“(Pawnee) indicates to me that the earthquake rate is continuing to rise even with the decrease in injection volumes over the year,” McNamara said.

McNamara said he has attempted to estimate the size and length of all the faults in Oklahoma to come up with an idea of how much energy could remain and how long it may take to dissipate.

“It could be 10 to 100 years. We don’t know — even if they shut down everything today,” McNamara said.

Boak said he would be surprised if it took 100 years, but he expects it to be a “long time” before Oklahoma gets back to its historical average of two 3.0 earthquakes a year. He is more interested in how long it will take to get back to 2012 levels (35 magnitude-3.0s), before seismicity took a terrific leap skyward.

Boak noted an apparent oddity in that Oklahoma’s three magnitude-5.0s since 2011 have occurred on the fringe — not in the heart — of seismic activity. He said he is unsure what that means seismically.

“It may mean nothing, but I’m intrigued by it,” Boak said.

New quake measures