It's hard to know when an earthquake is going to hit, but when it does it could cost you big.
Thursday is the Great ShakeOut, the biggest annual earthquake preparedness event in history. Throughout the day, 20.6 million drills will be run across the U.S. to teach civilians and students about earthquakes. Leaving their place of businesses or school to practice their emergency evacuation plan will be part of the activities.
But here's the thing: Earthquakes are really hard to predict. We know they'll happen. Tectonic plates are shifting beneath our feet all the time. (If you didn't take earth science in high school and you're unclear on how earthquakes work, here's a quick explainer.)
Seismologists spend a lot of time developing models to predict how and when different plates will shift in their best attempts to provide an early warning to civilians. Over the past few years for example, scientists have updated their prediction model for California, called the Third California Earthquake Rupture Forecast model (UCERF3). Under the new model, mid-range earthquakes are less likely than before, but the likelihood of a huge one has increased.
Recent research found a link between two known faults running under San Francisco Bay, which increases the risk of a simultaneous rupture. That could be devastating for such a highly populated area.