Published January 4, 2015 by Dana Hertneky (NewsOn6)
EDMOND, OK – The Oklahoma Corporation Commission took action Monday in regards to those recent Edmond earthquakes.
The commission directed the operators of five disposal wells within 10 miles of the epicenter to reduce volume. But a seismologist with the USGS said it may not have been disposal wells that triggered the last week’s earthquakes in Edmond.
USGS seismologist Dan McNamara thinks the rapidly rising water at Arcadia Lake, the result of Winter Storm Goliath may have triggered the 4.3-magnitude earthquake. The water rose two feet on the lake the day before that first 4.3-magnitude earthquake.
Ed Woods is a retired petroleum engineer. He lives in east Edmond, just a couple miles from the epicenter of the recent big earthquakes.
“It was the most severe one that we had felt since we had been here,” he said.
Woods has been looking into the earthquakes for the past year. Since he knew Arcadia Lake was close by, he looked up the lake levels and noticed they rose rapidly right before the first earthquake.
Woods did some calculating, and figured about 4.5 million tons of additional weight was added to the fault block right before the first earthquake.
“It’s another thing that needs to be considered, particularly since they are having trouble finding any active injection wells in this area,” Woods said.
McNamara thinks Woods may be on to something.
“Just based on our preliminary modeling, the distance from the fault and the time delay, it works out fairly well. This could be a possible cause,” he said.
McNamara said the Arbuckle formation underneath Oklahoma is already saturated, likely from disposal wells.
Any additional stress, such as a sudden lake level increase, can push a nearby fault to failure. In this case the earthquake reactivated a fault capable of producing an earthquake as big as a 6.0-magnitude and it runs right through a populated area.
“If you do get another large event like a 5.6 (magnitude) it would significantly more of a disaster in Oklahoma City than it was in Prague because more people are exposed,” McNamara said.Follow @FortySixNews