Relevant bibliographies by topics / Geophysics Observations

Academic literature on the topic 'Geophysics Observations'

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Published: 10 December 2022
Last updated: 29 January 2023

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Journal articles on the topic "Geophysics Observations"

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Doyle, H. "Geophysics in Australia." Earth Sciences History 6, no. 2 (January 1, 1987): 178–204. http://dx.doi.org/10.17704/eshi.6.2.386k258604262836.

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Geophysical observations began in Australia with the arrival of the first European explorers in the late 18th Century and there have been strong connections with European and North American geophysics ever since, both in academic and exploration geophysics. Government institutions, particularly the Bureau of Mineral Resources, have played a large part in the development of the subject in Australia, certainly more so than in North America. Academic research in geophysics has been dominated by that at the Australian National University. Palaeomagnetic research at the Australian National University has been particularly valuable, showing the large northerly drift of the continent in Cainozoic times as part of the Australia-India plate. Heat flow, electrical conductivity and upper mantle seismic velocities have been shown to be significantly different between Phanerozoic eastern Australia and the Western Shield. Geophysical exploration for metals and hydrocarbons began in the 1920s but did not develop strongly until the 1950s and 1960s. There are relatively few Australian geophysical companies and contracting companies, and instrumentation from North America and Europe have played an important role in exploration. Exploration for metals has been hampered by the deep weathered mantle over much of the continent, but the development of pulsed (transient) electromagnetic methods, including an Australian instrument (SIROTEM), has improved the situation. Geophysics has been important in several discoveries of ore-bodies. In hydrocarbon exploration the introduction of common depth point stacking and digital recording and processing in reflection surveys have played an important part in the discovery of offshore and onshore fields, as in other countries.
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Pollitz, F. F. "GEOPHYSICS: A New Class of Earthquake Observations." Science 313, no. 5787 (August 4, 2006): 619–20. http://dx.doi.org/10.1126/science.1131208.

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Loginov, D. S. "Cartographic support of geophysical research: current situation and prospects." Geodesy and Cartography 950, no. 8 (September 20, 2019): 32–44. http://dx.doi.org/10.22389/0016-7126-2019-950-8-32-44.

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The features of cartographic supporting geophysical research at the present stage of cartography and exploration geophysics development are discussed. The current situation and prospects of using GIS and web technologies are characterized basing on the analysis of scientific and industrial experience of domestic and foreign public as well as private geological and geophysical organizations. The analysis was performed at key stages of geophysical research, including the analysis of geological and geophysical studying the work area, designing geophysical works, field works, processing and interpretation of geophysical observations results, compilation of reporting materials, as well as the accumulation and storage of information. The examples of modern geoportals that provide quick access to geological and geophysical infor-mation in various forms of presentation, including cartographic data, are presented in article. The conclusions and recommendations were formulated according to results of the study. They are aimed at improving the efficiency of cartographic supporting geophysical research and the development of inter-sectoral interaction between cartography and geophysics.
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Ganiev, O. Z., T. A. Amashukeli, L. V. Farfuliak, and K. V. Petrenko. "Organization of the stationary seismological observations point." Geofizicheskiy Zhurnal 43, no. 5 (November 24, 2021): 232–40. http://dx.doi.org/10.24028/gzh.v43i5.244085.

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The Institute of Geophysics of the NASU organizes and carries out continuous regional and local seismic observations on the territory of Ukraine. The article presents a universal modern model of seismic activity monitoring process, which is used in most international seismological agencies (USGS, EMSC, NEIC) and describes a typical stationary point of seismological observations of the National Seismological Network of the Institute of Geophysics of NAS of Ukraine. Seismological network of observations is a complex of systems consisting of stationary seismological points of registration of seismic waves, the distributed system of transfer and collecting of the seismological information, and also the center of operative processing of the data arriving from data registration points. The process of conducting regime seismological observations of local and remote seismic events on the territory of Ukraine and adjacent regions is described. Some important aspects of the need for comprehensive processing of registered events to identify local earthquakes and assess the current activity of tectonic structures in Ukraine are presented. The seismological network of the National Seismological Center of the Institute of Geophysics of the National Academy of Sciences of Ukraine is represented by a small number of stationary observation points: «Kiev-IRIS», «MI02-Poltava», «MI03-Skvyra», «MI04-Dnipro», «MI05-Stepanivka», «MI07-Mykolaiv», «ODS-Odesa», «MIU-Kryvyi Rih», and «MI06-Kremenchug». This number of seismological observation points does not actually provide seismic observation data to the central, eastern and southern parts of the territory of Ukraine and does not allow to reliably determine the level and quantitative characteristics of its seismic hazard. The seismic recorder Guralp CMG-40T manufactured by the British company GURALP SYSTEMS LIMITED is offered as optimal for the conditions and financial realities of Ukraine when organizing a stationary seismic observation point. It is proposed to use the seismological processing package SeisComP, which works on the SeedLink protocol, which is the basis of the data collection system by the Internet. This software product is the de facto world standard in the field of seismological data processing.
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Zhang, Jie. "President's Page: Looking into the world of medical imaging from the perspective of a geophysicist." Leading Edge 41, no. 6 (June 2022): 372–73. http://dx.doi.org/10.1190/tle41060372.1.

