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| Titel |
Assessment of radiated P and S wave energy from shear and tensile picoseismicity in the Mponeng deep gold mine, South Africa |
| VerfasserIn |
G. Kwiatek, Y. Ben-Zion |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250069578
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| Zusammenfassung |
| We investigate the S-to-P radiated energy ratio (ES-EP) of picoseismic and nanoseismic
activity (MW>-4.1) following the MW1.9 earthquake recorded in the Mponeng deep gold
mine, South Africa. More than 25000 aftershocks were recorded during 6 days by the
JAGUARS (Japanese–German Underground Acoustic Emission Research in South Africa)
high-frequency seismic network. The network is composed of 8 acoustic emission sensors
(sensitivity 1 kHz-180 kHz) and 3-component accelerometer, located only 30 m from the
main event. Here, we extend previous studies on source scaling relations (cf. Kwiatek et al.,
BSSA 100(3), 2010; BSSA 101(6), 2011) and analyze the ES-EP ratio of about 500
high-quality aftershocks in order to determine the character of faulting (shear/tensile/mixed).
In cases where the moment tensor solutions are not available, low ES-EP ratio may
be a signature of tensile faulting. However, the observed values of ES-EP ratio
may also be biased due to path effects and the way energy is radiated from the
source (radiation pattern, directivity). In our study, we investigate the influence of
attenuation and the radiation pattern on calculations of ES-EP ratio and consider
two end-member cases: pure shear faulting and pure tensile faulting. The obtained
results suggest that the majority of events display a significant tensile component. |
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