On the space scales of seismoionospheric effects in the variations of critical frequency foF2 by the data of Tokyo, Petropavlovsk-Kamchatsky and Tashkent stations

Liperovskaya E.V.1, Meister C.-V.2, Bogdanov V.V.3, Liperovsky V.A.1
  1. Institute of Physics of the Earth of the Russian Academy of Sciences, B. Gruzinskaya, 10
  2. University of Technology Darmstadt, Schlossgartenstraße 9, 64289 - Darmstadt, Germany
  3. Institute of Cosmophysical Research and Radio Wave Propagation, 684034 Petropavlovsk-Kamchatsky, Russia

Disturbances of foF2 - the critical frequency of the main ionospheric maximum, arising a few days be-
fore earthquakes with the magnitudes M>5 and depths H<80 km are analyzed in the work using the data
of ionospheric stations of Japan, Kamchatka and Middle Asia. Seismoionospheric effects are distinguished on
the background of seasonal, geomagnetic, 11-years and 27-days Solar variations. Days with high Solar and
geomagnetic disturbances are excluded from the analysis. The superimposed epochs’ method is used to reveal
that statistically seismoionospheric effects take place at distances R<exp(M) km for earthquakes with 6>M>5.