Energy Related Geological Fluid Injections are Setting Off Earthquakes
Fracking for shale gas is not touching off the earthquakes that have been shaking previously calm regions of the central United States. But other energy-related fluid injection—including deep disposal of fracking’s wastewater, extraction of methane from coal beds, and creation of geothermal energy reservoirs—is setting off earthquakes of magnitude 4 and 5 that are rattling the local populace, shutting down clean energy projects, and prompting new regulations. Researchers have known for decades that deep, high-pressure fluid injection can trigger sizable earthquakes. But after a lull in triggered quake studies, researchers are playing catch-up with the latest round of temblors. As researchers link cause and effect in recent cases of triggered seismicity, they are beginning to see a way ahead: learn as you go. Thorough preinjection studies followed by close monitoring of cautiously increasing injection offer to lower, although never eliminate, the risk of triggering intolerable earthquakes.