Exploitng the South

We Fight Back (Fracking Causes Quakes)

Imagine developers want to frack gas, near a nuclear power plant, and many geological faults less than 20 miles from where you live. Imagine your town gets water from a river that flows through the formation that would be fracked. Imagine that 100 years ago the largest industrial accident in the state happened in a mine in that formation. Imagine your state legislature has just been overtaken by clueless Republicans seeing dollar signs from resource exploitation. That’s what’s happening where I live in central North Carolina. When my daughter in Pittsboro put me in touch with local activists who are fighting to stop this disaster from happening, I stopped blogging and got active locally.

We live in a fault bounded basin that formed in the beginning of the age of the Dinosaurs as Africa began the process of breaking up from North America. The Shearon Harris nuclear power plant is located close to the main boundary fault of the basin. Triassic basin boundary faults in other basins have shown a tendency to be reactivated by stress changes. And hydrofracturing has been shown to cause earthquakes. My daughter’s friend was very concerned about the possibility that gas fracking could induce an earthquake that might affect the nuclear power plant. Recent reports on induced seismicity support her concerns.

A previously unreported study out of the Oklahoma Geological Survey has found that hydraulic fracturing may have triggered a swarm of small earthquakes earlier this year in Oklahoma. The quakes, which struck on Jan. 18 in a rural area near Elmore City, peaked at magnitude 2.8 and caused no deaths or property damage.

The study, currently being prepared for peer review, follows news today that Cuadrilla Resources, a British shale gas developer, has found that it was “highly probable” its fracturing operations caused minor quakes of magnitude 2.3 and 1.5 in Lancashire, England. The Cuadrilla study could complicate the expansion of hydraulic fracturing for shale gas in risk-averse Europe, where France has already banned the practice.

That’s E&E News PM on the twin earth-shaking reports on an emerging concern about fracking, which involves blasting massive amounts of water through rock under high pressure to get the gas out.

Illustration demonstrating fracking

The geology of the Deep River Triassic basin in North Carolina is far more complex than the geology of shale gas plays that have had induced earthquakes and water contamination problems. Our source rock is actually a coal bearing formation, not a true shale. And the formation is very shallow on the northwest side of the basin near the Deep River which we get our drinking water from.

Local residents filled the large conference room. People who arrived on time had to stand in the hall outside. The state geologist and several other state representatives spoke, then the meeting was turned over to public comments.

I was amazed by quality of the comments. Each person except for one industry man presented a personal perspective on how fracking could damage our health, our water, our farmland and our communities. Local politicians talked about stopping predatory contracts by unscrupulous gas drilling companies. I talked about how the faults and basaltic dikes in the basin’s geology would provide barriers to horizontal hydrofracturing and pathways for hydrofracking fluids to go to the surface. I closed by pointing out that the state had budgeted a small fraction of the money and time to develop an effective plan to permit and regulate gas development. My daughter’s friend discussed the risk of earthquakes near the nuclear power plant.

This will be an ongoing battle for our communities in central NC.

Here’s the Sanford Herald’s article on the meeting.

North Carolina’s Deep River coal deposits have such a tragic history that old timers believe that there is a demon in them . Small scale coal mining, which began around the time of the Revolutionary war,  suffered a string of deadly accidents which culminated in the Coal Glen Mine disaster of 1925 which killed 53 miners. In all, over 100 men died mining small amounts of never-profitable Deep River coal. The cause of the mining difficulties wasn’t a demon. Numerous geologic faults made mining deadly.

Faults and Dikes in and around the Deep River Triassic basin near Sanford, NC
Faults and Dikes in and around the Deep River Triassic basin near Sanford, NC

The Deep River Triassic basin is bounded by the Jonesboro fault on its southwest side. The Jonesboro fault strikes from the southwest to the northeast. The Deep River basin is deepest along the side of the Jonesboro fault because it was the master fault where the basin pulled apart as North America and Africa began the process of separation. The Jonesboro fault has much greater vertical offset than the numerous parallel and sub-parallel faults that break up the basin to the northwest of the Jonesboro fault.  Thus, the coal and gas bearing rocks of the Cumnock formation slope upwards from thousands of feet deep neat the Jonesboro fault to surface exposures on the northwest side of the basin. Moreover, dozens of basalt dikes oriented perpendicular to the faults (oriented NW to SE) disrupt the sediments of the Deep River basin.

Faults in the coal deposits led to water intrusion, structural problems, and flow of explosive methane gas into the mine. The deadly explosions and mine flooding led to closure of all of the Deep River mines before World War II.

