Induced Seismicity in the United States

Danielle Sumy, Earth Science and Petroleum Engineering, University of Southern California

Summary

As the population of the United States continues to grow, so does the demand for energy resources. Earthquakes in the continental interior of the United States are historically rare, yet in 2011 alone, moderate-sized earthquakes occurred in Colorado, Texas, Oklahoma, Ohio, and Arkansas. The close proximity of these earthquakes to active fluid injection wells constructed to dispose of wastewater from hydraulic fracturing (or 'hydrofracking') suggests that ongoing oil and natural gas operations may be to blame [e.g. Horton, 2012; Keranen et al., 2013; Kim, 2013].

It is therefore important for the public to know the different types of oil and natural gas operations and understand their potential for inducing earthquake activity. In 2012, the National Research Council published a report that documents two main findings in the communication of seismic hazard with respect to oil and natural gas activities. First, the process of hydrofracking conducted to stimulate the production of oil does not pose a high risk of destructive earthquakes. This process more often results in earthquakes of M<2, which are generally not felt. Second, the wastewater disposal from hydrofracking operations can induce much larger earthquakes (the largest of these is the 2011 M5.7 Oklahoma earthquake [Sumy et al., 2014]), and therefore poses a higher seismic risk.

The recent increase in seismic events related to oil and natural gas operations suggest that some fluid injection wells, especially those close to densely populated areas, could pose significant seismic hazard and result in widespread damage. Improved seismic monitoring with large, regional networks as well as low-cost networks like the Quake-Catcher Network can help scientists better understand the distribution of earthquake activity, especially in close proximity to oil and natural gas production and injection wells. The investigation into the role of wastewater fluid injection in triggering earthquake activity is important to understand scientifically, and have the ability to communicate its hazard and risk in both political and scientific arenas.

Individuals with expertise/responsibilities in the following areas have helped create the case study:

• Seismology
• Engineering
• Federal, regional and state planning
• Public awareness/Media (such as National Public Radio)

Key teaching points:

• Understand different energy technologies and their potential for inducing earthquakes.
• Quantify the overall contribution of injection-induced seismicity to the seismic hazard of the United States, which requires both quantity and timeliness of information on injection volumes and pressures from regulatory agencies.
• Determination of clear requirements for oil and natural gas production and operation based on robust scientific information gathered from improved seismic monitoring in areas of increased injection operations.
• Determination of the best approaches to disseminate information to the public.

How this example is used in the classroom:
Improved seismic monitoring is key to better understand how oil and natural gas production and the injection of wastewater after hydrofracking induces earthquake activity. My shared activity discusses improved seismic monitoring with the citizen-science based Quake-Catcher Network, and applications to the M5.1 La Habra earthquake.

References

Ellsworth, W. L. (2013), Injection-Induced Earthquakes, Science, doi:10.1126/science.1225942.

Horton, S. (2012), Disposal of Hydrofracking Waste Fluid by Injection into Subsurface Aquifers Triggers Earthquake Swarm in Central Arkansas with Potential for Damaging Earthquake, Seismol. Res. Lett., 83(2), doi:10.1785/gssrl.83.2.250.

National Research Council (2012), Induced Seismicity Potential in Energy Technologies, National Academies Press, Washington, D.C.

Keranen, K. M., H. M. Savage, G. A. Abers, and E. S. Cochran (2013), Potentially induced earthquakes in Oklahoma, USA: Links between wastewater injection and the 2011 Mw 5.7 earthquake sequence, Geology, doi:10.1130/G34045.1.

Kim, W.-Y. (2013), Induced seismicity associated with fluid injection into a deep well in Youngstown, Ohio, J. Geophys. Res. Solid Earth, 118,
3506–3518, doi:10.1002/jgrb.50247.

Sumy, D. F., E. S. Cochran, K. M. Keranen, M. Wei, and G. A. Abers (2014), Observations of static Coulomb stress triggering of the November 2011 M5.7 Oklahoma earthquake sequence, J. Geophys. Res. Solid Earth, 119, doi:10.1002/2013JB010612.