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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
951

Técnicas de suavização aplicadas à caracterização de fontes sísmicas e à análise probabilística de ameaça sísmica

Pirchiner, Marlon 15 July 2014 (has links)
Submitted by Marlon Pirchiner (marlon.pirchiner.work@gmail.com) on 2014-09-09T12:41:58Z No. of bitstreams: 1 dissertacao_biblioteca.pdf: 20168048 bytes, checksum: 06f8b607a56d91eecc737ff55933780a (MD5) / Approved for entry into archive by Janete de Oliveira Feitosa (janete.feitosa@fgv.br) on 2015-09-09T18:43:32Z (GMT) No. of bitstreams: 1 dissertacao_biblioteca.pdf: 20168048 bytes, checksum: 06f8b607a56d91eecc737ff55933780a (MD5) / Approved for entry into archive by Marcia Bacha (marcia.bacha@fgv.br) on 2015-09-11T12:21:49Z (GMT) No. of bitstreams: 1 dissertacao_biblioteca.pdf: 20168048 bytes, checksum: 06f8b607a56d91eecc737ff55933780a (MD5) / Made available in DSpace on 2015-09-11T12:22:02Z (GMT). No. of bitstreams: 1 dissertacao_biblioteca.pdf: 20168048 bytes, checksum: 06f8b607a56d91eecc737ff55933780a (MD5) Previous issue date: 2014-07-15 / Seismic risk assesment is crucial to make better decisions about engineering structures and loss mitigation. It involves, mainly, the evaluation of seismic hazard. Seismic hazard assesment is the computation of probability which the level of some ground motion intensity measure, in a given site, which, in some time window, will be exceeded. Depending on geological and tectonic complexity, the seismic hazard evaluation becomes more sofisticated. At sites with low seismicity, which is the brazilian case, the relative (geolo- gically) low observation time and the lack of earthquake and tectonic information, increases the uncertainties and makes more difficult the standard analysis, which in general, consider expert opinions, to characterize the seismicity into disjoint zones. This text discusses some smoothing seismicity techniques and their theoretical foundati- ons as alternative methods for seismicity characterization. Next, the methods are exemplified in the brazilian context. / A avaliação de risco sísmico, fundamental para as decisões sobre as estruturas de obras de engenharia e mitigação de perdas, envolve fundamentalmente a análise de ameaça sísmica. Calcular a ameaça sísmica é o mesmo que calcular a probabilidade de que certo nível de determinada medida de intensidade em certo local durante um certo tempo seja excedido. Dependendo da complexidade da atividade geológica essas estimativas podem ser bas- tante sofisticadas. Em locais com baixa sismicidade, como é o caso do Brasil, o pouco tempo (geológico) de observação e a pouca quantidade de informação são fontes de muitas incer- tezas e dificuldade de análise pelos métodos mais clássicos e conhecidos que geralmente consideram, através de opiniões de especialistas, determinadas zonas sísmicas. Serão discutidas algumas técnicas de suavização e seus fundamentos como métodos al- ternativos ao zoneamento, em seguida se exemplifica suas aplicações no caso brasileiro.
952

Effect of Multi-support Excitation on the Seismic Behavior of Single-pylon Cable-stayed Bridges

Subedi, Arjun 01 December 2014 (has links)
Cable-stayed bridges are popular these days in spite of their complexity in shape and design. Cable-stayed bridges are ideal for a navigational channel due to their high clearance and long central span. These types of bridges also possess advantages over suspension bridges, especially when local site conditions are not suitable for anchoring the towers. In most of the cases, cable-stayed bridges are self-supportive or require less anchorage. Although symmetrical cable-stayed bridges are dominant, asymmetrical bridges are also common as well due to ground layouts and other restrictions like economy, aesthetic purpose. Added counter weight and eccentricity of asymmetrical bridge may highly affect the response of the structure under earthquake loading. For the same length span bridge, the response of the asymmetric one may have an amplified response compared to the symmetric one with the same span length and also, may not follow any predictable trend. This study presents a multi-support analysis for four models, which are, 200 m symmetrical, 400 m symmetrical, 200 m asymmetrical and 400 m asymmetrical bridges. Ground motions has been recorded by using accelerometers. The recorded ground motion depends on the direction of the accelerometer. To remove this dependency, the principal components of each ground motion were found and used for the analysis and the models were excited in the transverse direction. The models were run under both multi-support excitation and identical-support excitation for displacement time-history analysis using SAP2000. Ratio of stresses and deflections were compared for the bridges with the same span length. According to this study, on 200 m asymmetrical bridge, multi-support excitation factored responses up to 4%, while on 400 m asymmetrical bridge, responses are factored up to 20% compared to the identical-support excitation. It is noted that responses of asymmetrical bridges are factored up making identical-support excitation non-conservative.
953

