Geophysical Journal | 2001 volume 23 4

On morphological signs in the structure of geomagnetic variations on the eve and at the moment of earthquake in the Crimea-Black Sea and the Carpathian regions

© F.I. Sedova, T.A. Mozgovay, V.G. Bakhmutov, 2001

The observations made at the geophysical station "Yastrebovka" (Crimean Peninsula) for 1990-1994 were used to describe morphological effects in the geomagnetic field variation structure due to weak shocks in the Ukrainian Carpathians and in the Crimea-Black Sea seismic zone and strong deep-focus earthquakes in the Vrancea region. The shocks concern mainly the low values of the H-component of the field. The shock magnitude is related to the gradients (differences) in the geomagnetic field. The authors show a linear relation between the ratios of extreme values of H-component at the moment shock (H2) and in the previous period (H1) depending on the energy class of the earthquake. A linear relation of the period of PcS-pulsations from the focal depth especially significant for the Vrancea region has been established. The role of the observation points location relative to the earthquake focus in studies of geomagnetic effects is noted.

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