Lightning analsys can be done regionally across a large area like the Michigan peninsula. The map to the left shows topography, with gas wells ovelain in red and oil wells in green. There are a circle of reefs, which show up well at the top of the peninsula and are less dense at the bottom. The famous Albion-Scipio field is the linear set of green wells in the lower center part of the state. Porosity for this field was created by thermogenic alteration of limestone to dolomite where magnesium molecules have replaced calcium carbonate molecules along a strike-slip transform fault. The Stoney Point field is a right lateral splay in a more northernly direction. The right map shows lightning density across this same area. Note how patterns continue offshore into the Great Lakes. Also there are a lot fewer strikes to the north, where there is more snow and fewer thermals. There are no lightning anomalies in Detroit, where there is a lot of metal on the ground. The strike-slip fault interpretation started with Albion-Scipio and Stoney Point and was extended to show parallel faults which cut lightning patterns. When I showed this to an interpreter who had worked this area for 20 years, he said "This is the first time I've seen a reasonable map of the transform faults."