Application de géodésie satellitaire GNSS à haute résolution à la déformation de la marge Sud-Caraïbe. Implication pour l'aléa sismique dans l'Ouest et le Nord-Est du Venezuela / High resolution geodetic GNSS surveys of the present day deformation along the South-Caribbean margin. Implications for earthquake hazard assessment in western and north-eastern Venezuela

Reinoza Gomez, Carlos Eduardo 15 December 2014 (has links)
Cette thèse présente des observations GNSS dans l'Ouest et le Nord-Est Vénézuélien, et Trinidad utilisées pour contraindre la géodynamique de la zone d'étude et la cinématique des principales failles dans cette frontière des plaques. Je présente un travail intégral de conception, installations d'un réseau géodésique dans l'ouest du Venezuela et deux campagnes d'acquisition des données GNSS. Dans le Nord-Est Vénézuélien, une campagne d'acquisition des données a été réalisée avec la réoccupation des repères installés et mesurés depuis 2003. Lors du traitement des données, j'ai inclus l'ensemble des campagnes antérieures disponibles et les données des stations GNSS permanentes de la région. Les vitesses observées dans l'Ouest Vénézuélien correspondent bien avec le mouvement des plaques Caraïbes et Sud Amérique. Cependant, le lent taux de déplacement des failles principales et le court intervalle de temps entre les observations n'a pas permis d'obtenir un champ des vitesses avec suffisamment de précision. Au contraire, les observations épisodiques réalisées sur dix ans dans le Nord-Est du Venezuela ont permis contraindre la cinématique de la faille d'El Pilar (EPF). Dans cette région, nous avons étudié les effets de la variation des propriétés élastiques sur la faille et de part et d'autre de celle-ci. Le champ de vitesses asymétrique obtenu sur les deux côtés de la faille a été simulé avec cinq approches. Un premier modèle simple dans un demi-espace homogène montre une profondeur de blocage de 1,8 km. À l'aide d'un modèle hétérogène en considérant des contrastes entre les propriétés du matériel de part et d'autre de l'EPF, nous avons montré une profondeur de blocage de 3 km et un coefficient de rigidité de 0,37. Cette dernière valeur indique que le côté nord à l'EPF composé de roches ignées et métamorphiques présente une rigidité ~1,7 fois supérieure au côté sud composé de formations sédimentaires. À partir d'un modèle tridimensionnel élastostatique, la présence d'une zone de compliance a été suggérée. Cette zone proche de la faille caractérisée par une faible rigidité serait présente de la surface à 3 km de profondeur et présenterait une largeur de 1 à 5 km et une réduction de rigidité de 30%. La simulation des vélocités avec un modèle de distribution du glissement le long du plan de faille montre la présence de glissements asismiques dans toute la partie supérieure du segment Ouest tandis que la partie supérieure du segment Est se montre partialement bloquée, ce secteur partiellement bloqué correspondrait à la rupture en surface des séismes de 1797 et 1929. En se basant sur la combinaison des vélocités obtenues par comparaison GPS/GPS et triangulation/GPS nous avons étudié la cinématique des failles principales de Trinidad. Le champ de vitesses de part et d'autre de la faille de la cordillère centrale de Trinidad (CRF) indique une asymétrie du gradient de vitesse de part et d'autre de la faille. Le modèle simple de déformation interseismique montre une profondeur de blocage de 10 km et le modèle hétérogène asymétrique suggère une profondeur de blocage de 2,5 km avec un coefficient de rigidité de 0,20 %, qui suggère une rigidité trois fois supérieure du côté nord par rapport au côté sud. La simulation du glissement le long des failles de Trinidad montre un glissement asismique atteignant 12 mm/an le long de la partie supérieure de la CRF et de sa prolongation en mer la Warm Spring Fault. Ce comportement change vers le nord-est avec une diminution importante du creep le long de la partie supérieure de la faille. La prolongation de l'EPF se montre inactive à Trinidad. L'existence d'un creep important le long des failles d'El Pilar et de la faille de la cordillère centrale de Trinidad pourrait