It seems that Anthony Watts politely disagrees with my post about the connection between oil and gas production and earthquake activity. Actually that’s not a fair portrayal of his post. It’s a hatchet job against me personally. What a nice guy.



Watts does everything he can to dispute any connection, not only between earthquakes and fracking, but with injection wells (the destination of wastewater from fracking). He points out that a U.S. Geological survey report about the large (magnitude 5.6) Oklahoma earthquake doesn’t mention fracking or injection wells. He shows that a Scientific American article suggested that fracking was probably not the cause of Oklahoma’s biggest quake on record. And by God, if fracking isn’t wreaking seismic hell in Nebraska then Anthony Watts won’t accept that there’s any evidence of its having an impact anywhere. And he certainly doesn’t seem to accept that the U.S. Geological Survey supports a causal relationship between increased earthquake activity and oil/gas production.

Here’s what I actually said about the cause of the recent surge in earthquake activity:



The putative culprit is “injection wells,” the destination of wastewater from hydraulic fracking (and in some cases from dewatering operations). We looked at earthquake data a while ago, because of a study from the U.S. Geological Survey which reported a dramatic increase in earthquakes of magnitude 3.0 or greater over a large area of the U.S., stating that the increase is “almost certainly man-made,” and attributing it to oil and gas production.



The study, by W.L. Ellsworth, S.H. Hickman, A.L. Lleons, A. McGarr, A.J. Michael, and J.L. Rubinstein was presented at the 2012 annual meeting of the Siesmological Society of America. Here’s what the abstract says (added emphasis is mine, the words are theirs):



A remarkable increase in the rate of M 3 and greater earthquakes is currently in progress in the US midcontinent. The average number of M >= 3 earthquakes/year increased starting in 2001, culminating in a six-fold increase over 20th century levels in 2011. Is this increase natural or manmade? To address this question, we take a regional approach to explore changes in the rate of earthquake occurrence in the midcontinent (defined here as 85° to 108° West, 25° to 50° North) using the USGS Preliminary Determination of Epicenters and National Seismic Hazard Map catalogs. These catalogs appear to be complete for M >= 3 since 1970. From 1970 through 2000, the rate of M >= 3 events averaged 21 +- 7.6/year in the entire region. This rate increased to 29 +- 3.5 from 2001 through 2008. In 2009, 2010 and 2011, 50, 87 and 134 events occurred, respectively. The modest increase that began in 2001 is due to increased seismicity in the coal bed methane field of the Raton Basin along the Colorado-New Mexico border west of Trinidad, CO. The acceleration in activity that began in 2009 appears to involve a combination of source regions of oil and gas production, including the Guy, Arkansas region, and in central and southern Oklahoma. Horton, et al. (2012) provided strong evidence linking the Guy, AR activity to deep waste water injection wells. In Oklahoma, the rate of M >= 3 events abruptly increased in 2009 from 1.2/year in the previous half-century to over 25/year. This rate increase is exclusive of the November 2011 M 5.6 earthquake and its aftershocks. A naturally-occurring rate change of this magnitude is unprecedented outside of volcanic settings or in the absence of a main shock, of which there were neither in this region. While the seismicity rate changes described here are almost certainly manmade, it remains to be determined how they are related to either changes in extraction methodologies or the rate of oil and gas production.



They clearly state exactly what I claimed (in fact I quoted them), that the increase is “almost certainly man-made.” They clearly state that there result is not about the large (M 5.6) quake and its aftershocks. But hey, what the hell would they know about any of this? They only work for the Earthquake Science Center of the U.S. Geological Survey.

It turns out the U.S. Geological Survey isn’t the only organization making such claims. As 300-page report on the subject commissioned by the National Research Council (and available through the National Academies Press) includes this:



Felt induced seismicity potentially related to Class II water injection wells has been identified at individual sites in Arkansas (see Chapter 4), Ohio, and Texas (Box 3.7). USGS researchers are investigating whether a recent increase in the rate of M > 3.0 earthquakes in the state of Oklahoma (see Figure 3.13), might be attributed to wastewater injection (Ellsworth et al., 2012). One of the best documented cases of induced seismicity from fluid injection is in the Paradox Basin, Colorado, where brine from a natural seep has been re-injected in one disposal well at 14,000 to 15,000 feet (4,300 to 4,600 meters) depth since 1996 to prevent brine flow into the Colorado River (Appendix K). To date over 4,600 induced seismic events (M 0.5 – 4.3) as far away as 16 kilometers (9.9 miles) from the injection well have been documented in the Paradox Basin (Block, 2011).



Their report even includes a graphic from the presentation by Ellsworth et al., who apparently didn’t just study a large region of the central U.S., they also focused on Oklahoma:





It’s fairly clear, from Ellsworth et al. and from the report of the National Research Council, that yes, fluid injection related to oil and gas production does contribute to earthquakes.

As for fracking itself, I never stated that it was a direct cause of earthquakes, only that the massive quantities of wastewater it produces were implicated. But it turns out that fracking itself is implicated as well. As reader Miguelito (who seems to be reasonably knowledgeable about the subject) points out,



Earthquakes directly related to fracking have occurred in Wales (two small earthquakes) and in the Horn River Basin of northeast British Columbia (a series of very small earthquakes, hundreds if you count the tremors below 2 on the Richter scale, which can’t be felt at all on the surface), where it appears that fluid was directly injected into faults.



The National Research Council report includes this:



A hydraulic fracture treatment in January 2011 in Eola field, Oklahoma, coincided with a series of earthquakes. Eola field is located in central Oklahoma, southwest of Oklahoma City. Felt seismicity was reported on the evening of January 18 from one resident near Elmore City, Oklahoma. Further analysis showed fifty earthquakes occurred that evening, 43 of which were large enough to be located, ranging in magnitude from M 1.0 to 2.8. The earthquakes are coincident in location and timing with a hydraulic fracture in the Eola field, Picket Unit B well 4-18. The events all occurred within 24 hours of the first activity. The deepest hydraulic fracture in the Picket Unit B well 4-18 occurred 7 hours before the first earthquake was detected. Most of the events appear to be about 3.5 km (2.2 miles) from the hydraulic fracture well.



Anthony Watts pushes the idea that there’s no relationship between fracking and increased earthquake activity, he won’t even consider an indirect relationship due to the wastewater injection which fracking requires. Both the U.S. Geological Survey and the National Research Council disagree. Who you gonna believe?