An earthquake is an intense shaking of Earth's surface. Scientists use an instrument called a seismometer. It measures the shaking waves.

Earth's outer layer is made of giant puzzle pieces. They are called tectonic plates. They slowly move.

Here is what to do. If the ground shakes, drop down. Cover your head and neck. Hold on until it stops.

A tornado is a spinning column of air. It reaches from a storm cloud to the ground. It often looks like a funnel. It hangs from a dark cloud.

Here is a safe step. In a tornado warning, go to a small room with no windows. Use the lowest floor of a sturdy building.

A hurricane is a big storm. It forms over warm ocean water. It has a calm, clear center called the eye.

Each hurricane is given a name. People then know a new storm is on its way.

A flood is water that covers land. That land is usually dry. Floods can come from heavy rain. They can come from fast-melting snow.

Floods can also come when ocean waves come on shore. Never walk, swim or drive through flood water.

Weather forecasters send out warnings. People have time to get to a safe place. A NOAA Weather Radio has a tone alert. It is one way to hear a warning.

A family can make a plan together. Pick a place to meet if you are ever apart.

A disaster kit holds basic things a family may need. It may hold water, food and a radio. It may hold a flashlight and a first aid kit.

Words to know

• seismometer: shake measurer
• tectonic: of Earth's plates
• tornado: spinning air
• hurricane: big storm
• kit: a set