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CORRECTION OF ACCURATE GRAVITY SURVEYS BY CAREFULLY OBSERVED VERTICAL GRADIENTS OF GRAVITY *
Author(s) -
THYSSENBORNEMISZA S,
GROTEN E.,
BAZHAW W. O.
Publication year - 1972
Publication title -
geophysical prospecting
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.735
H-Index - 79
eISSN - 1365-2478
pISSN - 0016-8025
DOI - 10.1111/j.1365-2478.1972.tb00617.x
Subject(s) - geodesy , terrain , gravimeter , gemology , geology , instrumentation (computer programming) , vertical deflection , gravimetry , geophysics , gravity anomaly , seismology , physics , engineering geology , geography , geotechnical engineering , cartography , tectonics , computer science , paleontology , casing , quantum mechanics , volcanism , oil field , electromagnetic coil , reservoir modeling , operating system
A bstract Gravity surveys in western Texas with station spacing of about 400 m were complemented by carefully observed vertical gradients of gravity making use of specially designed and automated instrumentation. The presented areal surveys of 51 and 52 stations taken in relatively flat terrain are parts of a large survey of close to 1000 stations complemented by an equal number of vertical gradient measurements. Quite irregular anomalous vertical gravity gradients surpassing 10 microgal/m were often encountered. Assuming the causative density contrasts to be located not more than 10 m below ground surface then free air correction errors of ± 0.1 mgal and more must be accepted. From a practical point of view there seems to be no other way to control such unpredictable errors than to carefully observe the local variation of vertical gravity gradients with adequate equipment. Making use of very closely spaced gravity measurements to derive these anomalous features seems more costly and cumbersome.