The Kirovskiy explosion of September 29, 1996: Example of a CTB event notification for a routine mining blast

On September 29, 1996, a routine mining blast of about 390 metric tons was detonated underground at the Kirovskiy mine in the central Kola Peninsula. The United States was notified two weeks in advance that the blast was to t ake place and was given the date, approximate time, location and total char ge. The explosion was detected and located by the prototype International D ata Center (pIDC) and published in the Reviewed Event Bulletin (REB). Detai led information about the blast, including the type and depth of mining ope ration, the underground charge configuration, and the blasting delay patter n, is reviewed and combined with a seismological analysis of the event. The seismic analysis points to a possible associated tectonic component to the blast, consisting of a small rock burst or induced tremor, spall, or some combination of these mechanisms, that may have enhanced the shear waves, pr oduced large Rg waves at low frequency, and small Pn/Sn and Pn/Lg amplitude ratios at high frequency. While these discriminants might identify the eve nt as an earthquake, the spectral/cepstral analysis of the event clearly sh ows the ripple-fire delays. This event provides important confidence-buildi ng measures for both location calibration, in the form of travel-time corre ctions for location of mine events in this region, and for improved underst anding of seismic discriminants expected for large mine blasts that may hav e an associated induced tectonic component (e.g., spall, mine tremor or roc k burst).