ultra-low frequency

Seismogenic ULF variations of the magnetic field

The earthquakes monitoring in all world reveals that the “seismogenic” fluctuations of magnetic field in wide frequency band often occur before these seismic events. We believe that the most reliable information is concentrated in ultra low frequency (ULF) band (0.001-3 Hz). The earthquake ULF magnetic precursors of lithospheric origin are very weak as a rule and their frequency range is overlapping with signals of ionospheric origin. The new method of the seismomagnetic signals selection at the background of more powerful magnetic variations of other nature is proposed.