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I have worked in the geophysical industry and in academia as a geophysicist for 25 years. During the same time frame, I have also worked for 24 years in the medical industry. I founded a geophysical imaging company in 1998, and a year later I cofounded a medical imaging company. During the last seven years, I have led two biomedical companies to develop treatment solutions for bacterial infections and cancers. My career path offers me a unique insight into the world of medical imaging from the perspective of a geophysicist. In the following, I would like to share some of my observations, based on that unique perspective.
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Bell, Ernest, Nicholas Schmerr, Ryan Porter, Jacob Bleacher, Kelsey Young, Mong-Han Huang, Vedran Lekic, and Donald Pettit. "Active seismic exploration along a human lunar mission traverse analogue in the San Francisco volcanic field." Leading Edge 41, no. 10 (October 2022): 690–99. http://dx.doi.org/10.1190/tle41100690.1.

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Lunar surface activities during Apollo and terrestrial analogue lunar mission simulations have commonly focused on traverses that prioritize surface observations and sample collection activities. Along the way, geophysical measurements are often made. However, they are not necessarily made in a way that optimizes information about the physical subsurface properties, which is something that geophysics can provide. In 2010, NASA simulated a high-quality multiweek human lunar rover traverse analogue mission in the San Francisco volcanic field in Arizona. The traverse route and associated science station locations were selected based on addressing surface observation and sampling tasks. Geophysical studies were not included in the simulation. We returned to the same field area and obtained data on 19 active seismic refraction geophone lines from the science station locations accessed during the simulation. We analyzed the data to calculate 1D seismic velocity profiles for each of the lines. Results revealed up to seven distinct seismically defined material types, including a nearly ubiquitous veneer of regolith of variable thickness at the surface. Results also provided depth and thickness of the seven material types in the first 60 m of the subsurface at each of the science station locations. These cannot be obtained by geologic observations of the outcrops. Systematic interpretation of the area's overall subsurface stratigraphy was not feasible due to the geophysically nonsystematic nature of the original traverse's prioritization of the science station locations. The added geophysical understanding of a region could drive additional geologic investigations to locate samples of otherwise unknown material through the location of surface exposures or coring. This emphasizes the importance of synchronizing geologic and geophysical research requirements during lunar traverse planning and execution to optimize addressing scientific and utilization questions.
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Ozcep, F., and T. Ozcep. "Notes on the history of geophysics in the Ottoman Empire." History of Geo- and Space Sciences 5, no. 2 (September 5, 2014): 163–74. http://dx.doi.org/10.5194/hgss-5-163-2014.

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Abstract. In Anatolia, the history of geophysical sciences may go back to antiquity (600 BC), namely the period when Thales lived in Magnesia (Asia Minor). In the modern sense, geophysics started with geomagnetic works in the 1600s. The period between 1600 and 1800 includes the measurement of magnetic declination, inclination and magnetic field strength. Before these years, there is a little information, such as how to use a compass, in the Kitab-i Bahriye (the Book of Navigation) of Piri Reis, who is one of the most important mariners of the Ottoman Empire. However, this may not mean that magnetic declination was generally understood. The first scientific book relating to geophysics is the book Fuyuzat-i Miknatissiye that was translated by Ibrahim Müteferrika and printed in 1731. The subject of this book is earth's magnetism. There is also information concerning geophysics in the book Cihannuma (Universal Geography) that was written by Katip Celebi and in the book Marifetname written by Ibrahim Hakki Erzurumlu, but these books are only partly geophysical books. In Istanbul the year 1868 is one of the most important for geophysical sciences because an observatory called Rasathane-i Amire was installed in the Pera region of this city. At this observatory the first systematic geophysical observations such as meteorological, seismological and even gravimetrical were made. There have been meteorological records in Anatolia since 1839. These are records of atmospheric temperature, pressure and humidity. In the Ottoman Empire, the science of geophysics is considered as one of the natural sciences along with astronomy, mineralogy, geology, etc., and these sciences are included as a part of physics and chemistry.
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GUPTA, M. DAS, SOMESHWAR DAS, K. PRASANTHI, P. K. PRADHAN, and U. C. MOHANTY. "Validation of upper-air observations taken during the ARMEX-I and its impact on the global analysis-forecast system." MAUSAM 56, no. 1 (January 19, 2022): 139–46. http://dx.doi.org/10.54302/mausam.v56i1.871.

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During ARMEX-I several special observations were taken over Arabian Sea region and adjoining west coast of India, which gave an opportunity to study this region more thoroughly. To handle such voluminous data, ARMEX data center has been established at National Centre for Medium Range Weather Forecasting (NCMRWF), in collaboration with India Meteorological Department (IMD) and Indian Institute Technology (IIT), Delhi. One of the tasks of this center is to produce reanalysis for ARMEX period, utilizing these observations. It is essential to assimilate every observation from all available sources, especially over the data sparse oceanic regions for accurate determination of the three-dimensional structure of the atmospheric circulation. Before assimilating these data in global data assimilation system of NCMRWF, an attempt has been made to validate some of these data against observational facts from other sources. Upper-air observations (Digicora) from Dabolim, Goa have been compared with RS/RW observation of IMD, at Panjim, Goa. Though the trend in variations of all the meteorological parameters of these two stations is similar but there is a large difference in their absolute values. Reanalysis generated using the specially collected upper-air observations have been compared with the operational analysis of NCMRWF. The impact of these special observations on analysis and forecast system is found to be confined over the Arabian Sea region only in the lower troposphere. However, in the upper troposphere and stratosphere the impact is seen also over the equatorial Indian Ocean region.
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Carter, W. E., and D. S. Robertson. "Very-Long-Baseline Interferometry Applied to Geophysics." Symposium - International Astronomical Union 156 (1993): 133–44. http://dx.doi.org/10.1017/s0074180900173115.

