Hydaulic fracturing, or fracking, pumps a water and sand mixture deep below the earth’s surface – past the water table and freshwater aquifiers – into dense shale rock and tight rock formations. In so doing, fracking produces a myriad of long narrow fractures in the rock formation. Advances in technology have allowed the natural gas and oil industry to explore these shale plays, but has had industry critics ask the question: does fracking cause earthquakes?
An incredibly small amount of seismic activity accompanies the hydraulic fracturing process; however the low level of seismicity has resulted in no cases of injury or property damage in over one million instances. In fact, the largest microseism ever recorded had a measured magnitude of about 0.8 on a normalized scale, which is approximately 2,000 times less energy than a magnitude 3.0 earthquake. In most cases, microseismic energy ranges from 10,000 to 1,000,000 times less energy than a 3.0 magnitude. It’s safe to say that microseismic activity is never felt at the surface; fracking and earthquakes are not even on the same scale of seismic activity.
As new scientific studies regarding the relationship between fracking and earthquakes help guide the understanding of specific hazards, drilling operators will only improve upon an impressive overall track record. It’s important to note that among the 800,000 injection wells nationwide – only a small subset are in use by the petroleum industry, and of those wells there have been less than 40 incidents of surface felt seismic activity over the past 50 years.