The Unique Source Mechanism of an Explosively Induced Mine Collapse

Experiment and Data

Figure 1 shows the locations of the mine and two regional seismic stations EYMN and TBO, both of which participated in GSETT-3 experiment. EYMN is an auxiliary station of the prototype International Monitoring System for ground-based nuclear explosion monitoring. Both stations have recorded signals from the collapse with adequate signal to noise ratios.

Before the collapse experiment, an array of broad-band seismometers was deployed around the anticipated collapse area on the surface to record the seismic signals from the collapse and subsequent aftershocks. Figure 2 illustrates the array layout relative to the mine and the collapsed panel.

Ground motion from the collapse was recorded by the array and the data were transformed into vertical, radial and transverse components. Instrument response was removed from the data. An example of the data set and the spectra are presented in Figure 3.

To facilitate the analysis, the velocity model of the mine site was investigated by analyzing the aftershock P and S arrivals. The model was deduced based on the analysis results and the results of a previously conducted reflection and refraction survey. Figure 4 shows the model.

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Introduction | Experiment and Data | Analysis Results | Interpretation and Discussion | Conclusion