Geophysics Survey 5th June 2013

Mark and I headed over to the regular AVAS site yesterday evening to survey a couple more squares with the resistivity meter.  It was a glorious evening, sunny and warm, with swallows skimming the field and a couple of inquisitive horses trying to nibble our survey equipment.  There was a magnificent view across the Avon Valley.

Although the ground has started to dry out, the resistivity meter was working really well, and was really stable.  The first square we tackled was C8, which mostly covered a really flat plateau at the top of the hill.  After completing the square, we waited with great anticipation as the results were plotted.

C8 Resistivity Plot

C8 Resistivity Plot

As can be seen from the plot above, we weren’t to be disappointed.  There is a large low resistance feature (blue colour) passing diagonally across the square, plus some interesting areas of higher resistance.  Buoyed by the results, we pressed on and surveyed the adjacent square.  Again, the results did not disappoint, as shown below.

C9 Resistivity Plot

C9 Resistivity Plot

In the above plot, the cells to the top right of the square with the same green/yellow colour are dummy readings, as the fence at the edge of the field cuts across the corner of the square.  Again there are interesting areas of low resistivity, this time in an angled pattern.  The top of the slope is again an area of high resistivity.

After returning home, I loaded theses squares, plus the adjacent square surveyed a few weeks ago, into the Snuffler software package.  This allows the squares to be stitched together and edge matched.  The final plot, shown below, shows the combined, edge matched results for squares C8, C9 and D8.

Resistivity plot for squares C8, C9, D8

Resistivity plot for squares C8, C9, D8

As can be seen, the squares join together perfectly, showing how well the equipment is working.  The are a number of clear targets which can be considered for evaluation excavation later in the year.

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