Earthquakes and Fracking

Another concern about fracking is the recent swarm of earthquakes that have occurred in Oklahoma that occurred after a hydraulic fracking plant was built there. According to the Time Magazine article on the earthquakes,

“Between 1990 and 2008 there were between 0 and 11 earthquakes of a magnitude 2.0 or greater in Oklahoma every year. In 2009 there were 49. In 2010 there were 180. In 2013 there were 291 and so far in 2014 there have been 59-plus and counting. More than a dozen notable earthquakes have shaken north-central Oklahoma in the past three days. “

For those of you that do not recall how earthquake magnitudes work, the magnitude is a measure of how much energy an earthquake releases when it occurs. The magnitude is measured in a logarithmic scale and with each increase in magnitude, the energy increases by a magnitude of 10. Swarms of earthquakes with this number are usually rare for areas like Oklahoma as well. This earthquake swarm is thought to be the result of the fracking nearby, and people who are against fracking claim that fracking is the sole cause of this rare occurrence in Oklahoma.

While the process of fracking does cause earthquakes, the seismic events that occur naturally with the process of fracking have negative magnitudes on the Richter scale. These earthquakes release such a small amount of energy, humans would not be able to feel it. The USGS rates an earthquake with a magnitude 3 as one that would cause vibrations similar to the those caused by a truck driving by the area.

A common thought as to why these earthquakes are happening is that they are caused by the waste water wells. The waste water contains a high salt content, the additive chemicals, and radioactive materials. Waste water injections have not been associated with large earthquakes, those that have a magnitude of 6 and up, according to the USGS. The major earthquakes that have been caused by improper disposal of the waste water. This improper handling of the waste water can lead to spills and to other natural disasters. If the waste water was deposited into a location near an active fault, enough of the water could lubricate the fault to an extent that it could cause the fault to slip and cause an earthquake to happen.  One of the ways to safely discard the waste water is to put it into deep injection wells, which are also called brine wells. These wells were considered to be a class II underground injection wells.  According to State Impact Pennsylvania, these brine wells can be used to store any liquid related to oil and gas drilling.

Companies that dispose of their waste water in this way have to follow the regulations from the Environmental Protection Agency, through the Underground Injection Control Program, which is otherwise known as the UIC. Currently in Pennsylvania, the EPA states that there are seven active deep injection wells for this purpose. The wells are the alternative to how the waste water is disposed of. At the moment, the waste water is trucked to Ohio, where they are disposed of in the disposal wells there. However, this is very expensive and could cause a major spill if the truck overturns. Another way to dispose of the water is to send it to a private treatment facility. Here, the plant cleans the majority of the water solution, but a solid “cake” (the leftover minerals in the waste water) remains after the solution is processed. According to State Impact Pennsylvania, this cake still has to be disposed of safely. This cake needs to be injected back into the ground or taken to a landfill. These ways are the safest and most effective way to dispose of the waste water from the fracking process. This also stops the earthquakes from occurring in the ground, as long as the solid cake is placed in the well properly. Additionally, there is no fracking allowed with these disposal wells. The waste water is sent very far down into the ground, to a rock that can keep the waste water contained. This rock is usually a sandstone or a limestone, that stops the flow of the waste water. Finally, the disposal wells are sealed off, to avoid any spillage if the rocks allow some of the water to flow back upward, due to an external force.

 

http://time.com/8126/oklahoma-wonders-why-the-earth-is-shaking/

http://news.discovery.com/earth/could-fracking-cause-a-major-earthquake-150116.htm

http://www.energyfromshale.org/articles/fracking-and-earthquakes

http://earthquake.usgs.gov/research/induced/

http://earthquake.usgs.gov/research/induced/

Click to access fracking-wastewater-fullreport.pdf

http://stateimpact.npr.org/pennsylvania/tag/deep-injection-well/

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