Download 27th Seismic Research Review: Ground

27th Seismic Research Review: Ground-Based Nuclear Explosion Monitoring Technologies
While ground truth information for the mining sites is not yet available, it appears that the waveform-correlation
bootstrapping approach applied to the Swedish mining regions may also be applied here. Many of the analyst-located
events in the Kazakhstan bulletin occur within a small geographical region at times at which the mines are known to
conduct routine explosions. When the waveforms are filtered in a sufficiently low-frequency band, many events are
observed to show a high degree of waveform semblance indicating a small separation between the source regions.
Figure 5. Slowness and azimuth estimates in a predetermined set of fixed frequency bands for a first P-arrival from
regional event at a distance of approximately 150 km from the Akbylak array in Kazakhstan.
It appears that the events in the clusters identified so far exhibit a similar “slowness and azimuth as a function of
frequency band” to that observed at ARCES (see Figure 5). However, the frequency bands in which regional signals
are best observed are very different at the arrays in Kazakhstan from those in Fennoscandia. For ARCES and the
other Fennoscandian arrays, frequencies below 2 Hz are essentially unusable for regional signals because of the
high-microseismic noise. The SNR for most of the mining explosions simply improves as the frequency increases and
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