When the Seismological Society of America says that fracking earthquakes are a real thing, then it’s a good bet that they are. The annual SSA meeting last Thursday featured a daylong session on “Induced Seismicity” that featured new research indicating that oil and gas fracking, and the practice of disposing wastewater underground, can alter the state of an existing fault. The result is to spread the range of seismic hazard farther out from the faultline than previously thought.
While we’re waiting for Fox News to find a seismic denialist to let the public know that this is all just a bunch of hooey, let’s take a closer look at that research.
Fracking Earthquakes: Who’s Minding The Store?
It’s worth noting, first off, that given the thousands of fracking and disposal wells already in operation, and the thousands more that are drilled every year, the number of wells directly linked to seismic activity so far is miniscule.
Part of the reason for that involves a shortfall in research and monitoring resources, absence of a regulatory structure for self-monitoring, and the fact that induced seismic activity is a relatively new field of research.
More to the point, given the potential for significant damage and the fact that manmade earthquakes are virtually 100 percent avoidable, fracking earthquakes are a risk that needs to be defined and managed.
However, currently there is no platform for the US Geological Survey to include fracking earthquakes (or any other induced earthquake, for that matter), into its estimates of seismic hazards.
Seismologists have to come up with a new way to account for changes in seismic activity that covers all earthquakes regardless of whether they are manmade or not. That work is currently under way at USGS.
Let’s also note up front that while fracking (an oil and gas drilling method that requires pumping massive amounts of chemical brine underground) itself has not been directly linked to many seismic episodes so far, evidence is mounting that the disposal of fracking wastewater into wellbores is causing a significant number of manmade earthquakes.
The Latest Fracking Earthquake Research
Now for the meat of the matter. SSA cites significant increases in seismic activity linked to increased fracking and wastewater operations in Colorado, Oklahoma, Texas, Arkansas and Ohio among other states.
To give you an idea of how significant, the average rate of earthquakes above 3.0 was 21 from 1967 to 2000 according to the US Geological Survey, but it was about 100 per year between 2010 and 2012.
Those numbers are already jumping up. As of last month, in Oklahoma alone more than 100 3.0-and-up earthquakes have been recorded.
The Induced Seismicity session at the SSA meeting featured case studies in the aforementioned US states as well as locations in Spain and Italy (abstracts are available here).
One new study under discussion at the SSA meeting was conducted by Canada’s Western University in Ontario. It details how fracking wastewater disposal and other new sources of seismicity can create new hazards that are not accounted for in existing building codes and infrastructure planning:
…the hazard from induced seismicity can overwhelm the hazard from pre-existing natural seismicity, increasing the risk to structures that were originally designed for regions of low to moderate seismic activity.
When we say infrastructure planning, that includes dams, nuclear power plants, underground pipelines, and other features of the built environment that become damage multipliers when affected by earthquakes.
A key issue that seismologists are identifying is that the seismic hazard caused by fracking or related activities can have an impact much farther away from the fault line than previously thought.
That’s the finding of a joint study by Cornell University and the Lamont-Doherty Earth Observatory at Columbia University, which covered the 2008 earthquake swarm near Oklahoma city. Researchers found that for some wells, seismic activity migrated up to 50 kilometers away.
Perhaps in an attempt to avoid the political spotlight, seismologists with the US Geological Survey are extremely hesitant to link increased seismic activity to a specific well. However, the agency does point out that the recent increase in seismic activity is not in dispute, and that poses an additional risk regardless of the source. As USGS geophysicist Justin Rubinstein puts it:
In some sense, from a hazard perspective, it doesn’t matter whether the earthquakes are natural or induced. An increase in earthquake rate implies that the probability of a larger earthquake has also risen.
Earthquakes In Your Backyard
Although some of the linkage identified so far involves quakes too small to be felt on the surface, a growing number of US communities are not waiting around to feel the earth move under their feet.
Seismic hazard featured in a recent decision, for example, by the City of Los Angeles to prohibit fracking and related activity within city limits (there are actually quite a few wells in LA, who knew?).
Although local communities do not normally have the authority to regulate oil and gas activities specifically, they can deploy their zoning authority to prevent new industrial activity, including fracking. Communities in New York State have been taking the lead to ban fracking through local zoning, and Pennsylvania communities have just had their zoning rights reaffirmed by the state’s Supreme Court after challenging a new state law that would have overridden them.
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