Fourth Grade
Worksheets
What Are Earthquakes?
Caption: This picture shows part of the damage from a major earthquake that struck San Francisco, California, April 18, 1906.
The outside of the Earth is called the crust. Just like the crust on a loaf of bread, the Earth's crust has cracks in it. The cracks are called faults. The crust of the Earth isn't solid at all. It is made up of many pieces called plates.
The plates of the Earth's crust fit together like a giant puzzle. But unlike a puzzle, the plates of the Earth's crust are always moving. The Earth's plates float on a layer of hot, melted rock. This part of Earth is called the mantle.
