The phenomenon of synchronism in the magnetosphere-technosphere-lithosphere dynamical system

Synchronism in geophysical events became the focus of the research in the second half of the last century when the study of this subject was almost simultaneously launched in the former Soviet Union and the United States. Interest in this issue has recently risen after a 20�year hiatus. The impetus was provided by the successful application of the synchronous detection technique to analyzing vast volumes of digital data on the electromagnetic waves in the magnetosphere and on the earthquakes. These studies revealed signs of the strictly periodic synchronous influence of the technosphere on the regime of electromagnetic oscillations in cosmic plasma and on seismic activity. The phenomenon of synchronism between the electromagnetic and seismic events manifests itself in the form of the socalled hourmark effect and the weekend effect. The hour� mark effect shows itself in the 24th, 48th, and 96th harmonics, and the weekend effect, in the 7th subhar� monic of the circadian rhythm. The both effects indicate that the technosphere has a nontrivial impact on the magnetosphere and lithosphere. The present review aims to introduce the morphology of the phenomenon and to focus the attention of researchers on the physical interpretation of the effects of synchronism, which is a challenging problem. Both the fundamental and practical value of the problem is analyzed. In particular, it is hypothesized that the study of the anthropogenic modulation of the natural wave processes will promote the development of energy saving technologies.