An official University of California report has concluded that there is a link between oil drilling and earthquakes. The 2005 spate of earthquakes in California’s Central Valley was triggered by oilfield injection underground, researchers say Yahoo News reports: The research links a local surge in oil company injection of wastewater underground, peaking in 2005, with an unusual jump in seismic activity in and around the Tejon Oilfield in southern Kern County. In Oklahoma and some other Midwestern states, the U.S. Geological Survey and others have linked oilfield operations with a dramatic surge in earthquakes. Many of those quakes occur in swarms in places where oil companies pump briny wastewater left over from oil and gas production deep underground. “It’s important to emphasize that definitely California is not Oklahoma,” lead author Thomas Goebel at the University of California at Santa Cruz said Thursday. “We don’t really expect to see such a drastic increase in earthquake occurrences” in California given different oilfield methods and geology in the two areas. In Kern County, the shaking topped out on Sept. 22, 2005, with three quakes, the biggest magnitude 4.6, researchers said. Researchers calculated the odds of that happening naturally, independently of the oilfield operations, at [...]