No description available.

No description available.

The gravity field of the Earth is fundamental to subjects such as geodesy and geophysics. Many observations within geodesy refer directly or indirectly to gravity. Geodetic techniques provide information regarding the Earth and the processes that act on it. Mass and angular momentum are, according to physics, conserved in a closed system. The Earth interacts very little with components outside of it and can be thought of as a closed system. Mass components in one reservoir of the Earth system are exchanged with others. Mass redistribution within the Earth system is caused by geophysical processes. This movement of geophysical fluid (mass) causes variations in the Earth’s rotation, gravity field and geocentre. The improvement of geodetic techniques over the last few decades allows us to measure the effects of these processes on the Earth to an unprecedented accuracy. Earth rotation parameters (ERPs) are excited by variations in the mass distribution on the Earth’s surface and the exchange of angular momentum between the atmosphere and oceans and the solid Earth. The same mass redistribution causes temporal changes in the gravity field coefficients with the second degree harmonics related to the rotational deformation and hence to changes in the Earth’s inertial tensor. If precise models of the atmospheric and oceanic angular momentum are available solution for polar motion and degree-2 Stokes harmonics can be unified. In this study we utilise SLR tracking of LAGEOS to compare (i) degree-2 harmonics from ERPs and gravitation, and (ii) LAGEOS excitation functions and geophysical data (mass + motion). To what extent a unified approach is possible with current models for AM data and gravity mass change estimated from ERP within orbit determinations is investigated. Finally, the ability of SLR to calculate the motion of the Earth’s geocentre is also investigated.

IN DUBIO PRO GEO ist eine geodätische Cloud-Computing-Software. Sie bietet Werkzeuge für Geodätische Berechnungen und Ausgleichungen. Dieser Beitrag zeigt an einem Beispielprojekt die Herangehensweise und die Möglichkeiten dieser Software. / IN DUBIO PRO GEO is a geodetic cloud computing software. It offers tools for geodetic computations and adjustments. This contribution shows by means of an exemplary project the approach and the possibilities of this software.

Orientadores: Silvio Rogerio Correia de Freitas, Camil Gemael / Dissertação (mestrado) - Universidade Federal do Paraná / Resumo: O presente trabalho visa apresentar a concepção e as fases do projeto de uma base de dados geodésicos para o Estado do Paraná, dentro de um "Geographical Information System" (GIS). Como pressupostos, serão envolvidos todos os dados e informações complementares dos levantamentos de coordenadas geodésicas horizontais e verticais, assim como das grandezas gravimétricas. A estrutura da base tem uma arquitetura que permite a qualificação dos dados, usando modelos digitais de terreno (MDT) e modelos do Geopotencial (MGP), a seletividade por níveis de acurácia e tipos de usuários. / Abstract: This work aims to present the conception and steps of a project of the Geodetic Data Base for the Paraná State, inside of a Geographical Information System (GIS). All data and complementary information of horizontal and vertical geodectic coordinates as well as gravimetric data, will be involved. The structure of base has an architecture allowing data qualification, by means the use of models like DTM and of the geopotencial, the selectivity by different accuracy levels and class o f users.

