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- Volume 4, Issue 5, 1986
First Break - Volume 4, Issue 5, 1986
Volume 4, Issue 5, 1986
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Offset-dependent seismic amplitudes from karst limestone in northern Belgium
Authors N. Van den Berghe, E. Poggiagliolmi and G. WattsIn northern Belgium, karst limestones at the top of the Lower Carboniferous form a water-bearing reservoir at depths varying from 1000 to more than 2000 m. The temperature of the water and the hydrological characteristics make it an attractive reservoir for low enthalpy geothermal energy extraction. The depth range of the reservoir, its structure, and the sealing characteristics of the overlying rocks imply that it might form a trap for natural gas. The hypothesis that natural gas might he present in this Lower Carboniferous reservoir was recently confirmed by the discovery of a dissolved gas mixture, with methane, at the Merksplas-Beerse well. In the light of this varied economic potential of the reservoir, a preliminary seismic exploration programme was carried out by the Belgian Geological Survey. The reservoir properties, however, are rather heterogeneously distributed, as the pore space is made up of dissolution pockets and fractures. Therefore, a detailed analysis of the seismic reflection data was instigated in order to assess the potential of the seismic method for the detection of the karst distribution. This paper deals with the results of this analysis.
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Shallow seismic investigations in engineering practice in Belgium
Authors J.P. Henriet, A. Monjoie and C. SchroederIn the last ten to fifteen years, shallow seismic investigations have become standard practice in major geotechnical projects in Belgium. Most of these investigations involved a combined use of different seismic techniques, sometimes implemented with other geophysical methods such as geoelectrical or microgravimetric surface measurements and borehole logging. The objectives of applying seismic techniques were generally twofold: the determination of the structural context of a geotechnical site, with particular attention being paid to possible anomalies, and the evaluation of dynamic elastic properties of the bedrock. Relatively deep seismic investigations, carried out in engineering projects related to the exploitation of geothermal resources, nuclear energy projects (e.g. radioactive waste disposal) or feasibility studies of underground gas storage, fall beyond the scope of this paper.
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Internal geophysics at the Belgian research institutions
By P. MelchiorWhat is 'internal geophysics' and how is it related to exploration geophysics? To be a geophysicist means to study the earth with physical methods. We speak of 'internal geophysics' if we mean by 'the earth' its solid part. Understood in this way, internal geophysics includes exploration geophysics. The 'internal geophysicist' is motivated primarily by the desire to understand what goes on inside the earth, while the exploration geophysicist is motivated primarily by the economic necessity to find oil, minerals, or water. The different motivation leads us on different paths, but the common foundations of our work means that there are a number of similarities and sometimes surprising cross-connections. For more than a century research in internal geophysics has been conducted at three Belgian national scientific institutions: the Royal Observatory, the Royal Meteorological Institute and the National Geographical Institute. Fields of particular interest are: precise positioning, gravimetry, earth tides, seismology, magnetism and palaeomagnetism.
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Volumes & issues
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Volume 42 (2024)
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Volume 41 (2023)
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Volume 40 (2022)
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Volume 39 (2021)
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Volume 38 (2020)
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Volume 37 (2019)
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Volume 36 (2018)
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Volume 35 (2017)
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Volume 34 (2016)
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Volume 33 (2015)
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Volume 32 (2014)
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Volume 31 (2013)
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Volume 30 (2012)
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Volume 29 (2011)
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Volume 28 (2010)
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Volume 27 (2009)
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Volume 26 (2008)
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Volume 25 (2007)
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Volume 24 (2006)
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Volume 23 (2005)
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Volume 22 (2004)
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Volume 21 (2003)
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Volume 20 (2002)
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Volume 19 (2001)
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Volume 18 (2000)
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Volume 17 (1999)
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Volume 16 (1998)
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Volume 15 (1997)
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Volume 14 (1996)
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Volume 13 (1995)
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Volume 12 (1994)
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Volume 11 (1993)
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Volume 10 (1992)
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Volume 9 (1991)
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Volume 8 (1990)
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Volume 7 (1989)
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Volume 6 (1988)
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Volume 5 (1987)
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Volume 4 (1986)
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Volume 3 (1985)
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Volume 2 (1984)
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Volume 1 (1983)