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- Volume 6, Issue 4, 1988
First Break - Volume 6, Issue 4, 1988
Volume 6, Issue 4, 1988
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Improvements in field technique for use of the Lacoste and Romber gravimeter in microgravity surveys
Authors J.Fr. Thimus and M. van RuymbekeIn site investigation for civil engineering projects, microgravimetry prospecting is used in the search for galleries, karst phenomena or subsoil irregularity. The gravity anomalies typically have amplitudes of the order of 10 ugal, so it is essential to maximize the precision of the readings. With a LaCoste and Romberg (LCR) gravimeter, model G or D, equipped with electronic readout, it is possible to measure gravity changes up to 50 mgal with a precision of a few microgals. Systematic errors due to the gravimeter itself, operating errors during the measurement, and correction errors (tidal, topographic) may reduce the accuracy of the readings. In order to reduce the operating errors, some modified field techniques for making readings with the LCR gravimeter have been developed.
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A neglected area of Vibroseis development
By P.J. StanleyIt should be possible to improve the quality of Vibroseis data through attention to flexible processing ahead of correlation and ahead of summation. These processes include improved noise rejection, spectral whitening and 'beam-steering' techniques. In the past this has been considered impractical due to the difficulty of handling large volumes of raw data and to a lack of integration between field and processing operations. The use of a high-density medium, now available to record raw Vibroseis data without pre-processing in the field, will provide an opportunity for development of improved techniques through the introduction of flexible pre-correlation and pre-summation processing.
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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)