15:30 〜 16:30
[S01-P-10] The use of seismic arrays in geodynamic monitoring of the East European platform
The Institute of the Dynamics of Geospheres (IDG) of the Russian Academy of Sciences (RAS) operates several small-aperture seismic arrays, which are used in monitoring of the geodynamic regime of the East European platform (EEP) for a decade. One permanent array MHVAR (“Mikhnevo") and four portable arrays are equipped with 3-C seismometers improving their overall performance. Four from five arrays are installed on thick sediments that may negatively affect their sensitivity. Nevertheless, since its inception in 2004, MHVAR has been demonstrating all advantages of array processing. It reduces the amplitude detection threshold by a factor of 3 to 5 and respectively improves the seismological catalog issued by the Geophysical Survey (GS) of RAS for the EEP. In routine processing, beamforming enhances detection of P- and S-waves from near regional (ML>1.5) and teleseismic (mb>4.5) events. Within the EEP, mining blasts generate a bigger part of detected signals, and the method of waveform cross correlation (WCC) is optimal for detection and identification of repeating signals. The WCC is also suitable for the study of natural seismicity and related tectonic and geodynamic processes. For example, we used WCC to recover 12 aftershocks of the mb4.9 earthquake, which occurred on August 7, 2016 near the town of Mariupol. For this, we merged data from two IDG arrays and three primary stations (AKASG, BRTR, and KBZ) of the International Monitoring System. A similar station configuration was successfully used to detect and identify dozens of mines and quarries within the EEP. Overall, the combine use of seismic arrays and the WCC method enhances the effectiveness of artificial events identification, reduces the threshold of seismic catalogue completeness, and improves the accuracy of relative location and magnitude estimation most important for correct tectonic interpretation of natural seismicity.