expliquer le bas niveau de sismicité instrumentale, historique et préhistorique de ces accidents qui localisent pourtant un coulissement de 20mm/an. L'existence de ce creep induirait une réduction de l'aléa sismique de moitié. / The Caribbean-South American plate boundary is described as a wide active transpresional zone. This dissertation presents GNSS observations in Western and Northeastern Venezuela, and Trinidad used to constrain the geodynamic of the region and the kinematic of the principal faults along this plate boundary. Here, a whole work of conception, installation of network and measurements with two campaigns of GNSS observations in Western Venezuela is presented. In the case of Northeastern Venezuela, a GNSS data acquisition campaign was carried out measuring pre-existing sites installed and occupied since 2003 by FUNVISIS and University of Savoie team. The data processing for these sites includes data from previous acquisition campaigns and permanent GNSS stations. In Western Venezuela, observed velocities correspond roughly with the motion of Caribbean and South American plates. Nonetheless, the slow rate of fault-slip of main faults and the short span between the data acquisition campaigns in Western Venezuela do not allow assess the velocity field with sufficient accuracy. In northeastern Venezuela, I focused on the effects of variable elastic properties of the El Pilar Fault (EPF) and surrounding medium on inferred slip rates and locking depths. The asymmetric velocity field on both sides of EPF have been evaluated with five approaches. In a first step, a simple elastic half-space model was applied showing a 1.8 km locking depth. Next, a model considering contrast of material properties across the EPF depicts out 3 km locking depth and a 0.37 asymmetric coefficient indicating that the igneous-metamorphic northern side has a rigidity ~1.7 times higher than the sedimentary southern side. From a three-dimensional elastostatic model, the presence of a near-fault low-rigidity compliant zone has been evaluated suggesting a zone in the upper 3 km in depth and going from 1 to 5 km width with a 30 per cent of rigidity reduction. The creep associated to the shallow locking depth was clearly shown with the slip distribution model and the displacement simulation method. The results show a widespread partially-creep pattern in the eastern upper segment, while the upper western segment exhibits a partially locked area which coincides with the rupture surface of 1797 and 1929 earthquakes. From the compilation of GNSS observations and triangulation-to-GPS comparison of previous studies, the kinematic of main faults in Trinidad has been studied. The velocity field across the Central Range Fault (CRF) points out an asymmetry of velocity gradient on both sides. The heterogeneous asymmetric model point out a 2.5 km locking depth with a 0.20 asymmetric coefficient indicating that the northern side has a rigidity ~3.3 times higher to the southern side. Similar approaches have been applied to the EPF extension in Trinidad. The creep in the upper part of CRF as response to the shallow locking depth was quantified using a slip distribution model. A creep of 12 mm/yr was calculated in the southwestern onshore portion of the CRF and the Warm Springs Fault, nevertheless, this behavior changes northeastward where the CRF show a significant decrease of slip in the upper part. The slip along the EPF prolongation appears locked along its upper and lower part in the onshore portion demonstrating that this segment section is not needed to simulate observed velocities and is inactive. Furthermore, the Los Bajos Fault is shown with a slip of 7 mm/yr in the segment upon which the EPF in Venezuela transfers its slip eastward and that act as a synthetic Riedel shears. The localized aseismic displacement pattern associated with creeping or partially creeping fault segments could explain the low level of historical seismicity in the Northeastern Venezuela and Trinidad. The EPF in Venezuela and the CRF accommodate between 50-60% of the plate boundary zone motion that point out a reduction of the seismic hazard almost by half
954

