Abstract:
The frequency of occurrence of shocks within a zone depends upon the rate of tectonic movements and the dimensions of the foci. In some zones, shocks occur in various segments of the zone at intervals of tens of years; in others, the interval durations are of the order of hundreds of thousands of years. All of the foci in the various seismic zones of a large region such as the Caucasus become active in the course of a period of the order of thousands of years. However, systematic recording of earthquakes has only been done in Russia for the last 100 years, and instrumental records are even more recent, being only decades old. Therefore, only a small fraction of existing strong-earthquake foci has been identified. Many of these did become active during the indicated time period, but not with the full force they are capable of. Therefore, most strong shocks will occur in still-unidentified foci. Their locations and seismic potential must be defined in order to derive a scientifically-founded zoning. We used the above principles to formulate the following interrelated problems and define the order in which they need to be solved so as to arrive at an earthquake prediction scheme and seismic zoning maps showing high-seismicity zones, i.e., zones in which strong-earthquake foci may become activated on active faults. Therefore, we will discuss the geology first and then the seismics. The seismotectonic method has proved itself in this case, as in other regions. Let us emphasize that when significant new geological and geophysical data is obtained, seismic zoning for the given area should be revised with the aid of the same seismotectonic method. There cannot be another approach.