178 research outputs found

    SHINE: Web Application for Determining the Horizontal Stress Orientation

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    Interpolating the orientation of the maximum horizontal compressive stress with a well-established procedure is fundamental in understanding the present-day stress field. This paper documents the design principles, strategies and architecture of SHINE (http://shine.rm.ingv.it/), a web-based application for determining the maximum horizontal compressive stress orientation. The interpolation using SHINE can be carried out from a global database or from a custom file uploaded by the user. SHINE satisfies the usability requirements by striving for effectiveness, efficiency and satisfaction as defined by the International Organization for Standardization (ISO) covering ergonomics of human-computer interactions. Our main goal was to build a web-based application with a strong “outside-in” strategy in order to make the interpolation technique available to a wide range of Earth Science disciplines. SHINE is an easy-to-use web application with a straightforward interface guaranteeing quick visualization of the results, which are downloadable in several formats. SHINE is offered as an easy and convenient web service encouraging global data sharing and scientific research collaboration. Within this paper, we present a possible use of SHINE, determining fault kinematics compatibility with respect to the present-day stress field

    Seismic sources, seismotectonics and earthquake recurrence for the KZN coastal regions.

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    Doctor of Philosophy in Land Surveying. University of KwaZulu-Natal, Howard College 2016.Historical earthquake information forms a critical dataset for seismotectonic investigations that can be used for seismic hazard investigations of hazardous and high rise structures and national seismic hazard maps. This study systematically interrogates historical earthquake data for the region from various sources in order to have a better understanding of the origins of the larger earthquakes. Several previously undocumented earthquakes were found that can supplement the national catalogue. Various sources are postulated as origins of these tremors namely local sources located in Mtubatuba and offshore sources like the Mozambique Channel. A seismotectonic model of the study region is also presented from an analysis of earthquake data, structural and kinematic systems. Geo-spatial data from geology, tectonics, regional geophysical anomalies, historical and instrumental seismicity and kinematics are considered. For what was once considered as a diffuse seismotectonic region with low levels of seismicity and where insufficient, uncertain and incomplete data existed – we now have datasets that are more complete and have higher levels of accuracy. Earthquake epicentres from both the historical and instrumental record as well as thermal spring localities correlate with old Jurassic faults. An assembly of a variety of datasets and studies are performed followed by a delineation of respective seismotectonic provinces. Earthquake recurrence parameters were assessed for the seismic provinces. Many of the provinces had insufficient seismic data to compute parameters. Improved seismic monitoring of the east coast region is required to better characterise the seismic risk. These results re-emphasize the need to better understand the coastal environment for seismotectonic characterization and to densify the seismic network towards the eastern coastline

