My presumption is they’re either mining of some sort, or an OHV area, and maybe also patchwork differences in satellite pictures. Sometimes the called-for image is a spliced-together collage of pics taken at different times and days.
It’s not a patchup, it shows on multiple passes using different sources. Mining, or exploratory shafts, or something maybe.
What’s OHV?
Did you look at the terraserver link I put up?
The margin of error in the epicenter location is 2 miles, so it’s doubtful the grid of disturbed earth has anything to do with the quake. I’m just curious as to what’s there.