Much of the production, using new horizontal drilling techniques, produces at very high rates, with very high water-to-oil ratios. Thus many of the disposal wells, which re-inject the brine into underground formations, handle much more water at much higher pressures than has been common in other, often older, plays. When high volume, high pressure liquids follow the planes in some susceptible dormant faults, it frequently causes them to slip resulting in quakes. After the strongest earthquake in Oklahoma's history, at Pawnee, recorded at 5.8 on the Moment magnitude scale, concerns about the relationship between disposal wells and earthquakes caused state and federal regulators to respond by shutting down more than 50 disposal sites and wells across the state, considering their proximity to fault lines.