INDUCED SEISMICITY IN LARGE-SCALE MINING IN THE KOLA-PENINSULA AND MONITORING TO REVEAL INFORMATIVE PRECURSORS

Large volumes of rock mass, mined-out and moved within these deposits, resulted in irreversible changes in the geodynamic regime in the uppe r earth's crust of the adjacent territory. These changes manifest them selves in a more frequent occurrence of such intensive dynamic phenome na as tectonic rock bursts due to fault movement adjacent to the area which is mined-out and man-made earthquakes which sharply decrease min ing safety and result in great material losses. To develop the predict ion techniques of such phenomena, a monitoring system is created, base d on the program of the Kola Complex of geodynamic measuring stations. Most of this system is realized in the region of the Khibiny apatite mines. The system provides regional seismological monitoring, local pr ediction of seismicity in separate areas of a rock mass and, determina tion of stress and strain in rock masses, local geophysical monitoring over the state of rocks in a rock mass as well as physical and mathem atical modelling of geodynamic processes in the upper earth's crust. T he investigations have resulted in the distinguishing of some regulari ties in manifestations of induced seismicity and tectonic rock bursts and in the determination of strain precursors of intensive seismic eve nts in the Khibiny mines. The mechanism is provided by the induced sei smicity which resulted from the anthropogenic impact on the geological medium. A geodynamic monitoring complex is described, which is used t o reveal the precursors of powerful seismic events in situ, and monito ring results are shown, obtained in the Kola Complex of geodynamic sta tions. Methods of preventing tectonic rock bursts and induced earthqua kes are presented.