Flooding is an increasing problem in metropolitan Seoul and the management of floods and floodplains is a neglected priority for urban planning. The causes of flooding are triggered by heavy rain, or tropical storms, especially under conditions where soils are already saturated. Rivers overflow into surrounding built-up areas, bringing death and injury to people as well as considerable damage to buildings. Among the residents of Seoul, flooding is most often attributed to failure of the pumping system that is the city’s chief line of defense against inundation. However, other analysts believe that a major reduction in the amount of green open spaces is contributing to increased flood risks. The impacts of these events encompass tragic loss of life, damage to built and natural environments, and massive disruption to the lives of affected populations in the short term. In the longer term, the recovery and post-recovery phases can also cause distress, disruption, health problems, and financial hardship lasting many years. This professional report tries to focus the impact of flood on environment along Han River and Seoul, Korea’s flood prone area. Furthermore, this report prepares maps and its output that can be used during flood emergency in inundated areas. Arc GIS 10 software is used to analyze impact of flood in Seoul, Korea. / text

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Volcanic eruptions are powerful, spectacular, uncontrollable geophysical events which require management to mitigate loss of life and property. An essential part of volcanic risk management is to quantify the vulnerability of exposed elements of society to volcanic hazard. Agriculture takes advantage of the fertile soils of volcanic regions, but is vulnerable to damage and disruption from volcanic hazards, in particular ashfall. This thesis investigates the vulnerability of pastoral agriculture to volcanic ashfall by examining impacts on the resource base of pastoral farming (water supply, pasture and soil, and livestock) and explores mitigation and recovery strategies for ashfall hazards at varying levels. It provides a quantitative understanding of pastoral farming vulnerability to ashfall hazards, as part of probabilistic risk assessment. Surface farm water supplies are found to be more vulnerable to ashfall, through contamination and sedimentation, than groundwater supplies. After heavy ashfall, the physical impacts of ashfall overwhelm the more subtle chemical impacts on water supply systems, but even relatively thin ashfalls may cause potential toxic changes to water quality. Farm-scale assessment of water supplies was used to identify key areas of vulnerability to ash hazards. Modelling a large-scale evacuation of livestock following widespread, heavy ashfall found the logistical, time and cost requirements high and may make this action unrealistic. Perhaps most critically, it is doubtful that farms in surrounding regions have the capacity to accommodate the numbers of animals likely to be affected. Tunnel-house and field trials have shown pastures are relatively resilient to ashfalls of 10 mm, but this resilience rapidly reduces with increasing ashfall thickness and at .100 mm there is effectively no pasture recovery. Ashfall grain size, frequency, soluble salt volume, and different meteorological conditions also have a significant impact on pastures and soils. Pasture reestablishment will benefit from tillage of ash covered soils to mix ash and topsoil and break up the surface crust which may form on ash deposits. Targeted fertiliser treatments may also be required to buffer acidic soluble salts and remedy deficiencies of essential nutrients. Reworking of ash deposits was found to be highly disruptive to pasture re-establishment and in extreme cases may prolong and intensify the impacts following an ashfall. The majority of farmers impacted by ashfall will continue farming, albeit with varying levels of disruption. However real or perceived impacts to human health may result in farm evacuation in the short-term. Where ashfall thicknesses are too thick for a return to profitable farming, migration from impacted farms and agriculture-related industries will result in significant demographic changes to rural communities and potential social impacts. Stressed farming systems are most vulnerable to failure and psychosocial impacts.

