According to the definition of seismologists, a precursor of an earthquake is one of the signs of an
upcoming seismic event, expressed in a different form or phenomenon that is not typical for a given
area. As a result of the systematization of signs of seismic activity over the past ~300 years, a number
of typical phenomena have been identified that are considered precursors of earthquakes. They have
different mechanisms of occurrence, occur in different geological conditions, at different times of the
day and year, and may be different in nature and manifestation. Geophysicists often use earthquake
precursors to predict long-term seismic events and do not use them to promptly alert the public about
seismic hazards, because they recognize that precursor phenomena are not specific to specifically and
only for earthquakes that may occur in the near future, or may never occur. For example, atmospheric
phenomena can occur during periods of geomagnetic storms, and widespread animal disturbance can
be caused by weather conditions. We believe that when declaring earthquake precursors as signs of an
approaching earthquake, some seismologists are mistaken, because earthquake precursors are most
often evidence of an already begun and ongoing earthquake. The article is devoted to clarifying the
issue of the mechanism of occurrence of earthquake precursors, and how they affect the prediction of
the seismic situation in geological regions.
