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Seismologists Say Oklahoma's Man-Made Earthquakes Can't Be Un-Made Any Time Soon

Tina Casey headshotWords by Tina Casey
Energy & Environment
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Oklahoma has been making news in recent years for a sudden burst of seismic activity, ranging from barely-felt temblors to quakes strong enough to damage buildings and knock out power. Seismologists pinned the blame on the practice of disposing oil and gas wastewater in deep wells, a common practice in fracking operations. Oklahoma Governor Mary Fallin took emergency action last year to mitigate the problem -- but that may be a classic case of too little, too late.

The quakes have continued, and a new report from the University of California at Santa Cruz indicates that earthquake hazards will continue to bedevil Oklahoma for the foreseeable future.

Oklahoma's earthquake problem


Oklahoma's earthquake problem can be traced to its unique geology, which includes a sprawling sedimentary rock formation called the Arbuckle Group.

Over time, the practice of disposing oil and gas wastewater into wells in the Arbuckle Group raised pressure in the deep "basement" of the formation. The drilling operation known as fracking factors in because it involves vast amounts of water (and therefore wastewater), but brine from conventional oil and gas drilling is part of the problem, too.

Now that pressure in the Arbuckle basement has intensified, the more recent disposals are more likely to have an outsized impact, a bit like the old "straw that broke the camel's back" analogy.

So, cutting back on the amount of wastewater entering the Arbuckle may not have an immediate and equal impact on earthquake risks.

Here's an explainer from the U.S. Geological Survey:

The Arbuckle Group took a lot of water for a long time until we put so much in that it started causing earthquakes...It’s not a lot of flow into the basement but it’s transmitting a pressure wave. And the slight increase in pressure is enough to make it easier to move.

Cutting back on Arbuckle well disposal could also have an outsized impact the bottom line for the state's oil and gas industry.

That's because in Oklahoma, oil and gas wells generally bring up more brine than in other areas. That requires well operators to dispose of more wastewater than their competitors elsewhere:

...for every barrel of oil that can be produced, operators are left with 10 to 15 barrels of wastewater. That leaves a big disposal job that continues through the life of the well, long after drilling and hydraulic fracturing are complete...

A seismic spark of hope for Oklahoma


By early last year, seismologists gathered enough evidence to convince Oklahoma policymakers that the earthquake problem was induced by oil and gas wastewater disposal.

Governor Fallin first asked the industry for voluntary disposal curtailments, but after a record-tying 5.6 magnitude shocker hit last September, she ordered an emergency shutdown of all disposal wells in a large area of Pawnee County. Fallin also directed her agencies to work with EPA on a plan for another area where federal agencies have jurisdiction.

So, what are the chances for those efforts to work?

In November 2016, Stanford University seismologists produced a report exploring the impact of the state's earthquake mitigation efforts.

The researchers came up with a model indicating that a sharp reduction in wastewater disposal would have an immediate and significant impact:

...We present a calibrated statistical model that predicts that widely felt M ≥ 3 earthquakes in the affected areas, as well as the probability of potentially damaging larger events, should significantly decrease by the end of 2016 and approach historic levels within a few years.

On the down side, while the model indicates a sharp decline in the overall rate of induced earthquakes, it also indicates that the risk of potentially damaging earthquakes will remain relatively high over the next several years.

Another report, more bad news for Oklahoma


That brings us to the new University of California report, which appeared earlier this month in the journal Science Advances.

The new study takes a decidedly less optimistic view overall, according to co-author Emily Brodsky, who is a professor of Earth and planetary sciences:

"Although they were correct in saying that small earthquakes seemed to be decreasing, the moderate earthquakes are not decreasing. The problem has not been resolved to where we can stop worrying about it."

Overall, the new study predicted twice the probability of moderate earthquakes in areas already at risk, compared to the earlier study.

UC-Santa Cruz writer Tim Stephens noted that current events have borne out the more pessimistic finding:

As if to underscore the new findings, central Oklahoma experienced a series of earthquakes last week, including a magnitude 4.2 temblor Wednesday night (August 2) that knocked out power in Edmond, near Oklahoma City. State seismologist Jacob Walter, a coauthor of the new paper, said it was the fourth earthquake of magnitude 4 or greater in 2017. The rate of such earthquakes is somewhat lower than in 2016, he said, but they continue to pose a hazard.

The takeaway is that reducing wastewater disposal will make a difference, but it will take much longer than the earlier study indicates.

In other words, hoping that seismic activity will return to historically quiet levels within a few years is just that -- a hope.

Speaking of hope...and the bottom line...and jobs, jobs, jobs


The earthquake studies are much more than an academic exercise. They amount to a checkmark in the "negatives" column for businesses interested in locating or expanding in Oklahoma.

Existing property owners are also facing insurance issues due to ongoing seismic hazards.

On the bright side, while Oklahoma is dealing with the destructive legacy of its oil and gas industry, it is also emerging as a clean energy powerhouse.

The state was already ramping up its wind industry sector in 2012 thanks in part to early investor GE, which is also involved in a new wind energy transmission project -- a 4,000 megawatt monster aimed at bringing wind power from the Oklahoma panhandle to points east.

In the latest development, last month GE announced that its Renewable Energy offshoot is partnering with the company Invenergy on the world's second-largest onshore wind farm, a 2,000 megawatt, 800-turbine behemoth dubbed with the somewhat Games-of-Thronesy name "The Wind Catcher."

The idea is to send renewable-sourced electricity to more than 1 million customers in Louisiana, Arkansas, Texas and other parts of Oklahoma, in the territory of the utilities Public Service Company of Oklahoma and Southwestern Electric Power Company.

According to GE's press materials, the new wind farm plus the transmission line will deliver more than $7 billion in savings for customers of the two utilities over the next 25 years.

That's over and above the 4,000 direct and 4,400 indirect jobs created annually during construction. Some of the job creation involves manufacturing, as major components for the turbines will be manufactured in the U.S. including factories in Louisiana, Arkansas, Texas and Oklahoma.

Approximately $300 million in property tax revenues will also sweeten the pot over the life of the project.

As for permanent positions, there's an interesting parallel with the notorious Keystone XL tar oil sands pipeline.

For all their magnitude, Wind Catcher and the new transmission line will only account for about 80 direct, permanent jobs once they are commissioned.

Similarly, Keystone XL is a major infrastructure project that involves thousands of jobs during construction, but only a few dozen permanent positions.

The big difference -- and the only one that matters -- is that demand for wind power is running high, while there doesn't seem to be as much interest these days in buying what Keystone developer TransCanada is selling.

Image: via U.S. Geological Survey.

Tina Casey headshotTina Casey

Tina writes frequently for TriplePundit and other websites, with a focus on military, government and corporate sustainability, clean tech research and emerging energy technologies. She is a former Deputy Director of Public Affairs of the New York City Department of Environmental Protection, and author of books and articles on recycling and other conservation themes. She is currently Deputy Director of Public Information for the County of Union, New Jersey. Views expressed here are her own and do not necessarily reflect agency policy.

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