    A hydrogeological approach in urban underground infrastructures

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    The competition for space in urban areas due to an exponential growth of population makes derground engineering plays a crucial role in the development of cities. Urban underground infrastructures deal with variables such as cost, duration, safety, and management; faces political, social, economic and environmental issues; and guarantees future sustainability, maintenance, and energy efficiency. To do so, all these concepts and variables must be kept in mind during the whole construction process: (I) project design, (II) project construction and (III) project exploitation. This thesis aims to demonstrate how the construction cycle deals with the various impacts produced by the interaction of underground constructions with groundwater at each stage of the process, with a view to providing improved processes. During the project design previous data is collected, new data is generated, created and processed, helping to understand the context and to design the infrastructure. There are very advanced tools to store and process hydrogeological data, but most of these tools are not common in infrastructure projects. Often most of the constructions only perform the minimum legal requirement to characterize the ground: a pumping test. Therefore, there is a need to provide the constructors with a set of methods and tools to allow them to increase the quality of their hydrogeological analysis, which will allow early detection problems associated with the groundwater. The interaction of underground constructions with groundwater generates impacts. These impacts can usually be minimized by using mitigation measures. The most common impacts caused by underground constructions are the groundwater barrier effect and the groundwater pressure distribution and limitation under the bottom slab. In the literature there are many examples and designs to mitigate both groundwater barrier effect and groundwater pressure distribution impacts. However, there is no design that integrates both solutions. This thesis presents an innovative groundwater by-pass design that enables the groundwater to flow through the structure and provide a homogenous distribution of the water pressure under the bottom slab. The new integrated design was applied to the largest underground infrastructure of Barcelona: La Sagrera railway station. A hydrogeological model was implemented to test the original and the integrated designs in three different scenarios. This new solution mitigates the groundwater barrier effect and optimizes the bottom slab, considerably reducing the costs and increasing safety during the construction phase. Monitoring is required when dewatering underground constructions in order to anticipate unexpected events and preserve nearby existing structures. The most accurate and spread monitoring method to measure displacements is levelling, a pointlike surveying technique that typically allows for tens of discrete in-situ sub-millimetric measurements per squared kilometer. Another emerging technique for mapping soil deformation is the Interferometric Synthetic Aperture Radar (InSAR), which is based on SAR images acquired from orbiting satellites or by ground-based stations (GB-SAR). This remote sensing technique can provide better spatial point density than levelling, more extensive spatial coverage and cheaper acquisitions. Both satellite and ground-based SAR systems have been used and tested in a variety of analyses. However, nobody has applied this technology as a monitoring tool during construction works yet. This thesis contributes to data storing and data analysis software that implies new and significant method developments for increasing the quality of the hydrogeological analysis; it provides new approaches to address the groundwater corrective measures definition during the design stage, and it develops and applies new methods of nfrastructure monitoring using ground-based and satellite SAR sensors during the construction stage.Degut al creixement exponencial de la població i tenint en compte que l'espai dins les àrees urbanes és finit és, necessari la construcció d'infraestructures subterrànies. Variables com el cost, la durada, la seguretat i la gestió; els problemes polítics, socials, econòmics i ambientals; garantir la sostenibilitat futura, el manteniment i l'eficiència energètica, han d'estar presents durant totes les fases del procés constructiu: (I) fase de disseny, (II) fase de construcció, i (III) fase d'explotació. Les construccions subterrànies interactuen amb el medi subterrani, el resultat de la interacció són uns impactes en la construcció i en el medi ambient. Tots aquests impactes són avaluats al llarg del procés constructiu per tal de ser corregits o minimitzats. L'objectiu principal d'aquesta tesi és conèixer com s'avaluen els diferents impactes a cadascuna de les fas es del procés constructiu per poder així proposar millores. Durant el disseny del projecte i per tal d'entendre el context i el disseny de la infraestructura es recullen dades històriques i es generen noves dades . L'ús de la majoria d'eines hidrogeològiques no és habitual en els projectes d'infraestructures ja que la majoria caracteritzen el terreny amb una prova de bombament. Per tant, és necessari proporcionar als constructors un conjunt de mètodes i d'eines que permetin augmentar la qualitat dels seus anàlisis, per augmentar així la detecció primerenca de problemes associats a les aigües subterrànies. Els impactes produïts per la interacció de les construccions subterrànies amb les aigües subterrànies es poden minimitzar mitjançant l'ús de mesures de mitigació. Els impactes més comuns causats per construccions subterrànies són l'efecte barrera i la distribució i limitació de subpressions sota la llosa de fons. A la literatura hi ha molts dissenys que permeten mitigar l'efecte barrera i millorar la distribució de les subpressions, però no hi ha cap disseny que integri les dues solucions. Aquesta tesi presenta un disseny innovador per bypassar les aigües subterrànies a través de l'estructura proporcionant una distribució homogènia de les subpressions sota la llosa de fons. Aquesta nova solució minimitza l'efecte barrera de les