Fracking and earthquakes: Scientists link rise in seismic activity in Oklahoma to increased oil and gas exploration

In 2009, there were 50 quakes in the central US state; in 2010 there were more than 1,000. Tim Walker reports

Between 1975 and 2008, Oklahoma recorded an average of no more than six earthquakes per year, yet now it is the second most seismically active of the contiguous United States, beaten only by California. Scientists have linked this surge in seismic activity to a parallel increase in oil and gas exploration, including fracking.

In 2009, there were almost 50 quakes in Oklahoma. The following year, that number leapt to more than 1,000. Most were not “felt” earthquakes – those of magnitude 2.5 and above, which can be detected by humans. However, the state’s annual record of 222 felt quakes, set in 2013, has already been broken this year, with 253 so far. Seismologist Austin Holland of the Oklahoma Geological Survey told Reuters: “We have had almost as many magnitude 3 and greater already in 2014 than we did for all of 2013… We have already crushed last year’s record for number of earthquakes.”

Earthquakes rarely cause damage unless they are of magnitude 4 or higher. A 4.3-magnitude temblor struck the same area near Oklahoma City on 30 March. In November 2011, the state suffered a 5.6-magnitude quake – the largest ever recorded in Oklahoma – which destroyed 14 homes.

Scientists have connected a sharp rise in small earthquakes in several states to the boom in underground oil and gas exploration, notably the controversial practice of hydraulic fracturing, or fracking. Waste water from fracking and oil drilling is pumped back into the earth to be stored in so-called “injection wells”. Several studies have shown that the water, forced deep underground in layers of porous rock, can trigger seismic activity.

Oil and gas companies insist that the techniques are safe, yet federal scientists believe their activities have contributed to a 20-fold rise in the number of small earthquakes striking the central and southern US in recent years. So-called “earthquake swarms” have occurred not only in Oklahoma, but also in previously sedate regions of Arkansas, Colorado, Ohio and Texas.

During 2010 and 2011, up to 1,000 micro-earthquakes occurred in and around the town of Greenbrier in Arkansas, thought to have been caused by underground waste-water disposal, which forced open a small and previously inactive seismic fault, generating the quakes – the largest of which had a magnitude of 4.7. The state’s oil and gas commission declared a moratorium on injection wells within 1,000 square miles, and a group of residents filed a class-action lawsuit against two energy companies, Chesapeake Energy and BHP Billiton Petroleum, for the damage caused to their homes. Five homeowners reached an undisclosed settlement with the firms last August.

Read more: Fracking industry launches charm offensive
Fracking threat to British wildlife
US fracking has had a 'significant impact' on water supplies

Dozens of civil lawsuits related to fracking have been filed since 2009 in eight US states, for complaints including air pollution, noise pollution and groundwater contamination. But the Greenbrier case was the first in which oil and gas companies were sued for causing an earthquake. It may not be the last. Within 24 hours on 10 and 11 March, five earthquakes were recorded at a fracking well in Ohio, the largest of which registered as magnitude 3.

The state’s government ordered an immediate halt to the operations pending further investigation.

It is already familiar with the issue. In December 2010, an injection well in Youngstown began deep-storing waste water from fracking operations in neighbouring Pennsylvania. In the centuries since records began in 1776, Youngstown – which sits atop the Marcellus Shale gas-producing region – had never registered a single earthquake. In 2011, it experienced more than 100, with the strongest, a magnitude-3.9 temor, on 31 December.

The well was shut down shortly afterwards, and the quakes duly stopped. John Kasich, the state governor, issued an executive order demanding operators conduct seismic studies before being issued permits for injection wells.

The controversy has also come to California, a state that is all too familiar with seismic activity. This year, the Los Angeles city council voted to ban fracking in the city until council members were content that the process would not have a detrimental effect on Angelenos’ drinking water. The risk of earthquakes was also cited in the ban.

On 17 March a 4.4-magnitude earthquake struck the Santa Monica mountains near Los Angeles, close to an area where oil extraction activities have been reported. Though seismologists said it probably occurred too deep underground to be attributable to fracking, a group of LA council members have demanded an investigation into whether oil or gas exploration could have caused the quake.

Start your day with The Independent, sign up for daily news emails
Have you tried new the Independent Digital Edition apps?
ebooks
ebooksAn introduction to the ground rules of British democracy
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
SPONSORED FEATURES
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Recruitment Genius: Account Manager - Media Sales - £36,000 OTE

£28000 - £36000 per annum: Recruitment Genius: This award-winning company, whi...

Recruitment Genius: C# .NET Developer / Application Support - Junior

£21000 - £25000 per annum: Recruitment Genius: This business has an industry r...

Recruitment Genius: Office Administrator

Negotiable: Recruitment Genius: They make daily deliveries to most foodservice...

Recruitment Genius: Transport Planner

Negotiable: Recruitment Genius: They make daily deliveries to most foodservice...

Day In a Page

Turkey's conflict with Kurdish guerrillas in Iraq can benefit Isis in Syria

Turkey's conflict with Kurdish guerrillas in Iraq can benefit Isis in Syria

Turkish President Erdogan could benefit politically from the targeting of the PKK, says Patrick Cockburn
Yvette Cooper: Our choice is years of Tory rule under Jeremy Corbyn or a return to a Labour government

Our choice is years of Tory rule under Corbyn or a return to a Labour government

Yvette Cooper urged Labour members to 'get serious' about the next general election rather than become 'a protest movement'
Singapore's domestic workers routinely exploited and often abused in the service of rich nationals

Singapore's hidden secret of domestic worker abuse

David Cameron was shown the country's shiniest veneer on his tour. What he didn't see was the army of foreign women who are routinely exploited and often abused in the service of rich nationals
Showdown by Shirley Jackson: A previously unpublished short story from the queen of American Gothic

Showdown, by Shirley Jackson

A previously unpublished short story from the queen of American Gothic
10 best DSLRs

Be sharp! 10 best DSLRs

Up your photography game with a versatile, powerful machine
Solved after 200 years: the mysterious deaths of 3,000 soldiers from Napoleon's army

Solved after 200 years

The mysterious deaths of 3,000 soldiers from Napoleon's army
Every regional power has betrayed the Kurds so Turkish bombing is no surprise

Robert Fisk on the Turkey conflict

Every regional power has betrayed the Kurds so Turkish bombing is no surprise
Investigation into wreck of unidentified submarine found off the coast of Sweden

Sunken sub

Investigation underway into wreck of an unidentified submarine found off the coast of Sweden
Instagram and Facebook have 'totally changed' the way people buy clothes

Age of the selfie

Instagram and Facebook have 'totally changed' the way people buy clothes
Not so square: How BBC's Bloomsbury saga is sexing up the period drama

Not so square

How Virginia Woolf saga is sexing up the BBC period drama
Rio Olympics 2016: The seven teenagers still carrying a torch for our Games hopes

Still carrying the torch

The seven teenagers given our Olympic hopes
The West likes to think that 'civilisation' will defeat Isis, but history suggests otherwise

The West likes to think that 'civilisation' will defeat Isis...

...but history suggests otherwise
The bald truth: How one author's thinning hair made him a Wayne Rooney sympathiser

The bald truth

How thinning hair made me a Wayne Rooney sympathiser
Froome wins second Tour de France after triumphant ride into Paris with Team Sky

Tour de France 2015

Froome rides into Paris to win historic second Tour
Fifteen years ago, Concorde crashed, and a dream died. Today, the desire to travel faster than the speed of sound is growing once again

A new beginning for supersonic flight?

Concorde's successors are in the works 15 years on from the Paris crash