It was a glorious day for the geophysics training session at Godshill, with bright sunshine and hardly a cloud in the sky. However, not brilliant conditions for a resistivity survey, which is suited to moist ground.
It took a while to locate the baseline peg which had been left in the ground from a previous survey. A 20m grid square was then laid out, in progress below.
Everyone pitched in to help!!:
Despite Garry not being present, we managed to set up the equipment and set out across the grid.
Half way across the grid the readings dropped very low, and it soon became apparent that there was something wrong with the equipment :-(. We carried on anyway to give everyone present practice at collecting the readings. It was only after the grid had completed that we discovered one of the crocodile clips had come loose on the static probes. Schoolboy error but one we won’t make again! Another lesson learnt was to carry a screwdriver that can be used to replace the battery!
To everyone’s surprise, we actually managed to download the data first time onto the AVAS laptop and Mike’s netbook, and were able to see the plot immediately. The results are shown below:
The plots are different ways of visualising the data for the grid square (ref D21). The blue area to the right of the square represents the region where readings were incorrect. However, the area of successful readings to the left of the grid shows that the equipment was operating correctly, with clear indications of possible features.
Note that the photos above, plus a few more are on the AVAS Flickr page. I will add the results of the afternoon survey when available!