IASPEI - Picture Gallery

IUGG XXIV General Assembly July 2-13, 2007 Perugia, Italy
(S) - IASPEI - International Association of Seismology and Physics of the Earth's
Interior
JSW001 Oral Presentation 2398
Drift of the earth core to the North and inversion of global volcanic process
Prof. Yury Barkin
Laboratory of Gravimetry Sternberg Astronomical Institute IAG
The analysis of modern data of geodetic, gravimetry and geophysical observations testify a reality of the
phenomena of a drift of outer core of the Earth and its translational oscillations with a wide spectrum of
frequencies relatively to elastic mantle (Barkin, 1995, 2002; Barkin, Vilke, 2004; Barkin, Shuanggen,
2006). Displacements of the core are accompanied by elastic deformations of the mantle and by
variations of its tension state which in turn find reflection in variations of seismic, volcanic and, generally
speaking, in all planetary natural processes. This phenomenon is characterized by the slow secular
component of process and by periodic variations with interannual, decadal and more long periods, and
have inversion character. Activity of process increase in one hemisphere (on direction of the core drift)
and activity decrease in opposite hemisphere. It is principial property of considered phenomenon. This
theoretical conclusion based on a geodynamical model about forced small relative displacements and
rotations of the Earth shells under action of a gravitational attraction of the Moon, the Sun and other
celestial bodies, has obtained a set of confirmations at the analysis of variations of natural processes in
opposite hemispheres of the Earth (Barkin, 2000, 2002, 2006). In particular the drift of the core causes
the phenomenon of inversion in activity of volcanic processes in northern and southern hemispheres.
Dynamic studies and the satellite data about geocenter motion have confirmed the displacement of the
core in present epoch (predicted by author) to the north in the direction of a geographical point 70 N,
104 E (Barkin, 1997). In hemispheres N and S, separated by a plane of inclined equator, the subduction
zones and zones of rifting are located asymmetrically. In hemisphere N the magmatic volcanos of belts
of compression (of subduction zones) are mainly located, and magmatic volcanos of rifting zones (of
spreading zones) are located in opposite hemisphere. On our model the changes of tension states in
zones of volcanos in northern hemisphere will result in their activization. In southern hemisphere S the
changes of volcano activity will have the opposite tendency. The specified phenomenon is observed
actually. The number of eruptions of volcanos of subduction zones linearly increase with velocity about
5 eruptions per one year (for the period in hundred years). Thus the number of eruptions of volcanos of
rifting zones on the contrary decreases. This phenomenon was open as a result of the analysis of the
known data on volcanic activity for a time interval with 1850 on 1977 (Mekhtiev, Khalilov, 1987). By the
method of sliding average the diagrams of temporal series of numbers of eruptions of volcanos for the
period 1800 - 2000 have been constructed (Khain, Khalilov, Ismail-Zade, 2004). The geodynamic model
of the forced displacements of the core allows to describe a wide spectrum of its cyclic oscillations, in
particular with the decade periods. By reflection of cyclic polar displacements of the core between
hemispheres N and S will be corresponding cyclic antiphase variations of volcanic activity in the
specified hemispheres. It was actually revealed, that peaks of activization of volcanos of subduction
zones, falling on 1885, 1950, coincide with peaks of passivity of volcanos of rifting zones. Peaks of the
periods of passive volcanism of subduction zones of 1860, 1900, 1910, 1960 will be coordinated to
peaks of increase of activity of volcanos of rifting zones. Only to peaks of activity of volcanos of
subduction zones 1910, 1930 and to the peak of passivity of 1940 are not strongly pronounced
antiphase of zones of activity. These moments can be explain as result of some imposing of
corresponding zones of subduction and rifting with respect to hemispheres N and S. Thus, changes of
intensity of volcanism in the specified period of time in 127 years confirm prospective displacement of
the Earth core and developed geodynamical model of the forced swing of the Earth shells as a whole.
The cyclicities of volcanic eruptions revealed at the spectral analysis with the periods 20, 40 years and