It is known for a long time that the Tien-Shan seismic activity undergoes cyclical fluctuations. The periods of activization are replaced by the periods of relative calm. It is known also, that sources of strong earthquakes are drawn to extended lines whereas weak earthquakes occur everywhere. These results were received by the spatio-temporal analysis of earthquakes epicenters distribution.

The review of the literary data devoted to the analysis of the stress field on earthquakes focal mechanisms shows, that the sources of earthquakes arise under action of submeridian nearhorizontal compression. These results are received basically on the data of moderate force earthquakes.

We studied mechanisms of the earthquakes sources in a wide range of magnitudes and for a long time interval. The dependence fault-plane solutions types from a power level of earthquakes, and also periodical fluctuations of the compression axis plunge angle for weak events were revealed. The received values of the fluctuations periods coincide with those values which were revealed earlier at the spatio-temporal analysis of seismicity. Such coincidence of the periods can speak that the periodic fluctuations of the stress field provokes cyclicity of seismic activity. And these fluctuations, apparently, have a planetary nature as the same order the periods of seismic activization are marked in the very different regions of the world and are inherent in many natural phenomena in general.

The newness of results is the earthquakes occurred in different phases of stress field periodic changes, have the characteristic attributes. These results should be taken into consideration at statement of tasks of both active monitoring, and predictive researches.