While the emerging link between natural gas fracking and earthquakes has been grabbing a lot of attention, another problem has been bubbling up under our feet: a series of earthquakes in normally calm areas has been traced to conventional oil drilling operations. In particular, Oklahoma has been hit by a string of unusual earthquakes over the past couple of years, including the biggest one ever recorded in the state, a magnitude 5.7 temblor near Prague on November 6, 2011. The quakes are ongoing and in the meantime a study co-authored by researchers from Columbia University and the U.S. Geological Survey has uncovered positive evidence that wastewater from an active oil drilling operation was being pumped into a set of abandoned oil wells, putting increasing pressure on a documented fault nearby that finally “jumped” under the stress.
Like natural gas fracking, oil drilling produces copious amounts of chemical-laced wastewater, and the new Oklahoma earthquake study provides more evidence that disposing of that brine underground is not a sustainable solution.
What appears to concern the study authors the most is that the Prague earthquake involved a relatively small amount of wastewater, and this particular set of abandoned wells had been in use for wastewater disposal without incident, for 17 years. The theory is that as the wells gradually filled, more pressure was required to keep injecting more fluid in.
That theory is backed up by wellhead records, which show that the first 13 years of injection were conducted at low-to-zero pressure, and then pressure increased ten-fold from 2001 to 2006.
“There’s something important about getting unexpectedly large earthquakes out of small systems that we have discovered here…the risk of humans inducing large earthquakes from even small injection activities is probably higher [than previously thought].”
Overall, the Oklahoma earthquake study estimates an 11-fold increase in the middle of the U.S. compared to thirty years ago, including parts of Arkansas, Texas, Ohio and Colorado that are normally calm.
The study is also backed up by a U.S. Geological Survey report last year, which documented a “remarkable rise in small- to mid-size earthquakes” in that region and linked it to human activity.
Fossil Fuels And Earthquakes
Wastewater injection from natural gas fracking has also been linked recently to swarms of small earthquakes, too small to be felt on the surface, so in and of itself the link between underground wastewater disposal and seismic activity is not particularly alarming.
The problem is more one scale and scope. Gas and oil wells are proliferating rapidly and they are impinging on populated areas to a greater extent, while the new study points to the need for a far more sophisticated monitoring and regulatory structure than exists today.
The Prague earthquake is just a hint of the potential for damage. It was felt as far away as Milwaukee, a distance of 800 miles, and it resulted in two reported injuries. It also destroyed 14 houses and buckled a federal highway.
Prague is also not the only populated area to experience a problem. The city of Youngstown, Ohio felt a quake in 2011 that Columbia seismologists linked to disposal of wastewater from nearby gas fracking wells.
More Pressure On Fossil Fuels
Whether it’s oil, coal or natural gas, until a few years ago fossil fuel extraction in the U.S. was mainly confined to remote areas. A thin population, sometimes accompanied by chronic economic depression, helped to keep impacts under the radar and keep public pressure for reform at bay.
The encroachment of fossil fuel extraction into heavily populated areas has brought new attention to practices that were previously ignored, and that has resulted in new kinds of pressure on individuals and communities.
In Pennsylvania, Ohio, Colorado and Texas, for example, new state laws place restrictions on doctors that make it difficult to explore links between natural gas fracking and health problems in their patients, and local communities that attempt to prohibit drilling operations within their borders are also butting up against more permissive state regulations.
As the export market for U.S. fossil fuels has begun to grow, the issue of local control has also been growing beyond drilling and wastewater disposal to include transportation, too.
Local protests against the proposed new Keystone XL tar sands oil pipeline have been ongoing for the past couple of years, and a new issue has arisen for port communities in the Pacific Northwest that are facing increased coal traffic bound for overseas markets.