When kelleymcd uploaded the above image to Flickr in November 2011, he/she noted that it showed "earthquakes in Central Oklahoma over the past 36 hours. Another 3.3 happened while I was making this image. This patch is 10 miles x 14 miles in size. Then 5 more aftershocks in the 3.0 range since that."
Kelleymcd is an anti-fracking activist, and he clearly attributed the large amount of earthquakes to recent drilling activity—and not without reason. The US Geological Survey (USGS)had already linked 50 Oklahoma earthquakes to fracking, and a British fracking operation had recently fessed up to causing earthquakes in England.
No wonder people are getting nervous.
Now a new report from the USGS to be presented next month at the annual meeting of the Seismological Society of America in San Diego directly links an "unprecedented" increase in frequency and magnitude of earthquakes to drilling for oil and gas:
In Oklahoma, the rate of M >= 3 events abruptly increased in 2009 from 1.2/year in the previous half-century to over 25/year. This rate increase is exclusive of the November 2011 M 5.6 earthquake and its aftershocks. A naturally-occurring rate change of this magnitude is unprecedented outside of volcanic settings or in the absence of a main shock, of which there were neither in this region.
While the report's authors are unequivocal in linking the earthquakes to human activity, they say we are not yet able to determine whether the earthquakes are directly linked to the increased rate of drilling, or whether it is the specific techniques—such as hydraulic fracking—that are to blame.
Either way, it seems like one more reason to apply the precautionary principle. Those worried about fracking in their region can read up on our guide to fracking for communities and landowners, and we can all use it as a reminder that before we go dashing after the next cheap energy source—whatever it may be—we'd be well advised to take energy efficiency and conservation seriously as the safest, greenest and most cost efficient energy source of them all.