eprintid: 1833 rev_number: 15 eprint_status: archive userid: 6 dir: disk0/00/00/18/33 datestamp: 2017-03-02 10:27:14 lastmod: 2017-05-16 12:34:10 status_changed: 2017-03-02 10:27:14 type: article metadata_visibility: show creators_name: Kwiatek, Grzegorz creators_name: Martinez-Garzon, Patricia creators_name: Dresen, Georg creators_name: Bohnhoff, Marco creators_name: Sone, Hiroki creators_name: Hartline, Craig corp_creators: Geomechanics and Rheology, GFZ Potsdam German Research Centre for Geosciences, Potsdam, Germany corp_creators: Geomechanics and Rheology, GFZ Potsdam German Research Centre for Geosciences, Potsdam, Germany corp_creators: Geomechanics and Rheology, GFZ Potsdam German Research Centre for Geosciences, Potsdam, Germany Institute of Earth and Environmental Sciences, University of Potsdam, Potsdam, Germany corp_creators: Geomechanics and Rheology, GFZ Potsdam German Research Centre for Geosciences, Potsdam, Germany Institute of Geological Sciences, Free University Berlin, Berlin, Germany corp_creators: Geomechanics and Rheology, GFZ Potsdam German Research Centre for Geosciences, Potsdam, Germany Department of Civil and Environmental Engineering, Geological Engineering Program, University of Wisconsin-Madison, Madison, Wisconsin, USA corp_creators: Calpine Corporation, Middletown, California, USA title: Effects of long-term fluid injection on induced seismicity parameters and maximum magnitude in northwestern part of The Geysers geothermal field subjects: MP2 subjects: MP4 subjects: RU1_1 subjects: SG divisions: IP13 full_text_status: none abstract: The long-term temporal and spatial changes in statistical, source, and stress characteristics of one cluster of induced seismicity recorded at The Geysers geothermal field (U.S.) are analyzed in relation to the field operations, fluid migration, and constraints on the maximum likely magnitude. Two injection wells, Prati-9 and Prati-29, located in the northwestern part of the field and their associated seismicity composed of 1776 events recorded throughout a 7 year period were analyzed. The seismicity catalog was relocated, and the source characteristics including focal mechanisms and static source parameters were refined using first-motion polarity, spectral fitting, and mesh spectral ratio analysis techniques. The source characteristics together with statistical parameters (b value) and cluster dynamics were used to investigate and understand the details of fluid migration scheme in the vicinity of injection wells. The observed temporal, spatial, and source characteristics were clearly attributed to fluid injection and fluid migration toward greater depths, involving increasing pore pressure in the reservoir. The seasonal changes of injection rates were found to directly impact the shape and spatial extent of the seismic cloud. A tendency of larger seismic events to occur closer to injection wells and a correlation between the spatial extent of the seismic cloud and source sizes of the largest events was observed suggesting geometrical constraints on the maximum likely magnitude and its correlation to the average injection rate and volume of fluids present in the reservoir. date: 2015-10 date_type: published publication: Journal of Geophysical Research: Solid Earth volume: 120 number: 10 publisher: John Wiley & Sons pagerange: 7085-7101 id_number: doi:10.1002/2015JB012362 issn: 2169-9313 official_url: http://doi.org/10.1002/2015JB012362 access_IS-EPOS: limited owner: Publisher citation: Kwiatek, Grzegorz and Martinez-Garzon, Patricia and Dresen, Georg and Bohnhoff, Marco and Sone, Hiroki and Hartline, Craig (2015) Effects of long-term fluid injection on induced seismicity parameters and maximum magnitude in northwestern part of The Geysers geothermal field. Journal of Geophysical Research: Solid Earth, 120 (10). pp. 7085-7101. DOI: https://doi.org/10.1002/2015JB012362