Thesis (MScEng (Civil Engineering))--Stellenbosch University, 2008. / The South African code for the design loading of building structures, namely SABS 0160 (1989), was revised with the requirements for seismic design prescribed in SANS 10160: Part 4: Seismic actions and general requirements for buildings. SANS 10160: Part 4 incorporates the seismic design provisions of several seismic codes of practice, however, the influence of the value prescribed for the behaviour factor has not been established with regard to South African conditions. The behaviour factor is used by most seismic design codes to account for the energy dissipating effects of plastification in structural systems when subjected to earthquake ground motion, to reduce the elastically determined forces to be designed for. However, a considerable difference is observed in the values of the behaviour factor prescribed for the design of reinforced concrete walls between the leading international seismic codes. The aim of this study is to assess the value of the behaviour factor prescribed in SANS 10160: Part 4 for reinforced concrete structural walls under the influence of South African seismic conditions and code requirements. A method of quantifying the value of the behaviour factor was developed and implemented in the study by Ceccotti (2008). This method entails estimation of the maximum analytical behaviour factor as the ratio of seismic intensity at failure of the structure to the seismic intensity prescribed by the design code. Such a method is adopted for this study where the lateral force resisting systems of six-, eight- and tenstorey buildings are investigated with nonlinear static analysis to quantify the maximum computationally-determined value of the behaviour factor. Firstly, it is observed that it is possible to quantify the value of the behaviour factor through the use of a computational study. The nonlinear static method of analysis is shown to provide reliable results in the estimation of the behaviour factor for a sixstorey building, however, does not perform well for taller buildings. Further investigation with the use of dynamic time-history analysis is proposed to evaluate the influence of the factors identified in this study. The behaviour of structural walls, designed for reduced forces with the prescribed behaviour factor of 5.0, exhibits high yield strengths and resists the design seismic action entirely elastically. This high strength is found to be due to the reliability/redundancy factor prescribed by SANS 10160: Part 4 and because of the high values of structural overstrength. Similar studies observed high values of structural overstrength for buildings designed for low seismic intensity, which were shown to result from the fact that the resistance required to gravity loading became more critical than the seismic loads in the design of the structural system. This study identifies several factors that influence the value of the behaviour factor, such as the number of walls in the lateral force resisting system; the number of storeys of the buildings; available displacement ductility of the structural system; and the ground type designed for.

The aim of this thesis is to investigate the Chinese government’s disaster response over the past two decades, analyze any patterns or recurring management behaviors, and understand the government’s overall emergency response capability. Disaster response is one area that reflects the Chinese Communist Party’s ability to govern and exhibit performance legitimacy. As an authoritarian regime, the CCP relies on repression and performance to maintain its authority, especially so when national disasters occur. During times of crisis, the CCP is expected to maintain control and minimize potentially negative consequences. Not doing so results in a potential image crisis and loss of legitimacy. The cases studied in this thesis were the 2005 Songhua River benzene spill, the 2008 winter storms, the 2008 Wenchuan earthquake, the 2015 Tianjin warehouse explosions, and the 2016 June and July floods. The 2008 Wenchuan earthquake was the deadliest disaster in a generation and provides the most thorough example to investigate China’s government disaster response capabilities. Two of these crises were industrial chemical accidents near or in major Chinese cities. The remaining two were weather disasters spread over a large area that required a far-reaching and coordinated government response across multiple provinces. Each of these sets displays a type of national disaster that China experiences regularly. In conclusion, the investigation makes two conclusions about the government’s disaster response capabilities. First, the central government is able to make extensive use of its overall authority and hierarchical structure to mobilize state resources on a massive scale. This includes the CCP’s control of the People’s Liberation Army and state emergency personnel, the government’s economic authority to impose immediate regulatory measures, and ability to gather and distribute physical resources. Second, the CCP seeks to avert an image crisis to maintain a veneer of performance legitimacy. Two common tactics are repressing investigative journalism and jailing critics while molding an image of a paternalistic and protecting state through compassionate moral performance. However, the necessity for this last conclusions hints at why such practices are necessary in the first place. The CCP’s rush for economic growth, lack of accountability, and propensity for corruption among other things are the very factors that have allowed disasters to become crises. Extreme measures are necessitated because the system the Party has built is prone to crisis. Without fundamental change, the CCP will continue facing such crises in the foreseeable future.