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Very-long-baseline Interferometry (VLBI) has opened for study a broad new spectrum of geophysical phenomena including: direct observation of the tectonic motions and deformations of the Earth's crustal plates, observations of unprecedented detail of the variations in the rotation of the Earth, and direct measurement of the elastic deformations of the Earth in response to tidal forces. These new measurements have placed significant constraints on models of the interior structure of the Earth; for example, measurements of the variations in the Earth's nutation have been shown to be particularly sensitive to the shape of the core-mantle boundary. The VLBI measurements will allow us to construct a global reference frame accurate at the centimeter level. Such a frame will be essential to studying long-term global changes, especially those changes related to sea-level variations as recorded by tide gauge measurements.
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Meyers, Patrick, Daniel C. Bowden, Tanner Prestegard, Victor C. Tsai, Vuk Mandic, Gary Pavlis, and Ross Caton. "Direct Observations of Surface‐Wave Eigenfunctions at the Homestake 3D Array." Bulletin of the Seismological Society of America 109, no. 4 (June 25, 2019): 1194–202. http://dx.doi.org/10.1785/0120190026.

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Abstract Despite the theory for both Rayleigh and Love waves being well accepted and the theoretical predictions accurately matching observations, the direct observation of their quantifiable decay with depth has never been measured in the Earth’s crust. In this work, we present observations of the quantifiable decay with depth of surface‐wave eigenfunctions. This is done by making direct observations of both Rayleigh‐wave and Love‐wave eigenfunction amplitudes over a range of depths using data collected at the 3D Homestake array for a suite of nearby mine blasts. Observations of amplitudes over a range of frequencies from 0.4 to 1.2 Hz are consistent with theoretical eigenfunction predictions. They show a clear exponential decay of amplitudes with increasing depth and a reversal in sign of the radial‐component Rayleigh‐wave eigenfunction at large depths, as predicted for fundamental‐mode Rayleigh waves. Minor discrepancies between the observed eigenfunctions and those predicted using estimates of the local velocity structure suggest that the observed eigenfunctions could be used to improve the velocity model. Our results confirm that both Rayleigh and Love waves have the depth dependence that they have long been assumed to have. This is an important direct validation of a classic theoretical result in geophysics and provides new observational evidence that classical seismological surface‐wave theory can be used to accurately infer properties of Earth structure and earthquake sources.
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Dissertations / Theses on the topic "Geophysics Observations"

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Shcherbenko, Gina Nicole. "Post-Seismic Strain and Stress Evolution from Continuous GPS Observations." Thesis, State University of New York at Stony Brook, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1567846.

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Strain evolution and stress evolution following the 4 April 2010 M7.2 El Mayor-Cucapah earthquake are modeled using an adaptation of the strain transient detection tool developed by Holt and Shcherbenko 2013. The evolution of stress is calculated from postseismic strains, which are modeled from continuous GPS horizontal displacements. Strain fields are modeled in 2 ways; the total strain field based on total observed cGPS displacements, and the residual strain field, which subtracts a reference field from the total model. The residual shows anomalous strains resulting from the postseismic relaxation of the 2010 event. Anomalous and total strains are modeled in 0.1 year epochs for 2.4 years following the event. Both total and anomalous strains are converted into stress changes over time, assuming elastic incompressible behavior. Following the El Mayor event, the GPS constrained strain evolution shows the following: (1) The Southern San Andreas experiences a reduced rate of right-lateral strike slip strain accumulation between 3 July 2010 and 7 August 2012 (Figure 16a-d). (2) The San Jacinto Fault has normal rate of right-lateral strike-slip strain accumulation during this time. (3) Before the Brawley swarm of 26 August 2012, the state of strain evolves to enable unclamping of a left-lateral fault zone in the Brawley Seismic Zone (Figure 16a-d). (4) Large shear strains accumulate on the Laguna Salada Fault (northernmost segment)/southern Elsinore FZ (Figure 16a-d). We converted the strain changes into Coulomb stress changes on existing faults (both right-lateral and left-lateral). Several regions show increased Coulomb stress changes throughout the postseismic process. Furthermore, the Coulomb stress changes on the faults in the region progressively increase toward failure up to the time of the Brawley swarm.

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De, Michele Marcello. "Observations seismo-tectoniques par télédétection satellitaire." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2010. http://tel.archives-ouvertes.fr/tel-00656931.

