Download Volcanoes affect Earth`s land, air, and water.

KEY CONCEPT
Volcanoes affect Earth’s
land, air, and water.
STANDARDS
8–2.3 Explain how
Earth’s history has been
influenced by catastrophes (including the
impact of an asteroid or
comet, climatic changes,
and volcanic activity)
that have affected the
conditions on Earth
and the diversity of its
life-forms.
NOW, you will learn
• Rock fragments, lava, and
gases erupt from volcanoes
• Some volcanoes have explosive
eruptions
• How volcanic eruptions affect
Earth’s surface
• How volcanic gases affect the
atmosphere
• How volcanic activity affects
water
THINK ABOUT
Which volcano is more
dangerous?
Mauna Loa is a shield volcano that forms
a large part of the island of Hawaii. It is
one of the most active volcanoes on
Earth, frequently producing large
amounts of lava that flow long distances.
Mount Shasta is a composite volcano in
California. It has erupted at least once
every 600 to 800 years for the past 10,000
years. Mount Shasta can erupt with
devastating violence. Which volcano do
you think it is more dangerous to live
near. Why?
VOCABULARY
acid rain p. 276
geyser p. 277
CONTENT FRAME
BEFORE, you learned
Mauna Loa
Mount Shasta
Volcanic eruptions affect the land.
Add a content frame for
how eruptions affect Earth’s
land and air. Include
categories for what dangers
are caused and how long
the dangers last.
A volcanic eruption can knock down forests and clog rivers with
volcanic ash. Damage can occur far from the volcano. But volcanoes
build as well as destroy. Material erupted from volcanoes can form
new land. Over time, lava flows can form new, rich soil.
Many towns and cities are located close to volcanoes. The people
of Goma in the eastern Democratic Republic of the Congo experienced
an eruption of a nearby volcano in 2002. A lava flow cut the city in half
and destroyed the homes of tens of thousands of people, either by
flowing into the homes or by starting fires. Hilo (HEE-loh), the largest
city on the island of Hawaii, is built in part on young lava flows. The
city is at high risk from future volcanic activity.
272 Unit 2: The Changing Earth