@article{epos1510,
          volume = {153},
          number = {1},
           month = {November},
          author = {Shahrair Talebi and Tom J. Boone},
           title = {Source Parameters of Injection-induced Microseismicity},
       publisher = {Springer Verlag},
            year = {1998},
         journal = {Pure and Applied Geophysics},
           pages = {113--130},
        keywords = {Water injection, microseismic events, source parameters.},
             url = {https://episodesplatform.eu/eprints/1510/},
        abstract = {We analyze source parameters of microseismic events (M {\ensuremath{<}} ? 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.}
}