ON ATMOSPHERIC ELECTRIC FIELD ANOMALY BEFORE THE CARPATHIAN EARTHQUAKE OF 30. 08. 1986 AT THE POLISH OBSERVATORY (S)WIDER

摘要

Atmospheric electric field (Ez ) anomalies before earthquakes are classified as immediate precursors of earthquakes. However, there are not enough data on these anomalies due to significant influence of factors of meteorological and magnetospheric origin which might obscure or mask relations anomalies to seismic activity. Therefore, it still remains an urgent task to accumulate evidence on Ez anomalies in different geological and geophysical conditions and to refine models of electromagnetic earthquake precursors. The retrospective analysis of Ez data was conducted for 3 last great Carpathian earthquakes (4. 03. 1977, 30. 08.1986, 30. 05. 1990) with this aim at the Polish observatory (S)wider. Only the event on 30. 08. 1986 satisfied fair-weather and quiet geomagnetic conditions. Noticeable Ez anomaly (from –250 V/m to +750 V/m) was observed from 02 to 16 UT before this earthquake (origin time 21. 28 UT). The mechanism of such anomalies is still mysterious. However, authors point to massive emissions of ions from crystalline structures under variable stress and temperature, and to electric polarization and current phenomena in the rocks/ground, which may transfer charge anomalies to the surface and then, via atmosphere, change the electric field over the ground at considerable areas.