- © 2015 by the Seismological Society of America
Online Material: Description and figure representing the stratigraphy and construction of the two wastewater disposal wells.
As oil and gas well completions utilizing multistage hydraulic fracturing have become more commonplace, the potential for seismicity induced by the deep disposal of frac‐related wastewater and the hydraulic fracturing process itself has become an increasingly important issue (e.g., National Academy of Science [NAS], 2012). Although it is rare for a wastewater disposal well to induce felt seismicity, there have been several cases over the past half century that identify strong relationships between injected fluids and seismicity (e.g., Healy et al., 1968; Nicholson and Wesson, 1990; McGarr et al., 2002; Evans et al., 2012). Following the 2011 Youngstown earthquake sequence (YES) near a wastewater disposal well in northeastern Ohio (Fig. 1), which included hundreds of earthquakes up to an M 4.0 (Ohio Department of Natural Resources [ODNR], 2012; Kim, 2013; Skoumal, Brudzinski, Currie, et al., 2014), there has been a heightened concern over seismicity related to energy technologies in Ohio. The ODNR is actively setting new regulations to deal with induced seismicity (ODNR, 2014), which could serve as a blueprint for other states. Seismic monitors are to be installed near certain injection wells before commercial injection begins and will remain there for 12 months afterward. A number of regional long‐standing backbone seismic stations have been operating for over a decade, and studies of the YES significantly benefited from early adoption of EarthScope Transportable Array (TA) stations in western Pennsylvania in late 2010.