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	References of "Francis, Olivier 50001803" in Showing results 121 to 140 of 184 2 3 4 5 6 7 8 9 10 Absolute Gravity Measurements in Lomonosov, Saint-Petersbourg, Russia Francis, Olivier Report (2004) Detailed reference viewed: 111 (5 UL) Superconducting gravimeters in seismology Francis, Olivier ; van Dam, Tonie in Newsletter of the European-Mediterranean Seismological Centre (2004), 21 Detailed reference viewed: 87 (4 UL) Proceedings of the Workshop: The Sate of GPS Vertical Positioning Precision: Separation of Earth Processes by Space Geodesy van Dam, Tonie ; Francis, Olivier Book published by Centre Européen de Géodynamique et de Séismologie (2004) Detailed reference viewed: 137 (1 UL) Indication of the uplift of the Ardenne in long-term gravity variations in Membach (Belgium) Francis, Olivier ; Van Camp, Michel; van Dam, Tonie et al in Geophysical Journal International (2004), 158(1), 346-352 We report on the results of 7 yr of collocated gravity observations made with an FG5 abso- lute (AG) gravimeter and a GWR C-Series superconducting gravimeter (SG) located at the Membach Geophysical ... [more ▼] We report on the results of 7 yr of collocated gravity observations made with an FG5 abso- lute (AG) gravimeter and a GWR C-Series superconducting gravimeter (SG) located at the Membach Geophysical Station in eastern Belgium. The SG gravity residuals track changes in gravity periodically observed by the AG, at the microgal level. Further, in the SG resid- ual signal we distinguish a quasi-seasonal term that can be mostly explained by variations in local water storage effects. In the AG time-series we observe a small trend in the gravity of −0.6 ± 0.1 μGal yr−1 perhaps indicating that the Membach Station is being displaced up- wards by about 3.0 mm yr−1. An uplift of the region is confirmed by Global Positioning System (GPS) measurements performed 3 km away. We are able to explain the features in the gravity time-series in terms of water storage variability, post-glacial rebound and tectonic activity. [less ▲] Detailed reference viewed: 152 (3 UL) Concept and Status of the ECGN Project Ihde, J.; Baker, T. F.; Bruyninx, C. et al in Torres, João Agria; Hornik, Helmut (Eds.) EUREF Publication No. 13 (2004) Detailed reference viewed: 93 (0 UL) Processing of the Absolute data of the ICAG01 Francis, Olivier ; van Dam, Tonie in Francis, Olivier; van Dam, Tonie (Eds.) Proceedings of the Workshop: IMG-2002 Instrumentation and Metrology in Gravimetry (2003) Detailed reference viewed: 84 (1 UL) Analysis of the Results of the Sixth International Comparison of Absolute Gravimeters ICAG-2001 Vistuhskin, Leonid; Jiang, Zhiheng; Becker, Matthias et al in Tziavos, Ilias N. (Ed.) Gravity and Geoid 2002 (2003) Detailed reference viewed: 40 (0 UL) Unified European Gravity Reference Network 2002 (UEGN2002), a Status Report Kenyeres, A.; Boedecker, G.; Francis, Olivier in Tziavos, Ilias N. (Ed.) Gravity and Geoid 2002 (2003) Detailed reference viewed: 74 (2 UL) Genèse et Futur d'un laboratoire de Gravimétrie à Walferdange (Luxembourg) Melchior, Paul; Flick, Johny; Francis, Olivier in Helmut Moritz's Fetschrift zum 70. Geburtstag (2003) Detailed reference viewed: 56 (3 UL) Comparison between modeled and Observed Gravity Tidal Parameters at Ny-Alesund, Svalbard Sato, Tadahiro; Tamura, Y; Matsumoto, K et al in Francis, Olivier; van Dam, Tonie (Eds.) Proceedings of the Workshop: IMG-2002 Instrumentation and Metrology in Gravimetry (2003) Detailed reference viewed: 60 (1 UL) GGFC Special Bureau for Loading: Current status and plans van Dam, Tonie ; Plag, H. P.; Francis, Olivier et al in Richter, Bernd; Schwegmann, Wolfgang; Dick, Wolfgang R. (Eds.) Proceedings of the IERS Workshop on Combination Research and Global Geophysical Fluids (2003) Detailed reference viewed: 91 (3 UL) Proceedings of the Workshop: IMGC-2002 Instrumentation and Metrology in Gravimetry Francis, Olivier ; van Dam, Tonie Book published by Centre Européen de Géodynamique et de Séismologie (2003) Detailed reference viewed: 83 (2 UL) Sixth International Comparison of Absolute Gravimeters, ICAG-2001 Vitushkin, Leonid; Jiang, Zhiheng; Becker, Matthias et al in Francis, Olivier; van Dam, Tonie (Eds.) Proceedings of the Workshop: IMG-2002 Instrumentation and Metrology in Gravimetry (2003) Detailed reference viewed: 64 (4 UL) RESEAU DE GRAVIMETRIE ABSOLUE ALGERIEN Francis, Olivier in Bulletin des Sciences Géographiques (2003), 09(Avril), 3-9 Detailed reference viewed: 76 (7 UL) Comment on "Nature of the recent vertical ground movements inferred from high-precision leveling data in an intraplate setting: NE Ardenne, Belgium" by A. Demoulin and A. Collignon Camelbeeck, Thierry; Van Camp, Michel; Jongmans, Denis et al in Journal of Geophysical Research (2002), 107(B11), 2281-2281 Comment on ‘‘Nature of the recent vertical ground movements inferred from high-precision leveling data in an intraplate setting: NE Ardenne, Belgium’’ by A. Demoulin and A. Collignon Detailed reference viewed: 180 (4 UL) Absolute gravity measurements in Belgium: a tool for geodynamic interpretation Van Camp, Michel; Francis, Olivier ; Camelbeeck, Thierry in Degryse, Patrick; Sintubin, Manuel (Eds.) Contributions to the Geology of Belgium and Northwest Europe (2002) Detailed reference viewed: 66 (2 UL) Results of the Sixth International Comparison of Absolute Gravimeters, ICAG-2001 Vitushkin, L.; Becker, M.; Jiang, Z. et al in Metrologia (2002), 39(5), 407-427 The Sixth International Comparison of Absolute Gravimeters was