Orientador: Camil Gemael / Dissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências da Terra / Resumo: Nesta dissertação é apresentado o método que utiliza integrais elípticas para a solução dos problemas principais geodésicos direto e inverso. Neste método as latitudes de pontos sobre a linha geodésica são transformadas nas quantidades v ou então w, as quais são funções da latitude e do azimute. Para a solução do problema direto é feita uma comparação dos resultados de integração com valores teóricos, o que permite o melhoramento iterativo velozmente convergente do limite superior V2 de integração, com o qual calculam-se as demais quantidades procuradas. Já a solução do problema inverso é obtida pela determinação iterativa da latitude máxima que fixa a linha geodésica. Com o objetivo de pormenorizar didaticamente os procedimentos do método, procurou-se omitir o mínimo possível as demonstrações, a fim de oferecer condições para demonstrar as integrais elípticas aplicadas a estes problemas. Como tais integrais não possuem solução analítica, ou seja, não podem ser expressas por funções elementares, é apresentada uma síntese dos métodos para a sua integração numérica. Os problemas direto e inverso são calculados para linhas de 1 m, 200 m, 500 m, 1 km, 10 km, 40 km, 80 km, 500 km e 1000 km e também as soluções obtidas pelos diferentes métodos de integração numérica utilizados são comparadas. A consistência do método é constatada pela discrepância apresentada entre as soluções direta e inversa bem como pelo cálculo recíproco do problema direto. Conclui-se o trabalho com recomendações a respeito do método mais adequado para cada comprimento de linha utilizado, no que diz respeito à simplicidade do uso e acurácia dos resultados. / Abstract: This dissertation aims to present the method that uses elliptical integrals to solve the main direct and indirect geodesic problems. In this method the points latitudes on the geodesic lines are transformed into the v or w quantities, which are functions of the latitude and azimuth. In order to solve the direct problem a comparison between the integration results and the theoretical values is made, which allows the fast convergent iterative improvement of the integration superior limit V2, with which other searched quantities are calculated. The indirect problem solution is given by iterative determination of the maximum latitude that fixes the geodesic line. Aiming to detail the method procedures, trying to omit the demonstrations as less as possible in order to offer conditions to demonstrate the elliptical integrals applied to these problems. As such integrals don’t have an analytical solution, i. e., they can’t be expressed by elementary functions, a synthesis of the methods is presented for its numerical integration. The direct and indirect problems are calculated for 1 m, 200 m, 500 m, 1 km, 10 km, 40 km, 80 km, 500 km e 1000 km lines and but also the solutions given by different methods of numerical integration used are compared. The method consistence is checked by the discrepancy presented between the direct and indirect solutions as well as by the reciprocal calculation of the direct problem. The work is concluded along with recommendations on the most adequate method for each line length used, regarding the utilization simplicity and results accuracy.

Nous étudions dans un premier temps l'intérêt de l'utilisation de la "multichannel singular spectrum analysis" (M-SSA) sur des séries temporelles de positionnements GPS. Cette méthode permet de simultanément analyser un ensemble de séries temporelles et d'en extraire des modes de variabilités communs sans utiliser d'information a priori sur les structures spatiales et temporelles des champs géophysiques. Ces modes correspondent à des tendances non linéaires, des oscillations ou du bruit. Nous l'appliquons à des données enregistrées sur le volcan Akutan en Alaska. Nous y extrayons deux types de signaux. L'un correspondant à des déformations dites saisonnières, l'autre représentant deux cycles d'inflations et de déflations successifs du volcan Akutan. Les inflations sont rapides et courtes et suivies de déflations plus lentes et plus longues. Dans une seconde partie nous tirons parti de la M-SSA pour analyser des séries temporelles enregistrées sur plusieurs volcans. Les volcans Okmok et Shishaldin en Alaska et le Piton de la Fournaise à la Réunion possèdent une partie de leurs histoires de déformations qui est similaire à celle d'Akutan. Le caractère oscillatoire de ces cycles de déformations est comparé au régime oscillatoire d'un simple oscillateur non linéaire. Les données pétrologiques, géochimiques et géophysiques disponibles pour Okmok et le Piton de la Fournaise combinées aux contraintes sur la dynamique apportées par l'oscillateur non linéaire permet de proposer un modèle physique. Deux réservoirs superficiels sont connectés par un conduit cylindrique dans lequel le magma possède une viscosité qui dépend de la température. Un tel système se comporte de manière similaire à l'oscillateur non linéaire étudié précédemment. Lorsque que le gradient de température vertical présent dans le fluide est suffisamment important et que le flux de magma entrant dans le système de réservoirs est compris entre deux valeurs déterminées analytiquement un régime oscillatoire se met en place. / We study the use of the "multichannel singular spectrum analysis" on GPS time series. This method allows to simultaneously analyze a set of time series in order to extract from it common modes of variability without using any a priori on the temporal or the spatial structure of geophysical fields. The extracted modes correspond either to nonlinear trends, oscillations or noise. The method is applied on a set of GPS time series recorded at Akutan, a volcano located in Aleutian arc in Alaska. Two types of signals are extracted from it. The first one corresponds to seasonal deformations and the other represents two successive cycles of inflation and subsidence of Akutan volcano. The inflations are fast and short and are followed by deflations that are slower and longer. In the second part we take benefit of the M-SSA to analyze GPS time series recorded at several volcanoes. Okmok and Shishaldin in Alaska and Piton de la Fournaise in La Réunion possess a part of their deformation history that is similar to Akutan volcano. The cyclic nature of the observed deformations leads us to make an analogy between the oscillatory regime of a simple nonlinear oscillator and the deformation cycles of these volcanoes. Geochemical, petrological and geophysical data available for Okmok and Piton de la Fournaise combined with the constraint on the qualitative dynamics bring by the nonlinear oscillator allow to propose a physical model. Two shallow reservoirs are connected by a cylindrical conduit in which the magma have a viscosity that depends on the temperature. Such system behaves like the nonlinear oscillator mentioned above. When the temperature gradient inside theconduit is large enough and the flux of magma entering the shallow system is bounded by values that are determined analytically anonlinear oscillatory regime arises.

