Les glissements de terrain constituent un risque naturel majeur à l’origine de dégâts matériels et humains considérables. Les séismes sont l’une des principales causes de leur déclenchement dans les orogènes actifs. Dans la zone épicentrale, le passage des ondes sismiques perturbe le champs de contraintes local ce qui peut provoquer le dépassement du seuil de stabilité des versants. La probabilité de déclenchement d’un glissement de terrain sismo-induit sur une pente donnée est donc fonction de facteurs liés au mouvement du sol et aux caractéristiques géologiques et topographiques de celle-ci. Très peu de données sismiques sont disponibles sur les versants et les modèles d’interpolation sont peu précis. Or le mouvement sismique peut s’avérer très variable à l’échelle d’un bassin du fait de la présence d’effets de site. L’étude de la réponse sismique d’un relief taïwanais nous permet de documenter ces effets et de prendre connaissance de la complexité du mouvement enregistré sur ce relief à la suite du passage de l’onde. Un réseau de six stations larges-bandes a été déployé, au travers de ce relief large d’environ 3km. Entre mars 2015 et juin 2016, ce réseau a permis d’enregistrer la réponse des sites à plus de 2200 séismes régionaux (magnitude Ml>3, distance hypocentrale<200km). Bien que distants de quelques centaines de mètres, les sites présentent tous une réponse qui leur est caractéristique résultant d’une combinaison complexe entre la topographie et la géologie du site. A fréquences modérées, correspondant à des longueurs d’ondes du mouvement pouvant contribuer au déclenchement de glissements de terrain, l’amplification du mouvement sismique est principalement due à la géologie locale et non à la topographie, comme montré par les indicateurs classiques (SSR, PGA, PGV et Arias) extraits des réponses des stations aux séismes. La topographie semble néanmoins jouer un rôle dans la durée du mouvement sismique fort aux stations situées sur les crêtes et en bordure de bassin sédimentaire, par effet de résonance et génération d’ondes de surface. La contribution prédominante de la géologie dans le déclenchement des glissements de terrain sismo-induits est également montrée par l’analyse de leur position sur les versants pour les glissements associés aux séismes de Northridge (Mw 6.7, 1994, Etats-Unis), de Chi-Chi (Mw 7.6, 1999, Taiwan), et de Wenchuan (Mw 7.9, 2008, Chine). En effet, bien que les glissements sismo-induits se localisent statistiquement plus haut sur les versants que les glissements d’origine climatique, on note que cette tendance est fortement modulée par la géologie des bassins. En fonction des « attracteurs », tels que des failles ou forts contrastes lithologiques, présents dans les bassins, les glissements tendent à se déclencher plus ou moins haut sur les versants, là où le potentiel de rupture est plus fort. Les propriétés mécaniques des pentes sont peu contraintes dans les zones montagneuses. Souvent leurs paramètres géotechniques sont estimés à partir des cartes géologiques régionales, or ils peuvent varier fortement pour une même lithologie d’un bassin à un autre. En considérant un modèle frictionnel simple de stabilité des pentes, on propose d’inverser des paramètres de type Coulomb à partir de la distribution des pentes des glissements de terrain sismo-induits à l’échelle des bassins dans les zones épicentrales des séismes de Northridge, Chi-Chi et Wenchuan. La variation spatiale de ces paramètres semble cohérente avec celle de la lithologie et la profondeur des sols. / Landslides are a major natural hazard that cause significant damages and casualties to people. Earthquakes are one of their main triggers in active mountain belts. In epicentral area, the passage of seismic-waves that disrupt the stress-field, leads the slope stability threshold to be exceeded. Co-seismic slope failure probability thus depends on complex interactions between the ground-motion and the slope geology and geometry. A few seismic data are available on mountain slopes and the resolution of ground-motion models is generally low. Yet strong variation of ground-motion from one ridge to another can be felt due to site effects. We document site effects across topography and show the complexity of slope responses to earthquakes using a seismic network set across a Taiwanese ridge. Six broadband seismometers were set along the profile of this 3km wide ridge. From March 2015 to June 2016, more than 2200 earthquakes (magnitude Ml>3 and hypocentral distance<200km) were recorded. Although the sites are within a distance of hundreds of meters they all show different characteristic responses that are related to a complex combination of the geology and topography of the sites. At medium frequency corresponding to groundmotion wavelength that could affect slope stability, the ground-motion amplification is mostly related to the local geology and the topographic effect seems relatively negligible as attested by current indicators measured at the stations (PGA, PGV, Arias, SSR). However the duration of strong ground-motion at the ridge crests and slope toe seems to be related to possible resonance effects and surface wave generation due to the geometry of the topography. The strong contribution of the geology to co-seismic landslide trigger is demonstrated by the analysis of their position along hillslopes for the co-seismic landslides triggered by the Northridge earthquake (Mw 6.7, 1994, USA), the Chi-Chi earthquake (Mw 7.6, 1999, Taiwan), and the Wenchuan earthquake (Mw 7.9, 2008, China). Indeed, although co-seismic landslides are statistically located higher on hillslopes than the rainfall-induced landslides, we show that this tendency is strongly modulated by the geology. According to the “potential landslides attractiveness” of geological structures, such as faults or lithological contrasts, present in the watershed, the slope failure would occur more or less upslope, where the failure probability is the highest.Slope mechanical properties are not well constrained in mountain area. Their geotechnical parameters are usually estimated using information provided by geological maps, but even for the same lithology they can strongly differ for one basin to another. Considering one simple friction model for seismic slope stability, we propose to invert Coulomb related parameters using the slope distributions of the landslides triggered by the Northridge, Chi-Chi and Wenchuan earthquakes. The spatial variation of these parameters seems to be in agreement with the lithology and soil depth at the first order.

