Earthquakes Induced by Fluid Injection
No. Of more than 150,000 Class II injection wells in the United States, roughly 40,000 are waste fluid disposal wells for oil and gas operations.
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. Evidence from some case histories suggests that the magnitude of the largest earthquake tends to increase as the total volume of injected wastewater increases.
Earth's crust is pervasively fractured at depth by faults.
Of the case histories for which there is a scientific consensus that an injection operation induced earthquakes, the largest are magnitude*5.
Are earthquakes induced by fluid-injection activities always located close to the point of injection?
No. Given enough time, the injected fluids can migrate substantial horizontal and vertical distances from the injection location. Induced earthquakes commonly occur several kilometers below the injection point.
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 conclusive example linking injection operations to triggering of major earthquakes, however we cannot eliminate this possibility. More research is needed to either confirm or refute this possibility.
Is the recent sequence of earthquakes near Youngstown, Ohio, related to the wastewater disposal activities there?
There is a credible connection between the wastewater injection activities near Youngstown and the recent earthquakes, including the magnitude 4 earthquake that occurred on New Year’s Eve, 2011.
Does the production of natural gas from shales cause earthquakes? If so, how are the earthquakes related to these operations?
To produce natural gas from shale formations, it is necessary to increase the interconnectedness of the pore space (permeability) of the shale so that the gas can flow through the rock mass and be extracted through production wells.
USGS supports both internal and external (university-based) research on the causes of induced earthquakes. This research has a focus on injection-induced earthquakes, both from wastewater disposal and from enhanced geothermal technologies.