Remote sounding of the areas above earthquakes by thunderstorm electromagnetic signals

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An opportunity to use electromagnetic signals of lightning discharges (atmospherics), registered in Yakutsk,
for remote monitoring of seismic activity is considered. Amplitude variations of atmospherics, propagating
in a ground-ionosphere waveguide above the areas of earthquake epicenters, reflect the changes of electron
concentration in the lower ionosphere, occurring under the influence of lithospheric processes. Effects appear
from strong not deep earthquakes. On the day of an earthquake and after them the increase of atmospherics
amplitude is observed; and on previous days the variations appearing as an increase with the following decrease
of amplitude some days before an event are possible. Testing of the available database of atmospherics by
a simple algorithm of detection of potentially seismically active periods, based on the specified sequence of
amplitude variations, has shown that the probability of revealing of such periods can be 65-70 percent. Azimuthal
measurements testify that the sizes of the disturbed area in the lower ionosphere can reach the size of 5 Fresnel
zones ( signal frequency is 10 kHz) on the day of an earthquake and the size of 1-2 zones on previous days.
The work was supported by the Russian Foundation for Basic Research 09-05-98540-р_vostok_а and by
the Presidium RAS Programs №16, RNP 2.1.1/2555.