It was Oklahoma’s worst earthquake since 1952 — a 5.6 magnitude event that was felt in 17 states, with aftershocks that kept coming for at least 24 hours. Fourteen homes were destroyed, and two people were injured in the November 6, 2011 event. Now, a new study published today in Geology makes the case that it was caused by wastewater injection drilling.
A 4.7 earthquake had struck only a few hours earlier, and there were at least 30 aftershocks in less than 24 hours afterward. And it was all part of what the new study called a “swarm” of earthquakes.
An Oklahoma newspaper reported at the time that an old fault had woken up around February 10.CNN dates it back to 2010, stating that the Oklahoma Geological Survey had recorded over 1,000 quakes in that year alone, with over 100 being strong enough to be felt.
The US Geological Survey, which assisted in the new study, attributes the rise in earthquakes in middle America to human activity, most importantly wastewater injection. The National Academy of Sciences agrees and has said that it’s proven science going back to the 1920s that humans can induce earthquakes through such activities as injecting (or removing) fluids into the earth.
By acting quickly, a University of Oklahoma seismologist Katie Keranen and colleagues were able to get more than a dozen seismographs in place within hours of the November 6, 2011 event. In that way, they could trace the aftershocks back to the origin of the quake — a site of active wastewater injection wells that had been in use for almost 17 years.
So far, so good, and pretty much in line with proven science since at least the 1960s when the US Army found out the hard way at their Rocky Mountain Arsenal site near Denver, Colorado that you can make some pretty good earthquakes by injecting nasty fluids from weapons manufacturing into deep wells — perhaps the first documented example of earthquakes caused by wastewater injection and certainly one of the most notorious.
A Superfund site unsuitable for human habitation, the Rocky Mountain Arsenal land has since become a wildlife reserve complete with its own buffalo herd and a small museum that tells the story of the man-made quakes.
Other states besides Colorado have also acknowledged the risk. For instance, after a series of unusual earthquakes in Arkansas, the state Oil and Gas Commission banned wastewater injection wells from the newly tremor-prone region as a precaution against a potentially devastating quake.
However, everybody’s out of step except for the Oklahoma Geological Survey. Their seismologist Austin Holland responded to the study by saying, “It is still the opinion of those at the Oklahoma Geological Survey that these earthquakes could be naturally occurring.”
Homeowner’s insurance doesn’t cover earthquakes, and some of the victims of the November 6, 2011 event didn’t have separate earthquake insurance.
My gut tells me that wastewater injection wells work the same in every state and that somebody owes those homeowners some compensation for the Oklahoma earthquake damage. What do you think?
[Oklahoma City photo courtesy Daniel Mayer and Wikipedia Commons]