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With the current Oklahoma fracking earthquake lawsuit litigation, there are various misconceptions about the role of fracking in increased seismic activity. To help clear things up we answer some frequently asked questions.
Does Fracking Really Induce Quakes?
No. The fact is deep well injection of fracking waste is actually believed to induce seismic activity. While fracturing involves injecting fluids into the layers of rock and sediment to access natural gas and oil reserves. Waste from gas wells is injected under very high pressure into wells that reach thousands of feet deep into the Earth, potentially changing underground pressure and increasing stress on dormant and active fault lines.
So, All Deep Injection Wells are Dangerous?
Actually, most disposal wells are not connected to a increase in seismic activity because there are several factors that scientists believe are the cause of quakes. These factors include the volume of waste being injected and the pressure under which it is injected; if there are dormant or active fault lines nearby; stress changes that are large enough to induce a quake; whether there is a path that would allow the pressurized fluid to travel to a fault line.
Why does Fracking Produce So Much Waste?
Actually, wastewater is produced in most types of oil and gas extraction, not just hydraulic fracturing and saltwater is a byproduct of these processes. Also, fracking fluid is used to separate the layers of rock to allow access to gas and oil. This fracking fluid is extracted from the well and used again or injected in deep wells.
How Close Does a Well Have to Be to a Fault Line to Induce a Quake?
Deep well injection sites don’t have to be close to a fault line to trigger seismic activity. In fact, the United States Geological Survey (USGS) says that wells can trigger quakes 10 miles around the well and much deeper than the well is. Some researchers believe that wells can trigger activity father away then ten miles. In states that have a large number of disposal wells, this can mean that activity can be induced from nearly anywhere in the region.
Do Any Other Human Activities Cause Earthquakes?
Yes, there are many human activities that can cause earthquakes. For example, as Lake Mead filled behind the Hoover Dam, the shift weight increased stress underground and caused tremblors. Today, seismic activity changes with water levels of the lake.
Coal mining can also cause quakes, as can carbon sequestration, where geologic carbon dioxide is captured and injected deep underground. The volume of CO2 that would need to be injected underground to make an impact on above ground CO2 levels could also trigger seismicity.
Enhanced geothermal systems may also trigger quakes. EGS generate energy by injecting water deep into the Earth and then extracting the hot water to create steam that powers turbines which generate electricity.
Even skyscrapers may cause earthquakes. Take for example, in Taipei Taiwan, many small and two large earthquakes were believed to be triggered by the weight of the 700,000-ton Taipei 101 skyscraper, which may have put increasing stress on a long dormant fault line.