Earthquake rates down; officials uncertain about future

This graph, provided by the U.S. Geological Survey, shows monthly totals for earthquakes recorded in Oklahoma since late 2013. 

While Oklahoma’s earthquake rates are down compared to 2015, officials cannot say for sure if the decline is permanent.

We experienced a 16.9 percent decrease in magnitude 3.0 or greater earthquakes — down from 463 to 387 — recorded in Oklahoma between Jan. 1 and June 29, when compared to the same period in 2015, U.S. Geological Survey records show.

“Steps to reduce wastewater injection were a necessary and prudent step for Oklahoma to take. But the reduction has been taking place for only a few months. It would be premature to conclude that long-term earthquake activity has gone down permanently based on short-term data,” U.S. Geological Survey Geophysicist George Choy said. “Whether a decrease is a temporary statistical fluctuation or a permanent trend cannot be established in the few months that have passed. Even at a decreased rate, seismicity could go on for years.”

We’ve hit a noteworthy milestone. Apparently, the corner is turned on injection wells, but we don’t have solid data on the amount of water being pumped out.

We’re not sure how much of the decline is from regulation or decreased drilling. We assume both factors are at play.

In June, Oklahoma Geological Survey Director Jeremy Boak said the main reason the earthquake rate was down probably was the million-barrel-a-day reduction in injection in tracked wells in the earthquake area, and injecting into the Arbuckle group.

Here is what’s working: We still need the energy industry to share proprietary information.

With hopes of improved oil prices, we’ll also need to continue balanced oversight from the state’s regulatory authority, the Oklahoma Corporation Commission.

Oklahoma’s seismicity rate has decreased since last year but the issue is not over.

“We look to see the magnitudes are going down and the longer trend of three to six months are (in) decline,” Oklahoma State University Professor Todd Halihan said. “It shouldn’t go down uniformly, but it should have kicks and bumps. It’s an ugly pattern.”

While the decline may be bumpy at times, we hope the state’s seismicity situation continues to improve over time.