A short-term forecast of earthquake parameters based on the data of ULF/ELF magnetic field variations

  1. Institute of Physics of the Earth RAS, checkit@post.ru
  2. Institute of Terrestrial Magnetism, Ionosphere and Radiowave Propagation RAS
  3. Kamchatkan Branch of the Geophysical Survey RAS

The results of 10-year studies of seismo-electromagnetic phenomena in Kamchatka prove its applicability for
short-term forecast of time, place and magnitude of local earthquakes. The most perspective are depression of
ULF variations of the magnetic field and excitation of ULF/ELF radiations in the atmosphere, appearing 1-5
days before powerful Ms> 5.5 crust earthquakes with epicenter distance of <300-500 km. The depression effect
is registered in the frequency range of 0.01-0.1 Hz in a vicinity of local midnight and its magnitude depends
linearly on the magnitude of a forthcoming earthquake. The other preseismic effect is characterized by the
occurrence of a broadband emission in the frequency range from several Hertz to several tens of Hertz. The
signal typical form and timescale are similar to those of lightning discharges with an azimuth of a radiation
source, approximately coinciding with a direction on epicenter of a future earthquake. Both ULF depression
and ULF/ELF emission effects are confirmed by long-term statistics. To increase the reliability of the forecast
we suggest to develop the technique of network measurements and data processing of electromagnetic data in
ULF/ELF frequency range coordinated with the analysis of seismic and seismo-acoustic data.