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Pendant les 20 dernières années, notre connaissance de la déformation de la Terre a été complètement bouleversée par l'introduction de deux techniques de Géodésie spatiale. D'une part, ce que l'on appelle positionnement satellitaire ('point positioning') pas seulement à partir du système GPS (Global Positioning System) mais également à partir du système DORIS (Doppler Orbitography and Radio-positioning Integrated from Space). D'autre part, ont été développées des techniques d'imagerie satellitaire de corrélation d'images et d'interférométrie SAR (Synthetic Aperture Radar) ainsi que les méthodes de mesures de décalages sur des images panchromatiques à haute résolution spatiale. Ces nouvelles techniques, complémentaires de techniques plus classiques, ont permis une série d'avancées scientifiques notamment la confirmation et l'amélioration de la théorie de la tectonique de plaques, la cartographie fine de déplacements sismiques et asismiques, la cartographie de la distribution de la déformation en marges de plaques, l'amélioration de la compréhension des phénomènes de relaxation post sismiques, la détection de séismes lents et 'silencieux', la détection de signaux précurseurs de séismes ou d'éruptions volcaniques. Actuellement des nombreuses questions clés restent ouvertes. Notamment : - l'importance relative de la déformation accommodée sismiquement en bords de plaques par rapport à la déformation totale et à la contrainte tectonique ; - la contribution des séismes à la déformation par rapport au déplacement asismique sur les discontinuités (failles) ; - la possibilité de proposer des modèles pour les précurseurs des séismes et leur pertinence. Le but de la présente Thèse de Doctorat, est d'étudier le potentiel, les limitations et la complémentarité des données issues de l'Observation de la Terre pour prendre en compte et essayer de répondre à certains aspects des questions exposées ci-dessus. Nous avons concentré notre travail sur un nombre limité de zones telles que Bam (Iran), Parkfield (USA), et le Longmen Shan (China). Les travaux présentés se basent sur le Radar à Synthèse d'Ouverture (RSO), les techniques de corrélation d'image radar d'amplitude ainsi que les images panchromatiques à haute résolution du type SPOT-5 ou Quickbird. Dans notre recherche, nous avons essayé de développer des approches techniques originales (comme la corrélation d'images aériennes et Quickbird), nous avons étudié en particulier la modélisation et la suppression de la composante topographique (non désirée) des correlogrammes issus de l'imagerie optiques et radar et nous nous sommes également concentrés sur la contribution de la ionosphère au signal radar interférométrique en bande L. Pour résumer, notre travail s'est focalisé sur deux axes ; d'une part, on s'intéresse aux approches techniques originales; de l'autre, nous concentrons nos efforts de recherche sur la compréhension des processus néotectoniques, notamment le champ de déplacement cosismique, la répartition de la déformation pendant la phase intersismique et cosismique du cycle sismique sur failles majeures en bord de plaques (p. e. la faille de San Andreas) ou intra plaque (p. e. le Longmen Shan). Je suis inscrit à l'Ecole Doctorale de l'Université Pierre et Marie Curie de Paris depuis janvier 2009, mais je considère ce manuscrit de Thèse comme le résultat d'un chemin de travail qui a commencé bien avant. Dans ce manuscrit, je vous présente une synthèse des principaux résultats des recherches que j'ai menées depuis 2003. Chaque chapitre de ce manuscrit représente une étude dédiée et ciblée. Chaque étude a fait l'objet d'une publication scientifique ou a été présentée lors d'un congrès international.
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O'Toole, Thomas Bartholomew. "Studies of earthquakes and microearthquakes using near-field seismic and geodetic observations." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:9dcaca2e-c141-4e8a-94f6-34a9ff50d061.

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The Centroid-Moment Tensor (CMT) method allows an optimal point-source description of an earthquake to be recovered from a set of seismic observations, and, for over 30 years, has been routinely applied to determine the location and source mechanism of teleseismically recorded earthquakes. The CMT approach is, however, entirely general: any measurements of seismic displacement fields could, in theory, be used within the CMT inversion formulation, so long as the treatment of the earthquake as a point source is valid for that data. We modify the CMT algorithm to enable a variety of near-field seismic observables to be inverted for the source parameters of an earthquake. The first two data types that we implement are provided by Global Positioning System receivers operating at sampling frequencies of 1,Hz and above. When deployed in the seismic near field, these instruments may be used as long-period-strong-motion seismometers, recording displacement time series that include the static offset. We show that both the displacement waveforms, and static displacements alone, can be used to obtain CMT solutions for moderate-magnitude earthquakes, and that performing analyses using these data may be useful for earthquake early warning. We also investigate using waveform recordings - made by conventional seismometers deployed at the surface, or by geophone arrays placed in boreholes - to determine CMT solutions, and their uncertainties, for microearthquakes induced by hydraulic fracturing. A similar waveform inversion approach could be applied in many other settings where induced seismicity and microseismicity occurs.
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Morrow, Eric. "Estimates of Land Ice Changes from Sea Level and Gravity Observations." Thesis, Harvard University, 2014. http://dissertations.umi.com/gsas.harvard:11385.

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Understanding how global ice volume on the Earth has changed is of significant importance to improving our understanding of the climate system. Fortunately, the geographically unique perturbations in sea level that result from rapid changes in the mass of, otherwise difficult to measure, land-ice reservoirs can be used to infer the sources and magnitude of melt water. We explore the history of land-ice mass changes through the effect that these mass fluxes have had on both global and regional gravity and sea-level fields.
Earth and Planetary Sciences
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Enderlin, Ellyn Mary. "Observations and Modeling of Greenland Outlet Glacier Dynamics." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1372609057.

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Dardel, Cécile. "Entre désertification et reverdissement du Sahel : Diagnostic des observations spatiales et in situ." Phd thesis, Université Paul Sabatier - Toulouse III, 2014. http://tel.archives-ouvertes.fr/tel-00944267.

