide mapping forms the basis of research and practice of landslide hazard and risk analysis. A systematic framework is also presented to estimate landslide hazard at regional-scale using previous landslide incidents and establish a relationship between different triggering factors and landslide incidents. Further, a predictive model is proposed to estimate the evolution of seismically induced slope displacement with time. The developed model is based on the dynamic response surface method (DRSM). Various methodologies are proposed for local-scale analysis of slope systems under various causal factors, i.e., rainfall and earthquakes to estimate the uncertainty in soil parameters using probabilistic methods and machine learning algorithms. Several algorithms are developed and implemented in Python and MATLAB to add new features that introduce complexity in the numerical models and interface the deterministic and probabilistic analysis.
Overall, it is anticipated that the work presented in this thesis will facilitate guidelines for 1) landslide inventory and hazard mapping due to rainfall infiltration, 2) estimation of evolution of seismically-induced slope displacement with time using predictive models, and 3) probabilistic back analysis of slope system under various causal factors.
34
lee, you ren, and 李祐任. "Development of Earthquake-induced Landslide Fragility Curves Using an Empirical Statistical Model." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/49611973919438335587.
Анотація:
碩士逢甲大學
土木工程學系
104
The geological hillside is frail and the steep slope in Taiwan. Landslides mainly caused by earthquake and high intensity rainfall, especially Taiwan occurred 921 earthquake in 1999. It let Chelungpu fault and Tamaopu-Shuangtung Fault severe dislocation and let fragile geological less stable. The fragile geological cause serious disasters and it has large-scale collapse to Taiwan. The earthquake’s unpredictable nature causes collapses. Therefore, the related research tendency to statistical development and collect collapse cases or seismic observation records to analyzed. Consequently, the collapse disasters caused by the earthquake unable accordance rainfall resulting in collapse mode to use of real-time monitoring alert system. It needs to rely on the earthquake quick report and the concept of early assessment to develop armed mode. We use fragility curves to express the probability of damage in the earthquake factor and comprehensive apply on early earthquake disaster assessment or the planning for disaster reduction. This research for the 921 earthquake prophase and later period aerial imaging conduct landslide judgment. Besides, we take images to do match and create sample area for the collapse database. We generalize and analyze fragility curves reasons include geology, aspect, slope. Final, we discussion the slope unit that collapse of the slope fragility curves.
35
Huang, Ching-Ya, and 黃靖雅. "Numerical Simulation of Affected Area and Run-out Distance of Earthquake-induced Landslide." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/83494112140951475410.
Анотація:
碩士國立臺灣大學
土木工程學研究所
101
Landslides often cause deaths, and the loss of properties. The damages caused by 921 Chi-Chi earthquakes in Taiwan are tremendous, and are needed detailed investigation to access the affected area of landslides for mitigation measures. Study of landslide disasters had been conducted by the satellite images and aerial photos. However, the engineering projects often required assessment from the on-site data. To provide information for landslide hazard mitigation, the numerical simulation can offer a more reliable and assessment of affected area and run-out distance. A numerical model for simulation of earthquake-induced landslide to simulate the landslide affected area is developed in this study. The first step of simulation is to verify the small shaking table experiment. The maximum shear stress occurrence time is defined as the sliding surface forming period, and the sliding surface was determined with the graphic of maximum shear strain increment. The second step is developing the sliding model and input parameters of sliding surface. The material on the sliding surface deforms, then slides along the interface, and stops when energy deplete. We compare the results of numerical simulation with the experiment to discuss the correlation between affected area and run-out distance. The numerical model for simulation of landslide behavior was applied to real landslide cases in May River Basin, Nantou County. We developed the dynamic sliding model of each case for studying the influence of 921 Chi-Chi earthquakes, and discussions on the correlation between affected area and run-out distance with the analyzing result of case study were conducted. The statistics consequence from simulation results show that 2/3 of the horizontal length of the affected area is about the length of landslide block, and 1/3 of the horizontal length of the affected area is about the length of run-out distance. Furthermore, if the affected area could be determined with satellite images and aerial photos, the run-out distance can be calculated from the linear formula in this study.
36
Lin, Guan-Wei, and 林冠瑋. "The relationships between sediment discharge and landslide-induced by typhoon and earthquake along the Chenyoulan River." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/14527683699775450144.
