Scientists say a spate of earthquakes in the middle of the United States is “almost certainly” man-made.
Since 2001, the average number of 3.0-or-greater earthquakes each year spiked significantly, culminating in a six-fold increase in 2011 over 20th century levels, according to a new U.S. Geological Survey abstract to be presented Wednesday at a Seismological Society of America meeting.
From 1970 until 2000, the middle of the country averaged 21 quakes, then the average jumped to 50 in 2009, 87 in 2010 and 134 in 2011. Government scientists examined regions where energy production changed in recent years and although the data doesn’t suggest that hydraulic fracturing, or “fracking,” itself is inducing tremors, it did show that in some locations the increased seismic activity coincided with the injection of fracking wastewater in deep disposal wells.
“In preliminary findings, our scientists cite a series of examples for which an uptick in seismic activity is observed in areas where the disposal of wastewater through deep-well injection increased significantly. These areas tend to be in the middle of the country – mostly in Colorado, Texas, Arkansas, Oklahoma and Ohio,” David Hayes, deputy secretary of the U.S. Department of Interior, wrote in a recent blog that clarified the quakes were big enough to be felt by a great number of people but not big enough to do serious damage.
Scientists first tied the disposal of resource-extraction wastewater with the induction of earthquakes in a Colorado case dating back decades. They determined a swarm of small quakes were triggered by wastewater injections from 1962 to 1966 at the Rocky Mountain Arsenal well near Denver. They have also found the extraction of oil and gas can potentially trigger earthquakes when changes in the underground stresses created by the removal of huge volumes of oil, gas or water are large enough.Although the U.S. Geological Survey characterizes the size of the earthquakes in its research as “fairly small,” a 5.6-magnitude earthquake and its aftershocks in Oklahoma last year damaged buildings and fueled speculation that the 181 injection wells used for oil and gas exploration in the vicinity caused it. A new study says the quake “was possibly triggered by fluid injection” at the nearby wastewater wells.
Earthquakes naturally occur around the world but the middle of the United States hasn’t been known for having many of them — until fracking became mainstream. Last month, officials in Ohio said data “strongly indicates” a swarm of quakes there over a nine-month period last year were caused by the disposal of wastewater from natural gas extraction.
Concerns about the impacts of energy extraction, and fracking in particular, are mounting in resource-rich areas where residents are wary of the potential and actual impacts on air, water, noise, scenery and traffic. With the nation’s leaders committed to boosting domestic energy supplies, U.S. oil and gas exploration is in full swing with 1,950 active rigs, according to Houston-based Baker Hughes.
President Obama on Friday issued an executive order to better coordinate fracking oversight with the establishment of an “interagency working group” with members from the Environmental Protection Agency, the Interior Department, Energy Department, National Economic Council and other bodies.
The president’s announcement drew praise from oil and gas companies, which feared excessive and confusing rules from the 10 or more U.S. agencies that are considering new industry regulations.
In Colorado, fracking and the opposition to it are fierce.
Boulder County commissioners are scheduled to vote this afternoon on whether to modify or continue a moratorium on new oil and gas application. An anti-fracking group is planning a protest on the Pearl Street mall where they are calling for the commissioners to ban fracking throughout unincorporated Boulder County. On Tuesday, Longmont City Council, which also has a drilling moratorium in place, will consider its own oil and gas regulations. Other communities that are taking a close look at drilling regulations include Colorado Springs, Commerce City, Erie, Aurora, Arapahoe County, Douglas County, Elbert County, El Paso County and Huerfano County.
The EPA is also expected to issue new air-quality standards for drilling this week.
The U.S. Geological Survey, meanwhile, is continuing its research of induced seismicity. It has also partnered with universities to deploy seismometers at sites of known or possible injection-induced earthquakes in Arkansas, southern Colorado, Oklahoma, and Ohio.