Strain accumulation at Yucca Mountain, Nevada, 1983-1998

A 14‐station, 50‐km aperture geodetic array centered on the proposed radioactive waste disposal site at Yucca Mountain, Nevada, was surveyed in 1983, 1984, 1993, and 1998 to determine the rate of strain accumulation there. The coseismic effects of the 1992 (MS=5.4) Little Skull Mountain earthquake, which occurred within the array, were calculated from a dislocation model and removed from the data. The measured principal strain accumulation rates determined over the 1983–1998 interval are ε1 = 2±12 nanostrain/yr N87°W±12° and ε2 = −22±12 nanostrain/yr N03°E±12° (extension reckoned positive and quoted uncertainties are standard deviations). The N65°W extension rate is −2±12 nanostrain/yr, significantly less than the 1991–1997 N65°W rate of 50±9 nanostrain/yr reported by Wernicke et al. [1998]. The implied maximum right‐lateral engineering‐shear, strain accumulation rate is γ=ε1−ε2 = 23±10 nanostrain/yr, a marginally significant rate. Almost half (ε1 = 6 nanostrain/yr N90°W, ε2 = −6 nanostrain/yr N00°E, and γ = 12 nanostrain/yr ) of the measured strain rate can be attributed to strain accumulation on the Death Valley‐Furnace Creek (50 km distant) and Hunter Mountain‐Panamint Valley (90 km distant) faults. The residual strain rate after the removal of those fault contributions is not significant at the 95% confidence level.