High precision studies of an intraplate earthquake sequence in northeast Brazil

Takeya, Mario Koechi 09 1900 (has links)
Submitted by MARIO TAKEYA (mario.takeya@hotmail.com) on 2017-01-18T18:17:05Z No. of bitstreams: 1 Takeya, Mario_Tese.pdf: 10246686 bytes, checksum: 75915213c454d4042e3c7abe5793ff96 (MD5) / Approved for entry into archive by Elisangela Moura (lilaalves@gmail.com) on 2017-01-18T18:18:21Z (GMT) No. of bitstreams: 1 Takeya, Mario_Tese.pdf: 10246686 bytes, checksum: 75915213c454d4042e3c7abe5793ff96 (MD5) / Made available in DSpace on 2017-01-18T18:18:21Z (GMT). No. of bitstreams: 1 Takeya, Mario_Tese.pdf: 10246686 bytes, checksum: 75915213c454d4042e3c7abe5793ff96 (MD5) Previous issue date: 1992-09 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / From May 1987 to April 1988, a 9 station, seismic network was operated near the town of Jo?o C?mara (5?33'S, 35?51'W) in Rio Grande do Norte state, Brazil. The network was installed 6 months after the occurrence of a mb =5.1 earthquake. This thesis is concerned with the study of microearthquakes recorded by this network, which is in the Precambrian Borborema Province of northeast Brazilian shield. The study revealed a remarkably well-defined distribution of seismicity associated with a simple fault structure. Hypocentre location was done using the HYPO71 program. The results of the analysis show that the fault is divided into two main segments with the same N37?E strike. The north segment is dipping 76?NW. The south segment is more nearly vertical, dipping about 82?NW and composed of three or more closely spaced almost parallel faults. A small gap and a low seismicity zone were found to separate the north and south segments. No events deeper than 9 km were found in the entire region studied. Examination of the epicentral map and corresponding vertical cross sections also revealed that events are not random but are clustered. Right lateral strike slip with a small normal component was inferred as the fault mechanism from composite fault plane solutions. Off-fault events distant from the main fault were also observed, their pattern showing a classical example explained by the model of Das & Scholz as a consequence of off-fault shear stress increase after the occurrence of the main earthquake. Magnitude determinations for the events recorded by the telemetric network have been performed by developing a specific earthquake magnitude scale based on the duration of the observed seismic signal. A maximum likelihood estimate of b-value shows no significant variation during the recording period. Shear wave splitting was observed in the J.C?mara region in all the selected events recorded by the three component station JCAZ. The polarization direction of the first split shear-wave arrival for those events lay in the north-south direction which does not agree with the premise of extensive dilatancy anisotropy for a maximum compressive stress in the east-west direction as inferred by the fault plane solutions. / Uma rede s?smica telem?trica composta por 9 esta??es, operou em torno da cidade de Jo?o C?mara (5?33'S, 35?51'W) no Estado do Rio Grande do norte, Brasil, entre os meses de maio de 1987 a abril de 1988. A rede foi instalada 6 meses depois da ocorr?ncia de um terremoto de magnitude mb=5.1. A presente tese analisa os dados de micro tremores registrados por esta rede, e que ocorreram na Prov?ncia Pr? cambriana da Borborema do nordeste brasileiro. O estudo revelou uma distribui??o de sismos bem definida, associada a uma falha geol?gica de estrutura simples. A determina??o dos hipocentros foi feita usando-se o programa HYPO71. Os resultados das an?lise mostram que a falha ? dividida em dois grandes segmentos com a mesma dire??o de N37?E. O segmento norte da falha mergulha num ?ngulo de 76?NW. O segmento sul mergulha na mesma dire??o, num ?ngulo de 82?NW, e ? composto de tr?s ou mais falhas quase paralelas. Um pequeno vazio de epicentros, acompanhado de uma zona de baixa sismicidade, separam os dois grandes segmentos. N?o foi encontrado evento a profundidades maiores que 9 km. As an?lises dos mapas de epicentros, e das respectivas proje??es verticais, revelaram que os eventos est?o distribu?dos em v?rios aglomerados. O mecanismo de falha foi determinado como sendo do tipo transcorrente, dextr?giro com uma pequena componente normal. Foram detectados micro tremores distantes, v?rios quil?metros da falha principal. Estes eventos s?o explicados pelo modelo cl?ssico de Das & Scholz, como conseq??ncia do aumento das tens?es de cisalhamento em regi?es fora da falha principal ap?s a ocorr?ncia do sismo principal. As magnitude dos micro tremores foram calculadas atrav?s da determina??o de uma escala espec?fica de magnitudes, baseadas na dura??o do sinal s?smico. Os valores determinados para o par?metro tect?nico b, da lei de Gutenberg e Richter, n?o mostraram varia??es significativas durante o per?odo de observa??es. O fen?meno da dupla refra??o, nas ondas s?smicas de cisalhamento, foi observada na regi?o de Jo?o C?mara em todos os eventos selecionados e registrados pela esta??o de tr?s componentes JCAZ. As an?lises mostraram a dire??o norte-sul como sendo a dire??o de polariza??o da primeira onda separada, em desacordo com as previs?es da te?ricas da extensive dilatancy anisotropy.
955

