Two new studies of earthquakes near injection wells have seismologists using words rarely heard these days in earthquake science: prediction and warning. The research has also renewed calls for better seismic monitoring and reporting in regions experiencing man-made earthquakes.
"Shale gas operations have completely changed our energy policy and people are injecting in places they've never injected before. If we're going to do this safely, we need to address the environmental issues, including protecting water supplies and earthquake risk," said Cliff Frohlich, a seismologist at the University of Texas Institute for Geophysics who was not involved in the new studies.The two reports appear in today's (July 11) issue of the journal
Science.
Links between injection and earthquakesIn the Midwest, researchers discovered a warning signal that moderate-sized earthquakes may strike near
injection wells, where mining companies dispose of waste fluids. At three sites in Oklahoma, Colorado and Texas, passing seismic waves from faraway
earthquakes - the recent massive temblors in Japan, Sumatra and Chile - triggered swarms of small earthquakes. The seismic activity continued until magnitude-4 and magnitude-5 earthquakes struck, such as the large earthquakes near Prague, Okla., in November 2011.
