[M-IS12] [JJ] Electromagnetic phenomena associated with seismic and volcanic activities

[MIS12-P02] Ionospheric disturbance in D region possibly related to pre-earthquake activities observed by the DEMETER

*Hidetoshi Nitta¹, Togo Shoho¹, Masashi Kamogawa¹, Jean-Jacques Berthelier⁴, Tetsuya Kodama², Toshiyasu Nagao³ (1.Department of Physics, Tokyo Gakugei University, 2.Japan Aerospace Exploration Agency, 3.Tokai University, 4.LATMOS, France)

Keywords:Earthquake, Ionosphere, DEMETER

A decrease of electric field at the 1.7 kHz, i.e., VLF electromagnetic waves, within 4 hours before neighboring earthquake (EQ) with the magnitude of more than 4.8 was statistically shown through the data set of in-situ satellite measurement according to French groups. We found that the intensity originating from the whistler waves in the frequency of more than cutoff decreased in the orbit near the epicenter. The interpretation of the intensity decrease is due to the electron density increase in D region over the epicenter.