aigües subterrànies i optimitza la llosa de fons, reduint considerablement els costos i augmentant la seguretat durant la fase de construcció. Quan una construcció rebaixa el nivell freàtic cal auscultar els nivells i la deformació del terreny per tal d'anticipar esdeveniments inesperats i preservar les estructures properes existents. El mètode actual més utilitzat per mesurar desplaçaments és l'anivellament, que permet avaluar in situ desenes de punts discrets amb una precisi ó submil·limètrica. Una tècnica emergent és el Radar d'Obertura Sintètica Interferomètrica (InSAR), que es basa en imatges SAR adquirides des de satèl·lits en òrbita o bé des d'estacions al terra (GB-SAR). Aquesta tècnica de detecció remota proporciona una major cobertura espacial i més econòmica que els mètodes d'auscultació tradicionals. Tot i que la tecnologia SAR s'ha utilitzat i validat en una gran varietat d'anàlisis, ningú ha aplicat encara aquesta tecnologia com a eina d'auscultació durant la construcció d'infraestructures. Aquesta tesi contribueix a: (I) millorar l'emmagatzematge i processament de dades a través de nous desenvolupaments i mètodes que permeten augmentar la qualitat de l'anàlisi hidrogeològica; (II) oferir noves formes d'anàlisi per al disseny de mesures correctores durant l'etapa de disseny; i (III) desenvolupar i aplicar nous mètodes d'auscultació d'infraestructura a través de sensors SAR (terrestres i satèl·lit) durant la fase constructiva.La limitación de espacio en áreas urbanas junto al crecimiento exponencial de la población, hace necesaria la construcción de infraestructuras subterráneas. Nuevos conceptos en planificación urbana junto con los avances tecnológicos en la construcción hacen posible la ejecución de infraestructuras más grandes y de más eficiencia. No obstante, variables tales como el coste, la duración, la seguridad y la gestión; los problemas políticos, sociales, económicos y ambientales; y garantizar la sostenibilidad futura, el mantenimiento y la eficiencia energética, hacen de esta ejecución un problema complejo. Por ello, todas estas variables deben estar presentes durante todo el proceso constructivo: (I) diseño del proyecto, (II) construcción del proyecto y (III) explotación del proyecto. Esta tesis tiene como objetivo principal saber cómo el ciclo constructivo (diseño del proyecto, construcción y explotación de proyectos) procesa las problemáticas inducidas por la interacción de las nuevas infraestructuras subterráneas urbanas con las aguas subterráneas para luego mejorarlo. Durante el diseño del proyecto (fase I) se recogen los datos históricos, se generan nuevos datos (pozos, pruebas de campo, muestras químicas ...) y se procesa conjuntamente, lo que ayuda a entender el contexto y el diseño de la infraestructura. Existen herramientas muy avanzadas para almacenar y procesar información geológica, hidroquímica e hidrogeológica, aunque la mayoría de estas herramientas no son comunes en los proyectos de infraestructuras subterráneas ya que es común que la mayoría de las construcciones sólo se realice una prueba de bombeo para caracterizar el subsuelo. Por lo tanto, hay una necesidad de proporcionar un conjunto de métodos y de herramientas a los constructores para que puedan aumentar la calidad de su análisis (como pruebas de bombeo), para aumentar así la detección temprana de problemas asociados a las aguas subterráneas. La interacción de las construcciones subterráneas con las aguas subterráneas genera impactos. Estos impactos generalmente pueden minimizarse mediante el uso de medidas correctoras. Los impactos más comunes causados por las construcciones subterráneas son el efecto barrera (impacto en las aguas subterráneas) y la distribución y limitación de subpresiones bajo la losa de fondo (impacto en la construcción subterránea). En la literatura hay muchos ejemplos de diseños para mitigar tanto el efecto barrera y como para mejorar la distribución de las subpresiones bajo la losa de fondo. Sin embargo, no hay ningún diseño que integre ambas soluciones. Es ilógico diseñar una medida correctora sin tener en cuenta todos los factores que intervienen en el problema. Esta tesis presenta un diseño innovador de by-pass para las aguas subterráneas que permite el flujo de agua subterránea a través de la estructura a la vez que proporciona una distribución homogénea de las subpresiones bajo la losa de fondo. El nuevo diseño se ha aplicado en la infraestructura subterránea más grande de Barcelona: la futura estación de tren de La Sagrera. Se ha realizado un modelo hidrogeológico para probar los nuevos diseños en tres escenarios diferentes. Esta nueva solución mitiga el efecto barrera de las aguas subterráneas y optimiza la losa de fondo, lo que reduce considerablemente los costes y aumenta la seguridad durante la fase de construcción. Durante la construcción (fase II) se genera una gran cantidad de nuevos datos. Es necesario auscultar los niveles y la deformación del terreno cuando una construcción rebaja el freático con el fin de anticiparse a acontecimientos inesperados y a preservar las estructuras y / o edificios cercanos existentes. El método actual más usado para medir desplazamientos en el terreno es la nivelación, una técnica que permite evaluar in situ decenas de puntos discretos con una precisión sub-milimétrica. Una técnica emergente para medir la deformación del suelo es el Radar de Apertura Sintética Interferométrica (InSAR), que se basa en imágenes SAR adquiridas o bien desde satélites en órbita o bien desde estaciones en tierra (GB-SAR). Esta técnica de detección remota proporciona una mayor cobertura espacial y más barata que los métodos de auscultación tradicionales. Aunque la tecnología SAR se ha utilizado y validado en una gran variedad de análisis, nadie ha aplicado esta tecnología como una herramienta de auscultación durante la construcción de infraestructuras. Esta tesis contribuye a mejorar el almacenamiento y tratamiento de datos a través de nuevos desarrollos y métodos que permiten aumentar la calidad del análisis hidrogeológico; ofrece nuevas formas de análisis para el diseño de medidas correctoras durante la etapa de diseño; y desarrolla y aplica nuevos métodos de auscultación de infraestructura a través de sensores SAR (terrestres y satélite) durante la fase constructiv

