Statistical analysis of seismo-ionospheric perturbation before 14 Ms ≥ 7.0 strong earthquakes in Chinese subcontinent

The statistical analysis of seismo-ionospheric perturbation is of significance to earthquake monitoring and prediction.We investigate the pre-earthquake ionosphere f_oF₂ associated with 14 Ms ≥ 7.0 earthquakes that occurred in Chinese subcontinent by quartile method,which confirms the existence of seismo-ionospheric perturbation.We analyze the distribution and morphology of these ionospheric disturbances to obtain the connection between the ionospheric disturbances and the earthquakes.Results show that the ionospheric anomalies appear prevailingly during 11:00LT~17:00LT within 7 days prior to 85.7% (12 earthquakes)of the 14 earthquakes.In addition,the ionospheric abnormal amplitude has some relationship with the magnitude,depth and distance of the forthcoming earthquake.