Studies Link the Rise Of Significant Earthquakes to Oil and Gas extraction

Two new papers tie a recent increase in significant earthquakes to re-injection of wastewater fluids from unconventional oil and gas drilling.

The first study notes “significant earthquakes are increasingly occurring within the United States midcontinent.” In the specific case of Oklahoma, a Magnitude “5.7 earthquake and a prolific sequence of related events … were likely triggered by fluid injection.”

The second study, of the Raton Basin of Southern Colorado/Northern New Mexico by a U.S. Geological Survey (USGS) team, concludes;

”the majority, if not all of the earthquakes since August 2001 have been triggered by the deep injection of wastewater related to the production of natural gas from the coal-bed methane field here.”

Both studies are being presented at the annual meeting of the American Geophysical Union this week.

These studies, together with other recent findings, make a strong case that we need national regulations on wastewater injection to prevent induced earthquakes.

Background
As hydraulic fracturing has exploded onto the scene, it has increasingly been connected to earthquakes. Some quakes may be caused by the original fracking — that is, by injecting a fluid mixture into the earth to release natural gas (or oil).

More appear to be caused by reinjecting the resulting brine deep underground.

In August 2011, a USGS report examined a cluster of earthquakes in Oklahoma and reported:

Our analysis showed that shortly after hydraulic fracturing began small earthquakes started occurring, and more than 50 were identified, of which 43 were large enough to be located. Most of these earthquakes occurred within a 24 hour period after hydraulic fracturing operations had ceased.

In November 2011, a British shale gas developer found it was “highly probable” its fracturing operations caused minor quakes.

In March 2012, Ohio oil and gas regulators said “A dozen earthquakes in northeastern Ohio were almost certainly induced by injection of gas-drilling wastewater into the earth.”

In April, the USGS delivered a paper at the annual meeting of the Seismological Society of America that noted “a remarkable increase in the rate of [magnitude 3.0] and greater earthquakes is currently in progress” in the U.S. midcontinent.

The USGS scientists pointed out that ”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.”

They concluded:

While the seismicity rate changes described here are almost certainly manmade , it remains to be determined how they are related to either changes in extraction methodologies or the rate of oil and gas production.