held from 5 June to 28 August 2001 at the Bureau International des Poids et Mesures (BIPM), Sevres. Seventeen absolute gravimeters were used ... [more ▼] The Sixth International Comparison of Absolute Gravimeters was held from 5 June to 28 August 2001 at the Bureau International des Poids et Mesures (BIPM), Sevres. Seventeen absolute gravimeters were used to make measurements at five sites of the BIPM gravity network. The vertical gravity gradients at the sites and the ties between them were also measured using seventeen relative gravimeters. For the first time the ties were also measured using absolute gravimeters. Various methods of processing the absolute and relative data were tested to calculate the results. The final results of ICAG-2001 are presented. The acceleration due to gravity at a height of 0.90 m is given as (980925701.2 ± 5.5) Gal and (980928018.8 ± 5.5) Gal for sites A and B, respectively, calculated using a combined adjustment of the absolute and relative data. [less ▲] Detailed reference viewed: 131 (4 UL) Evaluation of the precision of using absolute gravimeters to calibrate superconducting gravimeters Francis, Olivier ; van Dam, Tonie in Metrologia (2002), 39(5), 485-488 We present an experiment in which four different FG5 absolute gravimeters (AG) were operated simultaneously alongside a superconducting relative gravimeter (SG). We demonstrate that 0.1 % precision can be ... [more ▼] We present an experiment in which four different FG5 absolute gravimeters (AG) were operated simultaneously alongside a superconducting relative gravimeter (SG). We demonstrate that 0.1 % precision can be achieved on the calibration factor of the SG by comparison with AG measurements, independently of the FG5 instrument used for the calibration and of the offsets among the FG5 absolute values. This experiment demonstrates the robustness of using any FG5 absolute gravimeter to calibrate any SG. This result is of value to geoscientists analysing data from (a) globally distributed SGs which most probably have been calibrated using different instruments; or (b) any individual SG calibrated with different FG5 absolute gravimeters. [less ▲] Detailed reference viewed: 144 (4 UL) Experiment to evaluate crustal motions across the Ardenne and the Roer Graben (north-western Europe) using absolute gravity measurements Van Camp, M.; Camelbeeck, Thierry; Francis, Olivier in Metrologia (2002), 39(5), 503-508 Absolute gravity measurements using the FG5-202 gravimeter have been conducted twice a year since September 1999 along a 120 km long profile across the Belgian Ardenne and the Roer Graben. As in this ... [more ▼] Absolute gravity measurements using the FG5-202 gravimeter have been conducted twice a year since September 1999 along a 120 km long profile across the Belgian Ardenne and the Roer Graben. As in this region there is a difference of an order of magnitude between the inferred vertical crustal movements deduced from the difference of levelling (about 1 mm/year) and geological information (0.1 mm/year), our goal is to better constrain the present-day deformation. The absolute gravity measurements are performed at Rochefort, Humain, Werpin, Manhay, Sprimont, Membach (Belgium) and Monschau, Julich and Bensberg (Germany). A complete description of the network is given, and specific difficulties at some stations are presented. The precision achieved, generally less than 2.0 Gal integrated over more than 24 h of observation, is quite satisfactory at all stations but Julich. The mining activities around Julich cause an increase in the noise up to 7 Gal integrated over more than 72 h. We also discuss possible causes of gravity variations in this region. At present, it is still not possible to detect any trend in the available data. However, after five years of observations, we should be able to detect or constrain any possible long-term trend with a limit of 2.5 mm/year, assuming that a height change of 1 mm causes a change in gravity of 0.2 Gal. To ensure that the absolute gravimeter is giving accurate results, it has been regularly compared with the superconducting gravimeter installed at the Membach reference station. [less ▲] Detailed reference viewed: 116 (3 UL) The New IERS Special Bureau for Loading (SBL) van Dam, Tonie ; Plag, Hans-Peter; Blewitt, Geoffrey et al in International VLBI Service for Geodesy and Astrometry: General Meeting Proceedings (2002) Currently, the establishment of the International Earth Rotation Service (IERS) Special Bureau for Loading (SBL) is in progress as part of the IERS Global Geophysical Fluids Center (GGFC). The main ... [more ▼] Currently, the establishment of the International Earth Rotation Service (IERS) Special Bureau for Loading (SBL) is in progress as part of the IERS Global Geophysical Fluids Center (GGFC). The main purpose of the SBL is to provide reliable, consistent model predictions of loading signals that have been thoroughly tested and validated. The products will describe at least the surface deformation, gravity signal and geo-center variations due to the various surface loading processes in reference frames relevant for direct comparison with existing geodetic observing techniques. To achieve these goals, major scientific advances are required with respect to the Earth model, the theory and algorithms used to model deformations of the Earth as well as improvements in the observational data related to surface loading. [less ▲] Detailed reference viewed: 101 (3 UL) 2 3 4 5 6 7 8 9 10

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