  An entirely different approach is used for the extraction of preseismic
electric signals from highly contaminated by noise data series. The basic
element of this method is the "Dirac Delta Function". Noise is injected,
instead of applying any known method of filtering, in the data series at
different amplitude levels (p value) and the generated "family" of filtered
data series is compared to different convergence criteria. In the case of
preseismic electric signals identification the most appropriate (p) value is
selected by testing the convergence of generated intersections of more than
three "families" of filtered data which were generated from more than three
monitoring sites. The "noise injection" method was tested against real data
recorded long before two large earthquakes in Greece and one in Turkey.
