Spectral Analysis and Moment Tensor Inversion of Seismic Events Induced in PolishCoal Mines: Search for Non-Shearing Components

摘要

The investigations conducted under this contract focused on research for non-shearing components of the source mechanism of seismic events induced in Polish coal mines. Such seismic events are expected to occur in close vicinity to the mining faces, where favorable conditions for generation of tensile failures or shear failures with tensile components are present. Simultaneous application of spectral analysis of seismic waves and moment tensor inversion was used to study this problem. The ratio of P-wave to S-wave energy radiated from mine tremors is, in many cases, anomalously large, implying that non-shear failures are often generated by mining excavations. We expected to show that the high P-wave energy tremors are generated by the sources with prominent non-double-couple components, as estimated from the moment tensor solutions.