Discussion on telluric field and seismic activity in Central Greece

Abstract

Two stations were installed in the Southeastern Thessaly basin (Central Greece), recording the geomagnetic and telluric fields from 1993 to 1996. The aim was to detect long-term abnormal changes of the telluric field, which were possibly related to imbedding earthquakes. Between January 1993 and October 1996, 213 and185 (Neraida and Mavrolofos stations respectively) abnormal changes of the telluric field were observed in association with the seismic activity. The duration of these changes varied from several minutes to 24 days and the maximum amplitude was 3.8 mV/m. Data recording detected 625 and 917 seismic events for Neraida and Mavrolofos station respectively. The percentage of the earthquakes associated with the telluric anomalies is 27% and 16% respectively for each station. Both percentages are considered to be very low. Telluric activity was followed by a burst of seismic activity in areas spreading to different directions from the stations. A correlation of the characteristics of the telluric field with the earthquake magnitude was attempted, but no reliable relationship was obtained.