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Schlagwörter:
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Zusammenfassung:
Anthropogenic earthquakes are rarely monitored with high-rate GNSS. Nevertheless, the progress in the GNSS processing techniques allows recording the mining tremors of smaller amplitudes, i.e., magnitudes about 4, with high-rate GNSS as well as complementary sensors to the seismic instruments. Although high-rate GNSS recording frequency and sensitivity are lower than seismic sensors, high-rate GNSS can capture the waveforms appropriately.
Here we demonstrate that if the GNSS observations are carefully filtered, we can retrieve the small signal of ground vibrations of the low-magnitude shallow anthropogenic earthquakes with the accuracy of very few millimetres for displacements and 1-2 cm/s for velocities. We analysed five mining tremors with magnitudes of 3.4-4.0 and presented the results from high-rate GNSS position changes calculated parallel with the PPP and variometric approach. We obtained satisfying correlations with seismological data in correlation, peak values comparison and earthquake first epoch determination.
Moreover, we show that high-rate GNSS can be a supplementary tool for seismic moment tensor inversion for small magnitude shallow anthropogenic earthquakes and might be crucial in case of a lack of seismic data, complementing unfavourable focal coverage. The obtained full, deviatoric, and double-couple solutions are similar, which shows that GNSS data may be added for moment tensor inversion in place of seismometers if needed without significant loss of the solution quality.
Finally, considering the high-rate GNSS positioning noise level, we demonstrate the capacity to resolve the dynamic displacements from high-rate GNSS at the epicentral distance of about 7-8 km.
