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| Titel |
Microseismic activity after blasting at Zinkgruvan Mine (Sweden) |
| VerfasserIn |
İrem Erguncu Güçlü, Savka Dineva, Jouni Hansen-Haug |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250122201
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| Publikation (Nr.) |
 EGU/EGU2016-1174.pdf |
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| Zusammenfassung |
| Local seismic system consisting of 18 sensors 4.5 Hz was installed in Zinkgruvan Mine
(Sweden) in 2015 at depth ∼1140 m. The system is concentrated in a small area of 40 x 50 m
and is able to record very small seismic events (magnitude -4 or lower) induced by the mining
activity. This study is related to two larger seismic events with moment magnitudes 0.6 and
1.2 that occurred in two consecutive days and their aftershock series on July 1 and 2,
2015. The first seismic events occurred seconds after a blast and the second one
during blasting. The latter one caused a rockburst and extensive damage in the
mine. More than 3000 seismic events were recorded at distances up to 100 m from
the local seismic system during these two days. Manual data processing was done
only for the events recorded by more than 15 sensors following the larger events
and 3 hours before them. In total approximately 240 events have been analyzed.
Seismic event locations and other source parameters were obtained by IMS Trace
software.
The aftershock areas of the two seismic events formed two separate aftershock areas, The
first series (Mw -3 to -1) lasted about one hour but the second one (Mw -3 to 0) was more
complicated with two larger aftershocks (Mw 0.3 and 0.7) with their own aftershock series
within 90 minutes. Based on the Es/Ep energy ratio the main events were classified as shear
seismic events (Es/Ep ∼10). The other events were approximately equally divided between
shear and not-shear (tensile) events. No apparent correlation was found between the type
of the events and the magnitude. The apparent stress of both series varied within
four orders (from 6.7*103 to 2.4*107 Pa) with a weak trend of increase with the
magnitude.
The configuration and source parameters of the aftershock series were related to the
observed damage due to the rockburst on July 2, 2015. The results were used to obtain a
possible mechanism of the main events. |
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