Seismoionospheric effects in the F2 layer over Kamchatka

By comparing the data of ionospheric radio sounding at Petropavlovsk and Magadan stations, we eliminated the identical disturbances induced by geomagnetic storms and identified the ionospheric responses to seismic activity. It was found that strong earthquakes in the area of Petropavlovsk station are preceded by positive ionospheric variations which are more pronounced the higher the magnitude of the earth-quake.