In my opinion the faults and geologic complexity that made coal mining deadly would  make it nearlyimpossible to control fluids used to hydrofracture the Cumnock formation to recover natural gas.  There is a growing body of evidence from existing studies of gas production by hydrofracturing that faults become conduits for  vertical migration of gas and hydrofracturing fluids. A report from Colorado observed:

While it is likely that some small amount of vertical migration of gas from the Wasatch Formation is naturally occurring, the low pre-drilling concentrations (<1ppm) and trend of increasing dissolved methane that is positively correlated to well numbers indicate that drilling and production activities are the cause. The locations of the most affected are near structural features where the faults and fractures maximize the vertical mobility of the gas, however it is not possible at this time to identify if leaking production tubing, leaking top-of-gas casing or un-cased Wasatch interval is the primary source of methane.

The trend and location of chloride, which is derived from Williams Fork production water shows similar trends of increasing concentration and locations near structural features. As was the case with methane the current data do not permit precise identification of the source.

A recent, 2011, study of production of the Marcellus shale published in the Procedings of the National Academy of Sciences, observed gas, with the isotopic signature of the gas in the Marcellus formation, in groundwater around the drilling zones.

Methane concentrations were detected generally in 51 of 60 drinking-water wells (85%) across the region, regardless of gas industry operations, but concentrations were substantially higher
closer to natural-gas wells (Fig. 3). Methane concentrations were 17-times higher on average (19.2 mg CH4 L−1) in shallow wells from active drilling and extraction areas than in wells from nonactive areas (1.1 mg L−1 on average; P < 0.05.

The average methane concentration in shallow groundwater in active drilling areas fell within the defined action level (10–28 mg L−1) for hazard mitigation recommended by the US Office of the Interior (13), and our maximum observed value of 64 mg L−1 is well above this hazard level.

Thus, even in the relatively simple shallow marine “layer cake” geology of the Marcellus shale gas production zones in  Pennsylvania and New York state, significant amounts of methane escaped into groundwater. Methane levels were so high in some water samples that they had the potential for explosion. Control of methane and hydrofracturing fluids will be much more difficult in the complex, faulted, land-based Triassic basins of North Carolina.

The history of repeated water intrusion into the Deep River coal mines is practical local evidence that the geologic structure and rock stress will lead to uncontrolled vertical movement of fluids if hydrofracturing is attempted.

The Deep River Basin coal and gas deposits were formed in a complex, active geologic setting very different from the simpler geologic settings under which the  majority of coal and gas deposits formed.

The history of the mines shows the catastrophic failures caused by applying conventional methods to this complex geologic environment.

In the early 1890s the Egypt mine was reopened but closed again within the year because of fire. It was flooded and pumped dry again and again and another explosion took another life. On Dec. 12, 1895, a large explosion of dynamite left 41 miners dead and two missing. Families sued, miners refused towork and money ran short. On May 23, 1900, an explosion killed 23 and the company declared bankruptcy. Then the Coal Glen Mine opened in 1921 across the Deep River from the Egypt. In 1925 an explosion took the lives of 53 men. The mine closed in 1929 when rain flooded the air shaft. It was pumped out but the mine flooded again in 1930 and was closed. Under the name of Raleigh Mining Company the Coal Glen mine opened briefly in 1947 and closed in 1951. The mine is also known as the Farmville Mine.

North Carolina’s Department of Environment and Natural Resources needs to develop it plans and assessments to investigate the multiple potential problems that may arise because of the many faults, dikes in the  Deep River basin. The plans must reflect the geologic complexity to protect health safety and the environment.

DENR has not been given close to the budget, manpower, and time to prepare an adequate plan for regulating the development and production of natural gas in the Deep River basin. The history of mining in the basin should be cause for reflection.

I strongly advise DENR and the governmental bodies of the state of North Carolina to wait for the EPA to complete its assessment of natural gas production by hydrofracturing. Waiting for the results of the EPA study will prevent the state of North Carolina from wasting taxpayers’ money by duplicating the EPAs work. Moreover, the EPA has better resources than the state of North Carolina and has already made the financial commitment to do the work. If the state of North Carolina rushes to produce an inferior plan in an inadequate amount of time, the state will be unable to protect health, safety and the environment.

“Those who fail to learn from history are doomed to repeat it.” – Churchill and others

Editor’s Note: This story originally published Thursday, November 3, 2011 at DailyKos.com.



Former Kauai body surfer now living near a pond in central North Carolina. I enjoy watching the blue herons in the early morning. Expertise:environmental geochemistry & energy & health and safety & govt regulation. Also, nuclear waste.