A brief tilt and strain survey was conducted in the Krafla-Namafjall area in the North of Iceland during August of 1979 in order to study the feasibility of applying solid earth tidal observations in the exploration of volcanic geothermal systems. The rationale of the survey was based on the expectation that various types of geological structures such as rift zones and magma chambers can lead to observable distortions of the local solid earth tidal amplitude field. The field procedure consisted in measuring the local tidal amplitudes and comparing them with normal theoretical amplitudes at the same location. The Krafla volcanic complex is a central volcano traversed by a N-S trending fissure swarm, that has been tectonically and volcanically active since December 1975. Accompanying this activity have been periodic inflations of the Krafla caldera, presumably caused by a flow of magma into a local magma chamber and resulting in long term tilts of the order 0.5 ��rad/day that have been observed at two sites south and southeast of the caldera. In computing theoretical amplitudes the effects of the ocean tides need to be estimated. In the case of north Iceland they are found to be of the same magnitude as the solid earth tides. The amplitudes of the M��� ocean loading tilt at Krafla are estimated to be 0.066 ��rad and 0.032 ��rad for the NS and EW components respectively. The most noteworthy result was obtained at a site in the Namafjall geothermal area inside the active Krafla fissure swarm. The ratios of the observed to the theoretical M��� tidal tilt amplitudes at this site as estimated by a least squares spectral analysis method are found to be 0.9 �� 0.3 and 3.2 �� 1.5 for the NS and EW components respectively. On the basis of some simple order-of-magnitude estimates we can exclude one of the numerous nearby fractures as a possible cause for the EW tilt anomaly and conclude that it is most likely to be generated by a large body of magma below the Krafla fissure swarm. Due to thermoelastic noise other tilt data obtained during this survey turned out to be less reliable. However, our work at a site east of the fissure swarm and southeast of the caldera indicated a possible anomaly. The strain data are highly contaminated by thermal noise and could not be successfully analyzed. These results tend to confirm that tidal tilt observations can be of use in explorations of volcanic and geothermal systems. Our work indicates that a few improvements of the simple field techniques adapted may enhance the quality of data. These include (1) increasing the instrument resolution, (2) selecting sites with surface layers that are incapable of transmitting thermal stresses and (3) obtaining more extensive higher quality temperature recordings, that should enable the thermal noise to be largely removed. / Graduation date: 1981

Thesis (Ph. D.)--University of Wisconsin--Madison, 1984. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographies.

Existing models for the response of artesian aquifers to earth tides have been examined anda new model developed. A formula for the computation of poresity from tidal water level measurement is presented. Tidal water level fluctuations in three artesian wells of southwest Virginia were recorded, digitized and harmonically analysed. Corrections for non tidal water level fluctuations and barometric pressure effects were made. Porosities of .22 near Blacksburg, Virginia, and .098 and .05 near Cripple Creek, Virginia, at depths of 156, 300, and 425 meters respectively were computed. An analysis of variability yields errors of about five per cent. Deviations of observed response from expected values is explained in terms of leakage and decoupling. It is concluded that values of porosity computed from tidal water level fluctuations must be considered as upper limits on true porosity. / Master of Science

Thesis (M.S.)--Ohio University, August, 2004. / Includes bibliographical references (p. 141-148)

Thesis (M.S.)--Ohio University, August, 2004. / Title from PDF t.p. Includes bibliographical references (p. 141-148)

