Orlecka-Sikora, Beata and Papadimitriou, Eleftheria E. and Kwiatek, Grzegorz (2009) A study of the interaction among mining-induced seismic events in the Legnica-Głogów Copper District, Poland. Acta Geophysica, 57 (2). DOI: https://doi.org/10.2478/s11600-008-0085-z
Full text not available from this repository.Abstract
Seismic hazard assessment in mining areas is of paramount importance for the nearby built environment since local events, although of small or moderate magnitude, because their locations are just beneath and very superficial, they have caused serious damage and often loss of life, and on top of that they exhibit a very high occurrence rate. Based on the fact that this activity also exhibits time dependence, as has been shown by several authors previously, and that small stress perturbation can enhance or prohibit future occurrences, we have applied the Coulomb stress transfer technique to investigate interactions among seismic events induced by mining works in the Rudna Mine in the Legnica–Głogów Copper District in south–west Poland. The coseismic stress changes due to tremor occurrences are only a small component of the stress field in mining areas and are not capable of generating a future seismic event. But if the rock mass at the location of the next event is already close enough to failure they can move it into the failure regime. Therefore, we have examined the influence of the cumulative static stress changes due to previous events on the generation of subsequent ones. For this purpose we considered events with energy greater than 105J with a known focal mechanism that occurred in the LGCD area during the time period 1993–1999. We then calculated Coulomb stress changes (ΔCFF) after the occurrence of each event inverting each time the derived stress field according to the faulting type of the next event in the sequence of seismic events. We assumed the state of stress before the first seismic event in the analyzed sequence to be zero and the time changes of stress were referred to this initial value. At each stage of our calculations we attempted to correlate the location of the seismic event with the calculated values of ΔCFF. The results of this study indicate that in many cases strong mining tremors produce changes in the state of stress of a sufficient magnitude to influence subsequent events. The location of over 60% of events is consistent with stress–enhanced areas where the values of positive ΔCFF were above 0.01 MPa. For most of the events located inside areas of a calculated negative ΔCFF, their modelled rupture zone was partially located inside stress enhanced, providing thus additional evidence for possible triggering at the nucleation point.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | LGCD, Rudna Mine, induced seismicity, Coulomb stress changes |
| Application references: | Moment Tensor Inversion |
| Subjects: | Methodology > Method and procesing > Source parameter estimation Region > Poland > Legnica-Glogow Copper District Inducing technology > Underground mining Methodology > Method and procesing |
| Project: | IS-EPOS project > LGCD: Regional seismicity and ground motion associating underground hard rock mining |