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IUGG XXIV General Assembly July 2-13, 2007 Perugia, Italy
(S) - IASPEI - International Association of Seismology and Physics of the Earth's
Interior
JSS009 Poster presentation 2047
Mechanisms of seismic effects in the atmosphere revealed from sounding
by VLF, LF and HF radio signals
Dr. Oleg Molchanov
Institute of the Physics of the Earth principal researcher IASPEI
Masashi Hayakawa, Pier Francesco Biagi
Besides the direct impact by seismic pulses a slower preseismic and postseismic influence upon the
atmosphere and ionosphere was recently theoretically discussed in relation to the observed effects in
the atmosphere and ionosphere. The clear agent of such an influence is gas/water release at the
ground surface resulting in the changes in the air temperature and density and in the density and
distribution of the charged particles (due to emanation of radioactive gases like Rn222 and aerosol
particles). The changes usually supposed in a thin near-ground layer (source layer) with thickness of
several hundreds meters, because of slow vertical diffusion of the heavy gases and temperature
variations. Extension of influence above the source layer is possible either by induced electric field
(other variant is modification of background electric field) or by excitation of atmospheric gravity waves
(AGW) with upward power flux. We discuss both types of models in explanation to short-time
precursory effects revealed from sounding by VLF, LF and HF radio-signals.
Keywords: seismoelectromagnetics, atmosphere