Far-field coseismic ionospheric disturbances of Tohoku earthquake

• We model the generation of infrasound in the far wave zone of Tohoku earthquake.
• We estimate the perturbations in the ionosphere at the height of 210–220 km.
• The calculated ionospheric disturbances coincide with the experimental results.
• Ionospheric perturbations have amplitudes of 1.5–7.5% of ambient value.

A computer code has been developed to simulate the generation of infrasonic waves by a strong earthquake at a distance of 9000 km from the epicenter, their propagation through the atmosphere and their effects in the ionosphere. We provide estimates of the perturbations in the ionosphere at the height (210–220 km) where radiowaves at the sounding frequency (3.595 MHz) of a continuous Doppler radar reflect. Ionospheric perturbations have a global character and amplitudes of 1.5–7.5% of ambient value. Perturbations exist for ~1 h. The form of calculated ionospheric disturbances coincides with the experimental results. The correlation coefficient between calculated and experimental forms was from 0.68 to 0.9.