Why are earthquakes common in the San Francisco Bay Area?

Earthquakes are common in the San Francisco Bay Area because big pieces of Earth are moving under our feet, like a puzzle being shaken.

Imagine you have a big wooden floor, and underneath it, there are sliding plates, just like pieces of a puzzle. These plates move slowly most of the time, but sometimes they jolt suddenly when they get stuck or bumped. That’s what causes an earthquake!

The Bay Area is right where two big Earth plates meet: the Pacific Plate and the North American Plate. They’re like two friends who are always pushing and pulling each other, sometimes they move smoothly, but other times they get stuck, and then suddenly whoosh!, an earthquake happens!

It's like when you're playing with your toy car on a ramp. If it gets stuck halfway down, and then all of a sudden it goes zoom!, that’s like an earthquake!