Deformation in continents is not restricted to narrow bands but is spread over great distances within their interiors. A number of lines of evidence, including the distribution of earthquakes, reveal that the strength of different continental regions varies markedly. While it is relatively easy to qualitatively map out these variations, little progress has been made in quantifying the range of strength in the continents and identifying the physical mechanisms that control these variations. I investigate crustal deformation associated with the earthquake cycle, inflation of magma chambers beneath volcanoes, and changes in surface loads. Results of these models has important implications for our understanding of large-scale continental deformation and mountain building, in addition to both seismic and volcanic hazard assessment. Novel analytic solutions for simple shear with depth-dependent linear and non-linear viscoelastic rheologies are derived, in addition to analytical solutions for imposed harmonic tractions and displacements on an elastic layer over a Maxwell viscoelastic half space.

Dans cette thèse, des simulations numériques ont d'abord été effectuées avec le logiciel FLAC (Itasca) sur un modèle de pente élastique linéaire homogène pour caractériser l'amplification de l'accélération le long de la surface située le long et à l’arrière de la crête d'une pente, et évaluer ainsi l'effet de la topographie sur l'amplification de l'accélération. L'interaction entre la fréquence du signal sismique appliqué à la base du modèle et l'angle et la hauteur de la pente a été particulièrement étudiée. Il a été constaté que le facteur d’amplification de l’accélération varie de manière significative avec l’angle de et la hauteur de la pente, la fréquence et la durée (nombre de cycle) du signal. De plus, l'amplification du mouvement du sol due à la topographie de la pente est influencée de manière significative par l'effet de couplage complexe entre les ondes incidentes et les ondes réfléchies sur la topographie, et qu’elle est fortement contrôlée par le rapport entre la longueur d'onde du signal incident et la hauteur de la pente.Les simulations numériques sont basées sur une étude géotechnique et une modélisation géomécanique nécessitant de valider les résultats par des comparaisons entre les résultats de modélisations et les données provenant des observations sur le terrain. L’analyse des domaines de fréquence, telle que la densité spectrale et la réponse en fréquence, est un moyen performant pour comprendre les caractéristiques des processus et les divers phénomènes qui ne peuvent pas être expliqués dans le domaine temporel. À cette fin, une étude de la crête du parc Xishan à Zigong au Sichuan en Chine a été réalisée. Les amplifications du site associées au mouvement du sol produit par le séisme de Wenchuan en 2008 ont été évaluées à l'aide de la technique du rapport spectral standard (SSR) et de la méthode d'accélération quadratique moyenne (arms) dans le domaine temporel. Une analyse numérique à 2D utilisant la méthode des différences finies au moyen du logiciel FLAC (Itasca) a été ensuite mise en œuvre et les résultats ont été comparés aux mesures de terrain. Les pics “simulés” des amplifications spectrales sont toujours inférieurs à ceux dérivés des enregistrements de terrain. L'effet d'atténuation important sur le mouvement d'entrée pour les hautes fréquences met en évidence le fait qu'un rapport d'amortissement du signal ne représente pas correctement la dissipation d'énergie dans les simulations numériques. Des amplifications significatives se sont produites à des fréquences élevées (> 10 Hz) et sont considérées comme résultant de conditions locales spécifiques telles que la fracturation des roches et les marches de faîtage; ils ne se produisent donc pas nécessairement au sommet de la colline.Enfin, des études paramétriques ont été réalisées avec des modèles élastiques en termes de diverses géométries de pente 2D et de couches géologiques de subsurface pour caractériser les amplifications du mouvement du sol. L’analyse paramétrique a pour but de comprendre le rôle joué par ces couches de surface, l’angle de la pente et la hauteur de la pente sur l’amplification du mouvement du sol,et donc d’évaluer si l’amplification du site peut être responsable du déclenchement du glissement de terrain. Ensuite, l'analyse dynamique sur des modèles de pente pour différentes magnitudes a été effectuée et une rupture de pente basée sur le déplacement a été créée pour évaluer la stabilité de la pente du site de Las Colinas au Salvador. Les résultats numériques ont clairement montré que les effets de site peuvent avoir induit d'importantes amplifications du mouvement du sol qui ont contribué à déclencher des glissements de terrain. / In this research work, numerical simulations using the finite difference FLAC software (Itasca) were first conducted with a homogeneous linear elastic slope model in order to characterize the acceleration amplification along the slope surface and behind the slope crest, and then to evaluate the topographic effect on the acceleration amplification. The interaction between the frequency of the seismic input motion applied at the base of the model with the slope angle and height has been deeply investigated. It was found that significant changes in the acceleration amplification factor result from variations in the slope angle and height as well as the signal frequency and duration. In addition, it has been shown that the ground motion amplification due to slope topography result from complex coupling effects between the input waves and the reflected waves on the topographic features and is highly controlled by the ratio between the wavelength of the input signal and the slope height.Numerical simulations are based on geotechnical investigations and geotechnical modeling, and it is necessary to validate the results through comparisons between modeling results and field observations. Frequency domain analysis such as spectral density and frequency response are an effective way to understand process characteristics and the various phenomena that cannot be explained in the time domain. For this purpose, a case study at Xishan Park ridge in Zigong in China has been studied. Site amplifications associated with the ground motion produced by the 2008 Wenchuan earthquake have been evaluated using the Standard Spectral Ratio (SSR) technique and root-mean-square acceleration (arms) method in time domain. 2D numerical analysis using finite difference method using the FLAC software (Itasca) has been then performed and results have been compared with monitoring data. The “simulated” peaks of the spectral amplifications are always lower than those derived from the field records. The strong attenuation of input motion at high frequencies highlights the shortcoming that a signal damping ratio does not adequately represent the energy dissipation in numerical simulations. Significant amplifications occurred at high frequencies (>10 Hz) and are considered to result from local specific conditions such as rock fracturing and ridge steps; thus they do not necessarily occur at the top of the hill. Finally, parametric studies were performed with elastic models in terms of various 2D slope geometries and geological layers to characterize the ground motion amplifications. The purpose of the parametric analysis is to understand the role of the geological layer, slope angle and slope height on the ground motion amplification, and thus to estimate if site amplifications could be responsible for the triggering of landslide. Then, the dynamic analysis on the slope model for different seismic magnitudes was performed and a slope failure based on displacement was created to evaluate the Las Colinas slope stability in Salvador. The numerical results clearly showed that site effects can have induced significant ground motion amplifications that contributed to trigger landslides.