Vem ska få veta? : En kunskapsöversikt angående risk- och kriskommunikation vid katastrofer.

Söderberg, Anna January 2018 (has links)
Harrisburg, Chernobyl and Fukushima have changed the world’s view of the probability that a nuclear disaster can happen. But they are also a reminder of how necessary a working crises management is in the times a disaster appears. This paper is a systematic review about accidents and disasters, and the communication in this time. The purpose of the study is to analyse the use of communication in these cases, but also how organizations and media are communicating, and which dimensions they use. The conclusion of this study shows that risk and crisis communication needs to improve in all cases. The best communication was with Sweden’s fire in Västmanland 2014 and the Tsunami 2004. Hurricanes and nuclear power needs better strategic in the whole process.
956

Implementación de bases geoespaciales para la vulnerabilidad sísmica de edificios de concreto armado

Palacios Castro, Harold Jesús Alberto, Pérez Elias, Kevin Jorge January 2015 (has links)
Nuestro país se encuentra ubicado en una zona de alta actividad sísmica, por ello es importante que los ingenieros civiles tengan una adecuada capacidad para realizar análisis de vulnerabilidad sísmica y comprendan la importancia de la prevención. En la presente tesis analizamos los diferentes escenarios de daño sísmico para edificios de concreto armado organizados por tipología de número de pisos. Para el desarrollo de la presente investigación utilizamos dos Software, el primer software de simulación sísmica, en el cual modelamos la muestra de edificaciones de concreto armado que representan el distrito de Santiago de Surco, para luego analizarlo con un sismo de tiempo historia que simula varias magnitudes del mismo sismo amplificado con aceleraciones del suelo que varían de 0.1g a 1.0g, con el objetivo de obtener cada vez mayores desplazamientos, y de esa manera mayores niveles de daño mediante la metodología Hazus M-H. Luego estos valores expresarlos en cuadros de curvas de fragilidad sísmica con cuatro tipos de niveles de daño. El Segundo Software que utilizamos es el Sistema de Información Geográfica (SIG), con este programa sistematizamos los datos obtenido de la curva de fragilidad para mostrar mapas de niveles de daño para distintos escenarios sísmicos que muestren el comportamiento de los edificios al ocurrir un evento sísmico. Our country is located in a zone of high seismic activity, it is important that civil engineers have adequate capacity for analysis of seismic vulnerability and understand the importance of prevention. In this thesis we analyze the different scenarios of seismic damage to reinforced concrete buildings organized by type of number of floors. For the development of this research we use two software, the first seismic simulation software, which model the sample of reinforced concrete buildings representing Santiago de Surco, and then scan it with an earthquake simulating various weather history amplified earthquake magnitudes thereof with ground accelerations ranging from 1.0g 0.1ga, in order to obtain increasing displacement, and thus higher levels of damage by HAZUS MH methodology. Then these values express them in boxes seismic fragility curves with four types of damage levels. The second software we use is the Geographic Information System (GIS), with this program systematize data obtained fragility curve to display maps for different levels of damage scenarios showing the seismic performance of buildings to a seismic event occur.
957

Seismicity Analyses Using Dense Network Data : Catalogue Statistics and Possible Foreshocks Investigated Using Empirical and Synthetic Data

