Secular variations of geomagnetic field

Variability of geomagnetic field in time and in a wide range of periods - from minutes to hundreds and thousands of years reflects a complicated spectrum of physico-chemical phenomena in the core, lithosphere, ionosphere and magnetоsphere of the earth, to investigate modern geodynamic processes at different depths, from the surface layers of the earth's crust to the core of the earth, data on geomagnetic variations with the periods over 1 year, the so-called secular variations (SV), are widely used. In general, geomagnetic field variations can be considered as a vector sum of the fields from different sources. In the spatial structure of secular variations of geomagnetic field there are distinctly distinguished global, regional and local components. Global peculiarities or focuses of SV embrace areas of thousands of kilometers and have their sources in the earth's core. Regional and local effects are determined by modern physico-chemical, geodynamic and electromagnetic phenomena in the earth's crust and upper mantle.

The existing chain of magnetic observatories on the territory of Europe allows to study in details the global and regional effects in SV. The local anomalies of SV or the so-called tectomagnetic effects ere studied, as a rule, in geodynamic and seismoprognostic testing grounds.

Дата добавления: 2015-07-19