TY  - JOUR
ID  - epos1837
UR  - https://episodesplatform.eu/eprints/1837/
IS  - B12
A1  - Mossop, Antony
A1  - Segall, Paul
Y1  - 1999/12/10/
N2  - During the 1970s and 1980s, The Geysers geothermal region was rapidly developed as a site of geothermal power production. The likelihood that this could cause significant strain within the reservoir, with corresponding surface displacements, led to a series of deformation monitoring surveys. In 1973, 1975, 1977, and 1980, The Geysers region was surveyed using first-order, class I, spirit leveling. In 1994, 1995, and 1996, many of the leveling control monuments were resurveyed using high-precision Global Positioning System receivers. The two survey methods are reconciled using the GEOID96 geoid model. The displacements are inverted to determine volume strain within the reservoir. For the period 1980-1994, pe?k volume strains in excess of 5 x 10 -4 ?re imaged. There is ?n excellent correlation between the observed changes in reservoir steam pressures and the imaged volume strain. If reservoir pressure changes are inducing volume strain, then the reservoir quasi-static bulk modulus K must be <4.6 x 10 ? Pa. However, seismic velocities indicate a much stiffer reservoir with K - 3.4 x 101ø Pa. This apparent discrepancy is shown to be consistent with predicted frequency dependence in K for fractured and water-saturated rock. Inversion of surface deformation data therefore appears to be a powerful method for imaging pressure change within the body of the reservoir. Correlation between induced seismicity at The Geysers and volume strain is observed. However, earthquake distribution does not appear to have a simple relationship with volume strain rate
PB  - John Wiley & Sons
JF  - Journal of Geophysical Research: Solid Earth
VL  - 104
SN  - 2169-9313
TI  - Volume strain within The Geysers geothermal field
SP  - 29,113
AV  - none
EP  - 29,131
ER  -