Study questions whether fracking causes earthquakes

Study questions whether fracking causes earthquakes


Fracking wikimediaA new 2013 study conducted by the University of Durham in the United Kingdom dispels the widespread contention that fracking is a major threat to triggering large earthquakes in California and the U.S.  Fracking is the hydraulic fracturing of subsurface rock formations to extract oil and gas by various chemical methods used since 1947, as distinguished from using steam.

The study is titled, “Induced Seismicity and Hydraulic Fracturing for the Recovery of Hydrocarbons,” was conducted by  Richard Davies, PhD. It reported that, of 198 human-induced earthquakes since 1929, only one was indirectly related to oil and gas fracking itself.

The major cause of the fracking-related earthquakes, on the other hand, was not related to fracking operations, but the disposal of fracking and shale gas wastewater required by toxic waste disposal laws.

No fracking earthquakes in California in 66 years

Based on the Durham study and other online data sources, only 10 human-induced major earthquakes from all causes occurred in California over an 84-year time span concurrent with rapid industrialization (see table below).  None was from fracking per se.

           Human-Caused Earthquakes in California and Worldwide (1929 to 2013)

Earthquake sources:

Number of incidents

Earthquake Magnitude on Richter Scale

Number of Earthquakes 5.0 and Over

Hydraulic Fracturing of oil and gas in California since 1947




Dams and reservoirs


2.8 to 6.1


Geothermal power plants (including Baja, California)


5.0 to 6.6


Oil and gas extraction (not fracking)


3.5 to 5.9


Total Human-Caused Large Earthquakes in California since 1929


2.8 to 6.6


Total Number of Large Natural-Caused Earthquakes in California 1680 to 2013


4.1 to 7.9


Total Number Man-Caused Earthquakes in world from all sources since 1929

198 +

1.0 to 7.3


Estimated Total of Natural-Caused Large Earthquakes in California since fracking began in 1947


2.0 and above


Estimated Total Natural-Caused Large Earthquakes in California from 1929 to 2013


2.0 and above


Estimated Total Number of Natural-Caused Large Earthquakes in World since 1929


2.0 and above


Four California man-made earthquakes were from subsurface water pressurization related to dams and reservoirs, three were from geothermal power plants, and three were from oil and gas extraction not related to fracking.

In addition to the Durham study, only three other fracking related earthquakes could be found in the world, one of which occurred in the U.S.  No fracking-related earthquakes are reported to have occurred in California.

The Durham University study considered an alleged fracking earthquake in Ohio in 2013 (up to 2.7 magnitude).  Omitted from the Durham University study was a quake in Oklahoma in 2011 (reported from 4.1 or 5.6 magnitude). Both the Ohio and Oklahoma earthquake swarms were caused by mandated deep reinjection of fracking wastewater into the ground to comply with state toxic waste disposal laws. Two other alleged fracking-related earthquakes occurred in Canada in 2009 and Great Britain in 2011.

Three fracking quakes worldwide out of 85 million earthquakes

To put this into greater perspective, the UC Berkeley Seismology Laboratory reports there were 558,434 total earthquakes greater than 1.0 from 1990 to 2011 in California alone.  Of earthquakes with a magnitude of 2.0 or larger, 25,383 were recorded and analyzed each year on average.  That reflects 2,115 earthquakes per month, 448 per week, and 70 per day in California.

About six to seven 5.0+ magnitude earthquakes occur each year on average in California.  Earthquakes of 5.0 in magnitude or with acceleration of 2 g’s (gravity force) are considered at the threshold at which damages to large lifeline infrastructure can occur.

There are about 1,300,000 earthquakes annually in the world over 2.0 in magnitude. Fracking technology began in 1947.  Of the 85,800,000 estimated earthquakes that have occurred worldwide since 1947, possibly only four have been confirmed as indirectly caused by disposal of wastewater from fracking.  Fracking has been unregulated in California for 60 years.