Adamaki, Angeliki January 2017 (has links)
Precursors related to seismicity patterns are probably the most promising phenomena for short-term earthquake forecasting, although it remains unclear if such forecasting is possible. Foreshock activity has often been recorded but its possible use as indicator of coming larger events is still debated due to the limited number of unambiguously observed foreshocks. Seismicity data which is inadequate in volume or character might be one of the reasons foreshocks cannot easily be identified. One method used to investigate the possible presence of generic seismicity behavior preceding larger events is the aggregation of seismicity series. Sequences preceding mainshocks chosen from empirical data are superimposed, revealing an increasing average seismicity rate prior to the mainshocks. Such an increase could result from the tendency of seismicity to cluster in space and time, thus the observed patterns could be of limited predictive value. Randomized tests using the empirical catalogues imply that the observed increasing rate is statistically significant compared to an increase due to simple clustering, indicating the existence of genuine foreshocks, somehow mechanically related to their mainshocks. If network sensitivity increases, the identification of foreshocks as such may improve. The possibility of improved identification of foreshock sequences is tested using synthetic data, produced with specific assumptions about the earthquake process. Complications related to background activity and aftershock production are investigated numerically, in generalized cases and in data-based scenarios. Catalogues including smaller, and thereby more, earthquakes can probably contribute to better understanding the earthquake processes and to the future of earthquake forecasting. An important aspect in such seismicity studies is the correct estimation of the empirical catalogue properties, including the magnitude of completeness (Mc) and the b-value. The potential influence of errors in the reported magnitudes in an earthquake catalogue on the estimation of Mc and b-value is investigated using synthetic magnitude catalogues, contaminated with Gaussian error. The effectiveness of different algorithms for Mc and b-value estimation are discussed. The sample size and the error level seem to affect the estimation of b-value, with implications for the reliability of the assessment of the future rate of large events and thus of seismic hazard. / Οι προσεισμοί αποτελούν τα πλέον υποσχόμενα πρόδρομα φαινόμενα για τη βραχυπρόθεσμη πρόγνωση των σεισμών, παρόλο που παραμένει άγνωστο το αν μια τέτοια πρόγνωση είναι εφικτή. Η χρήση της προσεισμικής δραστηριότητας ως ένδειξη ενός επερχόμενου μεγάλου σεισμού είναι αμφιλεγόμενη, κυρίως λόγω του περιορισμένου πλήθους των προσεισμών, γεγονός που πιθανά οφείλεται στην ανεπαρκή καταγραφή σεισμικών δεδομένων. Η άθροιση σεισμικών σειρών είναι μια μέθοδος που εφαρμόζεται προκειμένου να μελετηθεί η πιθανή παρουσία ενός γενικευμένου μοτίβου σεισμικότητας πριν από ισχυρούς σεισμούς. Η υπέρθεση σεισμικών ακολουθιών που προηγήθηκαν των κυρίων σεισμών αναδεικνύει μια αυξανόμενη μέση δραστηριότητα πριν από τους κύριους σεισμούς. Μια τέτοια συμπεριφορά θα μπορούσε να προκύψει και από την εγγενή τάση των σεισμών να ομαδοποιούνται χωρικά και χρονικά, με αποτέλεσμα τα παρατηρούμενα μοτίβα να έχουν περιορισμένη προγνωστική αξία. Τυχαιοποιημένοι έλεγχοι των πραγματικών δεδομένων υποδηλώνουν ότι ο παρατηρούμενος αυξανόμενος ρυθμός είναι στατιστικά σημαντικός σε σύγκριση με τη μεταβολή που οφείλεται στη γένεση απλών συστάδων σεισμών, αναδεικνύοντας την ύπαρξη προσεισμών αιτιολογικά συσχετιζόμενων με τους κύριους σεισμούς. Μια ενδεχόμενη αύξηση της ευαισθησίας των σεισμικών δικτύων πιθανά να συμβάλει στην αποτελεσματικότερη αναγνώριση των προσεισμών. Η πιθανότητα μιας τέτοιας βελτίωσης ελέγχεται με τη χρήση συνθετικών δεδομένων τα οποία προκύπτουν υπό προϋποθέσεις ως προς τη σεισμική διαδικασία. Οι επιπλοκές που μπορεί να προκύψουν από την παρουσία σεισμικότητας υποβάθρου και των μετασεισμικών ακολουθιών διερευνώνται αριθμητικά, με γενικευμένες περιπτώσεις και σενάρια που βασίζονται σε πραγματικά δεδομένα. Οι κατάλογοι που περιλαμβάνουν μικρότερους και επομένως περισσότερους σεισμούς μπορούν πιθανώς να συμβάλουν στην καλύτερη κατανόηση των σεισμικών διεργασιών και στη μελλοντική πρόγνωση των σεισμών. Σημαντική πτυχή σε τέτοιες μελέτες αποτελεί η σωστή εκτίμηση των ιδιοτήτων των σεισμικών καταλόγων, όπως είναι το μέγεθος πληρότητας και η παράμετρος b. Η επίδραση των σφαλμάτων των μεγεθών που υπάρχουν στους σεισμικούς καταλόγους στην εκτίμηση των προαναφερθέντων ιδιοτήτων ερευνάται χρησιμοποιώντας συνθετικά μεγέθη στα οποία ενυπάρχουν κανονικώς κατανεμημένα σφάλματα. Κατά τη διερεύνηση της αποτελεσματικότητας των διαφόρων μεθόδων που χρησιμοποιούνται για την εκτίμηση του μεγέθους πληρότητας προκύπτει ότι το μέγεθος του δείγματος και του σφάλματος των μεγεθών μπορούν να επηρεάσουν την εκτίμηση της παραμέτρου b, με επιπτώσεις στην εκτίμηση του ρυθμού των μελλοντικών ισχυρών σεισμών και την αξιολόγηση του σεισμικού κινδύνου.
958

