Since the 1920s we have recognized that pumping fluids into or out of the Earth has the potential to cause seismic events that can be felt. Seismic events in Basel, Switzerland between 2006 and 2008 were felt by local residents and were related to geothermal energy development. A string of small seismic events in Arkansas, Ohio, Oklahoma, and Texas in the past several years has been related to waste water disposal associated with oil and gas production. These seismic events have brought the issue of induced (human-caused) seismicity firmly into public view.
Anticipating public concern about the potential for induced seismicity related to energy development, Senator Bingaman requested that the Department of Energy conduct study of this issue through the National Research Council. The study was designed to examine the scale, scope, and consequences of seismicity induced during the injection of fluids related to energy production; to identify gaps in knowledge and research needed to advance the understanding of induced seismicity; to identify gaps in induced seismic hazard assessment methodologies and the research needed to close those gaps; and to assess options for interim steps toward best practices with regard to energy development and induced seismicity potential.
This study took place during a period in which a number of small, felt seismic events occurred that been caused by or were likely related to fluid injection for energy development. Because of their recent occurrence, peer-reviewed publications about most of these events were generally not available. However, knowing that these events and information about them would be anticipated in this report, the committee attempted to identify and seek information from as many sources as possible to gain a sense of the common factual points involved in each instance, as well as the remaining, unanswered questions about these cases. Through this process, the committee has engaged scientists and engineers from academia, industry, and government because each has credible and viable information to add to better understanding of induced seismicity.
Three major findings emerged from the study: (1) the process of hydraulic fracturing a well as presently implemented for shale gas recovery does not pose a high risk for inducing felt seismic events; (2) injection for disposal of waste water derived from energy technologies into the subsurface does pose some risk for induced seismicity, but very few events have been documented over the past several decades relative to the large number of disposal wells in operation; and (3) CCS, due to the large net volumes of injected fluids, may have potential for inducing larger seismic events.
Copyright 2012 by the National Academy of Sciences.