eprintid: 1251 rev_number: 19 eprint_status: archive userid: 2 dir: disk0/00/00/12/51 datestamp: 2015-02-16 08:45:42 lastmod: 2017-02-08 12:21:37 status_changed: 2015-04-27 12:10:33 type: article metadata_visibility: show creators_name: Kwiatek, Grzegorz creators_name: Ben-Zion, Yehuda creators_id: kwiatek@gfz-potsdam.de creators_id: corp_creators: Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Potsdam, Germany corp_creators: Department of Earth Sciences, University of Southern California, Los Angeles, California, USA title: Assessment of Pand Swave energy radiated from very small shear-tensile seismic events in a deep South African mine ispublished: pub subjects: RR subjects: SMU subjects: SS divisions: EPOS-P full_text_status: none keywords: radiated energy, tensile faulting, non-DC components 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 ≤ ML ≤ − 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 < 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., <1) may reflect enhanced P radiation associated with rock damage in the source volumes. date: 2013-07-25 date_type: published publication: Journal of Geophysical Research: Solid Earth volume: 118 number: 7 publisher: John Wiley & Sons, Ltd. pagerange: 3630-3641 id_number: doi:10.1002/jgrb.50274 refereed: TRUE issn: 2169-9313 official_url: http://dx.doi.org/10.1002/jgrb.50274 access_IS-EPOS: limited owner: Publisher citation: Kwiatek, Grzegorz and Ben-Zion, Yehuda (2013) Assessment of Pand Swave energy radiated from very small shear-tensile seismic events in a deep South African mine. Journal of Geophysical Research: Solid Earth, 118 (7). pp. 3630-3641. DOI: https://doi.org/10.1002/jgrb.50274