In early August 1972, a series of flares and other solar-storm phenomena generated extreme space weather events in what is considered a Carrington-class event. By the 4th, a coronal mass ejection had reached Earth, arriving in just 14.6 hours – a record. Electrical, telephone, and other communication-grid problems hit North America while bright aurora danced overhead, appearing much farther south than normally visible. But perhaps the most unique effect was the detonation of dozens of the U.S. Navy’s sea mines off the coast of North Vietnam: The mines were designed to detonate when a ship’s metal hull disrupted the magnetic field around them, and exploded after sudden magnetic spikes from the solar storm. The event prompted the Navy to accelerate the development of replacement mines that would be sensitive to not just magnetic field fluctuations, but seismic waves as well.
