Effect of strong earthquakes on the geodynamo

Using the data of magnetic observations performed at the INTERMAGNET network observatories during the period of the double earthquake on March 16, 2022 (Japan), the global nature of the induced geomagnetic variations was demonstrated. Their synchronism and comparable amplitude over a wide range of distances from 210 km to ~10 000 km, the delay time relative to the considered seismic events (~55 min) and the predominant period of variations ~30 min indicate that the source is a geodynamo perturbed by the action of seismic waves propagating deep into the earth.