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Le Sahel est une région semi-aride caractérisée par un fort gradient bioclimatique et qui est particulièrement sensible à la variabilité des précipitations. Les périodes de très forte sécheresse qui ont sévi sur l'ensemble du Sahel entre les années 1970 et 1980 ont eu des effets dévastateurs sur les écosystèmes, les populations et leurs ressources. La théorie d'une désertification du Sahel a été ravivée, ainsi que celle prédisant une avancée rapide du Sahara sur le reste du continent. Dès les années 1990, l'analyse des premiers indices de végétation satellitaires (NDVI) acquises à l'échelle du globe à une fréquence temporelle journalière a mis en évidence une nette augmentation du NDVI depuis les années 1980. On parle alors de reverdissement du Sahel. L'objectif de cette thèse est de faire la part de ce reverdissement et d'une éventuelle dégradation des écosystèmes sahéliens, sur les 30 dernières années. Les indices de végétation satellitaires basés sur les propriétés optiques de la végétation verte sont de "simples estimateurs" de la production annuelle : la validation des tendances de NDVI sur le long-terme nécessite une vérité terrain. De telles données sont très difficiles à acquérir sur des échelles spatiales compatibles avec la résolution des satellites d'observation de la Terre et sur une période de temps permettant l'analyse de tendances temporelles. Dans le cadre du projet AMMA et de projets antérieurs, nous bénéficions de séries longues de masse de la strate herbacée pour deux régions : le Gourma au Mali (1984-2011) et le Fakara au Niger (1994-2011). La confrontation des deux sources de données (NDVI GIMMS-3g et productivité végétale mesurée sur le terrain) montre que le Sahel pastoral du Gourma est marqué par un reverdissement ainsi que par une augmentation de la productivité végétale mesurée in situ. En revanche, le Sud-ouest Nigérien montre une tendance à la baisse de ces deux variables. La cohérence des données de terrain avec les observations satellitaires confirme que le NDVI peut être utilisé comme outil de détection de l'évolution des écosystèmes semi-arides sur de longues périodes de temps. A l'échelle du Sahel, des tendances au reverdissement sont mises en évidence sur la plus grande partie de la région, sur la période 1981-2011. L'analyse du RUE, le rapport de la production par le cumul de pluie, a montré que le reverdissement du Gourma est majoritairement expliqué par le rétablissement des précipitations, et que les écosystèmes sahéliens sont particulièrement résilients aux évènements climatiques extrêmes. Cette résilience, cependant, est surtout mise en évidence pour les sols profonds sableux. Des changements contradictoires sont en effet observés sur la partie du paysage constituée de sols superficiels qui connaissent une augmentation des coefficients de ruissellement et de l'érosion, provoquant parfois une dégradation du couvert végétal. Le reverdissement observé à l'échelle du Gourma doit donc être nuancé par des changements des écosystèmes pouvant toucher une petite portion du paysage (les sols superficiels). Sur le Fakara nigérien, des tendances à la dégradation du couvert herbacé sont mises en évidence par les deux sources de données et ne sont pas expliquées par les précipitations. Les changements d'occupation du sol (augmentation des superficies cultivées, raccourcissement des temps de jachère) peuvent expliquer une diminution de la fertilité du sol et donc de la capacité de production de la région. Nous n'observons donc pas de désertification du Sahel sur les 30 dernières années mais bien une reprise généralisée de la végétation qui suit globalement le rétablissement des précipitations. Cela n'exclut pas que dans certaines régions, ou à l'échelle locale, une dégradation du couvert puisse aussi être observée, comme par exemple sur les sols soumis à une forte érosion ou sur quelques terroirs agricoles, ce qui tend à réconcilier les deux théories.
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González-Caneda, María. "Investigation Of Source Parameters Of Earthquakes In Northern Sweden." Thesis, Uppsala universitet, Geofysik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-380133.

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By studying the frequency domain of seismic signals generated by earthquakes, the source parameters can be recovered, i.e., the seismic moment (M0) and the stress drop (Δσ). This method is an advantage especially since if the source parameters are calculated from the time domain a full waveform inversion is needed, therefore this procedure facilitates the computation. Besides, the moment magnitude (Mw) can be calculated from the seismic moment and, in turn, the local magnitude (ML) can be obtained by using an algorithm that matches different ranges of moment magnitude with their corresponding local magnitude. In the present thesis, small to moderate earthquakes in Northern Sweden have been used to develop a code that calculates the source parameters through the fitting of five different spectral models and, this way, discerns which model obtains the best determination of the parameters. These models have been chosen in a way that we can also extract information about the attenuation. The different models are; the Brune spectral model, Boatwright spectral model, Boatwright spectral model with a fixed fall-off rate, a general form of the spectral model with quality factor equal to 1000 and a general form of the spectral model with quality factor equal to 600. Among these models, the Boatwright model with fixed fall-off rate equal to 2, has been found to give the best fit to the data used in this thesis. This might be due to the regional conditions which are the low attenuation in the crust of northern Fennoscandia and the short hypocentral distances of the studied earthquakes. The earthquakes studied in the present thesis have shown a range of magnitudes from ML 4.2 to -0.2 with radius of an assumed circular fault ranging from 269 m to 66 m.
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Cotton, Julien. "Analyse et traitement de données sismiques 4D en continu et en temps réel pour la surveillance du sous-sol." Electronic Thesis or Diss., Paris Sciences et Lettres (ComUE), 2019. http://www.theses.fr/2019PSLEM023.