This thesis examines how and to what extent humanitarian aid organizations strategically focus on gender roles following disasters, and how they contribute to potential changes in gender roles. The case selected for the study is Nepal after the 2015 earthquakes where the reports of four international humanitarian aid organizations were examined through a qualitative content analysis. The thesis aims to provide a contribution to the disaster risk reduction literature with a special focus on the possibilities to use disasters as catalysts for changes in traditional gender roles. As humanitarian organizations are major actors in the aftermath of disasters, the purpose is to evaluate their efforts and connect that to previous literature in the field. As a theoretical foundation two contrasting theories are incorporated in the study, the first is the idea that a disaster can be a ’window of opportunity’ for changes in gender roles whereas the other one is that vulnerable people is often left more vulnerable after a disaster due to secondary consequences, a so called double disaster.  The main findings of the study demonstrate that none of the four international humanitarian organizations incorporated a gendered perspective in their aid efforts following the earthquakes in Nepal 2015. The organizations seldom separate women from men in their reports, demonstrating an unawareness of the gender power structures at play. Few activities had a potential to empower women and the ones that did lacked a long-term perspective to enhance gender equality and lower vulnerability.

By studying the frequency domain of seismic signals generated by earthquakes, the source parameters can be recovered, i.e., the seismic moment (M0) and the stress drop (Δσ). This method is an advantage especially since if the source parameters are calculated from the time domain a full waveform inversion is needed, therefore this procedure facilitates the computation. Besides, the moment magnitude (Mw) can be calculated from the seismic moment and, in turn, the local magnitude (ML) can be obtained by using an algorithm that matches different ranges of moment magnitude with their corresponding local magnitude. In the present thesis, small to moderate earthquakes in Northern Sweden have been used to develop a code that calculates the source parameters through the fitting of five different spectral models and, this way, discerns which model obtains the best determination of the parameters. These models have been chosen in a way that we can also extract information about the attenuation. The different models are; the Brune spectral model, Boatwright spectral model, Boatwright spectral model with a fixed fall-off rate, a general form of the spectral model with quality factor equal to 1000 and a general form of the spectral model with quality factor equal to 600. Among these models, the Boatwright model with fixed fall-off rate equal to 2, has been found to give the best fit to the data used in this thesis. This might be due to the regional conditions which are the low attenuation in the crust of northern Fennoscandia and the short hypocentral distances of the studied earthquakes. The earthquakes studied in the present thesis have shown a range of magnitudes from ML 4.2 to -0.2 with radius of an assumed circular fault ranging from 269 m to 66 m.

