PROBLEMS OF GEOCOSMOS

Proceedings of the 7th International Conference "Problems of Geocosmos" (St. Petersburg, Russia, 26-30 May 2008)
Thus, false alert days do not differ from events of earthquakes from the point of view of geomagnetic
disturbances. So, we think that geomagnetic disturbances cannot be used to explain the false alert days. At the
same time we see that the event of earthquakes were perhaps closely connected to geomagnetic disturbances.
Fig.4. The behaviour of average values of
Ар index in the previous days to the
moments of 3 false alerts.
Fig.5. The behaviour Ар (by the statistical
superposed method) for all considered
earthquakes.
5. Conclusions
Results of consideration of amplitude variations of VLF-signal of the storm nature which are passing
above areas of earthquakes with magnitude of more than 5, show that despite non-stationary state of their
sources, their amplitude drops 3-6 days before earthquakes with its subsequent restoration by the day of events.
The similar picture of behaviour of average atmospherics amplitude has been observed for a significant part of
events of strong earthquakes. The effect is similar to signal amplitude variations of low-frequency radio stations.
It allows us to consider such behaviour as typical and try to formulate one of the possible primitive
algorithms for the detection of earthquake precursor. Such an algorithm has been checked on the Kamchatka
peninsula region by data of atmospherics received in Yakutsk for winter periods of 2004-2006. A control
"blindly" retrospective analysis using of the elementary algorithm of defining alert days by average atmospherics
amplitude has shown that the probability of such short-term forecast of earthquakes is 60-70 %.
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