Field Tests of 3-Component geophones

Don C. Lawton and Malcolm B. Bertram

ABSTRACT

Field tests of Litton, Geosource and Oyo 3-component geophones showed similar performance characteristics for all three geophones for a test signal generated by a seismic cap at a horizontal distance of 7.5 m from the geophones. Output signal levels from the Litton and Geosource geophones were similar, with the Oyo output being about 20% lower. No cross-coupling between the elements within any of the geophones was observed, but the polarity of all of the horizontal elements is opposite to the recommended SEG standard. There is no consistent colour coding of the clip leads for the various elements between any of the geophones.

Polarization tests for a circle of test shots spaced around the cluster of geophones gave remarkably similar results for all three geophones. Generally, the polarization direction measured by the horizontal elements matched the source azimuth closely, and any deviations were attributed to inhomogeneities in the near-surface sediments.

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