relation: https://episodesplatform.eu/eprints/1685/
title: Spatiotemporal changes, faulting regimes, and source parameters of induced seismicity: A case study from The Geysers geothermal field
creator: Martinez-Garzon, Patricia
creator: Kwiatek, Grzegorz
creator: Sone, Hiroki
creator: Bohnhoff, Marco
creator: Dresen, Georg
creator: Hartline, Craig
subject: Source parameter estimation
subject: Collective properties of seismicity
subject: Technology-seismicity interaction
subject: Geysers
subject: Geothermal energy production
description: The spatiotemporal, kinematic, and source characteristics of induced seismicity occurring at  different fluid injection rates are investigated to determine the predominant physical mechanisms responsible  for induced seismicity at the northwestern part of The Geysers geothermal field, California. We analyze a  relocated hypocenter catalog from a seismicity cluster where significant variations of the stress tensor orientation  were previously observed to correlate with injection rates. We find that these stress tensor orientation changes  may be related to increased pore pressure and the corresponding changes in poroelastic stresses at reservoir  depth. Seismic events during peak injections tend to occur at greater distances from the injection well,  preferentially trending parallel to themaximum horizontal stress direction. In contrast, at lower injection rates the  seismicity tends to align in a different direction which suggests the presence of a local fault. During peak  injection intervals, the relative contribution of strike-slip faulting mechanisms increases. Furthermore, increases  in fluid injection rates also coincide with a decrease in b values. Our observations suggest that regardless of the  injection stage, most of the induced seismicity results from thermal fracturing of the reservoir rock. However,  during peak injection intervals, the increase in pore pressure may likewise be responsible for the induced  seismicity. By estimating the thermal and hydraulic diffusivities of the reservoir, we confirm that the characteristic  diffusion length for pore pressure is much greater than the corresponding length scale for temperature and also  more consistent with the spatial extent of seismicity observed during different injection rates.
publisher: John Wiley & Sons
date: 2014-11
type: Article
type: NonPeerReviewed
identifier:   Martinez-Garzon, Patricia and Kwiatek, Grzegorz and Sone, Hiroki and Bohnhoff, Marco and Dresen, Georg and Hartline, Craig  (2014) Spatiotemporal changes, faulting regimes, and source parameters of induced seismicity: A case study from The Geysers geothermal field.  Journal of Geophysical Research: Solid Earth, 119 (11).  pp. 8378-8396. DOI: https://doi.org/10.1002/2014JB011385 <https://doi.org/10.1002/2014JB011385>     
relation: http://doi.org/10.1002/2014JB011385
relation: doi:10.1002/2014JB011385