Japan megathrust earthquake on March 11, 2011: GPS-TEC evidence for ionospheric disturbances

Two-dimensional distributions of the vertical total electron content in the ionosphere above the Japan under-sea mega-earthquake on March 11, 2011 are reconstructed using high-temporal-resolution (2-min) data from the Japan GPS network. A diverging ionospheric perturbation with multicomponent spectral composition is identified emerging after the main shock. The disturbances in the ionospheric electron concentration caused by acoustic gravity waves generated by the earthquake-related processes. The initial phase of this disturbance can be used as a marker in the tsunami early warning systems. The surface energy of the earthquake estimated from the amplitude of the ionospheric disturbance is close to the estimate based on the seismic data. Other disturbances (ionospheric responses to the Rayleigh and tsunami waves, a solitary ionospheric pulse) are also analyzed. Physical interpretation of the identified ionospheric disturbances is presented.