Fracking

     Fracking allows difficult-to-reach resources of oil and gas in shale rock to be extracted. 
     In the US it has significantly boosted domestic oil production and driven down gas prices. Its advantage is that is estimated to have offered gas security to the US and Canada for about 100 years and has presented an opportunity to generate electricity at half the CO2 emissions of coal.
     Fracking is the process of drilling down and then water, sand and chemicals are injected into the rock at high pressure which forces the gas to flow out to the head of the well. The process can be carried out vertically or, more commonly, by drilling horizontally to the rock layer and can create new pathways to release gas or can be used to extend existing channels. 
     But, there are consequences using this method. A fracking well in Ohio triggered scores of small earthquakes in March 2014. The biggest quake, a magnitude 3, was one of the largest ever caused by fracking. State officials shut down the well two days after the earthquake hit. The earthquake was triggered when a hidden fault in ancient crystalline rock beneath a natural gas well was disturbed. 

     Gas company officials deny it poses any risks. One official claiming the earthquake “did not pose any risk" and it's rare for fracking to cause earthquakes that people can feel and the tiny tremors that occur are too small to be felt by people. 
     The majority of fracking-linked earthquakes in recent years (including those that rocked Oklahoma, Arkansas and Colorado) have been blamed on wastewater disposal wells, in which leftover drilling fluids are injected deep underground. The fluids unclamp faults, allowing rocks to slip. The claim is that fracking earthquakes are isolated cases. 
     Intensive shale gas drilling in Ohio has unleashed earthquakes from fracking. On December 31, 2011 Youngstown experienced a magnitude 4.0 earthquake, the largest of 12 quakes clustered near an injection well in that area. Fracking-caused quakes in September and October of 2013 also rattled Harrison County in Eastern Ohio. Companies are required to install seismometers when drilling within 3 miles of known faults or near an area that has recently experienced earthquakes. If quakes occur drilling is stopped and investigated. Obviously, this is after the damage has been done.

Risks associated with fracking are: 
Contamination of groundwater 
Methane pollution and its impact on climate change 
Air pollution impacts 
Exposure to toxic chemicals 
Blowouts due to gas explosion 
Waste disposal 
Large volume water use in water-deficient regions 
Fracking-induced earthquakes 
Workplace safety 
Infrastructure degradation 

For more details on the dangers of this practice visit Teach the Earth.