This thesis addresses a diverse range of topics in the area of probabilistic seismic risk analysis of engineering facilities. This intentional path of diversity has been followed primarily because of the relatively new and rapid development of this facet of earthquake engineering. As such this thesis focuses on the rigorous scrutinization of current, and in particular, simplified methods of seismic risk assessment; the development of novel aspects of a risk assessment methodology which provides easily communicated performance measures and explicit consideration for the many uncertainties in the entire earthquake problem; and the application of this methodology to case-study examples including structures supported on pile foundations embedded in liquefiable soils. The state-of-the-art in seismic risk and loss assessment is discussed via the case study of a 10 storey New Zealand office building. Particular attention is given to the quality and quantity of information that such assessment methodologies provide to engineers and stakeholders for rational decision-making. Two chapters are devoted to the investigation of the power-law model for representing the ground motion hazard. Based on the inaccuracy of the power-law model at representing the seismic hazard over a wide range of exceedance rates, an alternative, more accurate, parametric hazard model based on a hyperbola in log-log space is developed and applied to New Zealand peak ground acceleration and spectral acceleration hazard data. A semianalytical closed-form solution for the demand hazard is also developed using the hyperbolic hazard model and applied for a case-study performance assessment. The power-law hazard model is also commonly used to obtain a closed-form solution for the annual rate of structural collapse (collapse hazard). The magnitude of the error in this closed-form solution due to errors in the necessary functional forms of its constitutive relations is examined via a parametric study. A series of seven chapters are devoted to the further development of various aspects of a seismic risk assessment methodology. Intensity measures for use in the estimation of spatially distributed seismic demands and seismic risk assessment which are: easily predicted; can predict seismic response with little uncertainty; and are unbiased regarding additional properties of the input ground motions are examined. An efficient numerical integration algorithm which is specifically tailored for the solution of the governing risk assessment equations is developed and compared against other common methods of numerical integration. The efficacy of approximate uncertainty propagation in seismic risk assessment using the so-called First-Order Second-Moment method is investigated. Particular attention is given to the locations at which the approximate uncertainty propagation is used, the possible errors for various computed seismic risk measures, and the reductions in computational demands. Component correlations have to date been not rigorously considered in seismic loss assessments due to complications in their estimation and tractable methodologies to account for them. Rigorous and computationally efficient algorithms to account for component correlations are presented. Particular attention is also given to the determination of correlations in the case of limited empirical data, and the errors which may occur in seismic loss assessment computations neglecting proper treatment of correlations are examined. Trends in magnitude, distribution, and correlation of epistemic uncertainties in seismic hazard analyses for sites in the San Francisco bay area are examined. The characteristics of these epistemic uncertainties are then used to compare and contrast three methods which can be used to propagate such uncertainties to other seismic risk measures. Causes of epistemic uncertainties in component fragility functions, their evaluation, and combination are also examined. A series of three chapters address details regarding the seismic risk assessment of structures supported on pile foundations embedded in liquefiable soils. A ground motion prediction equation for spectrum intensity (found to be a desirable intensity measure for seismic response analysis in liquefiable soils) is developed based on ground motion prediction equations for spectral accelerations, which are available in abundance in literature. Determination of intensity measures for the seismic response of pile foundations, which are invariably located in soil deposits susceptible to liquefaction, is examined. Finally, a rigorous seismic performance and loss assessment of a case-study bridge structure is examined using rigorous ground motion selection, seismic effective stress analyses, and professional cost estimates. Both direct repair and loss of functionality consequences for the bridge structure are examined.

The identification of possible hazards in chemical plants is a very important part of the design process. This is because of the potential danger that large chemical installations pose to the public. One possible route for speeding up the identification of hazards in chemical plants is to use computers to identify hazards automatically. This will facilitate safe plant design and will avoid late design changes which can be very costly to implement. Previous research at Loughborough has concentrated on developing a model-based approach and an analysis algorithm for automating hazard identification. The results generated have demonstrated the technical feasibility of the approach. This approach requires a knowledge-base of unit models. This library of models describes how different plant equipment behaves in qualitative terms. The research described in this thesis develops a method for creating and testing the equipment models. The model library was previously achieved by an expert writing the models in a format that could be directly used by the system described above. An engineer unfamililar with the system would find this difficult. An alternative method would have been to use an intermediary (a knowledge engineer) to gather information from the engineer and convert it into the system format. This would be expensive. Both methods would take up a lot of the engineer's time. An engineer should be able to enter information personally in order to maintain efficiency and avoid information loss through the intermediary. A front end interface has been built to the system which enables an expert to enter information directly without needing to understand details of the application system. This interface incorporates ideas from the knowledge acquisition field in order to produce a tool that is simple to use. Unit-based qualitative modelling can lead to incorrect or ambiguous inference. The method developed here identifies situations where ambiguities may arise. A new modular approach is presented to overcome this type of problem. This method also presents a technique to verify that the models created are both complete and correct.

