The
pattern of earthquake precursors could be described as “pre-earthquake
signature” since every reoccurrence maintains common characteristics.
Observing
the recorded signal, one realizes that, throughout the spectrum 1-40Hz, there
are lines almost parallel to each other at any given time. Any spectral line
differs 1-3Hz from the previous one.
The
duration of the “pre-earthquake signature” varies from 15 minutes up to 3
hours, while for the specific spectral impressions, the intensity of the
magnetic field varies from 2 PT to ~20 PT.
It is most likely that the common characteristics of the signal will still appear in frequencies higher than 40 Hz. Further observation is required in order to verify the following:
