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The meaning of seismoacoustic emission for estimation of time of mining tremors occurrence |
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The meaning of seismoacoustic emission for estimation of time of mining tremors occurrence Authors: A. Cianciara, B. Cianciara
In the paper the meaning of seismoacoustic emission for estimation of time of mining tremors occurrence
is discussed. Concept is based on the PASH method used for fracturing process of rock mass
investigation. Probabilistic assessment of a seismic hazard is carried out by analyzing of seismoacoustic
emission recorded in the frequency range of 30 Hz-1000 Hz. Emission recorded in that frequency range
is a one of main carriers of information on rock mass fracturing processes. The dynamics of fracturing
process is the reason that hazard analysis should be carried out based on measurement data recorded in
Θ-time windows several dozens hours wide. It follows then, that emission recorded in the seismoacoustic
range only, because of its high activity and great number of recorded events, allows for statistic analysis.
Traditionally, seismic hazard is based on physical energy of events. However, in the seismoacoustic range
energy estimation is practically impossible. Therefore, it was assumed to carry out the seismic hazard
assessment based on analysis time intervals between events. The concept is justifi ed by presence of linear
statistic relation between mentioned intervals and logarithm of event energies. As a result, estimation
of hazard parameters in Θ-window is possible. Moving the Θ-window by step of Δ and by subsequent
repetitions of hazard parameters estimation, time series of those parameters are obtained. Time series
include random factor and therefore their expected value is estimated. Such obtained time series of hazard
parameters are the base for defi ning of a so called “Indicating function”. Allowing for estimation of time
of rockburst occurrence and assessment of rockburst risk level. |
2011