Abstract:
The conditions of the performed experiments were as follows. A three-component receiver was installed in a thermostatic pavilion of the seismological station "Novosibirsk". A vibrator (force amplitude 50-100 tons) was functioning out-of-doors. The source-receiver distance was 49 100 m. Vibration sessions were performed each one-two weeks during 1.5 years. The experiments have shown that seismograms are highly reproducible when obtained under summer ground conditions (from June till October) or in winter (from January till March). The "summer" seismograms strongly differ in appearance from the "winter" ones, but the domains of the first arrivals of P waves show the presence of stable waves. These waves are virtually the same in the "summer" and "winter" seismograms. They are recommended for monitoring the stress-strained state of a medium by periodical vibrating dangerous zones of active seismicity. The high reproducibility of vibroseismic signals (under the same seasonal conditions) enables one to register wave fields on large areas by resetting receivers. This method was used to reveal fracture sites in the Baikal Rift Zone from changes in the spectrum of received vibroseismic signals.