Have you ever heard of the Ring of Fire? It might sound like something straight out of science fiction, but it is a real place. The Ring of Fire is the name used by scientists to describe an area where frequent volcanic eruptions and earthquakes take place. In fact, about 75 percent of the world's 1,900 active and dormant, or inactive, volcanoes are located there.

In some parts of the world, giant pieces of Earth's crust, called plates, are constantly in motion. They collide and slowly slide over, under, and past one another. The Ring of Fire is located at the juncture of the Pacific plate with several other plates. The Ring of Fire is an arc-shaped region that runs along the coast of North and South America, along the eastern edge of Asia, across Alaska's Aleutian Islands, and along the coast of New Zealand in the South Pacific.

Sometimes, plates move past one another without creating much of a disturbance. Other times, when two plates collide, an earthquake occurs. This is exactly what happens at the well-known San Andreas Fault in California, and it is why earthquakes are so common in that part of the country.

Even though the plates move relatively slowly, at about the same rate that human fingernails grow, the friction they create as they slide into one another produces a great deal of energy. The heat from inside Earth is hot enough to melt rock and turn it into magma, or molten rock. Eventually, the magma rises because it is lighter, or less dense, than the rocky material that surrounds it. When it reaches the surface, it becomes known as lava and forms volcanoes.

The presence of dissolved gases in the magma determines whether or not the eruption will be explosive. Picture a bottle of soda that has been shaken. When the bottle is opened, the gases cause the liquid to explode from the bottle with force. In the same way, volcanoes that have a high concentration of gases will explode with greater force.

Although most people view volcanoes as enormous and potentially dangerous mountains, scientists see them as temporary structures on Earth's surface. They may not change much over the course of a lifetime, or even several lifetimes. Still, scientists know that over time volcanoes move and shift. They rise and fall with the movement of Earth's plates.

I. Word List

earthquakes: a sometimes dangerous happening that occurs when volcanic plates release tension

constantly: always, never stopping

temporary: for a short time only

II. Vocabulary skills—Find the correct words in the reading.

1. to crash or strike: c _ _ _ _ _ _

2. a place where two things come together: j _ _ _ _ _ _ _

3. the rubbing together of two surfaces: f _ _ _ _ _ _ _

4. heavy, packed tightly together: d _ _ _ _

5. magma on the Earth's surface: l _ _ _

III. Reading skills—Answer the following questions.

1. Why is the San Andreas Fault well known?

___________________________________________________________.

2. What are two continents that border the Ring of Fire?

___________________________________________________________.

3. What percentage of the world's volcanoes are located in the Ring of Fire?

___________________________________________________________.

4. Why does magma rise to the surface?

___________________________________________________________.

5. How do scientists view volcanoes?

___________________________________________________________.

IV. Word groups—Find words in the reading that are opposite to these ones.

1. western: e _ _ _ _ _ _

2. rare: c _ _ _ _ _

3. inland: c _ _ _ _

4. dormant: a _ _ _ _ _

5. freeze: m _ _ _

6. safe: d _ _ _ _ _ _ _ _