On the earthquake effects in the regime of Pc1

While searching for electromagnetic effects of the earthquakes, impulse-type signals in the frequency range of 0-5 Hz preceding the earthquake or following it have been detected. The advance or delay time is from 0 to 5 min. The signals are observed as single or pair impulses. It is supposed that the signals make a significant impact on the state of the magnetosphere and ionosphere. As a result, a sharp change in the regime of Pc1 geomagnetic pulsations is possible. These effects are analyzed on the basis of observations of the geomagnetic pulsations at the Borok Geophysical Observatory.