Effect of Strong Earthquakes on the Geodynamo

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