Tests of sand-bags to couple geophones to the earth's surface

Peter M. Manning

ABSTRACT

Sandbags were used as a means of coupling geophones to the ground as part of the Priddis testing in July of 2012. The main object was to see if better shear wave data could be obtained. Twenty older geophones were deployed at ten metre intervals along a short portion of the main test line, and their response was recorded from all the source tests that were done. A source line of dynamite charges was used to match the two data sets, but very little shear wave data could be found. The investigation was continued by comparing ground-roll data, where the sand-bag data seemed to be more consistent than the comparable spike-phone data. From this it was concluded that further tests should be done, with a larger number of geophones in an area of high data quality.

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