Oklahoma’s Options Now That State and Federal Scientists Confirm Big Earthquake Impact from Water Disposal

Apr 24, 2015 by

Earlier this week, Oklahoma’s state geologist and state seismologist issued a statement that should largely end debates about the causes of a recent burst of seismic activity in that state. They said it was “very likely” that several thousand weak to moderate earthquakes in recent years were triggered by deep-earth injection of water extracted from the ground as thousands of wells have been drilled into shale oil and gas deposits.

You only have to watch the explosive increase in seismic activity in the animated map above, from the United States Geological Survey, to see just how profound the change in earthquake activity has been — from an average of 1.5 earthquakes a year in the state to 2.5 a day.


A frame from an <a href="http://earthquake.usgs.gov/earthquakes/states/oklahoma/OKeqanimation.php">animated map</a> of a burst of small and moderate earthquakes that Oklahoma geologists say are probably linked to injection of water produced when drilling oil and gas wells.
A frame from an animated map of a burst of small and moderate earthquakes that Oklahoma geologists say are probably linked to injection of water produced when drilling oil and gas wells.Credit U.S. Geological Survey

Here’s an interactive map from Oklahoma’s state geologist providing more detail.

Yesterday, widening the view, the federal geological survey released a nationwide view of such “induced seismicity.” Richard Pérez-Peña has an excellent piece summarizing that report in The Times.

In Oklahoma, the majority of the earthquakes have been below 2.0 in magnitude, a category described by the geological survey as microearthquakes that are often imperceptible to residents. But some, including a magnitude-5.7 temblor east of Oklahoma City in 2011, have caused damage.


Sparks, Okla., in 2011. A report says Oklahoma has been hardest hit by human-caused quakes.
Sparks, Okla., in 2011. A report says Oklahoma has been hardest hit by human-caused quakes.Credit Sue Ogrocki/Associated Press

State geologists had been criticized in previous years for not making the connection to the water disposal surge from the drilling boom. In their report, they explained just how much the data pointing to human causes had shifted in the past year or so:

The seismicity rate in 2013 was 70 times greater than the background seismicity rate observed in Oklahoma prior to 2008. While unlikely, this rate could have been potentially explained by natural variations in earthquake rates from naturally occurring swarms. The seismicity rate is now about 600 times greater than the background seismicity rate, and is very unlikely the result of a natural process.

Read the timely Yale Environment 360 interview with Todd Halihan, a geology professor at Oklahoma State University, for more. One issue he stressed is the lack of coordination of water injection in the state’s array of disposal wells: 

And so now if you look at the various states that manage their groundwater systems, I don’t know of any of them that are managing on a per-well basis. But on the oil and gas side, we’re still doing that. It’s a per-well basis, it’s not a system basis.

And so when you have 1,000 disposal wells operating at the same time, you start asking questions like, “At this point right here I’d like to know what happens when we have monthly averages of what they injected.” You actually don’t have the data to solve the problem. You either would have to increase the data density tremendously for each location, or you’d have to start managing in an alternate way.

For more on the lack of oversight of such wells, there’s no better place to start than ProPublica’s 2012 investigation.

The generations-old habit of pumping wastes deep into the ground — largely premised on the “out of sight, out of mind” notion — clearly does not apply to water produced in drilling.

What should Oklahomans do besides lobbying for stronger rules?

The state’s geologists, pointing to the state’s emergency management agency, said this:

It is important for Oklahomans to learn what to do during a significant earthquake, and be prepared.

To close, here’s a bit of an email conversation I had with Prof. Halihan at Oklahoma State (I’ve cleaned up some shorthand).

First, I said I was trying to find damage estimates reported from the earthquakes in recent years, noting that they were likely “in the weeds compared to the value of extracted oil and gas and related economic activity?” I added, “This gets at the uncomfortable reality that all of our energy decisions come with tradeoffs of one kind or another…. Has this argument been made there?

“Some people have suggested that small levels of seismicity are good in exchange for benefits, although they haven’t talked to the people on top of these quakes,” he wrote.

I asked, “How many of these are seen as ‘anyway’ quakes that would otherwise have happened but scattered over many years, if not decades or centuries (I’m not saying this is good, just wondering)?”

He responded: “Some people look at it like that. Although we are supposed to have about two per year, so we have had several thousand years of quakes so far.”

Halihan added: “The two [issues] that are currently unclear are damage assessment of what a large quake would do on a particular fault and how liability would be assessed. The second unknown is the net damage from hundreds of small quakes to structures. These things would not happen if the quakes were spread over 5,000 years.”


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