GLOBAL VARIATIONS OF THE EARTH'S SEISMIC REGIME IN THE YEARS 1965-2005

Abstract

Significant variations of the Earth’s seismic regime in the period 1965–2005 were revealed on the basis of a new methodical approach. The frequency of large earthquakes during an 11-yr interval (1982–1993) was three or more times lower than in the preceding period. This was accompanied by their intense activation in the entire range of seismic source depths. The seismic regime is traditionally displayed as recurrence graphs of earthquakes of various magnitudes. The evolution of seismic processes is commonly characterized by the total number and total energy of all earthquakes over a certain time interval. Such an integral presentation of the seismic regime smoothes away specific natural features of its spatiotemporal evolution and thus hampers their investigation.