Problems of Engineering Seismology: article

Аnnotation: More than thirty years ago for the eastern regions of the North Caucasus (Dagestan and Chechnya) on an area of 300×300 km for the period 1800–1985 at a qualitative level the existence of a regular quasi-cyclic regime of seismicity was revealed. The regularity was that the level of seismicity during one cycle lasting 10–30 years decreased from the peak event (magnitude 5.0–6.5) to background values. Then there was a rapid increase in seismicity (2–3 years) until the next peak event. This hypothetical phenomenon was strictly analyzed by us in a formalized way on the data of the extended catalog, including year 2022. The regularity established earlier for the development of seismicity within the specified part of the North Caucasus as a quasi-cyclic process, observed in its purest form within a block of the earth's crust with a size of approximately 3×3 degrees, has been confirmed. This regularity can be used to test the theoretical models of the seismic process. The possibility of a medium-term forecast of the development of seismicity on a time scale of tens of years for a certain block of the Earth’s crust is shown. It is shown that the next largest earthquake in the quasi-cycle is prepared in a very short time – 2–3 years.