    STRUCTURAL STYLE AND TECTONIC EVOLUTION OF THE NORTHWEST SIRT BASIN–CRETACEOUS- TERTIARY RIFT, LIBYA

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    The Cretaceous-Tertiary northwest-trending Sirt Basin system, Libya is a rift/sag basin formed on Pan-African to Paleozoic-aged basement of North Africa. This study is an investigation of the rift-basin architecture and tectonic framework of the western Sirt Basin. A combination of several geological and geophysical methods (remote sensing interpretation supported by surface geologic maps, borehole data analysis, from about 300 deep wells, extensive seismic reflection profiles and maps, and paleostress analysis), have been used to construct geological cross sections, and surface and subsurface geology maps that have proved particularly useful in identifying various regional and local structures in the study area. Indication of the relative timing of structures and movement along faults has been determined where possible. We recognize six lithostratigraphic sequences (phases) in the area's stratigraphic framework. A Pre-graben (Pre-rift) initiation stage involved the Pre-Cretaceous sediments formed before the main Sirt Basin subsidence. Then followed a Cretaceous to Eocene graben-fill stage that can divided into four structurally-active and structurally-inactive periods, and finally a terminal continental siliciclastics-rich package representing the Eocene post-rift stage. Late Eocene rocks exposed in the western part of the basin exhibit a complex network of branching segmented normal and strike-slip faults, generally with a NNW-SSE structural grain. Many surface structural features have been interpreted from satellite images which confirm sinistral strike-slip kinematics. Relay ramp structures, numerous elongate asymmetric synclines associated with shallow west limbs and steeper dipping east limbs are developed in the hangingwalls adjacent to west downthrowing normal faults. These structural patterns reflect Cretaceous/Tertiary extensional tectonics with additional control by underlying pre-existing Pan-African basement fabrics and ENE-WSW trending Hercynian structures. The interpretation of a large volume of two-way time seismic data has allowed the construction of long regional seismic cross sections and resultant time structure contour and thickness maps, thus enabling an understanding of the structural and stratigraphic relationships on a regional scale. Six major fault systems were identified initially from the remote sensing study and was subsequently expanded to seven on the basis of interpretation of 2D seismic data. These fault systems dissect the study area into geomorphological elevated blocks and depressions. Most of the oil fields present in the study area are associated with structural hinge zones and adjoining highs. A new kinematic and structural conceptual model is proposed here for the evolution of NW Libya (Jifarah Basin and the Nafusah Uplift) and Hun Graben during Late Eocene times. The multidisciplinary approach used in this study has resulted in good surface and sub-surface structure correlation and future petroleum prospectivity has been identified in this study. We relate the Sirt Basin rift development as exemplified in our study area to the break-up of Gondwana represented by the structural evolution of the West-Central African rift system and the South and Central Atlantic, the Tethys and the Indian Oceans

