Criteria of explosions and earthquakes identification for estimation of seismic danger of the region

The system of seismic monitoring of the Kola Peninsula and adjacent areas has been described. Criteria of discrimination of explosions and earthquakes have been considered. It is shown that P/S body waves amplitudes ratio that is commonly used for explosion and earthquakes discrimination is not reliable in some cases. It is noticed that spectra of many man-caused seismic events vary slowly in time. A quantitative estimation of a spectrum variance in time has been developed. It can be used as a criterion of man-made events discrimination. Infrasonic signals registered by microbarographs and seismometers after seismic events confirm their explosive origin. Taking into account the criteria we have revised our data base of earthquakes. As a result of retrospective (since 1992) analysis of seismic events of the base an improved picture of seismic activity on the Kola Peninsula and adjacent areas has been developed.