  A promising short term precursor of major earthquakes (EQ) is very crucial in
saving people and preventing huge losses. Ez, atmospheric electrostatic field
vertical component, under fair air conditions, is generally oriented downwards
(positive). Anomalous negative Ez signals could be used as an indicator of a
great number of radioactive gases which are released from great number of rock
clefts just before major earthquakes. Enhanced emission of radon radioactive
decay will produce an anomalously large number of ion pairs. The positive
particles will be transported downward by the fair weather electrostatic field
and pile up near the surface. Finally, obviously and abnormally, an oriented
upward atmospheric electric field Ez near the ground could be formed.
Therefore, monitoring this Ez may be applied effectively in earthquake warning.
