Governmental Roles and Responsibilities Related to Underground Injection and Induced Seismicity - Induced Seismicity Potential in Energy Technologies - page 106

BOX 4.1
BLM Regulation of Class V Geothermal Injection Wells: Seismicity Concerns
The BLM, through an informal agreement with the EPA, regulates the Class V geothermal injection wells
in California. Under this arrangement the BLM has recently issued its “Conditions of Approval” for a proposed
enhanced geothermal systems project that stipulated the specific procedures to be followed in the event that
induced seismicity is observed to be caused by the proposed stimulation (hydraulic fracturing) operation. a
As issued by the BLM, the specific procedures include the use of a “traffic light” system that allows hydraulic
fracturing to proceed as planned (green light) if it does not result in an intensity of ground motion in excess
of Mercalli IV “light” shaking (an acceleration of less than 3.9%g), as recorded by an instrument located
at the site of public concern. However, if ground motion accelerations in the range of 3.9%g to 9.2%g are
repeatedly recorded, equivalent to Mercalli V “moderate” shaking, then the hydraulic fracturing operation
is required to be scaled back (yellow light) to reduce the potential for a further occurrence of such events.
Finally, if the operation results in producing a recorded acceleration of greater than 9.2%g, resulting in
“strong” Mercalli VI or greater shaking, then the active hydraulic fracturing operation is to immediately
cease (red light).
a R.M. Estabrook, BLM, Conditions of Approval for GSN-340-09-06, Work Authorized: Hydroshear, The Geysers,
January 31, 2012.
U.S. Geological Survey
The USGS provides scientific information to describe and understand the Earth; mini-
mize loss of life and property from natural disasters; manage water, biological, energy, and
mineral resources; and enhance and protect quality of life in the United States. 9 It is the
only federal agency with responsibility for recording and reporting earthquake activity
worldwide, and it is often asked to aid state agencies in the investigation of possible induced
seismicity. Its Earthquake Hazards Program serves as the USGS component of the mul-
tiagency National Earthquake Hazards Reduction Program, which develops, disseminates,
and promotes knowledge, tools, and practices for earthquake risk reduction that improve
national earthquake resilience. The Earthquake Hazards Program also houses the National
Earthquake Information Center (NEIC), which aims to determine the location and size
of all destructive earthquakes worldwide and to disseminate this information to concerned
agencies, scientists, and the general public.
The USGS is continuing to enhance its earthquake monitoring and reporting capabili-
ties through the Advanced National Seismic System (ANSS). Since 2008 the USGS has
9 See www.usgs.gov/aboutusgs/.