    Technology 2003: The Fourth National Technology Transfer Conference and Exposition, volume 2

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    Proceedings from symposia of the Technology 2003 Conference and Exposition, Dec. 7-9, 1993, Anaheim, CA, are presented. Volume 2 features papers on artificial intelligence, CAD&E, computer hardware, computer software, information management, photonics, robotics, test and measurement, video and imaging, and virtual reality/simulation

    Earthquake Engineering

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    The book Earthquake Engineering - From Engineering Seismology to Optimal Seismic Design of Engineering Structures contains fifteen chapters written by researchers and experts in the fields of earthquake and structural engineering. This book provides the state-of-the-art on recent progress in the field of seimology, earthquake engineering and structural engineering. The book should be useful to graduate students, researchers and practicing structural engineers. It deals with seismicity, seismic hazard assessment and system oriented emergency response for abrupt earthquake disaster, the nature and the components of strong ground motions and several other interesting topics, such as dam-induced earthquakes, seismic stability of slopes and landslides. The book also tackles the dynamic response of underground pipes to blast loads, the optimal seismic design of RC multi-storey buildings, the finite-element analysis of cable-stayed bridges under strong ground motions and the acute psychiatric trauma intervention due to earthquakes

    Modeling, Visualizing, and Understanding Complex Tectonic Structures on the Surface and in the Sub-Surface

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    Plate tectonics is a relatively new theory with many details of plate dynamics which remain to be worked out. Moving plates can interact by divergence, lateral sliding, convergence, or collision. At a convergent plate boundary, a lithospheric slab of oceanic crust and upper mantle is subducted at a trench and dips down under a magmatic arc — either oceanic or continental. Textbooks show a static view of convergent boundaries but plate dynamics require that subduction zones and magmatic arcs must migrate with time. Therefore I develop animated models to help convey this motion. Also, convergent plate boundaries cannot continue along strike or down dip indefinitely without changing. Subduction zones change orientation and eventually terminate. They may bend and shear or tear and open a window for asthenospheric flow. Two different convergent plate boundaries are the primary focus of my studies: the Tonga subduction zone where the Pacific plate moving beneath an island arc is torn along the Samoan Island Archipelago, and the Andean subduction zone in central South America where the Nazca plate moves beneath a continental arc. I choose these zones because they exhibit tears or shears, where subduction stops, or changes dip suddenly. To examine these features I use several modeling and visualization techniques. COLLADA (COLLabrative Design Activity) models in Google Earth and Google Earth Application Programming Interface (API) are used for visualizing and teaching of plate boundary systems. The testing of COLLADA models for geoscience concepts showed positive learning gains. Kinematic models are made to study strain rates and possible methods of plate evolution. Dynamic COMSOL numerical models are created to probe temperature and flow fields in the subduction zone. Animated COLLADA models are designed for different models of subduction initiation and development for the Tonga trench for both research and educational purposes. The development of these models led to a new hypothesis of this region\u27s formation. Using these models and Google Earth materials studies in undergraduate classes tested the effectiveness of Google Earth based lab activities for enhancing student understanding of geoscience. In the central Andean subduction zone, emergent COLLADA models are made from mining GeoMapApp (http://www.geomapapp.org) and published contour data to demonstrate the unique geometry of the Nazca plate having adjacent subduction angles of 10° and 30°. This led to the research question, can theNazca plate support this geometry by shearing without tearing? A literature review shows efforts to explore this topic by means of hypocenter, teleseismic, and thermal data to have no consensus on the topic. To this end a new approach is taken to examine this region by applying the methods of kinematic and dynamic modeling to further explore this question. These different models of the Andean system lead to the conclusion that no major magmatic window could have opened between the fiat and steep subduction areas given the time and deformation mechanisms available