This is a Minor Field Study (MFS) which is a scholarship financed by the Swedish International Development Cooperation Agency (Sida). The study was held in 2007 in Yogyakarta, Indonesia and is based upon retrospective qualitative interviews with five Bachelor nurses who experienced the disaster work during the earthquake 27th of May, 2006. The aim of the study is to explore the experiences, feelings and thoughts of Bachelor nurses who were involved in this natural disaster. The interview, transcription and analyse work were made one year after the earthquake were a qualitative content analysis method was used. Two group interviews were held at the University of Gadjah Mada. The result is based upon the respondents’ stories from these group interviews. In the result are the respondents’ experience, feelings and thoughts presented in themes which are put in three phases: before, during and after the earthquake. Previous studies are based on western disaster work and they are of a quantitative aspect. Finding qualitative studies from a helper’s view and especially from developing countries are difficult. This Minor Field Study increases the understanding for helpers’ feelings and thoughts during a natural disaster. It can easily be used by rescue personnel and hospital staff as a preparing literature of what they might experience before, during and after the work of a natural disaster. / <p>Program: Sjuksköterskeutbildning</p><p>Uppsatsnivå: C</p>

Ce travail vise à rendre compte des relations créées entre les événements naturels de forte intensité et dont les conséquences destructrices les ont fait nommer catastrophes naturelles, en partant du fameux tremblement de terre de Lisbonne, en 1755 jusqu’au milieu du XIXe siècle, avec l’avènement des nouvelles techniques et sciences, ce qui a engendré un nouveau rapport entre l’homme et la Nature. Ce changement de la représentation de la catastrophe en littérature, mais aussi dans la peinture s’appuie sur des mutations culturelles dans le plan religieux, scientifique et esthétique, dont les traces évidentes nous avons essayé d’expliciter dans ce travail. L’enjeu de cette thèse est d’analyser les métamorphoses du discours écrit et visuel de la période mentionnée, et d’attirer l’attention sur le passage entre l’horreur suscitée par un événement catastrophique et la dimension sensorielle et la fascination provoquée par le spectacle des phénomènes naturels. Toutefois, nous avons recherché le symbolisme des motifs attachés aux grands mythes de l’humanité, tels le Déluge, le thème de transgression-punition-rédemption inscrit dans la catastrophe, qui se transforme dans un nouveau concept, un objet d’analyse, de réflexion et de contemplation, qui nous incite à voir différemment. / This research aims to report on the relationships created among natural events of high intensity which can be categorized as natural disasters due to their destructive consequences starting with the famous earthquake of Lisbon in 1755 until the mid-nineteenth century, the advent of new technology and science, which created a new relationship between man and nature. This change in catastrophe representation in literature but also in the painting is based on religious, scientific and aestethetic changes, the key elements that we explored in this work. The aim of this dissertation is to analyze the metamorphoses of writing and visual discourse of the above-mentioned period and draw attention to the transition from horror triggered by a catastrophic event to a sensory dimension and fascination caused by the spectacle of natural phenomena. We also examined the symbolism of the motifs attached to the great myths of humanity, such as the Flood, the theme of transgression-punishment-redemption part of the disaster, which generates into a new concept, an object of analysis, reflection and contemplation, which inspires us to see the catastrophic events differently.

Catastrophes are usually seen as a threat to a country’s stability and progress. Some countries are regarded as prepared to face them and ready to deal with the consequences, but still, a disaster is always presented at the very least as an inconvenience. Contrary to this line of thinking, this dissertation shows that catastrophes can present an opportunity for state-building. Catastrophes, and the profound sense of insecurity they cause, force institutions to demonstrate their adeptness, or change. Specifically, catastrophes challenge state power because they test its basic role as protector from physical harm. Consequently, when disaster happens the state is put to the test. States that arise triumphant from this challenge may use the opportunity to increase its strength and develop new capacities.

Title: Development of effective code for earthquake dynamic source simulations Author: Bc. Jan Premus Department: Department of Geophysics Supervisor: doc. RNDr. František Gallovič, Ph.D, Department of Geophysics Abstract: Dynamic rupture modeling coupled with strong motion data fitting offers an insight into physical mechanisms behind earthquake sources [Gallovic et al., 2019]. Running a large number of dynamic model simulations is required due to the nonlinearity of the inverse problem. The goal of this Thesis is a development of an efficient forward solver for the dynamic inversions. The fi- nite difference staggered grid code FD3D by Madariaga and Olsen [1998] served as a basis for the development, offering sufficient speed, but rather low accu- racy. Traction at split node implementation of the fault boundary condition and perfectly matched layers as the absorbing boundary condition were required to obtain desirable accuracy. In addition to the slip weakening friction law, fast ve- locity weakening friction law has been implemented, increasing the applicability of the code. We test the new code FD3D TSN using USGS/SCEC benchmarks TPV5 (slip-weakening friction) and TPV104 (fast rate weakening friction) [Harris et al., 2018], showing very good agreement with results calculated by advanced numerical...