“The dramatic increase in Oklahoma earthquakes has led some media outlets to refer to Oklahoma as the ‘new earthquake capital of the United States,’” notes Daniel Raimi in his 2017 book “The Fracking Debate: The Risks, Benefits, and Uncertainties of the Shale Revolution.”
Never mind that the earthquakes in Oklahoma are much smaller and release much less seismic energy than those in California or Alaska (the latter of which witnessed one of the largest earthquakes in world history—The Great Alaska Earthquake, a 9.2 magnitude quake in 1964). The number of 3+ magnitude earthquakes in Oklahoma rose from 109 in 2013 to 579 in 2014 to 903 in 2015 before dropping to 623 in 2016.
“Almost everyone I asked had a story about a friend or neighbor who suddenly noticed cracks in their walls, had pictures fall from their shelves, or noticed an eerie swaying while lying in bed on the second story of their home,” relates Raimi about his experience traveling through Oklahoma while researching The Fracking Debate.
What is Oklahoma doing to reduce the number of earthquakes?
We posed this question to Daniel Raimi, a senior research associate at Resources for the Future, a non-profit organization that “improves environmental, energy, and natural resource decisions through impartial economic research and policy engagement.”
To reduce the number of earthquakes Oklahoma is trying to do a better job of mapping underground fault networks so they can understand where you might not want to inject wastewater because there’s a pretty significant fault that could be activated. They are also putting into place detailed seismic monitoring networks to measure with great accuracy any small seismic events that might not be picked up by the larger U.S. Geological Survey instruments.
There are a number of places [including Oklahoma] that have implemented what are called “traffic light” systems where if the state or [disposal well] operator detects a small earthquake—say, 1.5 or 2.0 in magnitude—then they are given a yellow light that says proceed with caution with your wastewater injection or hydraulic fracturing activity.
If they then see a larger quake—say, magnitude 2.5—then there is a red light which says you need to stop all activities immediately until the state and the operator can figure out what’s going on and reassess the situation.
So there are two strategies that can reduce the risk of earthquakes in the future. It’s unlikely they are going to eliminate the risk entirely because the subsurface is extremely complex and it’s unlikely that we are going to understand every nook and cranny that could contribute to an earthquake. But we can reduce the risk of large-scale earthquakes.