An analysis of factual data on volcanic eruptions (during the period of 1900 to 1977) has revealed a pattern in eruptions distribution over latitudinal zones of the Earth and elucidated special features of the distribution related to the Earth's rotation and precession of its axis. The general rotation-dependent regularity consists in total number of eruptions decreasing from; it is complicated by regular alternation of zones of active volcanism and relatively quiet zones. The distribution of eruptions resembles a standing wave with vibration amplitude damping out towards from equator toward poles; it reflects wave character of processes of crustal deformation of the Earth ellipsoid. The wave length is ~20° of latitude in the Northern Hemisphere and ~15° in the Southern Hemisphere. Maximums are at 15-20°, 35—40°, 55-60° in the Northern Hemisphere, and at 0-10°, 20-25°, 35—40° and 50-55° in the Southern one. The rate of eruptions decrease with latitude amounts to about 3 eruptions per 1° in the Northern Hemisphere and about 5 in the Southern. Distribution of seismic events over latitude was analyzed using USGS/NEIC Significant Worldwide Earthquakes database. Some regularities in earthquakes number changes with latitude have been established for both hemispheres.
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