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How do geomagnetic storms create electric currents in the ground?

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Space weather Earth's full North Polar auroral oval, in an image taken in ultraviolet light by the U.S. Polar spacecraft over northern Canada, April 6, 1996. In the colour-coded image, which simultaneously shows dayside and nightside auroral activity, the most intense levels of activity are red, and the lowest levels are blue. Polar, launched in February 1996, was designed to further scientists' understanding of how plasma energy contained in the solar wind interacts with Earth's magnetosphere.

Geomagnetic storms create electric currents in the ground through the process of electromagnetic induction, a phenomenon governed by Faraday’s law of induction.12

During a geomagnetic storm, interactions between the solar wind and Earth’s magnetosphere cause rapid, intense fluctuations in the geomagnetic field. According to Faraday’s law, a changing magnetic field induces an electromotive force (voltage) in any nearby electrical conductor.3412

When these magnetic field variations occur, they induce transient electric fields at Earth’s surface. These fields drive electric currents through conductive materials, including the ground itself, as well as human-made infrastructure like power distribution systems and pipelines. These induced currents can be highly disruptive, potentially damaging electrical transformers and causing widespread power grid failures, as seen during historical space weather events.56