Orientadores: Camil Gemael, Nelsí Cogo de Sá / Tese (doutorado) - Universidade Federal do Paraná / Resumo: Neste trabalho são apresentados os dados, a metodologia e os resultados do calculo de um modelo geoidal de alta precisão e resolução para o Uruguai, denominado de Projeto UruGeoide 2000. Pode-se descrever o trabalho apresentado no texto, nas seguintes linhas gerais: O objetivo do projeto, e calcular um modelo geoidal de alta precisão e resolução para a área, situada entre os paralelos -30° e -35° e os meridianos 301,5° e 307° (-58,5° e -53°). A finalidade do modelo e fornecer uma transformação acurada, entre as altitudes ortometrica e elipsoidal e também servir de base para estudos na área das geociencias no Uruguai. O método consiste no calculo do geoide gravimétrico, através da formula de Stokes na forma esférica e com núcleo rigoroso, avaliada no domínio das frequências via transformada rápida de Fourier unidimensional (1DFFT). A técnica principal de calculo e a decomposição da altura geoidal (Sideris, 1991), usando uma adequada combinação de modelos geopotenciais de alto grau, anomalias gravimetricas e dados topograficos contidos em um modelo topográfico digital (MTD). A premissa da não existência de massas externas a superfície limitante (o geoide) foi contemplada com o uso do segundo método de condensação topográfica de Helmert, levando em consideração o correspondente efeito indireto. Foram gerados 7 modelos geoidais, usando diversas opções que a metodologia e os programas ofereceram. Os modelos passaram por uma avaliação, baseada em dados GPS/RNs, na forma absoluta e relativa, na qual foi escolhido aquele que forneceu o melhor desempenho geral. O modelo geoidal escolhido, denominado de UruGeoide 2000, tem uma precisão absoluta de 0, 25 m, e relativa 2 ppm por km, atingindo as metas planejadas previamente no projeto. / Abstract: It is presented the results and methodology, used to calculate a high precision and resolution geoidal model for Uruguay, named UruGeoide 2000 Project. The project can be describe on the following general lines: The objective was to calculate a high precision and resolution geoidal model for the area located between latitudes -30° to -35° and longitudes 301.5° to 307° (-58.5° to -53°). The planned use of the geoidal model, will be to provide an accurate transformation, between elipsoidal and orthometric heights and as a base for geo-sciences in Uruguay. The calculation method, was the gravimetric one, through the Stokes formula in spherical form and with rigorous function kernel, via the one dimensional Fast Fourier Transform (1DFFT). The main calculation technique was a remove-restore procedure (Sideris, 1991), using an adequate combination of a high degree geopotencial model, gravimetric anomalies and topographic data from a DTM. The imposed condition of no having masses outside to the boundary surface, was satisfied using the Helmert' second condensation method for the topography, taking in account the correspondent indirect effect. Because of the various options and methodologies, offered by the available programs, a total of 7 geoidal models were generated. The different models, were evaluated with two set of GPS observations over benchmarks, in absolute and relative form, being choosing that one who show the best overall performance. The geoidal model chosen, named UruGeoide 2000, has an absolute precision o f 0,25 m and a relative one o f 2 ppm, satisfying the planned aimed of the project.