Made available in DSpace on 2014-06-11T19:24:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-07Bitstream added on 2014-06-13T18:51:55Z : No. of bitstreams: 1 pinto_jv_me_guara.pdf: 1385196 bytes, checksum: 8f4e005504bfa301a50295aa1563c0d7 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Universidade Estadual Paulista (UNESP) / Aplicações recentes de satélites artificiais da Terra com finalidades geodinâmicas requerem órbitas determinadas com bastante precisão. Em particular, marés terrestres influenciam o potencial terrestre causando perturbações adicionais no movimento de satélites artificiais, as quais têm sido medidas por diversos processos. A atração exercida pela Lua e pelo Sol sobre a Terra produz deslocamentos elásticos em seu interior e uma protuberância em sua superfície. O resultado é uma pequena variação na distribuição da massa na Terra, conseqüentemente alterando o geopotencial. As perturbações nos elementos orbitais de satélites artificiais terrestres devidas à maré terrestre podem ser estudadas a partir das equações planetárias de Lagrange, considerando-se um potencial conveniente. Alguns modelos têm sido propostos para o cálculo de perturbações orbitais devidas à maré, tais como os modelos de Kaula, de Kozai, de Balmino e o utilizado pelo IERS. Os resultados encontrados na literatura são, em geral difíceis de serem comparados, pois os cálculos são feitos com diferentes modelos. Neste trabalho são apresentadas, para os potenciais mencionados, as expressões analíticas em forma expandida. Alguns cenários são propostos mostrando, para tais modelos, as diferenças nas perturbações de longo período e seculares, nos elementos orbitais de satélites artificiais, devidas á maré terrestre. / Recent applications of artificial Earth's satellites, as for instance with geodynamics purposes, require very high precision orbit determination. In particular, terrestrial tides affects the geopotential causing additional orbital perturbations that can be measured by several methods. The Sun and Moon attraction on the Earth produces both an elastics displacements in the Earth's interior and a bulge in its surface. The resulting effect is a small variation in the Earth's mass distribution. The perturbations in the orbital elements due to the terrestrial tides can be analysed using the Lagrange planetary equations considering a convenient potential. Some models have been proposed to compute orbital perturbations due to the terrestrial tides, such as the models proposed by Kozai, Kaula, Balmino and the model used by the IERS. The results found in the literature about orbit perturbations due to terrestrial tides were obtained using different models being difficult to be compared. In this work the above-referred models are presented. Expanded analytical expressions are presented. Some scenarios are proposed showing, for such models, the differences in the secular and long period perturbations of the orbital elements, due to the terrestrial tides.

Orientador: Rodolpho Vilhena de Moraes / Banca: Maria Cecília França de Paula Santos Zanardi / Banca: Hélio Koiti Kuga / Resumo: Aplicações recentes de satélites artificiais da Terra com finalidades geodinâmicas requerem órbitas determinadas com bastante precisão. Em particular, marés terrestres influenciam o potencial terrestre causando perturbações adicionais no movimento de satélites artificiais, as quais têm sido medidas por diversos processos. A atração exercida pela Lua e pelo Sol sobre a Terra produz deslocamentos elásticos em seu interior e uma protuberância em sua superfície. O resultado é uma pequena variação na distribuição da massa na Terra, conseqüentemente alterando o geopotencial. As perturbações nos elementos orbitais de satélites artificiais terrestres devidas à maré terrestre podem ser estudadas a partir das equações planetárias de Lagrange, considerando-se um potencial conveniente. Alguns modelos têm sido propostos para o cálculo de perturbações orbitais devidas à maré, tais como os modelos de Kaula, de Kozai, de Balmino e o utilizado pelo IERS. Os resultados encontrados na literatura são, em geral difíceis de serem comparados, pois os cálculos são feitos com diferentes modelos. Neste trabalho são apresentadas, para os potenciais mencionados, as expressões analíticas em forma expandida. Alguns cenários são propostos mostrando, para tais modelos, as diferenças nas perturbações de longo período e seculares, nos elementos orbitais de satélites artificiais, devidas á maré terrestre. / Abstract: Recent applications of artificial Earth's satellites, as for instance with geodynamics purposes, require very high precision orbit determination. In particular, terrestrial tides affects the geopotential causing additional orbital perturbations that can be measured by several methods. The Sun and Moon attraction on the Earth produces both an elastics displacements in the Earth's interior and a bulge in its surface. The resulting effect is a small variation in the Earth's mass distribution. The perturbations in the orbital elements due to the terrestrial tides can be analysed using the Lagrange planetary equations considering a convenient potential. Some models have been proposed to compute orbital perturbations due to the terrestrial tides, such as the models proposed by Kozai, Kaula, Balmino and the model used by the IERS. The results found in the literature about orbit perturbations due to terrestrial tides were obtained using different models being difficult to be compared. In this work the above-referred models are presented. Expanded analytical expressions are presented. Some scenarios are proposed showing, for such models, the differences in the secular and long period perturbations of the orbital elements, due to the terrestrial tides. / Mestre

