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- Volume 2, Issue 4, 1954
Geophysical Prospecting - Volume 2, Issue 4, 1954
Volume 2, Issue 4, 1954
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THE PREPARATION OF PAPERS FOR “GEOPHYSICAL PROSPECTING” AND THEIR PRESENTATION AT TECHNICAL MEETINGS
More LessAbstractThe efficient production of “Geophysical Prospecting” depends upon the co‐operation of the individual authors and this paper serves as a guide for them. Some suggestions are also made on the presentation of papers at meetings in the hope of promoting successful discussions.
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DIE ABHÄNGIGKEIT DES SCHEINBAREN WIDERSTANDES VOM SONDENABSTAND BEI DER VIERPUNKT‐METHODE*
More LessAbstractThe dependence of the apparent resistivity on the distance between the potential electrodes is examined and a numerical method is described permitting quantitative calculations. Such a numerical relation is also established for the transformation of Wenner graphs into Schlumberger graphs.
In addition it is shown, in which manner the jumps in observed Schlumberger curves, that result from changing the probe spacing, must be smoothed out.
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SOME OBSERVATIONS ON SEISMIC WEATHERING CORRECTIONS
By O. KOEFOEDAbstractWhen a rather extensive network of short distance refraction profiles was shot the following two observations were made. Firstly, the wave velocity in the weathered layer showed a quite considerable fluctuation in horizontal direction, the extreme values being of the order of 300 and 700 m/sec. A practical result of this scattering of the velocities is that an uncertainty of about 10% is introduced in the computation of the weathering corrections. The second observation is that, in the majority of cases, the travel time curve does not pass through the origin. It could be ascertained that this observation was not caused by errors in the method of observation. A probable explanation of the phenomenon is found in a theory that has been developed by Gassmann, who derived the velocity distribution for a hexagonal packing of spherical solid bodies. According to this theory extremely low velocities would occur in the first few centimeters of the crust of the earth. Qualitatively, our observations are in agreement with the theory of Gassmann.
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A REMARK CONCERNING THE PROBLEM OF HOW TO PLACE THE REFERENCE PLANE (DATUM LEVEL) IN REFLECTION SEISMIC PROSPECTING*
By T. KREYAbstractIt has been shown in a paper by L. Y. Faust that the wave velocity in rock depends on the depth below the ground surface according to a specified equation. It follows that the attitude of the planes of equal velocity is influenced by the topographic relief. Under these conditions the problem arises of how to place the reference plane in such a manner, that the fluctuations of the planes of equal velocity, that result from the fluctuations in the topography, shall not affect the results of the depth computations. In the present paper an analytical solution of this problem is given.
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SOME REMARKS ON THE ERRORS IN THE CALCULATION OF THE VERTICAL GRADIENT OF GRAVITY*
Authors V. BARANOV and J. TASSENCOURTAbstractIn a previous paper by the first author a method has been presented for computing the first vertical derivative of the gravity field or of the magnetic field. In the present paper an analysis is given of the errors in the first vertical derivative that result when the latter is computed by the above method. Two sorts of errors are considered. Firstly, the error in the first vertical derivative that results from the errors in interpolating between isogam lines on the Bouguer anomaly map. Secondly, the error in the first vertical derivative that results from the approximations upon which the computation method is based. The conclusion is reached that both sorts of error are only of minor importance.
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ROLE JOUÉ PAR LA CORRECTION LUNI‐SOLAIRE EN PROSPECTION GRAVIMETRIQUE*
By R. NEUMANNAbstractThe luni‐solar corrections are considered under the three following aspects:
Quality of results: the application of tidal corrections to all stations is pointless as long as the operations do not substantially exceed two hours.
Working conditions: it seems possible to increase the duration of programs without any loss of precision, but operating in such a way requires particular care.
Behaviour of gravity meters: the introduction of tidal corrections allows to separate three kinds of instrumental drifts; a good knowledge of the mean operational drift enables to appreciate the quality of a given set of measurements.
An example is given to show the possibility in some cases to detect small errors which are close to the limit of precision of the instrument.
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Volumes & issues
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Volume 72 (2023 - 2024)
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Volume 71 (2022 - 2023)
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Volume 70 (2021 - 2022)
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Volume 69 (2021)
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Volume 68 (2020)
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Volume 67 (2019)
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Volume 66 (2018)
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Volume 65 (2017)
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Volume 64 (2015 - 2016)
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Volume 63 (2015)
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Volume 62 (2014)
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Volume 61 (2013)
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Volume 60 (2012)
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Volume 59 (2011)
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Volume 58 (2010)
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Volume 57 (2009)
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Volume 56 (2008)
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Volume 55 (2007)
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Volume 54 (2006)
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Volume 53 (2005)
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Volume 52 (2004)
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Volume 51 (2003)
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Volume 50 (2002)
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Volume 49 (2001)
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Volume 48 (2000)
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Volume 47 (1999)
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Volume 46 (1998)
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Volume 45 (1997)
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Volume 44 (1996)
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Volume 43 (1995)
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Volume 42 (1994)
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Volume 41 (1993)
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Volume 40 (1992)
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Volume 39 (1991)
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Volume 38 (1990)
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Volume 37 (1989)
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Volume 36 (1988)
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Volume 35 (1987)
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Volume 34 (1986)
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Volume 33 (1985)
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Volume 32 (1984)
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Volume 31 (1983)
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Volume 30 (1982)
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Volume 29 (1981)
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Volume 28 (1980)
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Volume 27 (1979)
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Volume 26 (1978)
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Volume 25 (1977)
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Volume 24 (1976)
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Volume 23 (1975)
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Volume 22 (1974)
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Volume 21 (1973)
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Volume 20 (1972)
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Volume 19 (1971)
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Volume 18 (1970)
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Volume 17 (1969)
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Volume 16 (1968)
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Volume 15 (1967)
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Volume 14 (1966)
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Volume 13 (1965)
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Volume 12 (1964)
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Volume 11 (1963)
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Volume 10 (1962)
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Volume 9 (1961)
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Volume 8 (1960)
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Volume 7 (1959)
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Volume 6 (1958)
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Volume 5 (1957)
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Volume 4 (1956)
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Volume 3 (1955)
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Volume 2 (1954)
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Volume 1 (1953)