Ionospheric plasma response to the seismic activity

Electromagnetic emissions observed in the nearest earth environment are a superposition of natural emissions and various types of artificial noises. The wave activity detected at the low orbiting satellites can also be a consequence of thunderstorms, earthquakes and volcanic activity. Electromagnetic effects associated with earthquakes have been known for a long time, but no clear explanation of observed facts has been put forward so far. The aim of this paper is to present some selected processes occurring within the ionospheric plasma during seismic activity. The wave measurements detected by the SORS instrument in the 0.1–15 MHz frequency range, as well as the gamma ray fluxes in the energy range 0.12–0.32 and 3.0–8.3 MeV, detected by the SONG instrument, located on the low orbiting satellite CORONAS-I were used to present ionospheric plasma response to the strong seismic activity on 31.03.1994 during quiet geomagnetic conditions and on 6.04.1994 during geomagnetic storm period. In order to better understand the physical conditions and the physical processes in the ionospheric plasma we also presented the character of typical ionospheric parameters registered by a network of ground-based ionosondes.