California recently passed Senate Bill 4 to regulate fracturing of subsurface rock formations by fracking or “acidization.” 

CA launches European-like earthquake prediction bureaucracy?

On Sept. 23, 2013, Gov. Jerry Brown signed into law Senate Bill 135 to build and operate in five years a statewide earthquake prediction system at a cost of $80 million. The impetus for this law was a 2013 study conducted by Caltech and the Japan Agency for Marine-Earth Science and Technology that found a statewide earthquake involving both Los Angeles and San Francisco metropolitan areas may be possible.

A recent study by UC Santa Cruz seismologist Emily Brodsky indicates that small, localized earthquakes from geothermal power plants, and possibly fracking, could be forecasted. But a 2012 study of the PXP Inglewood Oilfield using data from Caltech sensors found no seismic activity from fracking or fracking water disposal. Experts generally agree that there is little likelihood of dangerous earthquakes generated by fracking in the Monterey Shale Formation in California.

The California Office of Emergency Services, Caltech, California Geological Survey, University of California and U.S. Geological Survey already operate the California Integrated Seismic Network, which reportedly has earthquake early warning capabilities.

No appropriation from the California General Fund was authorized under SB135.  Instead, SB135 is looking for funding from the debt-plagued Federal government.  Revenues from oil and gas companies and geothermal power plant operators may be a likely target for funding the new system. To do that, fracking and geothermal related earthquakes may have to be sold to the public as a high risk.

On October 22, an Italian court convicted seven seismologists from its “Great Risks Commission” of manslaughter for providing “false assurances” of no earthquake risk involving the L’Aquila Earthquake that killed over 300 people.

This raises the question whether California’s earthquake forecast system would be prone to politicization, as with the model in Italy.

                  Human Induced Earthquakes in California (and other quakes)

(data source)
Location Resource Activity Year Earthquake Magnitude
Oil Production
California Oil Production 1987 5.9
Orcutt Field
California Oil Production 1991 3.5
California Oil Production 1947 to 1961 5.1
Water Reservoirs
Shasta Dam
California Reservoir Water Storage & Green Power 1944 3.0
Hoover Dam
Nevada Reservoir Water Storage & Green Power 1939 5.0
Monticello Dam(1) California Reservoir Water Storage & Green Power 1979 2.8
Oroville Dam
California Reservoir Water Storage & Green Power 1975 6.1
Geothermal Power Plants
Salton Sea(3) California Geothermal Green power Ongoing 5.1
The Geysers
Sonoma County CA Geothermal Green power Ongoing 5.0 Max
Cerro Prieto
Baja, Calif.Mexico Geothermal Green power Ongoing 6.6
Academic Research
Major faults(1) California Seismic Research Boreholes & vibrating Ongoing 2.8 to 3.1
Fracking (outside California)
Blackpool(6) England Fracking Oil 2011 2.3
Horn River Basin (7) British Columbia, Canada Fracking Oil 2009 3.6
Ohio Fracking Water disposal injection 2011 2.8
Sparks (1) Oklahoma Fracking Water disposal injection 2011 4.1 to 5.6
Background Natural Causes Major Quakes
Major Quakes – 68 quakes 1680 to 2013 California Plate tectonic, sub-thrust faults Natural causes Ongoing 4.1 to 7.76.3 avg.
Sources cited:1.  Induced Seismicity and Hydraulic Fracturing for the Recovery of Hydrocarbons, University of Durham, U.K., (April 2013).2. Induced Seismicity article.3. University of California Santa Cruz, “Geothermal Power Facility Induces Earthquakes, Study Finds,” (July 2013).

4. The Geysers article.

5. Induced Seismicity article.

6. Popular Mechanics, “How Big Could a Man-Made Earthquake Get?,” April 2, 2013.

7.  NBC News, “Fracking Energy Exploration Connected to Earthquakes Say Studies,” July 11, 2013.

8.  “List of Earthquakes in California.”


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