I was watching TV around 10:30 on Wednesday night when I thought one of grandkids–we were hosting a sleepover–was shaking my chair. I reached around to grab the culprit, but there was no one there. Then it happened again. Then the other adults in our living room, including some Californians, said “Earthquake!”
This was the first one I’ve actually felt since moving back to Oklahoma. There was another noticeable one a few months ago, but I slept through it. I learned the next day that this was the second biggest quake in our fair state since 2011, a 4.7 followed 30 seconds later by a 4.8.
Oklahoma had more earthquakes of 3.0 on the Richter scale or more last year than all of the other states (except Alaska) combined! We never had any when I was growing up. I remember debates with Californians on which was worse, Oklahoma’s tornadoes or California’s earthquakes. We argued that at least you could run away from a tornado or go into a hole. You couldn’t escape an earthquake!
Scientists put on the case have said that the reason we now have so many earthquakes is not fracking, as such–the practice of injecting water at high pressure to fracture underlying rock structures so as to extract more oil from otherwise pumped-out field–but the disposal wells. Virtually all oil wells bring up highly-contaminated water, as well as oil, so to get rid of that, along with the water used in fracking, special wells have been drilled to pump that water deep into the earth, which might be setting off faults by, in effect, lubricating them.
From Juliana Keeping, The Morning Brew: Oklahomans rattled by large earthquakes | News OK:
The earth unleashed a string of earthquakes Wednesday and Thursday, including a 4.8-magnitude temblor that has tied for the second largest earthquake since 2011.
“Since 2011”– that’s significant. That’s because between 1975 and 2008, the state registered zero to three earthquakes a year at 3.0-magnitude or above. Since 2009, quakes of this magnitude have smashed records each year, becoming a regular fixture in the state’s natural disaster menagerie.
There were 20 in 2009, 35 in 2010, 64 in 2011, 35 in 2012, 109 in 2013 and 585 in 2014. Along came 2015 and another earthquake record obliterated: 857 earthquakes.
According to this report, that means Oklahoma had more 3.0-magnitude earthquakes in 2015 than every state in the U.S., combined – if you exclude Alaska. . . .
The culprit: The injection of huge volumes of brackish water into disposal wells. This is a process that follows fracking and scientists agree is causing faults to slip and the earth to shake. Scientists don’t agree on how large a quake wastewater injection could unleash, with one camp prognosticating 4.0 and 5.0-range quakes, and another speculating earthquakes at 7.0 and higher, according to USGS scientists.