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La sismique réflexion 3D est largement utilisée dans l'industrie pétrolière. Cette méthode d’auscultation du sous-sol fournit des informations sur les structures géologiques et peut être utilisée pour construire des modèles de réservoir. Cependant, les propriétés dérivées des données sismiques 3D (et 2D) ne sont que statiques: elles ne permettent pas d’évaluer ce qui change avec le temps. L'ajout d'une dimension temporelle aux données 3D est obtenue par la répétition des mesures à plusieurs dates séparées de plusieurs mois voire même de plusieurs années. Ainsi, la sismique4D (time-lapse) permet d’appréhender les modifications du sous-sol sur le long terme. Depuis les années 90, cette méthode est utilisée dans le monde entier en mer et à terre. Pour réaliser une surveillance beaucoup plus fréquente (quotidienne), voire continue (quelques heures) du sous-sol, CGG a développé, en collaboration avec Gaz de France (désormais ENGIE) et l’Institut Français du Pétrole (maintenant IFPEN), une solution basée sur des sources et des récepteurs enterrés: SeisMovie. SeisMovie a été initialement conçu pour suivre et cartographier en temps-réel le front de gaz lors des opérations de stockage en couche géologique. Il est aussi utilisé pour observer l’injection de vapeur nécessaire à la production d’huile lourde. Dans cette thèse, nous apportons des contributions à trois défis qui apparaissent lors du traitement des données sismiques issues de ce système. Le premier concerne l'atténuation des variations de proche surface causées par les ondes « fantômes » qui interfèrent avec les ondes primaires. Le second concerne la quantification des modifications du sous-sol en termes de variation de vitesse de propagation et d’impédance acoustique.Le troisième concerne le temps-réel : le traitement doit être au moins aussi rapide que le cycle d’acquisition (quelques heures). En effet l’analyse des données doit permettre aux ingénieurs réservoirs de prendre rapidement des décisions (arrêt de l’injection, diminution de la production). Dans un cadre plus général, il existe des similitudes conceptuelles entre la 3D et la 4D. En 4D, ce sont les acquisitions répétées qui sont comparées entre elles (ou avec une référence). En3D, pendant l’acquisition, les géophysiciens de terrain comparent les points de tir unitaires entre eux afin d’évaluer la qualité des données pour prendre des décisions (reprendre le point de tir, continuer). Dès lors, certains outils 4D temps réel développés pendant cette thèse peuvent être appliqués. Ainsi une toute nouvelle approche appelée TeraMig pour le contrôle qualité automatisé sur le terrain sera également présentée
3D seismic reflection is widely used in the oil industry. This standard subsoil auscultation method provides information on geological structures and can be used to build reservoir models. However, the properties derived from3D (and 2D) seismic data are only static: 3D does not allow to evaluate the changes with calendar time. The addition of a temporal dimension to 3D data is obtained by repeating the measurements at several dates separated by several months or even several years. Thus, 4D seismic (time-lapse) makes it possible to measure and to analyze the changes of the subsoil in the long term. Since the 90s, this method is used worldwide at sea and on land. To carry out a much more frequent monitoring (daily), even continuous (a few hours) of the subsoil, CGG developed, in collaboration with Gazde France (now ENGIE) and Institut Français du Pétrole (now IFPEN), a solution based on buried sources and receptors: SeisMovie. SeisMovie was originally designed to monitor and map the gas front in real time during geological disposal operations. It is also used to observe the steam injection required for heavy oil production. In this thesis, we bring contributions to three challenges arising in the processing of seismic data from this system. The first one concerns the attenuation of near-surface variations caused by "ghost" waves that interfere with primary waves. The second one concerns the quantification of subsurface changes in terms of propagation velocity variation and acoustic impedance.The third one concerns real-time: the data processing must be at least as fast as the acquisition cycle (a few hours). Infact, the analysis of the data must enable the reservoir engineers to make quick decisions (stop of the injection, decreaseof the production). In a more general context, there are conceptual similarities between 3D and 4D. In 4D, the repeated acquisitions are compared with each other (or with a reference). In 3D, during acquisition, field geophysicists compare unitary shot points with each other to assess the quality of the data for decision-making (reshooting, skipping orcontinuing). Therefore, some 4D real-time tools developed during this thesis can be applied. A new approach called TeraMig for automated quality control in the field will also be presented
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Cordisco, Emmanuel. "Etude de la synergie des observations satellites pour la caractérisation du manteau neigeux." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2005. http://tel.archives-ouvertes.fr/tel-00089376.

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La neige étant une composante importante du climat terrestre, il convient de l'étudier à l'échelle du globe pour en comprendre son rôle.

Ces travaux visent ainsi à étudier le contenu en information sur le manteau neigeux à l'échelle globale des observations satellites réalisées à partir de différents instruments couvrant différents domaines du spectre électromagnétique (visible, infrarouge et micro-ondes). Des paramètres autres que la neige interférant dans la problématique, il est nécessaire de les déterminer afin d'encadrer leurs influences. Ensuite, on cherchera comment limiter la pollution qu'engendre ces paramètres sur l'information accessible du manteau neigeux, on aura alors recours à ce que l'on appelera des statistiques locales.
Hélas ces statistiques locales ne sont pas disponibles sur l'ensemble du globe. Il est donc inévitable d'utiliser la modélisation pour permettre l'interpolation. Toutefois, une méthode originale d'ajustement de modèle par analyse en composantes principales sera présentée. Au final, la synergie entre les observations satellites, la modélisation et les mesures in situ devra être utilisée pour extraire de façon optimale l'information contenu dans les données et permettre l'inversion de l'épaisseur de neige à grande échelle.
D'autre part, il sera intéressant de caractériser les différents types de neiges existants selon une classification non-supervisée des observations satellites afin d'extraire les similitudes et les spécificités de chacun de ces types.
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Eymin, Céline. "Etude des mouvements à la surface du noyau terrestre : du 17ème au 21ème siècle." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2004. http://tel.archives-ouvertes.fr/tel-00007173.

