At this time sampling would be a waste of money and time. No one pays any attention.
I have looked at these features off and on for the past three years. If you search 'Neolithic Man and the Electric Universe', this is an article I wrote explaining the reason why Sardinia's nuraghi were built. Sardinia was heavily impacted by past electrical environments. If you look at the landscape around Mandas, Sardinia with google earth, the agricultural fields could only have been given their shape by cosmic thunderbolts.