relation: https://episodesplatform.eu/eprints/1994/ title: Temporal static stress drop variations due to injection activity at The Geysers geothermal field, California creator: Staszek, Monika creator: Orlecka-Sikora, Beata creator: Leptokaropoulos, Konstantinos Michail creator: Kwiatek, Grzegorz creator: Martinez-Garzon, Patricia subject: Technology-seismicity interaction subject: Technology induced stress field redistribution subject: Evolution of stress field changes subject: Geysers subject: Geothermal energy production description: We use a high-quality data set from the NW part of The Geysers geothermal field to determine statistical significance of temporal static stress drop variations and their relation to injection rate changes. We use a group of 322 seismic events which occurred in the proximity of Prati-9 and Prati-29 injection wells to examine the influence of parameters such as moment magnitude, focal mechanism, hypocentral depth, and normalized hypocentral distances from open-hole sections of injection wells on static stress drop changes. Our results indicate that (1) static stress drop variations in time are statistically significant, (2) statistically significant static stress drop changes are inversely related to injection rate fluctuations. Therefore, it is highly expected that static stress drop of seismic events is influenced by pore pressure in underground fluid injection conditions and depends on the effective normal stress and strength of the medium. publisher: Geophysical Research Letters date: 2017-07 type: Article type: NonPeerReviewed identifier: Staszek, Monika and Orlecka-Sikora, Beata and Leptokaropoulos, Konstantinos Michail and Kwiatek, Grzegorz and Martinez-Garzon, Patricia (2017) Temporal static stress drop variations due to injection activity at The Geysers geothermal field, California. Geophysical Research Letters, 44 (14). pp. 7168-7176. DOI: https://doi.org/10.1002/2017GL073929 relation: https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2017GL073929 relation: doi:10.1002/2017GL073929