Greeley quake may be related to nearby disposal wells

Joel Dyer

At approximately 9:30 p.m. on Saturday, May 31, Greeley residents were startled by a rare earthquake measuring 3.4 on the Richter scale.

The quake was felt in at least five northern Colorado communities.

While there were no immediate reports of damage, the anti-fracking community was quick to blame the oil and gas industry for the tremor.

While some in the oil and gas industry still try to deny the connection between earthquakes and oil and gas development, it is a debate that the scientific community resolved long ago, even before the word fracking became a rallying cry for those opposed to the controversial method of extracting oil and natural gas from shale gas formations.

Part of the confusion that has allowed the industry to escape its responsibility for such quakes has been the language used by many activists who claim that the actual act of fracking a well is causing the quakes. While on rare occasions such a claim could be accurate, most times it is not and that plays into the industry’s ability to deny responsibility for such quakes.

The vast majority of man-made quakes are caused by waste injection wells, not the act of fracking. For every barrel of oil or the equivalent amount of gas that is produced, nearly 10 barrels of contaminated wastewater are produced. This produced water, which is highly salty, contains many contaminants, including fracking fluid, heavy metals such as mercury and arsenic and other toxic compounds. In many cases when it isn’t just dumped onto the ground, which is legal in Colorado, this produced water is pumped back into a deep porous rock formation under extremely high pressure.

Earthquakes occur because naturally occurring faults in the rocks are pressured apart by the slick fluid, allowing the formation to slip. This slip is what we refer to as a quake.

The understanding that disposal wells cause quakes has been known, studied and fully documented by the federal government for more than 30 years.

In fact, one of the last times Greeley felt a quake would have been in 1967 when a quake measuring 5.3, the largest to ever hit the Front Range, was felt from Denver to Goodland, Kan., to Laramie, Wyo. It was later determined that this quake was caused by the toxic liquids disposal well at the Rocky Mountain Arsenal in Commerce City. As a result of the Arsenal’s quake, the government began studying the well, determining exactly how much pressure caused how large of a quake. By the time the experiment ended, the government had intentionally caused more than 1,300 earthquakes for the sake of research.

This research continues at various locations today. A disposal well in western Colorado, located 110 miles south of Grand Junction known as the Paradise Valley Unit, has now been studied by the federal government for 25 years and has generated more than 4,000 quakes on demand for research.

It is disposal well research such as that described above that has allowed the U.S. Geological survey to say that the damage-causing earthquakes near Trinidad, Colo., the past few years were the result of oil and gas disposal wells.

In the past year there have also been more than 500 earthquakes in Oklahoma, an area of stable seismic activity like Greeley, that have also likely been caused by disposal wells. In Oklahoma, the U.S. Geological Survey is warning that so many quakes could actually lead to a massive quake.

There are four disposal wells located near the epicenter of the Greeley quake.