Scientists: 'Fracking' should be part of assessing earthquake hazards

Researchers are now including waste-water injection – including the ‘fracking’ used in oil and gas development – to estimate earthquake hazards. The central and eastern US have seen a steep increase in earthquakes.

|
Brennan Linsley/AP
A worker adjusts hoses during a hydraulic fracturing operation at an Encana Corp. gas well, near Mead, Colo., March 25. Some scientists suspect that earthquakes may be linked to such 'fracking.'

Researchers with the US Geological Survey are developing an estimate of earthquake hazards that for the first time includes hazards posed from earthquakes triggered or suspected to have been triggered by waste-water disposal wells used by the oil and gas industries.

The effort stems from two earthquakes in 2011 that topped magnitude 5 and were suspected to have been triggered by waste-water injection – one in southern Colorado, at magnitude 5.3, and another in Oklahoma, at magnitude 5.7. The Oklahoma quake was preceded by a magnitude 5.0 foreshock.

The quakes are part of an increase in earthquake activity in the central and eastern US in recent years.

Between 1967 and 2000, the areas experienced an average of 21 quakes a year with a magnitude of 3.0 or higher. Between 2010 and 2012, the average exploded to some 300 quakes a year of magnitude 3.0 or higher, according to a 2013 analysis by USGS researcher William Ellsworth and published in the journal Science.

Prior to the 2011 quakes in Oklahoma and Colorado, "people had really believed that waste-water-injection induced earthquakes could not exceed magnitude 5," said Justin Rubinstein, a USGS researcher working on the new assessment, during a briefing Thursday at the Seismological Society of America's annual meeting in San Francisco. "These really demonstrate that this is a significant hazard."

Nor is the risk restricted to injection wells, noted Gail Atkinson, an earthquake scientist at Western University in London, Ontario.

"Waste water is the dominant cause," she said, "but what we are seeing as time goes on is that there are also events being induced from hydraulic fracture operations."

These operations, known as fracking, inject fluids into oil- or gas-bearing rock formations to liberate oil and gas from reserves that otherwise would be hard to exploit.

The new hazard assessment, which would augment the USGS's 2014 National Seismic Hazard Map, will key off the recent increase in quakes east of the Rockies.

For now, the project isn't trying to determine whether the quakes are natural or human-triggered, Dr. Rubinstein said, although he and his team, as well as other researchers, are trying to find ways to tell the difference.

Data are sparse on fault locations, underground fluid flows, the pace and volume of water being pumped into the ground at any given site, and how readily nearby faults can in effect be lubricated by waste fluids, he said.

"To some degree, it doesn't actually matter whether or not these earthquakes are induced," he added. "The increased rate indicates there is an increase in hazard."

The number of wells suspected of triggering moderate quakes is small compared with the total number of injection wells in the US, researchers note. But while the number of suspects may be small, they can have a long reach, Dr. Atkinson explained.

She has been studying a swarm of more than 200 earthquakes of magnitude 3 or larger that has been shaking central Oklahoma since 2009. The trigger appears to be a group of injection wells pumping high volumes of fluid deep underground – fluid that then travels to facilitate the rupture of faults tens of kilometers from the wells.

As Rubinstein and colleagues work on the new assessment, "we're trying to leave open the possibility that these earthquakes are natural,” he said. “We need to consider all the possibilities.”

Those possibilities include the prospect that induced quakes of even greater magnitude than those recorded so far are possible, he added, as well as the possibility that if the quakes are induced, actions can be taken to end the activities triggering them in that location.

You've read  of  free articles. Subscribe to continue.
Real news can be honest, hopeful, credible, constructive.
What is the Monitor difference? Tackling the tough headlines – with humanity. Listening to sources – with respect. Seeing the story that others are missing by reporting what so often gets overlooked: the values that connect us. That’s Monitor reporting – news that changes how you see the world.

Dear Reader,

About a year ago, I happened upon this statement about the Monitor in the Harvard Business Review – under the charming heading of “do things that don’t interest you”:

“Many things that end up” being meaningful, writes social scientist Joseph Grenny, “have come from conference workshops, articles, or online videos that began as a chore and ended with an insight. My work in Kenya, for example, was heavily influenced by a Christian Science Monitor article I had forced myself to read 10 years earlier. Sometimes, we call things ‘boring’ simply because they lie outside the box we are currently in.”

If you were to come up with a punchline to a joke about the Monitor, that would probably be it. We’re seen as being global, fair, insightful, and perhaps a bit too earnest. We’re the bran muffin of journalism.

But you know what? We change lives. And I’m going to argue that we change lives precisely because we force open that too-small box that most human beings think they live in.

The Monitor is a peculiar little publication that’s hard for the world to figure out. We’re run by a church, but we’re not only for church members and we’re not about converting people. We’re known as being fair even as the world becomes as polarized as at any time since the newspaper’s founding in 1908.

We have a mission beyond circulation, we want to bridge divides. We’re about kicking down the door of thought everywhere and saying, “You are bigger and more capable than you realize. And we can prove it.”

If you’re looking for bran muffin journalism, you can subscribe to the Monitor for $15. You’ll get the Monitor Weekly magazine, the Monitor Daily email, and unlimited access to CSMonitor.com.

QR Code to Scientists: 'Fracking' should be part of assessing earthquake hazards
Read this article in
https://www.csmonitor.com/Environment/2014/0501/Scientists-Fracking-should-be-part-of-assessing-earthquake-hazards
QR Code to Subscription page
Start your subscription today
https://www.csmonitor.com/subscribe