Update: An earlier version of this post accidentally misrepresented the link between earthquakes and fracking. Although fracking has been increasingly shown to cause earthquakes, it's in fact wastewater disposal wells in Oklahoma that are specifically linked to induced earthquakes.
Onshore oil and gas excavation may still be relatively cheap in parts of the United States, but scientific research has clearly shown that it’s terrible not just for the environment, but for anyone living nearby. After all, it's clearly linked to powerful and potentially hazardous artificial earthquakes.
When it comes to hydrocarbon-related tremors, you can’t find anywhere rumblier than Oklahoma right now. Over the last decade, the state has upped the ante on its natural gas exploration efforts, and – this animation reveals – it's had quite the effect.
It must be pointed out though that wastewater disposal, not normally fracking itself, is in fact the primary driver of these tremors, known as "induced earthquakes" - at least in Oklahoma. Although research is increasingly linking fracking to induced earthquakes, this hasn't been conclusively demonstrated just yet in this part of the US.
"In Oklahoma, which has the most induced earthquakes in US, only 1-2% of the earthquakes can be linked to hydraulic fracturing operations. The remaining earthquakes are induced by wastewater disposal," the United States geological Survey (USGS) explains.
Wastewater is produced at oil and gas extraction sites, both of which are plentiful in Oklahoma, and it's often injected back into the ground to stop it polluting nearby freshwater aquifers or other potable water sources. It's this injection process that can cause induced earthquakes, although not every wastewater disposal process triggers them.
Either way, the USGS and the Seismic Sound Lab have collated the most significant recent tremors in the state into a single gif, and it’s a marvel to behold. Much like that spiraling temperature anomaly gif that appeared back in 2016 in order to demonstrate the speed of man-made climate change, this new animation makes the underlying science very hard to argue with: exploring for oil and gas in this way is causing an earthquake surge.
There are two notable upticks in seismic activity in Oklahoma: back around 2011, and then again in 2014. In fact, back in 2010, there were just 41 quakes registering as 3.0M or above in the state. In 2015, this peaked at 903.
All in all though, the trend is clear to see: Quakes haven’t just been getting more energetic, but more common, in the Sooner State.
Previous work by the USGS revealed that the state is one of the most high-risk for significant, damaging earthquakes in the entire country – and yes, that includes California with its San Andreas Fault network. Overall, 4 million Americans are at risk of experiencing a major seismic event this year, and 88 percent of them live in states that engage in fracking and wastewater injection.
There are no major fault networks in Oklahoma, and yet – as two majors quakes in 2011 and 2016 revealed – it is still able to experience quakes that almost hit 6.0M. These are powerful enough to destroy homes and take lives, and they’re completely man-made. Continuing to frack and to dispose of wastewater in this way, and to not acknowledge this hazard more explicitly, is nothing less than reckless.
Fortunately, it looks as if authorities have sat up and taken notice; additional restrictions on drilling practices have seen the number of 3.0M or greater quakes drop to 623 as of 2016. So far this year, there’s been just 180. Still, the risk remains.
It’s such a shame that there’s no other way to source energy so cheaply without endangering the environment, the climate, and everyone living nearby. Oh, wait.