Basin and Range Province Earthquake Working Group
A Basin and Range Province Earthquake Working Group (BRPEWG) was convened in 2006, to develop consensus recommendations from a broad-based group of technical experts on seismic-hazard issues in the Basin and Range Province (BRP) important to the U.S. Geological Survey (USGS) for the 2007 update of the National Seismic Hazard Maps (NSHMs).
Scientists attending the Western States Seismic Policy Council (WSSPC)-sponsored Basin and Range Province Seismic Hazard Summit II (BRPSHSII) held in Reno, Nevada, in May 2004, identified six important seismic-hazard issues relevant to the BRP. Following BRPSHSII, WSSPC incorporated the issues into their Policy Recommendation (PR) 04-5, which advocated convening a broad-based group of technical experts to evaluate each of the issues and advise the USGS regarding the 2007 NSHM update.
In response to PR 04-5, the WSSPC Basin and Range Province Committee (BRPC) and the Utah Geological Survey (UGS) convened the first BRPEWG (BRPEWGI) in 2006, under the auspices of WSSPC and the USGS NSHM Project and National Earthquake Hazards Reduction Program.
The BRPEWGI was charged with reviewing information regarding five of the six BRPSHSII identified seismic-hazard issues (the sixth issue was addressed through a separate USGS-sponsored process [Next Generation of Attenuation Models], and therefore was not considered by the BRPEWGI), and developing consensus recommendations for the 2007 NSHM update.
The BRPEWGI drew its members from several BRP state geological surveys, federal government agencies, academic institutions and seismological laboratories, and geotechnical consulting firms. The BRPEWGI met on March 8-10, 2006, in Salt Lake City, Utah. The results of BRPEWGI were published as UGS Open-File Report 477.
Based largely on deliberations of the Utah Quaternary Fault Parameters Working Group (UQFPWG) since 2006, and the Working Group on Utah Earthquake Probabilities, eight additional questions related either to geologic evaluation of seismic sources or seismology in the BRP important to the next NSHM update in 2013 have surfaced.
The USGS requested that the UGS convene a BRPEWGII meeting, similarly cosponsored by WSSPC, to address those eight questions and provide consensus recommendations on how to accommodate them in the 2013 USGS NSHM update. The BRPEWGII met on November 14-16, 2011, in Salt Lake City, Utah. The results of BRPEWGII were published as UGS Open-File Report 591.