Comparison of foF2 variations observed prior to a strong earthquake in Italy near Rome and during a magnetic storm

Legenka A. D., Khegay V. V., Kim V. P.
  1. Pushkov Institute of Terrestrial Magnetism, Ionosphere, and Radiowave Propagation, Russian Academy of Sciences (IZMIRAN), Troitsk, Moscow Region, 142190 Russia

On the data of some European sites of ground-based vertical ionosphere sounding an investigation of pos-
sible seismo-ionospheric effects was carried out for a strong earthquake which occurred in Italy near «Rome»
site (M=6.0). The analysis of the behavior of ionosphere F2-layer critical frequency (foF2) allowed us to con-
sider simultaneously by the same method both the effects, appearing during preparation of the earthquake on
January 7, 1962 in calm geomagnetic conditions, and the effects, caused by the magnetic storm, which began
on January 10, 1962. It was shown that the detected forecast seismo-ionospheric effect of the earthquake is
located in the region with the epicentral distance of the order 500 km, whereas the disturbances, caused by the
magnetic storm, have planetary character. The maximum amplitude of foF2 seismo-ionospheric disturbances is
three times less than the maximum variations caused by the magnetic storm, however, their absolute value is
1.5 times more than a standard deviation from monthly median.