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Afin d'étudier la dynamique du noyau terrestre, nous reconstruisons les mouvements à la surface du noyau liquide compatibles avec les observations du champ magnétique. La similitude des mouvements obtenus par deux méthodes indépendantes et les résultats de tests synthétiques confirment la pertinence de ces reconstructions. Deux types d'observations sont utilisées : des observations terrestres couvrant la période 1590-1990 et des observations satellitaires haute-résolution récentes. Une série temporelle des mouvements
historiques et un modèle détaillé des mouvements actuels sont obtenus. L'estimation des marges d'erreurs associées permet d'identifier les structures fiables. Nos reconstructions sont en accord avec différents phénomènes mis en évidence par des modélisations 3D du noyau. Nous montrons aussi que les jerks géomagnétiques ont une signature dynamique très nette. Enfin, nous posons les bases d'une méthode d'assimilation variationnelle de données adaptée à l'étude du noyau.
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Books on the topic "Geophysics Observations"

1

Pragmatic inversion of geophysical data. Berlin: Springer-Verlag, 1992.

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Bodhaine, Barry A. Geophysical monitoring for climatic change, no. 16: Summary report, 1987. Edited by Environmental Research Laboratories (U.S.). Boulder, Colo: U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, Environmental Research Laboratories, 1988.

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Séminaire ORSTOM (1991 Université de Savoie). Du capteur aux banques de données: Techniques d'instrumentation en géophysique : Séminaire ORSTOM, Université de Savoie, Aussois, du 10 au 12 juin 1991. Paris: Editions de l'ORSTOM, 1993.

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Hitchman, A. P. First-order regional magnetic survey of Australia for epoch, 1990.0, 1986-89. Canberra: Australian Govt. Pub. Service, 1990.

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Nikolaevich, Rykunov Lev, ed. Seĭsmologicheskie donnye nabli͡u︡denii͡a︡ v SSSR i za rubezhom. Moskva: "Nauka,", 1986.

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King, A. Applications of geophysical methods for monitoring acid mine drainage. Ottawa, Ont: Canada Centre for Mineral and Energy Technology = Centre canadien de la technologie des minéraux et de l'énergie, 1994.

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Grau, Jordi Seguí. Análisis de la serie de temperatura del Observatorio del Ebro (1894-2002). Roquetes, Tarragona: Observatori de lʼEbre, 2003.

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March, Rod. Mass balance, meteorological, ice motion, surface altitude, and runoff data at Gulkana Glacier, Alaska, 1992 balance year. Fairbanks, Alaska: U.S. Geological Survey, 1996.

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March, Rod. Mass balance, meteorological, ice motion, surface altitude, and runoff data at Gulkana Glacier, Alaska, 1992 balance year. Fairbanks, Alaska: U.S. Geological Survey, 1996.

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March, Rod. Mass balance, meteorological, ice motion, surface altitude, and runoff data at Gulkana Glacier, Alaska, 1992 balance year. Fairbanks, Alaska: U.S. Dept. of the Interior, Geological Survey, 1996.

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Book chapters on the topic "Geophysics Observations"

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Bloxham, J. "The determination of fluid flow at the core surface from geomagnetic observations." In Mathematical Geophysics, 189–208. Dordrecht: Springer Netherlands, 1988. http://dx.doi.org/10.1007/978-94-009-2857-2_9.

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Chadha, R. K. "Seismic Signals in Well Water Observations." In Encyclopedia of Solid Earth Geophysics, 1–6. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-10475-7_188-1.

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Davis, Earl E., and Andrew T. Fisher. "Heat Flow, Seafloor: Methods and Observations." In Encyclopedia of Solid Earth Geophysics, 1–13. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-10475-7_65-1.

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Cahalan, Robert F. "Landsat Observations of Fractal Cloud Structure." In Non-Linear Variability in Geophysics, 281–95. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-009-2147-4_22.

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Davis, Earl E., and Andrew T. Fisher. "Heat Flow, Seafloor: Methods and Observations." In Encyclopedia of Solid Earth Geophysics, 582–91. Dordrecht: Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-90-481-8702-7_65.

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Chadha, R. K. "Seismic Signals in Well Water Observations." In Encyclopedia of Solid Earth Geophysics, 1493–98. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-58631-7_188.

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Davis, Earl E., and Andrew T. Fisher. "Heat Flow, Seafloor: Methods and Observations." In Encyclopedia of Solid Earth Geophysics, 736–49. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-58631-7_65.

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Starchenko, S. V. "Simple Estimations for Planetary Convection Turbulence and Dynamo Magnetism from Optimized Scaling and Observations." In Springer Geophysics, 501–11. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-90437-5_34.

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Diamond, P. J. "Observations of Cosmic Masers." In The Impact of VLBI on Astrophysics and Geophysics, 213–22. Dordrecht: Springer Netherlands, 1988. http://dx.doi.org/10.1007/978-94-009-2949-4_75.

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Khalid, Zubair, and Abubakr Muhammad. "Compressive Sensing on the Sphere: Slepian Functions for Applications in Geophysics." In Compressive Sensing of Earth Observations, 33–54. Boca Raton, FL : Taylor & Francis, 2017.: CRC Press, 2017. http://dx.doi.org/10.1201/9781315154626-2.

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Conference papers on the topic "Geophysics Observations"

1

Cole, S., and M. Karrenbach. "Multi-well DAS Observations for Hydraulic Fracture Monitoring." In Fifth EAGE Workshop on Borehole Geophysics. European Association of Geoscientists & Engineers, 2019. http://dx.doi.org/10.3997/2214-4609.2019x604059.

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Nikitin, A. A., and A. N. Lebedev. "Integrated processing and interpretation of multilevel geophysical observations." In Geophysics of the 21st Century - The Leap into the Future. European Association of Geoscientists & Engineers, 2003. http://dx.doi.org/10.3997/2214-4609-pdb.38.f120.

