Does fracking cause earthquakes? A newly released report from England reportedly confirms a link between hydraulic fracturing of a shale gas well and earthquake activity. And this is not an injection well, but a standard, hydraulically fractured natural gas well. A copy of the report is embedded below. MDN will walk you through the background, what really happened—and why it happened. This is “the rest of the story” you won’t get anywhere else.
In 2011, Cuadrilla Resources Ltd had drilled and had started to hydraulically fracture the “Preese Hall” well in the Blackpool area of England. The fracking took place more than 8,000 feet below the surface (a mile and a half). On April 1, the Blackpool area experienced a magnitude 2.3 earthquake. On May 27, there was a second earthquake with a magnitude of 1.5. There were also 48 “much weaker” seismic events in the area, undetectable at the surface, but detectable using special equipment below the surface. Caudrilla voluntarily stopped drilling after the second (1.5) earthquake in May and ordered a full-blown study to be done.
Published in November 2011, “The Geo-mechanical Study of Bowland Shale Seismicity” study concluded that indeed it was “highly probable” the hydraulic fracturing of the Presse Hall well had caused the earthquakes and small tremors. At the time the initial report was released, Mark Miller, CEO of Caudrilla, said:
“We unequivocally accept the findings of this independent report and are pleased that the report concludes that there is no threat to people or property in the local area from our operations. We are ready to put in place the early detection system that has been proposed in the report so that we can provide additional confidence and security to the local community. Cuadrilla Resources is working with the relevant local and national authorities to implement the report’s recommendations so we may safely resume our operations.”(1)
On April 17 of this year, the British Department of Energy and Climate Change (DECC) published an independent expert report reviewing the Bowland study as well as other available data, and “confirms that minor earthquakes detected in the area of the company’s Preese Hall operations near Blackpool in April and May last year were caused by fracking” (see the report below). Three experts in seismology and hydraulic fracturing authored the DECC report.
The “high level view” is that a number of experts, numbering in the dozens, all conclude the same thing: Fracking at the Presse Hall well caused earthquakes. So MDN concedes the point and accepts it as fact. Does that mean fracking everywhere is unsafe and has the potential to cause earthquakes?
Here’s what MDN has not read in press accounts of this matter, but picked up by reading the reports: The earthquakes and tremors near Presse Hall were caused when fracking fluid under pressure leaked into a nearby, and previously unknown, geological fault. As was the case with earthquakes at injection wells near Youngstown, Ohio last year, and prior to that at injection wells in Arkansas, when fluid is pumped under pressure into the ground and that fluid escapes into a geological fault, it results in earthquakes. The fault in Blackpool is, as of yet, uncharted, but the inescapable conclusion of the reports is that fluid in the fault caused the earthquakes.
So the question becomes: How prevalent are underground faults, especially faults that are not yet known? Based on the fact that fracking (at least in the U.S.) has been performed in hundreds of thousands of wells over the past 40 years with no detectable earthquake activity, MDN would conclude that undetected faults are not all that common. In fact, they are exceptionally rare.
In the British DECC report just released, the authors all agree that with certain precautions in place, fracking at Preese Hall can safely proceed—even with a fault nearby. Caudrilla CEO Mark Miller said:
“We are pleased that the experts have come to a clear conclusion that it is safe to allow us to resume hydraulic fracturing, following the procedures outlined in the review. Many of today’s recommendations were contained in the original expert studies we published in November last year, and our supplementary information sent to DECC in January.
We have already started to implement a number of the experts’ recommendations in the pursuit of best practice and look forward to the final decision by DECC ministers concerning the resumption of hydraulic fracturing following the six week period for public comment commencing on 17 April.”(2)
Does fracking cause earthquakes? In isolated, exceptionally rare circumstances when fracking is done in a geological fault—yes. Otherwise, in 99.99 percent of cases, no.
(1) Caudrilla Resources (Nov 2, 2011) – Press Release Geomechanical Study
(2) Caudrilla Resources (Apr 16, 2012) – Response to DECC review on seismic events