Coburn et Spence (2002) rappellent qu'au cours du dernier siècle, le coût des séismes ramené à la valeur de l'année 2000 est de l'ordre de mille milliard de dollars. Rapporté par an, ils constatent que cette valeur augmente au cours du XXème siècle, essentiellement à cause de l'augmentation et de la concentration des populations dans les grands centres urbains exposés à un aléa sismique fort. Des agglomérations de plus en plus grandes, exposées aux séismes et constituées d'un habitat hétérogène et de qualité très variable, sont donc les ingrédients qui positionnent le milieu urbain à l'étape la plus critique de l'évaluation du risque sismique. Cette position est renforcée du fait que de nombreuses villes gigantesques (mega-cities) exposées se trouvent, pour des raisons historiques et sociologiques, sur des remplissages sédimentaires majeurs, facteur aggravant de l'aléa sismique local. Le bâti existant va également présenter une hétérogénéité forte, conséquence de l'évolution de ses caractéristiques structurales au cours du temps, renforçant l'idée d'une ville vulnérable et fragile. Enfin, tandis que le risque sismique consiste bien souvent à aborder séparément l'aléa de la vulnérabilité, il n'est pas surprenant que l'urbain puisse modifier, perturber, voir même contaminer le mouvement sismique incident, en particulier lorsque l'habitat est dense et massif, ce qui à l'aube du 21ème siècle semble être l'évolution majeure des grandes concentrations urbaines. Au cours de cet exposé, nous aborderons la sismologie urbaine en essayant de comprendre sur des résultats expérimentaux récents la façon de réagir d'un milieu urbain à une sollicitation sismique. Deux échelles d'espace seront discutées: la réponse de la ville en montrant comment celle-ci peut à la fois subir le séisme (vulnérabilité sismique) et contribuer de façon significative au mouvement du sol (interaction site-ville); et la réponse d'une structure simple en évaluant sa capacité à se déformer sous une sollicitation sismique (analyse modale opérationnelle) et à prédire son intégrité à la fin de la secousse (courbes de fragilité et structural health monitoring).