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Bychkov, S. G., A. A. Simanov, and V. V. Khokhlova. "Control of The Process of Subsidence of The Earth's Surface by Monitoring Gravimetric Observations." In Engineering and Mining Geophysics 2021. European Association of Geoscientists & Engineers, 2021. http://dx.doi.org/10.3997/2214-4609.202152028.

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Olhoeft, Gary R. "Geophysical Observations of Geological, Hydrological and Geochemical Heterogeneity." In Symposium on the Application of Geophysics to Engineering and Environmental Problems 1994. Environment and Engineering Geophysical Society, 1994. http://dx.doi.org/10.4133/1.2922059.

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R. Olhoeft, Gary. "Geophysical Observations Of Geological, Hydrological And Geochemical Heterogeneity." In 7th EEGS Symposium on the Application of Geophysics to Engineering and Environmental Problems. European Association of Geoscientists & Engineers, 1994. http://dx.doi.org/10.3997/2214-4609-pdb.208.1994_009.

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Shapovalov, V. L., A. V. Morozov, D. R. Tagirova, and V. A. Yavna. "Forecasting Changes in The Water Level in The River Based on Long-Term Observations of Influencing Factors." In Engineering and Mining Geophysics 2021. European Association of Geoscientists & Engineers, 2021. http://dx.doi.org/10.3997/2214-4609.202152054.

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Shulakov, D. Y., F. G. Verkholantsev, and A. S. Zvereva. "Detailed Seismological Monitoring Technology Based on Observations in the Krasnoslobodsky Fault Zone of the Starobinsk Potash Deposit." In Engineering and Mining Geophysics 2020. European Association of Geoscientists & Engineers, 2020. http://dx.doi.org/10.3997/2214-4609.202051057.

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Tokarev, M., A. Pirogova, A. Roslyakov, N. Shalaeva, Y. Terekhina, S. Glubokovskikh, and N. Rybin. "Evaluation of Potential Geological Hazards in the Sea of Okhotsk from Conventional 3D Seismic Observations." In 3rd Applied Shallow Marine Geophysics Conference. Netherlands: EAGE Publications BV, 2018. http://dx.doi.org/10.3997/2214-4609.201802684.

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Walters, Shelby L., Richard D. Miller, Joseph B. Dunbar, and Steve Smullen. "Repeatability Observations from a 2D Time‐Lapse Seismic Survey." In Symposium on the Application of Geophysics to Engineering and Environmental Problems 2007. Environment and Engineering Geophysical Society, 2007. http://dx.doi.org/10.4133/1.2924750.

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Kovachev, S. A., A. A. Krylov, and S. G. Mironyuk. "Seismic Hazard Assessment Along The Gas Pipeline Route in The Russian Sector of The Black Sea Using Bottom Seismological Observations." In Engineering and Mining Geophysics 2021. European Association of Geoscientists & Engineers, 2021. http://dx.doi.org/10.3997/2214-4609.202152117.

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Reports on the topic "Geophysics Observations"

1

Cenedese, Claudia, and Mary-Louise Timmermans. 2017 program of studies: ice-ocean interactions. Woods Hole Oceanographic Institution, November 2018. http://dx.doi.org/10.1575/1912/27807.

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The 2017 Geophysical Fluid Dynamics Summer Study Program theme was Ice-Ocean Interactions. Three principal lecturers, Andrew Fowler (Oxford), Adrian Jenkins (British Antarctic Survey) and Fiamma Straneo (WHOI/Scripps Institution of Oceanography) were our expert guides for the first two weeks. Their captivating lectures covered topics ranging from the theoretical underpinnings of ice-sheet dynamics, to models and observations of ice-ocean interactions and high-latitude ocean circulation, to the role of the cryosphere in climate change. These icy topics did not end after the first two weeks. Several of the Fellows' projects related to ice-ocean dynamics and thermodynamics, and many visitors gave talks on these themes.
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Berndt, Christian. RV SONNE Fahrtbericht / Cruise Report SO277 OMAX: Offshore Malta Aquifer Exploration, Emden (Germany) – Emden (Germany), 14.08. – 03.10.2020. GEOMAR Helmholtz Centre for Ocean Research Kiel, January 2021. http://dx.doi.org/10.3289/geomar_rep_ns_57_20.

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SO277 OMAX served two scientific projects. The objectives of the first project, SMART, were to develop multi-disciplinary methodologies to detect, quantify, and model offshore groundwater reservoirs in regions dominated by carbonate geology such as the Mediterranean Sea. To this end we acquired controlled-source electromagnetic, seismic, hydroacoustic, geochemical, seafloor imagery data off Malta. Preliminary evaluation of the geophysical data show that there are resisitivity anomalies that may represent offshore freshwater aquifers. The absence of evidence for offshore springs means that these aquifers would be confined and that it will be difficult to use them in a sustainable manner. The objective of the second project, MAPACT-ETNA, is to monitor the flank of Etna volcano on Sicily which is slowly deforming seaward. Here, we deployed six seafloor geodesy stations and six ocean bottom seismometers for long-term observation (1-3 years). In addition, we mapped the seafloor off Mt. Etna and off the island of Stromboli to constrain the geological processes that control volcanic flank stability.
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Lithologic, geophysical, and well-construction data for observation wells in the Melton Valley area, Oak Ridge Reservation, Tennessee. US Geological Survey, 1989. http://dx.doi.org/10.3133/wri884197.

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