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Abstract—Ground-based magnetometers and ionospheric radio probing by means of GPS were used to analyze and interpret specific variations of the geomagnetic field and the total electron content of the ionosphere during strong catastrophic earthquakes in Turkey on February 6, 2023. It is shown that the ionospheric responses to these earthquakes recorded at distances of 1200–1600 km from the epicenter in the lower ionosphere and at distances of up to 500 km from the epicenter in the upper ionosphere can be interpreted in terms of the propagation of the Rayleigh seismic wave and atmospheric waves—shock, acoustic and internal, that is, those waves that are generated by the earthquake itself. The energy of seismic events was estimated from the ionospheric response. [ABSTRACT FROM AUTHOR]

In June 2014, a number of meteotsunamis were detected in the Mediterranean and Black Sea area. These meteotsunamis were initiated by a unique high-altitude dynamical system which was initially originated above Spain and traveled across the Mediterranean Sea towards Black Sea and Turkey. Meteotsunamis unlike tsunamis driven by strong earthquakes are local events, and their formation has different mechanism. Atmospheric internal gravity waves (IGWs) are one of the main known sources of meteotsunamis (e.g. Vilibić et al. in Pure Appl Geophys 165:2169–2195, 2008). The synoptic system produced short-lived and small-scale atmospheric pressure perturbations which drifted with the jet stream-like bubbles and generated tsunami-like waves in the open waters. The bubbles with typical dimensions 15–60 km continuously form and collapse in the atmosphere at altitudes of 3–6 km. Such a "boiled" atmosphere generated IGWs propagating both downward, where they produced meteotsunamis (presumably under Proudman resonance condition) and upward into the ionosphere, with following dissipation and excitation of plasma density perturbations. One of the few experimental techniques, which can monitor perturbations of the ionization within the lower ionosphere, uses long-wave probing by very low and low frequency (VLF/LF) radio signals. To study the ionospheric disturbances observed during the chain of meteotsunamis affecting the Mediterranean Sea, we used VLF/LF data collected in South Europe by "The International Network for Frontier Research on Earthquake Precursors". By applying the spectral analysis method to the anomalous VLF/LF signals, it was found that revealed periods of the signal variations were from 10 to 40–70 min in different stations, which are in the range of the atmospheric pressure oscillations and the meteotsunami events. These periods also correspond to the periods of IGWs. [ABSTRACT FROM AUTHOR]