Changes to the Earth’s Surface

The surface of the Earth is always changing.

Changes to the surface can be made by forces that are fast and forces that are slow.

Today we’ll focus on fast changes to the surface of the Earth.

The fast changes to the surface of the Earth can be caused by events that can change the landscape in the blink of an eye!

Landslides happen when a mound of earth or rock slides down from the edge of a mountain or a cliff.

Landslides can happen from natural causes, such as torrential rain or earthquakes. They can also be caused by human activity, like machinery blasting that weakens the ground.

In 2004, a landslide in Japan left massive devastation in its wake. Click here to watch a Youtube video taken during the landslide.

A volcano is an opening in the Earth's crust which allows hot magma, volcanic gas or ash to escape.

Click here to watch a Youtube video that explains: “What is a volcano?”

Some volcanoes are explosive and some aren’t Some volcanoes are explosive and some aren’t. The different types of volcanoes, based upon shape, are: Shield Volcano Cinder Volcano Composite Volcano Lava Dome Volcano

Volcanoes are found in all corners of the world Volcanoes are found in all corners of the world. Today we’ll look at them from three different continents.

Our first volcanic stop is in Hawaii, United States. mainland United States Hawaii

Mauna Kea Volcano in Hawaii, United States is a shield volcano. They are created when lava flows out in all directions and create a shield like a warrior.

Our next volcanic stop is in British Columbia, Canada.

Cinder Cone is a cone volcano in British Columbia, Canada. They are created when magma explodes into the air, cools quickly, and falls as cinder or cinder-like material.

Our next volcanic stop is in Naples, Italy.

Mount Vesuvius near Naples, Italy is a composite volcano. They have steep sides and periodic explosive eruptions.

Our next volcanic stop is in Chile, South America.

Michinmahuida Volcano in Chile, South America is a dome volcano. A dome volcano has the shape of a dome and is created by lava that is so thick that it doesn’t travel very far.

Although volcanoes have characteristics in appearance that make them different, they also have a lot that makes them the same.

All volcanoes have magma All volcanoes have magma. Once it reaches the Earth's surface and flows it is called lava. Lava can be extremely harmful to life around the volcano.

Click here to watch this Youtube video on how volcanoes work.

An earthquake is the shaking of the ground caused by the sudden movement of tectonic plates beneath the Earth’s crust.

Plate Tectonics is a scientific theory that supports the idea that tectonic plates exist beneath Earth’s surface. They believe they are attached to and move the continents and remaining crust of the Earth’s surface.

When the continents and plates move, it is called Continental Drift.

Scientists have traveled all over the Earth and found evidence that supports the theory of plate tectonics.

All of the continents fit together like a jigsaw puzzle. Evidence #1: All of the continents fit together like a jigsaw puzzle.

Evidence #2: Scientists examined fossils on the different continents. They found that fossils in Australia were similar to the ones in Southern Asia.

Scientists agree that these are too similar to be a coincidence. Evidence #3: When scientists were digging, they also looked at the types of rocks. The West Coast of Africa has very similar rock formations to those on the East Coast of South America. Scientists agree that these are too similar to be a coincidence.

Scientists believe continental drift has formed several super-continents, like the one below, Pangaea.

Click here to watch a Youtube video (14:38) about plate tectonics: “Tectonics of Planet Earth.”

“Colliding Continents.” On another class session, this is an excellent video (50:04) explanation of plate tectonics from National Geographic. Click here to watch “Colliding Continents.”

A tsunami is a single enormous wave, or a series of huge waves A tsunami is a single enormous wave, or a series of huge waves. Most tsunamis are caused by underground earthquakes or volcanoes occurring beneath the ocean.

Tsunamis move huge volumes of water at such a quick rate that the waves build to enormous heights. They are nearly impossible to project or detect, and are therefore incredibly dangerous.

Click here to watch a tsunami 3-D simulation on Youtube.

Let’s Play! Click here to transform land on the surface of the Earth with an online GAME!