How can fracking cause earthquakes

Oil-well pads dotting the landscape of typical badland topography. Thousands of new wells are drilled into the Bakken and Three Forks annually, making this one of the most productive plays in the Nation. Skip to main content. Search Search. Natural Hazards. Apply Filter. Oklahoma has had a surge of earthquakes since Are they due to fracking? Beginning in , Oklahoma experienced a surge in seismicity. Bar graph showing the How large are the earthquakes induced by fluid injection?

The largest earthquake induced by fluid injection that has been documented in the scientific literature was a magnitude 5. In , a magnitude 5. Are earthquakes induced by fluid-injection activities always located close to the point of injection? Given enough time, the pressure increase created by injection can migrate substantial horizontal and vertical distances from the injection location. Induced earthquakes can occur 10 or more miles from injection wells.

Induced earthquakes can also occur a few miles below injection wells. Is there any possibility that a wastewater injection activity could interact with a nearby fault to trigger a major earthquake that causes extensive damage over a broad region? So far, there is no documented example linking injection operations to triggering of major earthquakes.

However, we cannot eliminate this possibility. How does the injection of fluid at depth cause earthquakes? The fluid that is injected at depth is sometimes hydraulically connected to faults. When this happens, fluid pressures increase within the fault, counteracting the frictional forces on faults.

This makes earthquakes more likely to occur on them. An analog to this system is an air hockey table. When an air hockey table is off, the puck does not Is it possible to anticipate whether a planned wastewater disposal activity will trigger earthquakes that are large enough to be of concern? Currently, there are no methods available to do this in a definitive sense. But while the state figures out what to do, residents are taking matters into their own hands. Sandra Ladra, who lives is Prague, the site of the 5.

A favorable finding would make wells a legal liability. In the meantime, insurance companies have already increased their rates , highlighting the risk.

Despite the increasingly apparent threat posed by fracking-related earthquakes, many states are ignoring the issue :. On the rare occasion, fracking has resulted in a seismic event of magnitude 4 or greater and the vibrations felt at surface are similar to those felt when a large truck passes by. These events are referred to as anomalous induced seismicity as they are unusual or inconsistent with what is expected.

In the rare case that anomalous induced seismicity occurs, operations must stop immediately and may not resume until the regulator investigates and provides permission for operations to resume. Scientific evidence in western Canada indicates that anomalous induced seismicity resulting from fracking has not caused injury or property damage, nor does it pose a risk to public safety or the environment.

Industry, regulators, academia and governments are cooperating to understand, monitor and manage anomalous seismic activity in order to ensure the continued safe development of energy resources. You are using an outdated browser. For the best experience, we recommend that you update your browser before using the website. Photo: Trican Well Service Ltd. That said, hydraulic fracturing has only been recognized as a source of induced earthquakes very recently.

In the simplest conceptual model, fluids injected in a subsurface well must be connected to a fault via some permeable pathway. This allows the fluid pressure inside of the fault to increase during stimulation, hydraulically opening the fault. How widespread, frequent, and large are hydraulic fracturing induced earthquakes? Typically less than 1 per cent of hydraulically fractured wells cause induced earthquakes.

This rarity appears to be related to the unlikely scenario of having all the correct geological conditions together in same place: tectonic, geomechanical, and hydrological. Hydraulic fracturing induced earthquakes occur most frequently during the hydraulic stimulation processes. If earthquakes do occur, the large majority happen within this timeframe. That said, earthquakes can linger after hydraulic fracturing has been completed — for periods of up to weeks or months. In some cases, the largest earthquakes have occurred after the well has been completed.

Observationally, the largest earthquake caused by hydraulic fracturing was magnitude 5. Some plays in North America have hosted events larger than magnitude 4.