Three-dimensional reconstruction of seismo-traveling ionospheric disturbances after March 11,2011, Japan Tohoku earthquake

摘要

The electron density structures of the seismo-traveling ionospheric disturbances (STIDs) during the Tohoku earthquake are reconstructed by applying the three-dimensional computerized ionospheric tomography (3DCIT) technique with a 30-s time resolution for the first time. The vertical distribution of 3DCIT results is consistent with the constellation observing system for meteorology, ionosphere and climate (COSMIC) observations. The horizontal speeds of STIDs at different altitudes are estimated, and the three types of STIDs related to Rayleigh waves, acoustic waves and gravity waves are identified by their propagation characters. The magnitude of STIDs related to Rayleigh waves decreased with altitude, and there was no significant difference between the speeds (similar to 2500 m/s) at different altitudes. The STIDs caused by acoustic waves traveled faster at 300 km altitude (similar to 666-724 m/s) than at 150 km altitude (similar to 500-550 m/s). From 150 to 250 km altitudes, in the STIDs induced by gravity waves, the magnitude of positive and negative wave fronts showed the opposite trend. The speed at 300 km altitude (similar to 332 m/s) was slightly larger than at 150 km altitude (similar to 310 m/s). The Rayleigh waves related STIDs showed a conic-like geometry, whereas the acoustic waves and gravity waves induced STIDs showed inverted conic-like geometries. The possible propagation mechanisms of different types of STIDs are also discussed.