eprintid: 1930 rev_number: 11 eprint_status: archive userid: 2 dir: disk0/00/00/19/30 datestamp: 2017-05-16 13:35:24 lastmod: 2017-05-16 13:35:24 status_changed: 2017-05-16 13:35:24 type: article metadata_visibility: show creators_name: Martinez-Garzon, Patricia creators_name: Kwiatek, Grzegorz creators_name: Bohnhoff, Marco creators_name: Dresen, Georg creators_id: creators_id: kwiatek@gfz-potsdam.de creators_id: bohnhoff@gfz-potsdam.de creators_id: dre@gfz-potsdam.de corp_creators: GFZ German Research Centre for Geosciences, Geomechanics and Rheology, Helmholtz Centre Potsdam, Potsdam, Germany corp_creators: GFZ German Research Centre for Geosciences, Geomechanics and Rheology, Helmholtz Centre Potsdam, Potsdam, Germany corp_creators: GFZ German Research Centre for Geosciences, Geomechanics and Rheology, Helmholtz Centre Potsdam, Potsdam, Germany corp_creators: GFZ German Research Centre for Geosciences, Geomechanics and Rheology, Helmholtz Centre Potsdam, Potsdam, Germany title: Volumetric components in the earthquake source related to fluid injection and stress state subjects: MP1 subjects: MP4 subjects: MP6 subjects: RU1_1 subjects: SG divisions: IP13 full_text_status: none abstract: We investigate source processes of fluid-induced seismicity from The Geysers geothermal reservoir in California to determine their relation with hydraulic operations and improve the corresponding seismic hazard estimates. Analysis of 869 well-constrained full moment tensors (Mw 0.8–3.5) reveals significant non-double-couple components (>25%) for about 65% of the events. Volumetric deformation is governed by cumulative injection rates with larger non-double-couple components observed near the wells and during high injection periods. Source mechanisms are magnitude dependent and vary significantly between faulting regimes. Normal faulting events (Mw < 2) reveal substantial volumetric components indicating dilatancy in contrast to strike-slip events that have a dominant double-couple source. Volumetric components indicating closure of cracks in the source region are mostly found for reverse faulting events with Mw > 2.5. Our results imply that source processes and magnitudes of fluid-induced seismic events are strongly affected by the hydraulic operations, the reservoir stress state, and the faulting regime. date: 2017-01 date_type: published publication: Geophysical Research Letters volume: 44 number: 2 publisher: American Geophysical Union pagerange: 800-809 id_number: doi:10.1002/2016GL071963 issn: 0094-8276 official_url: http://doi.org/10.1002/2016GL071963 access_IS-EPOS: limited owner: Publisher citation: Martinez-Garzon, Patricia and Kwiatek, Grzegorz and Bohnhoff, Marco and Dresen, Georg (2017) Volumetric components in the earthquake source related to fluid injection and stress state. Geophysical Research Letters, 44 (2). pp. 800-809. DOI: https://doi.org/10.1002/2016GL071963