Ionospheric Response to the Seismic Wave Induced by the Kamchatka Earthquake on July 29, 2025

The July 29, 2025 earthquake near the eastern coast of the Kamchatka Peninsula induced a high-amplitude seismic wave that propagated thousands of kilometers from the epicenter. Ground vibrations caused variations in surface air pressure with periods in the infrasonic range, which propagated almost vertically into the upper atmosphere and modulated the ionospheric plasma. The resulting ionospheric disturbances were, in turn, recorded by a number of radiophysical facilities monitoring the ionosphere. In this paper, we provide an overview of the effects caused by the passage of the seismic wave, which were observed during ionospheric monitoring using vertical, oblique, and sky-wave backscatter sounding techniques in the Asian part of Russia.