Hydraulic fracturing (fracking) is the well-publicized process by which "tight" rocks can be made to produce oil and gas. It involves explosives, and in a handful out of approximately a million cases small earthquakes have resulted as existing stresses in unmapped faults were released. One of those exceedingly rare cases happened in Ohio last month, and the authorities revised the regulations today to ensure greater caution when the signs arise again.
Now, when permits are issued for drilling within 3 miles of areas of known seismicity (magnitude 2 events, which are usually barely felt), the drillers must install seismic monitors. When the monitors detect events of magnitude 1, drilling stops while the cause is investigated. Interested groups approve: the Interstate Oil and Gas Compact Commission calls it "a sensible response to a serious issue" and the Groundwater Protection Council says "these additional standards add even more strength to Ohio's already comprehensive regulatory program."