Анотація:
碩士國立臺灣大學
地質科學研究所
93
Abstract Examining the effects of four events -- typhoon Herb, 921-earthquake, typhoon Toraji and typhoon Mindulle -- along the catchments of Chenyoulan River, we found that newborn landslide rate increased to 70%, while the reactive landslide rate decreased to 40%. Regression exponent results show that the landslides associated with these four events were all greater than 1.5, indicating that the landslides in Chenyoulan watershed are dominated by small landslides, which tend to be less than 2000m2. Probability distribution in the upslope area at the lower most point reached by landslides shows that 90% of the landslides remained confined to hillslopes after 921-earthquake. In addition, the post-earthquake average sediment discharge was 37 Mt/yr, some 13 times the pre-earthquake amount. The post seismic unit sediment concentration also increased by 4 times in the Chenyoulan River. The post-earthquake landslide rate for Nanchuang formation increased 17times. In contrast, the landslide rate for Hoshe formation only increased 3.4 times, and the metamorphic formation only increased 4.8 times. These results reveal that the rock strength of Nanchuang formation was smaller than that of Hoshe formation and metamorphic formation. The post-earthquake reactive landslide rate for Nanchuang formation and Hoshe formation decreased to 25%, but at the same time the metamorphic formation decreased only 6%. The controlling factor came from the discontinuities distribution, because the joints sets for Nanchuang formation and Hoshe formation were only 2/3 of the metamorphic formation. Analysis of the correlation between landslide distribution and distance from the Chelungpu fault revealed that the 921 co-seismic landslide rates decayed more rapidly after 20 km; landslide effects of typhoon Toraji indicated similar results. The relation between accumulated rainfall and landslide rate display that during typhoon Herb the landslide rate increased with the accumulated rainfall, and the correlation coefficient reached 0.99. But during typhoon Toraji and Mindulle the landslide rate didn’t have good relation with the accumulated rainfall, the landslides during typhoon Toraji and Mindulle maybe affected by 921 earthquake.
37
Tsou, Ming-Cheng, and 鄒明城. "The Study of Knowledge Discovery from Spatial DatabaseChi-Chi Earthquake-Induced Landslide As A Case Study." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/27065692691035638833.
Анотація:
博士國立臺灣大學
地理環境資源學研究所
93
With the progress of information science and technology, the data collection march toward the automation and computerization. The fast accumulation of the spatial data, such as satellite image, GPS data recorder, mobile communication equipment and various kinds of location-based transaction, offer a large number of geo-referenced data. There include a lot of valuable information and knowledge among these data. How to refine out valuable knowledge from these data is a great subject faced at present. Data mining can help the policymaker to find out valuable knowledge from a large amount of data, but most application are still only limited to the analysis of the attribute data. It is difficult to deal with the spatial data. And though geographical information system is powerful in analyzing spatial data, but it lack the advanced ability to deal with sophisticated attribute data analysis. Because Taiwan is located in the earthquake zone, some areas go through a lot of earthquakes and periodic heavy earthquakes every year and cause serious landslide. If after going through the torrential rain again, will bring serious debris flow and cause great losses of the lives and properties. An earthquake of magnitude 7.3 on Richter scale occurred in the middle region of Taiwan on September 21, 1999. This earthquake caused more than two thousand people died, severe property loss, and a large number of landslides. A large number of landslide data and earthquake strong motion records were obtained for the experts and scholars to carry on the research of landslide influence of the earthquake. This research collects data of landslides triggered by Chi-Chi earthquake, and with the powerful data-processing function and spatial analysis ability of Geographic Information System (GIS), Data Mining modeling, the basic data of research region, and Chi-Chi earthquake strong motion records to establish the landslide database and data warehouse. A new strategy, which combines several models based on different philosophy, not only reduce the uncertainty of predictive modeling, but also improve the accuracy. In our study, a Decision Tree, Artificial Neural Network, Bayes Classfier, and Exemplar-based Concept Learning were individually applied to a spatial data warehouse. The result of each model and two kinds of modeling-integration methods, including horizontal integration and vertical integration, were then evaluated. Furthermore, the spatial association patterns are typically not encoded in database, but are rather embedded within the spatial framework of the geo-referenced data. The analysis of the association pattern between the occurrence of Chi-Chi earthquake-induced landslide and background environmental characteristics is used as a case study to demonstrate the potential of spatial data mining techniques, like OLAP, association rule mining and Spearman rank correlation. With the analysis results, we derived a suspecious potential map and build the knowledge base and model base. Verification proofed the result to be good. So the analysis methods mentioned by this research are suitable for the risk assessment of landslide hazard triggered by earthquake and can be used as the tool for disaster mitigation decision support.
