@article{epos1251,
          volume = {118},
          number = {7},
           month = {July},
          author = {Grzegorz Kwiatek and Yehuda Ben-Zion},
           title = {Assessment of Pand Swave energy radiated from very small shear-tensile seismic events in a deep South African mine},
       publisher = {John Wiley \& Sons, Ltd.},
            year = {2013},
         journal = {Journal of Geophysical Research: Solid Earth},
           pages = {3630--3641},
        keywords = {radiated energy, tensile faulting, non-DC components},
             url = {https://episodesplatform.eu/eprints/1251/},
        abstract = {We discuss requirements for reliable estimates of radiated seismic energy in S and P phases and derive ratios of S-to-P radiated energy (ES/EP) of 539 seismic events with local magnitudes ? 5.23 {$\leq$} ML {$\leq$} ? 2.41 (subdecimeter size) recorded by high-frequency acoustic emission (AE) sensors of the JAGUARS seismic network in the Mponeng deep gold mine, South Africa. The analyzed events are aftershocks of a MW1.9 earthquake, and the recording AE sensors are located within about 40 m of the events. A shear-tensile model is used to simulate the radiation pattern of P and S phases from a family of rupture models ranging from pure shear to pure tensile failure. The calculations include correction factors for energy estimates associated with given source-receiver geometries and expected focal mechanism with possible tensile component. Synthetic calculations are used to assess the effects of limited observed frequency band and attenuation on the estimated ES/EP ratios. The model calculations provide guidelines on when different approximations may be used. The obtained ES/EP ratios for the analyzed events are relatively low (median value {\ensuremath{<}} 5) for the full range of model parameters tested, suggesting that significant number of the events display a tensile component. Events with very small ratios (e.g., {\ensuremath{<}}1) may reflect enhanced P radiation associated with rock damage in the source volumes.}
}