eprintid: 1510 rev_number: 16 eprint_status: archive userid: 2 dir: disk0/00/00/15/10 datestamp: 2015-02-11 12:51:20 lastmod: 2017-02-08 12:21:42 status_changed: 2015-04-27 12:11:01 type: article metadata_visibility: show creators_name: Talebi, Shahrair creators_name: Boone, Tom J. creators_id: stalebi@nrcan.gc.ca creators_id: corp_creators: CANMET, Canada corp_creators: Imperial Oil Resources Ltd., Canada title: Source Parameters of Injection-induced Microseismicity ispublished: pub subjects: MP1 subjects: RCA1 subjects: SHU divisions: EPOS-P full_text_status: none keywords: Water injection, microseismic events, source parameters. abstract: We analyze source parameters of microseismic events (M < − 1) associated with high flow-rate water injections in a shale formation at a depth of 220 m. Two types of events were observed several hundred impulsive events with clear P- and S-wave arrivals, and continuous emissions with peaked spectra detected well into the experiment. For a representative collection of impulsive events, an −2 model provided satisfactory fits to displacement spectra corrected for attenuation, and average quality factors of 34 and 15 were obtained for P and S waves. P-wave first motion analysis and E S  /E P ratios indicated the existence of a non-double-couple component in some events, particularly early in the experiment. A clear difference was observed for estimates of stress release parameters as non-double-couple events had smaller stress drops and apparent stresses. The seismic efficiency of double-couple and non-double-couple events was limited to 0.9% and 0.05% respectively, with average values being 0.25% and 0.02%. A comparison of our results with those reported for a similar magnitude range in a hard-rock formation indicates considerably smaller estimates of stress drop and apparent stress in our case while seismic efficiencies are comparable. date: 1998-11 date_type: published publication: Pure and Applied Geophysics volume: 153 number: 1 publisher: Springer Verlag pagerange: 113-130 id_number: doi:10.1007/s000240050187 refereed: TRUE issn: 0033-4553 official_url: http://dx.doi.org/10.1007/s000240050187 access_IS-EPOS: limited owner: Publisher citation: Talebi, Shahrair and Boone, Tom J. (1998) Source Parameters of Injection-induced Microseismicity. Pure and Applied Geophysics, 153 (1). pp. 113-130. DOI: https://doi.org/10.1007/s000240050187