38
Chen, I.-Hui, and 陳宜徽. "The relationship between vegetation and landslide-induced by typhoon and earthquake along the catchment of Chenyoulan River." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/90242729964064028293.
Анотація:
碩士國立臺灣大學
地質科學研究所
93
In the study, we are trying to find out the relationship between landslide distribution and vegetation along the catchments of Chenyoulan River from 1996 to 2004. We use SPOT satellite imagines and air photos to map the landslide and analysis the Normalized Difference Vegetation Index of typhoon Herb, 921-earthquake, typhoon Toraji and typhoon Mindulle. We use both the Experimental Forest of NTU and Taiwan Forestry Bureau’s data to estimate the biomass. Using the data from the test of geomaterial to discuss relationship between lithology and landslides. In general, the NDVI values of landslide area are between -0.2 to 0.2, and biomass is between 50t/ha to 350t/ha. When NDVI increases 0.1, vegetation cover rates will add 20%, and elevation increase 1000 meters, biomass add around 80t/ha to 100t/ha. It means when NDVI values increase and vegetation cover rates will add in the same time in this study area. From the mapping of the landslide, we found that in 1999 921-earthquake’s landslide areas are 2.6 times, flux biomass is 3.4 times, and NDVI values decrease 0.08 than typhoon Herb’s. In 2001, typhoon Toraji’s landslide areas are 2.1 times, flux biomass is 1.6 times, and NDVI values decrease 0.04 than 921-earthquake’s. In 2004, typhoon Mindulle’s landslide areas are 1.1 times, flux biomass is 1.2 times, and NDVI values decrease 0.09 than typhoon Toraji’s. It is say that landslide areas have the negative relation with NDVI. From the result of rock strength, sonic wave test and vegetation, we can find out metamorphic rock strength is between 100MPa to 150MPa. Rock strength and sonic wave test are 2 and 1.5 times than Nanchuang formation. Discontinuities and NDVI values are 2 and 0.5 times than Nanchuang formation. According to the result, NDVI values have negative relation with rock strength, sonic wave test and discontinuities. In several typhoon events, sediment discharge is from 0.3Mt to 28.7Mt and biomass is from 9.4kt to 97.4kt. It means in rainfall most sediment is from the geomaterial rather than vegetation. Because vegetation is only 0.36% of sediment discharge.
39
Peng, Wen-Fei, and 彭文飛. "Modeling the Earthquake-Induced Landslide Hazard Assessment Based on the Cumulative Displacement Method Incorporating Topographic Amplification and Sliding Area Effects." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/75510257845714519671.
Анотація:
博士國立成功大學
資源工程學系碩博士班
96
A procedure that considers topographic effects and runout behavior is proposed for analyzing seismic landslide hazards. The theoretical topographic amplification factors and corresponding amplified ground motion are calculated. By using the amplified motion, a cumulative displacement map is generated through Newmark’s displacement method. The high displacement areas are defined as the source areas of landslides. A runout simulation that identifies sliding routes and the final deposition areas of the sliding material from these source areas is performed. Finally, the complete set of landslide zones, including source, and sliding and deposition areas, is predicted. Three landslide hazard maps of the 99 Peaks region, Mt. Yan region and Mt. Baishiya region are evaluated, and the maps of actual landslides triggered by the September 21, 1999, Chi-Chi earthquake are compared with the prediction. Relative to the conventional procedure, the results show that the proposed procedures which include the topographic effect can obtain a better result for predicting the source area of landslides. And the proposed procedures, which combines topographic effects and runout simulation, can generate more accurate predictions for predicting the complete set of landslide zones, including source, and sliding and deposition areas.