Investigation of the Pre- and Co-Seismic Ionospheric Effects from the 6 February 2023 M7.8 Turkey Earthquake by a Doppler Ionosonde

During the catastrophic M7.8 earthquake in Turkey on 6 February 2023, anomalous effects were revealed ionosphere associated with various propagation mechanisms of seismogenic disturbance from lithosphere up to height ionosphere. Seventeen minutes after main shock, a co-seismic was detected by Doppler ionosonde an inclined, 3010 km long, two-hop radio path “Kuwait—Institute Ionosphere (Almaty)”. An appearance acoustic waves at 232 fixed 568 s arrival surface Rayleigh wave sub-ionospheric point, and such delay agrees calculated time vertically moving wave. The lasted 160 s, its double amplitude above 2 Hz, which noticeably exceeds background fluctuation frequency. best coincidence between waveforms signal seismic observed over duration two leading periods, correlation coefficients 0.86 0.79, correspondingly. Pre-seismic 8 days before shock both variations frequency critical f0F2. probable origination mechanism pre-seismic ionospheric disturbances region preparation determined Dobrovolsky radius may be considered accordance concept lithospheric–atmospheric–ionospheric coupling.