Analytical Investigation of Inertial Force-Limiting Floor Anchorage System for Seismic Resistant Building Structures

Zhang, Zhi, Zhang, Zhi January 2017 (has links)
This dissertation describes the analytical research as part of a comprehensive research program to develop a new floor anchorage system for seismic resistant design, termed the Inertial Force-limiting Floor Anchorage System (IFAS). The IFAS intends to reduce damage in seismic resistant building structures by limiting the inertial force that develops in the building during earthquakes. The development of the IFAS is being conducted through a large research project involving both experimental and analytical research. This dissertation work focuses on analytical component of this research, which involves stand-alone computational simulation as well as analytical simulation in support of the experimental research (structural and shake table testing). The analytical research covered in this dissertation includes four major parts: (1) Examination of the fundamental dynamic behavior of structures possessing the IFAS (termed herein IFAS structures) by evaluation of simple two-degree of freedom systems (2DOF). The 2DOF system is based on a prototype structure, and simplified to represent only its fundamental mode response. Equations of motions are derived for the 2DOF system and used to find the optimum design space of the 2DOF system. The optimum design space is validated by transient analysis using earthquakes. (2) Evaluation of the effectiveness of IFAS designs for different design parameters through earthquake simulations of two-dimensional (2D) nonlinear numerical models of an evaluation structure. The models are based on a IFAS prototype developed by a fellow researcher on the project at Lehigh University. (3) Development and calibration of three-dimensional nonlinear numerical models of the shake table test specimen used in the experimental research. This model was used for predicting and designing the shake table testing program. (4) Analytical parameter studies of the calibrated shake table test model. These studies include: relating the shake table test performance to the previous evaluation structure analytical response, performing extended parametric analyses, and investigating and explaining certain unexpected shake table test responses. This dissertation describes the concept and scope of the analytical research, the analytical results, the conclusions, and suggests future work. The conclusions include analytical results that verify the IFAS effectiveness, show the potential of the IFAS in reducing building seismic demands, and provide an optimum design space of the IFAS.
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Immigration: An Expedient Complement To Disaster Response? An Examination of Canada's Post-Earthquake Immigration Measures for Haiti and the Influence of the Haitian Diaspora in Canada

