frac sand mining sites in WisconsinThis morning I happened to read that the mysterious booming sounds heard by residents of Clintonville, Wisconsin, over the last week or so have been explained by the USGS to have been caused by earthquakes. Very low-level earthquakes: 1.5s. Really? Earthquakes? I am no geologist, but I googled fracking in Wisconsin and learned that much of the sand used for fracking comes from the Midwest, and a lot of that from Wisconsin: A map of active frac sand mining operations in the state shows a mine in Appleton, a crow-fly distance from Clintonville of about 30 miles (according to my funky atlas). My question is whether it might be more reasonable to suspect that the "thunder"-like booming heard in Clintonville is caused by the explosives used in the mining of frac sand in Appleton.