Thesis (M.S.)--University of Hawaii at Manoa, 2005. / Includes bibliographical references (leaves 104-105). / vi, 105 leaves, bound ill. (some col.), col. maps 29 cm

Arthur’s Pass township, located close to the Main Divide of the central Southern Alps, is highly exposed to natural hazards and has been affected by hazard events since it was founded in 1906. The village is a small alpine township, with a permanent resident population of approximately 54. Its location within the Arthur’s Pass National Park and on the main road between the east and west coasts of the South Island makes it popular with tourists, trampers, climbers and skiers, which can expand the local population to up to 500 people. Its position on the Bealey River floodplain within a highly dynamic tectonic and geomorphic environment makes it vulnerable to earthquakes, landslides, rockfalls, debris flows, heavy rain and snow, river flooding and riverbed erosion. Previous investigations on natural hazards in the area are limited to the Otira Gorge and State Highway 73, with little focus on hazards affecting the village area. Natural hazard events are persistent and frequent in the Arthur’s Pass region and the village is susceptible to being isolated from external resources during and after a disaster, making it necessary for the village to be self-sufficient during a large-scale disaster. The hazards were identified and analysed using aerial photographs and satellite images, historical data, supported by in-field reconnaissance at various times of the year to record seasonal changes. Hazard mapping used the same methods to illustrate the spatial and volumetric hazard changes over a range of time scales; >2% annual probability of occurrence (0-50 years recurrence interval), 2%-0.2% annual probability of occurrence (50-500 years recurrence interval) and <0.2% annual probability of occurrence (500+ years recurrence interval). The hazard maps show that that most hazards are not restricted to a specific temporal or spatial scale, and that they are often interdependent. It is difficult to determine the precise effects that climate change and global warming will have on natural hazards, but they are expected to increase the unpredictability of hazard events and alter weather patterns significantly in the long-term. A visitor questionnaire undertaken in the village indicated that many visitors do not regard the hazards as severe enough to represent a legitimate threat; hence the public perceptions of natural hazards are affecting the vulnerability of the village. Additionally, many people do not feel confident that they would know what to do if a disaster did occur in the village. This level of awareness can be improved by providing more information to visitors and displaying details on emergency procedures. The village does not currently have an emergency plan that specifies particular preparedness and response procedures; it relies heavily on a plan adapted from Mt. Cook/Aoraki village. Current emergency management in the village could be improved by the production of an emergency plan specifically for the region, the use of education schemes and information sessions, and the installation of warning signs. The provision of this detailed hazard investigation and hazard maps is intended to assist emergency managers to identify, prioritise, mitigate the hazards to reduce the vulnerability of the village to natural hazards in the short- and long-terms.

Thesis (Ph. D.)--University of Missouri--Rolla, 2007. / Vita. The entire thesis text is included in file. Accompanying "this dissertation is a CD-ROM, which contains site amplification and seismic hazard results for each grid point (1974 points) considered in the study. The results have prepared as .txt files. The CD-ROM also contains the maps generated from these estimated results. The maps are prepared as .png files." Title from title screen of thesis/dissertation PDF file (viewed January 28, 2008) Includes bibliographical references (p. 249-269).

Thesis (Ph. D.)--University of Hong Kong, 2008. / Includes bibliographical references (leaf 208-225) Also available in print.

Master-Arbeit Univ. St. Gallen, 2008.