Deep slurry injection is a process of solid waste disposal that involves grinding the solid waste to a relatively fine-grained consistency, mixing the ground waste with water and/or other liquids to form slurry, and disposing of the slurry by pumping it down a well at a high enough pressure that fractures are created within the target formation. This thesis describes the site assessment criteria involved in selecting a suitable target reservoir for deep slurry injection. The main goals of this study are the follows: <ul> <li>Identify the geological parameters important for a prospective injection site</li> <li>Recognize the role of each parameter</li> <li>Determine the relationships among different parameters</li> <li>Design and develop a model which can assemble all the parameters into a semi-quantitative evaluation process that could allow site ranking and elimination of sites that are not suitable</li> <li>Evaluate the model against several real slurry injection cases and several prospective cases where slurry injection may take place in future</li> </ul> The quantitative and qualitative parameters that are recognized as important for making a decision regarding a target reservoir for deep slurry injection operations are permeability, porosity, depth, areal extent, thickness, mechanical strength, and compressibility of a reservoir; thickness and flow properties of the cap rock; geographical distance between an injection well and a waste source or collection centre; and, regional and detailed structural and tectonic setup of an area. Additional factors affecting the security level of a site include the details of the lithostratigraphic column overlying the target reservoir and the presence of overlying fracture blunting horizons. Each parameter is discussed in detail to determine its role in site assessment and also its relationship with other parameters. A geological assessment model is developed and is divided into two components; a decision tree and a numerical calculation system. The decision tree deals with the most critical parameters, those that render a site unsuitable or suitable, but of unspecified quality. The numerical calculation gives a score to a prospective injection site based on the rank numbers and weighting factors for the various parameters. The score for a particular site shows its favourability for the injection operation, and allows a direct comparison with other available sites. Three categories have been defined for this purpose, i. e. average, below average, and above average. A score range of 85 to 99 of 125 places a site in the ?average? category; a site will be unsuitable for injection if it belongs to the ?below average? category, i. e. if the total score is less than 85, and the best sites will generally have scores that are in the ?above average? category, with a score of 100 or higher. One may assume that for sites that fall in the ?average? category there will have to be more detailed tests and assessments. The geological assessment model is evaluated using original geological data from North America and Indonesia for sites that already have undergone deep slurry injection operations and also for some possible prospective sites. The results obtained from the model are satisfactory as they are in agreement with the empirical observations. Areas for future work consist of the writing of a computer program for the geological model, and further evaluation of the model using original data from more areas representing more diverse geology from around the world.

This thesis is focused on increasing productive actions in construction by a procedure known as Activity Analysis. Activity Analysis is a continuous productivity improvement tool for identifying barriers to site productivity with the goal of decreasing them and thereby increasing the direct work rate. A preceding study validated this approach, however it had two limitations. No reevaluation was conducted on projects in Canada by the authors, and not enough resources or data were available to understand behaviour of the activity rates in absolute value terms across many projects. Based on three case studies and data collected over 17 days by the author and a colleague, Activity Analysis was validated as being applicable in Canadian conditions. A desired value, known as a target rate, was then studied in order to be able to set expectations with respect to the productivity to be achieved in each cycle. The premise behind setting a “target rate” is that 100% direct work is neither possible nor desirable, since some time must always be spent on communications and planning. However, a higher direct work rate is generally better than a lower rate. Thus, a target rate is needed. A mathematical model called ANFIS was developed as a means of setting the desired level of activities. Through consideration of a variety of factors that affect labour productivity, the developed model was trained based on 65 data points. The model was found to be easy to use and flexible enough to be appropriate for all of the factors considered. Based on the data points available from 5 different past projects and 3 recent projects and the experience associated with these projects, three additional methods of defining the target rate were developed. The impact of these results is that companies now have appropriate methods and an initial data set for industrial construction in order to establish target rates for direct work and supporting activities. This should help reduce project costs and improve productivity.

In this thesis it is aimed to compile the Turkish strong-motion database for its efficient use in earthquake engineering and strong-motion seismology related studies. Within this context, the Turkish strong-motion database is homogenized in terms of basic earthquake source parameters (e.g. magnitude, style-of-faulting) as well as site classes and different source-to-site distance metrics. As part of this objective, empirical relationships for different magnitude scales are presented for further harmonization of the database. Data processing of the selected raw (unprocessed) strong-motion accelerograms that do not suffer from non-standard problems are realized. A comparative study is also conducted between the peak ground-motion values of Turkish strong-motion database with the estimations computed from different ground-motion prediction models. This way the regional differences of Turkish database are evaluated by making use of global prediction models. It is believed that the main products of this thesis will be of great use for reliable national seismic risk and hazard studies.

Thesis (M. Arch.)--University of Hong Kong, 2002. / Includes special study report entitled: Media art : space. Includes bibliographical references.