D'Aoust, Sarah January 2012 (has links)
The Canadian response following the Haitian earthquake of 2010 was not solely focused on providing humanitarian assistance. Canada also used several immigration measures both at the federal level and the provincial level in Quebec in order to facilitate the immigration of eligible Haitians to Canada and their subsequent reunification with their Canadian family members. This thesis explores these immigration measures and evaluates their effectiveness. In addition, the research examines the role that the large Haitian Diaspora in Canada played in bringing about the adoption of a set of immigration measures specifically for Haitians. The research shows that the Canadian measures implemented were both multi-dimensional – as a variety of immigration mechanisms were used, and multi-level – as the Canadian response included both federal and provincial initiatives in Quebec. While a number of measures were introduced federally, none of these measures could be considered “special” as they were all possible under Canada’s immigration legislation, and they were not unique to the post-earthquake context. In contrast, Quebec’s Humanitarian Sponsorship Program for Haitians was very “special” in that it was the first time such a program was implemented for a large group of people. The research also points to the fact that although using immigration mechanisms to respond to a humanitarian crisis has its benefits, these mechanisms are not designed to provide prompt protection and relief to individuals affected by crisis situations. The research also demonstrates that the use of the available complementary protection measures (humanitarian and compassionate considerations, moratorium and protected person status) did not make up the primary thrust of the Canadian immigration response to the earthquake in Haiti. This fact is indicative of the inadequacy of these measures in providing protection to individuals displaced by environmental factors. Finally, it is argued that although the existence of a large Haitian Diaspora was influential in creating a climate open to the adoption of special measures for Haitians, the Haitian Diaspora did not necessarily influence the specifics of the measures adopted to a significant degree.
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Cycle sismique et déformation continentale le long de la subduction Péruvienne / Earthquake cycle and continental deformation along the Peruvian subduction zone

Villegas Lanza, Juan Carlos 05 November 2014 (has links)
La zone de subduction entre les plaques Nazca et Amérique du Sud est une des régions les plus actives de notre planète. De grands tremblements de terre et tsunamis associés se produisent de façon récurrente presque tout au long de sa marge. Néanmoins, le segment de subduction au nord du Pérou (de lat.3oS à 9oS) est resté le seul segment sismiquement silencieux depuis les premières informations historiques sur les séismes qui remontent au XVème siècle. Avant les travaux présentés dans ce manuscrit, aucune information sur les processus accommodant la convergence de la plaque Nazca vers le continent Sud-Américain n’était disponible le long du segment de 1000km au nord Pérou et sud Equateur. Les techniques de géodésie spatiale, en particulier le GPS/GNSS, nous permettent de quantifier les mouvements à la surface de la plaque supérieure avec une précision millimétrique. Ces mesures, couplées à l'utilisation de modèles élastiques, nous permettent de déterminer le niveau du couplage intersismique le long de l'interface entre les plaques. Le but de ma thèse est d'étudier le cycle sismique et la déformation continentale le long de la zone de subduction du Pérou, avec un intérêt particulier pour son segment nord. Nous utilisons des mesures GPS acquises depuis 2008 dans le cadre d'un projet international (le projet Andes Du Nord, ANR- ADN). Le champ de vitesse GPS obtenu couvre l’ensemble de la marge de subduction péruvienne, avec des mesures dans la cordillère et dans une moindre mesure dans la région sub-Andine. L'analyse et la modélisation du champ de vitesse GPS ont permis d'obtenir les résultats suivants: Premièrement: nous mettons en évidence l'existence d'un nouveau domaine continental, que nous avons baptisé comme le sliver Inca et qui est en translation a une vitesse de 4-5 mm/an en direction sud-est par rapport au craton Sud Américain. Le sliver Inca s’étend tout le long de la marge péruvienne. / The Nazca/South American subduction zone is one of the most active regions on Earth. Large earthquakes and associated tsunamis occur recurrently almost all along its margin. Nevertheless, the ~1000 km long (from lat.2oS to 9oS) segment in northern Peru and southern Ecuador subduction has remained in relative seismic silence for at least the past five centuries. Before the work presented in this thesis, no information about the processes accommodating the convergence was available for this region and it was impossible to answer whether it could host a great Mw>8.5 earthquake in future or not. Nowadays, spatial geodesy, and more specifically GPS/GNSS enable us to quantify the surface displacement on the overriding plate with millimeter accuracy. Geodetic measurements together with the use of elastic models allow us to determine the amount of interseismic coupling at the plate interface. My thesis focuses on the seismic cycle and the continental deformation along the Peruvian subduction margin, with particular interest along its northern and central segments. We use GPS measurements acquired since 2008 in the frame of an international French-Peruvian- Ecuadorian project (the Andes Du Nord project, ADN). Our GPS velocity field covers the entire Peruvian subduction margin, with measurements in the Andean cordillera and part of the sub-Andean region. Modeling of GPS velocity field show the existence of a new tectonic microplate that we baptized as the Inca Sliver, which is in southeastward translation a rate of 4-5 mm/yr with respect to stable South America.

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