Shear Waves from Isotropically Dominated Sources: Comparison of the 2013 Rudna, Poland, and 2007 Crandall Canyon, Utah, Mine Collapses

Comparison of observed and synthetic radiation patterns suggests that Love waves generated by the 2007 Crandall Canyon Mine collapse (M-w 4.1) are the result of shear waves generated by a relatively large compensated linear vector dipole component at the source, whereas the Love waves associated with a 2013 Rudna Mine collapse (M-w 4.2) are minimal except where amplified by a deep sedimentary basin. We examine the source of the 19 March 2013 Rudna Mine, Poland, collapse with a full moment tensor inversion method, using the complete waveforms of regional-distance seismic data. The computed source is primarily composed of a dominant, and statistically significant, implosive component. The Rudna source is more similar to previous mine collapses than to double-couple tectonic earthquakes. Although source mechanisms are similar, there are clear differences in Love-wave amplitudes.