UCSC study: Energy production causing quakes

SANTA CRUZ -- A new UC Santa Cruz study concludes that a CalEnergy geothermal field near the Salton Sea is triggering small earthquakes very close to the San Andreas Fault, a finding with potentially big implications.

Published Thursday in the journal Science, the study draws a straight line between pulling water out of the ground and increasing numbers of temblors. The conclusion is sure to add to a growing debate about whether a new generation of energy production methods -- even those aimed at renewable sources -- could have unintended effects with potentially serious consequences.


The study examined more than 30 years of data from CalEnergy production facilities near Brawley, but could have broader implications. Tinkering with subterranean pressure dynamics is a staple of modern oil and gas production, and if they cause earthquakes it could prove a sensitive topic in California, where lawmakers are grappling with new regulations for the emerging technologies.


But some of the water is lost during the process, which is one source of the problem. CalEnergy's facilities are in a seismically active area, and the vast majority of the earthquakes are not large enough to pose a threat to human life or property.



Scientists at Lawrence Berkeley National Laboratory said "induced seismicity" is an accepted phenomenon within the scientific community. As far back as the 1930s, oilmen around Long Beach noticed they needed to replace oil with saltwater or the ground would shake, said Ernest Majer, a senior adviser in the lab's geophysics department.






In a state riven with fault lines and vast, untapped oil potential -- particularly beneath the Monterey Shale, a geologic formation that expands east into the Central Valley from Monterey County -- there has been surprisingly little debate about the earthquake risks from fracking. There are 88,000 active wells in California, helping make the state the fourth-largest oil producer in the U.S. California also tops the nation in geothermal production.

This year, various state lawmakers proposed a series of fracking-related bills, but just one survives. It now includes the remnants of a bill proposed by Assemblyman Mark Stone, D-Scotts Valley, establishing standards governing fracking wastewater.


"If they're potentially causing earthquakes in areas that don't have earthquakes" such as the Midwest, Stone said, "what's going to happen in areas that are susceptible to earthquakes?"


Last year, the U.S. Geological Survey concluded that a new prevalence of Midwest earthquakes had to be manmade -- with a sixfold increase over the previous century -- but stopped short of saying what human activity was causing the earthquakes.


Jason Marshall, chief deputy director for the California Department of Conservation, said more than a million fracking wells have been drilled nationally without evidence they cause earthquakes. The state recently studied available data from California wells and found they are drilled to an average of nearly 3,000 feet and use an average of 143,000 gallons of water, which is much less than in other states.



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