Our sun is a restless star. When it’s particularly active, it can eject effervescent packages of magnetic energy and charged particles known as solar flares. If it releases a minor flare aimed at Earth, the solar material can produce harmless but spectacular displays of auroras when it slams into our atmosphere.

However, more powerful solar outbursts can give birth to geomagnetic storms that wreak havoc in Earth’s magnetic bubble, potentially delivering serious damage to the planet’s electrical infrastructure. (See pictures of solar storms being made in the lab.)

And, as it turns out, your city’s ability to weather a powerful geomagnetic storm may depend on the types of rocks below your feet.

Recent research by the U.S. Geological