IN DUBIO PRO GEO ist eine geodätische Cloud-Computing-Software. Sie bietet Werkzeuge für Geodätische Berechnungen und Ausgleichungen. Dieser Beitrag zeigt an einem Beispielprojekt die Herangehensweise und die Möglichkeiten dieser Software. / IN DUBIO PRO GEO is a geodetic cloud computing software. It offers tools for geodetic computations and adjustments. This contribution shows by means of an exemplary project the approach and the possibilities of this software.

Le point triple d’Hatay ne peut pas être décrit par un modèle simple à trois grandes plaques comme il était proposé par les études précédentes. Un modèle de bloc plus complexe est proposé dans cette étude en rajoutant les micros blocs d’Iskenderun et d’Amanous; la faille de Karasu et la faille de Karatas-Osmaniye ont été définies comme des failles individuelles et non pas comme l'extension d'autres failles majeurs dans la région. Notre modélisation assume que la jonction triple de Maras est formée par la connexion de et la faille de Karatas-Osmaniye (KOF) avec la faille de Karasu (KF) et la faille East Anatolienne (EAF). La KF montre un taux de glissement senestre de 4,0±1,0 mm/an et un comportement de compression, avec un taux de raccourcie de 2.1 à 2.7 mm/an, ce qui contredit la nature extensionnelle proposée par les études précédentes. L'EAF montre un taux pur de glissement latéral gauche de 9,0±0,3 mm/an sans extension ou compression significative, la DSF a un taux de glissement de 3,5±0,3 mm/an sur les segments nord et sud, la KOF a 3,6±0,7 mm/an; l'arc de Chypre a une déformation de compression clair avec un taux de glissement revers de 2.0 à 5.0 mm/an et sans significative dérochement. Les pôles relatifs d’Euler ont été estimés dans cette modélisation de blocs, nous définissons l’Euler pôle de l'Anatolie-Arabie à (27.61±0.98 °N, 45.127±2.45 °E, 0.391±0.056 °/Ma), et l’Euler pôle de Sinaï-Arabie à (31.012±1.51 °N, 46.464±4.44 °E, 0.202±0.067 °/Ma). / The Hatay Triple Junction (HTJ) cannot be described by a simple model with three major plates as proposed by previous studies. A more complex block model is proposed in this study by adding the Iskenderun block and Amanous micro block, the Karasu fault and Karatas-Osmaniye fault being defined as individual faults not as the extension of other major faults in the region. Our modeling assumes that the Maras triple junction is formed by the connection of the Karatas-Osmaniye Fault (KOF) with the Karasu Fault (KF) and the East Anatolian Fault (EAF). The KF shows a sinistral slip rate of 4.0±1.0 mm/yr and a compressional behavior with a compression rate of 2.1-2.7 mm/yr which contradicts the extensional nature proposed by previous studies. The EAF shows pure left lateral slip rate of 9.0±0.3 mm/yr with no significant extension or compression; the DSF has a slip rate of 3.5±0.3 mm/yr over the northern and southern segments; the KOF has a 3.6±0.7 mm/yr; the Cyprus arc has a clear compressional deformation with a revers slip rate of 2.0-5.0 mm/yr and with no significant strike-slip component. The relative Euler poles are estimated in this block modeling, we define the Anatolia-Arabia Euler pole at (27.61±0.98 °N, 45.127±2.45 °E, 0.391± 0.056°/Myr), and (31.012±1.51 °N, 46.464±4.44 °E, 0.202±0.067°/Myr) Sinai-Arabia Euler pole.