Timescale of Earth’s Events

During an earthquake the ground shakes. Sometimes things fall off shelves or out of cabinets if the earthquake is strong.

A volcanic eruption is when lava flows out of the top of a volcano. The lava may run down the side or it can shoot up into the air. When the lava cools, it hardens into rock.

Earthquakes, volcanoes, mudslides and flash floods can change the Earth’s surface quickly.

Rain and wind can change the Earth’s surface slowly. A great example is the Grand Canyon. Glaciers can also change the Earth’s surface very slowly.

The river flooded and moved rocks into people’s yards. New roads have been built where there used to be fields.

You could hide under a table or desk. You could also stand in a doorway.

An earthquake can cause cracks in the Earth’s surface. Roads can break into pieces and bridges can fall down.

Lava can flow down the sides of a volcano and spread over the land. It can even flow into the ocean. Once the lava cools it hardens into rock.

A landslide is when heavy rain soaks into the Earth and causes the land to fall down because of gravity. If there are no plants to hold the soil in place, it is more likely to happen.

Over very long periods of time weathering and erosion from wind or water can make a rough rock smooth.

Over millions of years, the Colorado River has worn away rock to form the Grand Canyon. Even today, it continues to change very slowly. Wind has also helped form the Grand Canyon, but not as much as water.

A glacier is a very slow-moving chunk of ice. Because it is so heavy, it changes the shape of the land as it slowly moves over it.