THE EFFECT OF GEOLOGICAL ANISOTROPIES ON THE DETECTABILITY OF SEISMIC ELECTRIC SIGNALS

The detectability of seismic electric signals was examined in relation to the geological anisotropies both at the large scale of geotectonics and neotectonics and at the smaller scale of electric stations. The distribution of the detected seismic events, in the cases of the Ioannina and Assiros stations, showed a strong dependence upon the geotectonic zonation and especially upon the ophiolite suture zones of North Pindos and Almopia (Axios/Vardar). The major neotectonic transcurrent faults did not show an important effect. Keratea station and especially point A on a granitic dyke showed an extraordinary detectability, independant of the geotectonic zonation, attributed to the local anisotropy and to its connecton with batholiths at depth within the Aegean paleo-volcanic arc of Upper Miocene age.