Perched water zones have been identified in the fractured, welded tuff in the semiarid to arid environments of Yucca Mountain, Nevada and near Superior, Arizona. An understanding of the formation of such zones is necessary in order to predict where future perched water might form at Yucca Mountain, the proposed site of a high-level nuclear waste repository. The formation or growth of a perched zone above a repository is one factor of the factors to be considered in the risk assessment of the Yucca Mountain site. The Apache Leap Research Site (ALRS) near Superior, Arizona is a natural analog to the Yucca Mountain site in terms of geology, hydrology, and climate. Perched water has been identified over an area of at least 16 km² in the Apache Leap Tuff, a mid- Miocene fractured, welded ash-flow tuff. A primary goal of this investigation was to characterize the physical and hydrologic properties of the tuff in the region above and including the perched zone, and to evaluate those characteristics to develop a model for a perching mechanism in the tuff. A second goal was to determine what fraction of water entering a watershed reaches the subsurface, to potentially recharge the perched zone. The Apache Leap Tuff has been subject to considerable devitrification and vapor phase crystallization, which dominate the character of the rock. With depth to the perched zone, pumice fragments become increasingly flattened and segregated; the pumice fragments are the primary locations of porosity in the rock, therefore porosity also becomes greatly reduced with depth, to the extent that the rock matrix is virtually impermeable at the perched water zone. Fractures are the primary pathways by which water moves through the rock; fracture hydraulic conductivity values were determined to be nine orders of magnitude greater than measured matrix hydraulic conductivity at the perched zone. An increase in fracture filling by silica mineralization beneath the perched zone reduces the secondary permeability, enhancing the formation of perched water. Thus, the primary mechanisms for the formation of the perched zone include fracture flow bringing water into the subsurface, combined with extremely low matrix hydraulic conductivity at depth, and reduced secondary permeability by filled fractures and lower fracture density. Water budgets were calculated for two years in a 51.4-ha watershed. Direct measurements were made of precipitation and runoff', evapotranspiration was both directly measured, and modeled based on measurement of a number of weather parameters. Infiltration was calculated as the residual of precipitation after runoff and evapotranspiration were removed. Infiltration was determined to be less than 10% of the annual water budget; evapotranspiration removes on the order of 90% of precipitation on an annual basis.

No description available.

In reconstructing the meaning of prehistoric artifacts, the art historian's task is particularly difficult. Scholars dealing with this period of time have to build their arguments on scarce archeological data, often unaided by written documents. Due to this lack of information, prehistoric female figurines are the subject of innacurate iconographic interpretations. In the case of the Mesoamerican Preclassic, the missing data is supplemented by subjective perceptions about people who do not belong to the scholar's own sex or ethnic background. The resulting misinterpretations fill the interstices between the information available and the historical facts. The traditional view that considers these figurines nothing more than beautiful women stop any further inquiries into the subject. Sometimes, the scholar's own fantasies substitute for logical arguments. Scholars writing on Mesoamerican iconography must be careful not to follow many of their predecessors to avoid confusing their colleagues, students and the general public.

Ecosystem-specific forest management requires comprehension of tree species productivity in managed settings, and how this productivity varies with the ecological determinants of site quality, i.e., the environmental factors that directly affect the growth of plants: light, heat, soil moisture, soil nutrients, and soil aeration. A good understanding of this variation is necessary for making species- and site-specific silvicultural decisions to maximize productivity. Productivity of a given species is usually measured by site index (tree height at 50 years at breast height age). Quantitative relationships between site index and these measures of site quality provide predictive models for estimating site index. Pacific silver fir (Abies amabilis (Dougl. ex Loud.) Forbes) is an important timber crop species in the coastal forests of British Columbia. In relation to climate, its range in southwestern British Columbia extends from sea level to almost timberline, and from the hypermaritime region on western Vancouver Island to the subcontinental region on the leeward side of the Coast Mountains. In relation to soils, its range extends from slightly dry to wet sites and from very poor to very rich sites. In view of this relatively wide climatic amplitude, a large variability in productivity can be expected. It is particularly important to consider the growth performance of Pacific silver fir when decisions are made regarding whether or not to cut stands on high-elevation sites. In the study summarized here, relationships between Pacific silver fir site index and selected ecological measures of site quality were examined, and site index models using these measures as predictors were developed.