polar light centre



When a geomagnetic storm erupts, most eyes naturally turn to the sky, looking for auroras. But during the surprisingly strong G3-class geomagnetic storm of Aug. 26th, there was action underfoot as well. Probes buried in the ground in Norway detected strong currents of electricity moving through the soil. This chart recording made by Rob Stammes at the Polarlightcenter in Lofoten shows wild swings in current during the storm's peak.

"The currents were remarkably strong," says Stammes, who has been monitoring ground currents outside his Arctic observatory for many years. "During the magnetic storm, voltages surged to 10mv/m or 10v/km. That's about 10 times stronger than normal. These are pretty rare readings without a strong solar flare during solar minimum."

geomag reading aug 25 2018
Why does electricity flow through the ground during a geomagnetic storm? It's basic physics. Changing magnetic fields cause currents to flow in wires and other conductors. In most places, soil can conduct electricity due to the presence of dissolved salts and minerals. So when the local magnetic field begins to vibrate, electricity naturally begins to flow. Currents induced by geomagnetic storms can cause voltage fluctuations in power systems and in rare cases complete blackouts.