Volcanoes

Notes: Volcanoes are mountains with openings in Earth's crust through which magma, gases, and ash reach the Earth's surface. Volcanoes can change the Earth's surface. When magma (melted rock) erupts from the volcano the top of the mountain can be changed, either built up or exploded off.

The lava and ash can destroy forests and bury fields. Magma is melted rock beneath the Earth's surface. Once magma reaches the Earth's surface, it is called lava. Volcanic eruptions can change Earth's weather patterns.

Are volcanoes considered to be a constructive or destructive force? Why?

Earthquakes, Tsunamis, and Landslides

Let's take a closer look at plate tectonics... How does Earth move? The Earth is made of layers. The outer layer is the crust. The crust is broken into 30 pieces called tectonic plates. The crust floats on the next layer of the Earth called the mantle. The mantle is made of molten rock called magma. The tectonic plates have been moving for hundreds of million years! This movement is the cause of many of the Earth's landforms. Let's take a closer look at plate tectonics...

Where are Earth's plates?

How does the Earth's movement create mountains? When Earth plates push toward each other, a mountain is formed.

What are earthquakes? Earthquakes are vibrations on Earth's surface caused by a sudden movement in the Earth, often along a fault. A fault is a break in the Earth's surface. Some earthquakes cause little damage while others cause a lot of damage.

The scale that scientists use to measure the strength of an earthquake is called the Richter Scale.

Here is another form of the Richter Scale.

What is a landslide? Landslides occur in all U.S. states and territories. In a landslide, masses of rock, earth, or debris move down a slope. Landslides may be small or large, slow or rapid. They are activated by: sstorms searthquakes svolcanic eruptions sfires salternate freezing or thawing ssteepening of slopes by erosion or human modification

What are tsunamis? A tsunami is a series of enormous waves that happen after an undersea disturbance, such as an earthquake, landslide, or volcano eruption. Please remember that tsunamis are NOT related to the weather!!!!