Fracking: Can a deep injection well cause an earthquake?

What happened at the Rocky Mountain Arsenal in the 1960s?

From the Rocky Mountain Arsenal deep injection well fact sheet:

Deep well injection for liquid waste has been safely used for many years at sites throughout the United States without documented damage to human health or the environment. After an extensive study of deep injection wells across the country by the U.S. Environmental Protection Agency (EPA), it was concluded that this procedure is effective and protective of the environment.

The Rocky Mountain Arsenal deep injection well was constructed in 1961, and was drilled to a depth of 12,045 feet. The well was cased and sealed to a depth of 11,975 feet, with the remaining 70 feet left as an open hole for the injection of Basin F liquids. For testing purposes, the well was injected with approximately 568,000 gallons of city water prior to injecting any waste. However, when the Basin F liquids were actually introduced, the process required more time than anticipated to complete because of the impermeability of the rock. The end result was approximately 165 million gallons of Basin F liquid waste being injected into the well during the period from 1962 through 1966.

The waste fluid chemistry is not known precisely. However, the Army estimates that the waste was a more dilute version of the Basin F liquid which is now being incinerated. Current Basin F liquid consists of very salty water that includes some metals, chlorides, wastewater and toxic organics. From 1962 — 1963, the fluids were pumped from Basin F into the well. From 1964 — 1966, waste was removed from an isolated section of Basin F and was combined with waste from a pre-treatment plant, located near Basin F, and then pumped into the well. The waste from the pre-treatment plant was generally a solution containing 13,000 parts per million sodium chloride (salt), with a pH ranging from 3.5 to 11.5. The organic content of the solution was high but is largely unknown.

The injected fluids had very little potential for reaching the surface or useable groundwater supply since the injection point had 11,900 feet of rock above it and was sealed at the opening. The Army discontinued use of the well in Feb. 1966 because of the possibility that the fluid injection was triggering earthquakes in the area. The well remained unused for nearly 20 years.

In 1985 the Army permanently sealed the disposal well in stages. First, the well casing was tested to evaluate its integrity. Any detected voids behind the casing were cemented to prevent possible contamination of other formations. Next, the injection zone at the bottom 70 feet of the well was closed by plugging with cement. Additional cement barriers were placed inside the casing across zones that could access water-bearing formations (aquifers). The final step was adding Bentonite, a heavy clay mud that later solidified, to close the rest of the hole up to the ground surface.

But according to the Journal of Foreign Relations, the EPA has since replaced “possibility” with much more certain language:

The Army discontinued use of the well in February 1966 because of the possibility that the fluid injection was “triggering earthquakes in the area,” according to the RMA. In 1990, the “Earthquake Hazard Associated with Deep Well Injection–A Report to the U.S. Environmental Protection Agency” study of RMA events by Craig Nicholson, and R.I. Wesson stated simply, “Injection had been discontinued at the site in the previous year once the link between the fluid injection and the earlier series of earthquakes was established.”

Twenty-five years later, “possibility” and ‘established” changed in the Environmental Protection Agency’s July 2001 87 page study, “Technical Program Overview: Underground Injection Control Regulations EPA 816-r-02-025,” which reported, “In 1967, the U.S. Army Corps of Engineers and the U.S. Geological Survey (USGS) determined that a deep, hazardous waste disposal well at the Rocky Mountain Arsenal was causing significant seismic events in the vicinity of Denver, Colorado.”

So the question is how did the RMA’s “possibility” get transformed into “established” and “was causing”? Additional data? Revised analysis? Improved candor? Inadvertent bureaucratic sloppiness? Intentional exaggeration?

The U.S. Geologic Survey says on its web site:

Earthquakes induced by human activity have been documented in a few locations in the United States, Japan, and Canada. The cause was injection of fluids into deep wells for waste disposal and secondary recovery of oil, and the use of reservoirs for water supplies. Most of these earthquakes were minor. The largest and most widely known resulted from fluid injection at the Rocky Mountain Arsenal near Denver, Colorado. In 1967, an earthquake of magnitude 5.5 followed a series of smaller earthquakes. Injection had been discontinued at the site in the previous year once the link between the fluid injection and the earlier series of earthquakes was established. (Nicholson, Craig and Wesson, R.L., 1990, Earthquake Hazard Associated with Deep Well Injection–A Report to the U.S. Environmental Protection Agency: U.S. Geological Survey Bulletin 1951, 74 p.)

Other human activities, even nuclear detonations, have not been linked to earthquake activity. Energy from nuclear blasts dissipates quickly along the Earth’s surface. Earthquakes are part of a global tectonic process that generally occurs well beyond the influence or control of humans. The focus (point of origin) of earthquakes is typically tens to hundreds of miles underground. The scale and force necessary to produce earthquakes are well beyond our daily lives. We cannot prevent earthquakes; however, we can significantly mitigate their effects by identifying hazards, building safer structures, and providing education on earthquake safety.

How much fracking wastewater get injected into wells? According to this Associated Press report:

Pennsylvania has six active deep-injection disposal wells, all in the western half of the state, but state Department of Environmental Protection records show drillers rely completely on Ohio to take their waste. Companies sent nearly 14.8 million gallons for underground disposal in the last six months of 2010, the most recent statistics available.

So does the injection of all this (and more) wastewater have anything to do with Friday’s 4.0 earthquake in Ohio? We’ll just have to see what the data say.

8 thoughts on “Fracking: Can a deep injection well cause an earthquake?”

  1. FYI unfortunately the Rocky Mountain Arsenal document you initially linked to has been moved. It is still available at the site, but in different format and as a .pdf. Like you I saw the original.

  2. I could give credence to the ‘lubrication’ theory. However, I still don’t see any mainstream studies on this related to actual pumping activities as opposed to Mother Nature doing her thing. Consider that the Midwest has fault lines all over the place. In addition the Midwest portion of the tectonic plate is STILL rising in response to the massive melt off of the ice age glaciers.

    Just as with AGW, I am very skeptical of anyone proposing that man’s puny efforts have such macro effects on our planet.

  3. How do we reduce the intensity of an earthquake? A recurring suggestion is to trigger the big earthquake before the conditions make it big. Precision explosive detonations, etc. If fracking were to cause an early small quake, what is the problem? Proof one way or the other will never happen. Proving negatives, world-wide experiments with unknown, unproveable results, etc.

  4. Thanks for placing this summary on line. I was in the process of looking for those two reports to respond to some “absolutely no chance you crazy greenie” biased hate mail.

  5. I still find it hard to believe that injecting a liquid under thousands of pound of force(?), can cause millions of tons of rock to shift enough to cause an earthquake. It seems that orders of magnitude are being ignored.

  6. I experienced these earthquakes because I was attending Colorado School of Mines in Golden, west of Denver, during this time. The consensus at the time was that fluid injection did indeed cause the earthquakes because of the local geology. The pressurized fluid was hypothesized to have lubricated a deep range-front fault along the eastern edge of the Rocky Mountains.

  7. I was 5 years old when that earthquake happened and remember it shaking us awake. I was always told that it was because of pumping wastewater into the ground. It’s interesting to hear that fracking may not have been the cause.

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