Fracking can cause earthquakes

No, we're not referring to Starbuck and Apollo getting it on on Battlestar Galactica — but rather, "fracking" is a technique of drilling for natural gas. And it can cause even bigger disruptions than an ill-judged hookup between two Colonial pilots.

A British report indicates that fracking may have caused two small earthquakes. And the mechanism of fracking may be able to cause more.

On April 1st and May 27th, the area of Blackpool got shaken, but only shaken a bit. Two earthquakes hit the area, the first a 2.3 and the second a 1.5. These were not huge events. To put it in perspective, the more seismically active regions of California and Nevada see about five to ten earthquakes of that size per day, and sometimes a couple per hour. Even the relatively stable UK gets about 15 earthquakes of magnitude 2.3 per year. Still, the two quakes in short order turned all eyes towards a company practicing fracking in the region.

Fracking involves pumping large quantities of water into a region rich in natural gas. The water cracks rock in the area, creating thousands of little channels through which the natural gas can bubble upwards. The water also trickles down, getting into municipal water supplies while carrying enough natural gas that some people can set their tap water on fire. It wasn't cracks or combustion that caused the earthquakes. Instead it was the presence of the water itself. The water allowed rocks that ordinarily would have remained locked together, at least for some time, to become slippery and glide past each other. This caused large-scale movement, and lead to the earthquakes.

Fracking, geologists say, may lead to the discover of previously unknown fault lines, which have been too small to be noticed until now. Possibly there are better ways to discover these, though, than by feeling them shake the countryside. Since there are no ways to be sure that fracking is done in a faultless area, geologists recommend that all seismic activity in an area undergoing fracking be monitored.

Image: Ruhrfisch

Via New Scientist and the USGS.