What is strike-slip?

Strike-slip is when two parts of the Earth move past each other side to side, like a sliding door.

Think about your favorite sliding door, the kind that goes from one room to another. When you push it open, one part moves left and the other moves right. That’s exactly what happens in strike-slip: rock layers on either side of a fault (a crack in the Earth) move past each other like that sliding door.

In California, there's a big fault called the San Andreas Fault. It’s famous for causing earthquakes. When parts of the Earth on one side of the fault move left and parts on the other side move right, it's strike-slip in action! You can feel this movement during an earthquake, it's like the ground is sliding beside you.

Sometimes, these movements are slow and steady, but sometimes they're quick and shakey, just like when you suddenly push a door open instead of sliding it gently.