Introducing Plate Tectonics
The Building Blocks of the Earth
Think about the last time you put together a puzzle. There were several pieces of all different shapes that fit together to form a finished picture. The Earth is kind of like a giant puzzle, made up of large pieces called "tectonic plates." These plates are part of the crust and mantle, known as the lithosphere.
There are seven main plates that you need to know:
- African Plate
- Antarctic Plate
- Eurasian Plate
- Indo-Australian Plate
- North American Plate
- Pacific Plate
- South American Plate
Where the "puzzle pieces" come together is called a "fault line." In the United States, many people know of the fault line known as San Andreas Fault. This is where the North American plate and Pacific plate meet.
Even as large as these plates are (see the previous page for the map), they are always moving in a process known as "continental drift." The continents are actually drifting as they "float" on top of the mantle in the Earth's core. However, they are moving very, very slowly. Sometimes, these plates are moving in different directions and the fault lines (where two plates rub up against each other) will move a large distance in a short period of time. Because these plates move more than normal in a short period of time, there is a lot of energy stored up. The sudden release of energy is known as an "earthquake."
Sometimes, these earthquakes happen near or under the ocean. Because earthquakes release such a large amount of energy, the water is displaced. This displacement creates a giant wave called a tsunami, which can be very dangerous when it reaches land.
View more about Earthquake and Tsunami.
Tectonic plates are also responsible for things like ocean basins and the creation of mountains. Some mountains aren't just rocks, though. Some mountains are actually a portal to the Earth's mantle, which can escape out through the crust. The formations where this occurs are called "volcanoes."
Volcanoes allow hot magma and ash from beneath the Earth's crust to escape and usually occur where two tectonic plates are either converging (coming together) or diverging (separating).
Like tsunamis and earthquakes, volcanic eruptions can cause devastation for people in the surrounding area in addition to the amount of ash and smoke that pollutes the air and can be carried to other parts of the world by the wind.
Review
- Tectonic plates are like giant puzzle pieces that make up the surface of the Earth.
- The movement of these plates is known as "continental drift."
- The lines where these plates meet are called "fault lines" and sometimes rub against each other.
- Sometimes, the plates shift too far, too fast. This causes an earthquake, where the ground shakes violently.
- If the earthquake is too close to water, it can cause a tsunami.
- A tsunami is a giant wave (sometimes known as a tidal wave, only larger) that can cause destruction once it reaches land.
- As the tectonic plates drift, they can converge (come together) and diverge (separate), and also create ocean basins, mountains, and volcanoes.
- Volcanoes are formations that allow hot magma and ash from the Earth's mantle to escape through the earth's crust.
