Anthropogenic earthquakes on the rise

Nature : Three papers published in Science this week link the injection of fluids underground—during natural-gas extraction, geothermal-energy production, and other activities—with increased seismic activity. According to the studies, the number of US earthquakes of magnitude 3.0 or higher has increased almost 10-fold in the past decade, and at least half of those of magnitude 4.5 or higher have occurred near injection-well sites. The study by William Ellsworth of the US Geological Survey indirectly links the increase in the number of earthquakes to the practice of hydraulic fracturing, or fracking, by claiming it is the wastewater from the process that is causing the problem. The study by Nicholas van der Elst of Columbia University and colleagues suggests that some well sites are more sensitive than others and that earthquakes there can be triggered by large quakes that occur in other parts of the world. The third study , by Emily Brodsky and Lia Lajoie of the University of California, Santa Cruz, acknowledges that increased seismicity accompanies geothermal power production, although the rate at which earthquakes are induced cannot yet be forecast.