Geophysical Journal | 2006 volume 28 1

Morphological features in the structure of geomagnetic variations in relation to earthquakes in vrancea

© Bakhmutov V.G., Sedova F.I., Mozgovaya T.A.

Geomagnetic situation was studied in relation to earthquakes in the Vrancea zone for the period 1977, 1988-1996. It has been found that realization of seismic energy is related to abrupt changes (gradients) in H-component of geomagnetic field. It has been shown that near-midnight polar sub-storm in Vrancea is such a gradient before the earthquake and a degree of its mid-latitudinal manifestation. To the amplitude of the change in H-component (gradient) energetic class of the shocks is related: the more the amplitude, the higher energetic class. Distinctions between duration of near-midnight polar sub-storms preceding the shocks within the earth's crust and deep-focus earthquakes have been determined. A uniform linear dependence has been obtained for them between the depth of the focus and duration of polar sub-storms. Realization of seismic energy after a sub-storm occurs in a definite temporal interval (hours). A relation of (hours) to the depth of the focus h (km) has been found under different magnetic disturbance.

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