Changes in transfer functions with time

The paper contains data on the transfer functions of the electromagnetic field of the Earth and their changes with time.The results show that these changes are caused by the instability of parameters of the external sources of the geomagnetic field variations in high latitudes and by the changes in the physical properties of rocks and deep matter in the region of recordings of electromagnetic field components.A statement is made that under certain conditions the observations of changes in transfer functions of the electromagnetic field of the Earth can be used as long-term forerunners of earthquakes.