    EVOLUTION OF THE SUBCONTINENTAL LITHOSPHERE DURING MESOZOIC TETHYAN RIFTING: CONSTRAINTS FROM THE EXTERNAL LIGURIAN MANTLE SECTION (NORTHERN APENNINE, ITALY)

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    Our study is focussed on mantle bodies from the External Ligurian ophiolites, within the Monte Gavi and Monte Sant'Agostino areas. Here, two distinct pyroxenite-bearing mantle sections were recognized, mainly based on their plagioclase-facies evolution. The Monte Gavi mantle section is nearly undeformed and records reactive melt infiltration under plagioclase-facies conditions. This process involved both peridotites (clinopyroxene-poor lherzolites) and enclosed spinel pyroxenite layers, and occurred at 0.7–0.8 GPa. In the Monte Gavi peridotites and pyroxenites, the spinel-facies clinopyroxene was replaced by Ca-rich plagioclase and new orthopyroxene, typically associated with secondary clinopyroxene. The reactive melt migration caused increase of TiO2 contents in relict clinopyroxene and spinel, with the latter also recording a Cr2O3 increase. In the Monte Gavi peridotites and pyroxenites, geothermometers based on slowly diffusing elements (REE and Y) record high temperature conditions (1200-1250 °C) related to the melt infiltration event, followed by subsolidus cooling until ca. 900°C. The Monte Sant'Agostino mantle section is characterized by widespread ductile shearing with no evidence of melt infiltration. The deformation recorded by the Monte Sant'Agostino peridotites (clinopyroxene-rich lherzolites) occurred at 750–800 °C and 0.3–0.6 GPa, leading to protomylonitic to ultramylonitic textures with extreme grain size reduction (10–50 μm). Compared to the peridotites, the enclosed pyroxenite layers gave higher temperature-pressure estimates for the plagioclase-facies re-equilibration (870–930 °C and 0.8–0.9 GPa). We propose that the earlier plagioclase crystallization in the pyroxenites enhanced strain localization and formation of mylonite shear zones in the entire mantle section. We subdivide the subcontinental mantle section from the External Ligurian ophiolites into three distinct domains, developed in response to the rifting evolution that ultimately formed a Middle Jurassic ocean-continent transition: (1) a spinel tectonite domain, characterized by subsolidus static formation of plagioclase, i.e. the Suvero mantle section (Hidas et al., 2020), (2) a plagioclase mylonite domain experiencing melt-absent deformation and (3) a nearly undeformed domain that underwent reactive melt infiltration under plagioclase-facies conditions, exemplified by the the Monte Sant'Agostino and the Monte Gavi mantle sections, respectively. We relate mantle domains (1) and (2) to a rifting-driven uplift in the late Triassic accommodated by large-scale shear zones consisting of anhydrous plagioclase mylonites. Hidas K., Borghini G., Tommasi A., Zanetti A. & Rampone E. 2021. Interplay between melt infiltration and deformation in the deep lithospheric mantle (External Liguride ophiolite, North Italy). Lithos 380-381, 105855
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