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ABINGDON ARCHAEOLOGICAL GEOPHYSICS

 

 

 

 

RESISTIVITY TEST

Resistivity, or earth resistance, has the drawback that it is quite time consuming although mechanised systems of collection have recently been developed. It is however faster than digging and is non-destructive although it misses some things such as most post holes.

Here is a test we did to see the best mobile probe separation to use, as the wider the separation the deeper the reading is assumed to be taken. We thus surveyed the same 5 metre by 20 metre area using a twin probe array with 3 different probe spacings.

To gain a view concerning the best sample interval it was first surveyed with a 0.5metre sample interval and that data was then processed to remove data so a 1.0metre sample interval could be compared with the 0.5 metre interval results.

It should be remembered that a 0.5 metre sample interval will require 4 times as many data points as a 1.0 metre sample interval.

Comparison of different probe spacings and reading intervals.