Volcanoes can have many shapes and sizes.
CONTENT FRAME
Make a content frame for
types of volcanoes. Add
categories for shape, size,
makeup, and examples.
Mount St. Helens is a cone-shaped volcano in Washington. Its eruption
in 1980 killed 57 people. One side of the volcano exploded, blasting out
a mixture of hot rock, ash, and gases that destroyed trees tens of kilometers away. Since 1980, this volcano has had many smaller eruptions.
Volcanoes can have many shapes, including steep cones and nearly
flat land. Most volcanoes erupt from openings in bowl-shaped pits
called craters. Some volcanoes erupt from long cracks in the ground.
The type of magma feeding a volcano determines its shape.
1
Shield Volcano A shield volcano is shaped like a broad, flat dome.
It is built up by many eruptions of lava that is relatively low in silica
and therefore flows easily and spreads out in thin layers. The
largest volcano on Earth, Mauna Loa (MOW-nuh LOH-uh), is a
shield volcano. It makes up much of the island of Hawaii. The total
height of this volcano is about 17 kilometers (10.5 mi), but only
about 4 kilometers (2.5 mi) are above sea level. At the top of
Mauna Loa is a crater that is 5 kilometers (3 mi) across at its
widest point. Mauna Loa is one of Earth’s most active volcanoes.
2
A cinder cone is a steep, cone-shaped hill formed by
the eruption of cinders and other rock fragments that pile up around
RESOURCE CENTER
CLASSZONE.COM
Learn more about
historic and current
volcanic eruptions.
Cinder Cone
1
Shield Volcano
Three Types of Volcanoes
Two types of material form volcanoes:
rock fragments that fall close to the
openings they erupted from and lava
flows that have cooled and hardened.
shield volcano
266 Unit 2: The Changing Earth
A shield volcano is built up of many thin layers of
hardened lava. Rangitoto, a shield volcano in New
Zealand, is broad and has gently sloping sides.