Investigation of the preparation process of seismic events with the help of seismic noise analysis

Abstract

The ability to identify the preparation process of seismic events using spectral analysis of microseismic noise was earlier shown in laboratory experiment in the form of reduction of natural frequency of oscillations during the transition of the system to a metastable state. Field studies of the Chilean subduction zone allowed us to identify large earthquakes with the same effects before them. In this paper investigation of the natural frequencies of block oscillations, which can be detected in the spectrum of seismic noise, was performed at a lower scale. Measurements were performed near Gubkin (Belgorod region, Russia), where the development of iron ore deposits and explosive works are carried out regularly. We used the data of the high-frequency accelerometer that was installed at the depth of 300 m from the surface. Spectral centroid reduction in the frequency range of 20–1200 Hz was identified before small seismic events with the amplitude of more than 10 mm/s2.The ability to identify the preparation process of seismic events using spectral analysis of microseismic noise was earlier shown in laboratory experiment in the form of reduction of natural frequency of oscillations during the transition of the system to a metastable state. Field studies of the Chilean subduction zone allowed us to identify large earthquakes with the same effects before them. In this paper investigation of the natural frequencies of block oscillations, which can be detected in the spectrum of seismic noise, was performed at a lower scale. Measurements were performed near Gubkin (Belgorod region, Russia), where the development of iron ore deposits and explosive works are carried out regularly. We used the data of the high-frequency accelerometer that was installed at the depth of 300 m from the surface. Spectral centroid reduction in the frequency range of 20–1200 Hz was identified before small seismic events with the amplitude of more than 10 mm/s2.