In the equatorial Pacific Ocean, earthquakes are used as an indicator of tectonic stress for normal faults in the Galapagos Spreading Center, transform faults along the East Pacific Rise and thrust faults in the Middle American subduction zone. Linkages between seafloor tectonic processes and oceanographic and lunar conditions were explored using time-series cross-correlation analyses on two different time scales. Data for earthquakes in the eastern tropical Pacific study area are obtained using the hydrophone arrays of the NOAA-VENTS Program. Hydroacoustic monitoring (listening to underwater sounds) provides scientists with a detailed dataset that includes even small earthquakes, starting as low as magnitude 0.6, that are not perceived by land-based seismographs. Data for sea surface heights (SSH) consist of two different datasets. On a moon's quarter time scale, SSH data used to investigate the influence of the earth tide and changes in oceanic conditions were remotely acquired by the altimeter on board the TOPEX/Poseidon (T/P) satellite. SSH data used to investigate the influence of the ocean tides were obtained from the Tidal Model Driver (Padman and Erofeeva 2003), that predicts SSH for locations every hour. The Geographic Information System (GIS) was used for the visual display of the data and to compute basic descriptive statistics. A lab-book was created for the educational-outreach section of this work, explaining step by step how GIS has been used. Significant results show correlations between normal faults and ocean tides and between the thrust fault and earth tides. Also, the Quebrada and the Discovery transform faults show high correlation of earthquake events, suggesting that at such temporal and spatial resolution, the plate moves as a rigid block. / Graduation date: 2006

Orientador: Jorge Luiz Alves Trabanco / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-21T16:53:48Z (GMT). No. of bitstreams: 1 Amarante_RogerioRodrigues_D.pdf: 8479306 bytes, checksum: c6760b22f8c1f110ad1b61e48c59508b (MD5) Previous issue date: 2012 / Resumo: Com o uso de métodos adequados, receptores GNSS podem determinar coordenadas com acurácia suficiente para aplicação em projetos de engenharia. Porém a altitude elipsoidal obtida não utiliza o mesmo sistema de referência da engenharia de transportes. A altitude elipsoidal pode ser transformada em ortométrica com a utilização de modelos geoidais que são gerados a partir de dados gravimétricos. Neste trabalho são apresentados alguns conceitos introdutórios sobre a geração de modelo geoidais. Em seguida mostra o desenvolvimento de uma nova sistematização do tratamento de dados gravimétricos com objetivo de facilitar a detecção de erros, aumentar a produtividade e melhorar a organização de resultados obtidos. Dentro deste desenvolvimento, são revisadas as teorias utilizadas para transformar medições feitas com gravímetros diferenciais em aceleração da gravidade. Apresenta também técnicas de ajustamento de observações com intuito tratar erros aleatórios. A nova abordagem sugerida foi utilizada para o desenvolvimento de um software objetivando validar as idéias propostas, permitir a comparação com outras soluções existentes e também servir como uma contribuição tecnológica. Dados gravimétricos reais foram testados dentro da abordagem proposta tendo sido observados mais organização, ganho de produtividade e principalmente a detecção de erros grosseiros e aleatórios. Com a revisão do cálculo da correção da maré, percebeu-se que programas e equipamentos atualmente em uso não possuem configuração do fator gravimétrico, fato que pode influenciar em até 0; 007mGals no processamento das observações / Abstract: With the use of appropriate methods, GNSS receivers can determine coordinates with sufficient accuracy for use in projects. The ellipsoidal height obtained, however, does not use the same reference system as the one used in transportation engineering. The ellipsoidal height can be transformed to orthometric height using geoid models that are generated from gravimetric data. In this work some introductory concepts on the generation of geoid model are presented. Then it shows the development of a new approach in systematization of gravimetric data processing aiming to facilitate the detection of errors, increase productivity and improve the organization of the results obtained in the gravimetric surveys. Within this development, the theories used to convert measurements of the differences in gravity acceleration are revised. It also features adjustment techniques of observations in order to deal with random errors. The new suggested approach was used to develop software in order to validate the proposed ideas, allow comparison with other existing solutions, and also serves as a technological contribution. Gravimetric data were tested within the suggested approach. It was observed better organization, productivity gains and mainly detection of gross errors and random. With the review of the tide correction calculation, it was realized that programs and equipments now widely used have no gravimetric factor setting, a fact that can influence up to 0; 007mGals in processing the readings / Doutorado / Transportes / Doutor em Engenharia Civil

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