eprintid: 1994 rev_number: 19 eprint_status: archive userid: 10 dir: disk0/00/00/19/94 datestamp: 2017-09-19 09:43:26 lastmod: 2018-09-07 13:13:03 status_changed: 2017-09-19 09:43:26 type: article metadata_visibility: show creators_name: Staszek, Monika creators_name: Orlecka-Sikora, Beata creators_name: Leptokaropoulos, Konstantinos Michail creators_name: Kwiatek, Grzegorz creators_name: Martinez-Garzon, Patricia creators_id: creators_id: orlecka@igf.edu.pl creators_id: kleptoka@igf.edu.pl creators_id: kwiatek@gfz-potsdam.de creators_id: corp_creators: Institute of Geophysics, Polish Academy of Sciences, Warsaw, Poland corp_creators: Institute of Geophysics, Polish Academy of Sciences, Warsaw, Poland corp_creators: Institute of Geophysics, Polish Academy of Sciences, Warsaw, Poland corp_creators: Section 4.2: Geomechanics and Rheology, Helmholtz-Centre Potsdam, GFZ German Research Centre for Geosciences, Potsdam, Germany corp_creators: Section 4.2: Geomechanics and Rheology, Helmholtz-Centre Potsdam, GFZ German Research Centre for Geosciences, Potsdam, Germany title: Temporal static stress drop variations due to injection activity at The Geysers geothermal field, California subjects: MP4 subjects: MP6_2 subjects: MP6_3 subjects: RU1_1 subjects: SG divisions: IP13 divisions: SHEER-5 full_text_status: none abstract: 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. date: 2017-07 date_type: published publication: Geophysical Research Letters volume: 44 number: 14 publisher: Geophysical Research Letters pagerange: 7168-7176 id_number: doi:10.1002/2017GL073929 issn: 00948276 official_url: https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2017GL073929 access_IS-EPOS: limited owner: Publisher acknowledgments2: IS-EPOS_platform acknowledgments2: SHEER_project citation: 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