BACKGROUND:
Volcanic hazards occur where there are active or
dormant volcanoes near inhabited areas, especially urban regions. An
"active volcano" is defined as a volcano in an eruptive stage or
shows signs of eruption. A dormant volcano is a volcano that has been active
in the past, but is presently "sleeping." Dormant volcanoes can
erupt again. Dormant volcanoes often have small earthquakes, suggesting
magma is moving underneath them. Volcanic areas may have active hot springs,
triggered by water heated by the magma. A third type of volcano, an extinct
volcano, does not have a magma sources, and will never erupt again.
Your students should realize by now that volcanoes are
a hazard. Many volcanoes are located in the western United States, in
California, Oregon, and Washington. The most recent eruption in this area
was at Mt. St. Helens, in Washington, in 1980. This eruption deposited ash
over a wide area stretching as far east as Montana. Landslides caused major
damage in the surrounding area, and even prevented river travel on the
Columbia River (between Washington and Oregon). Mt. St. Helens continues to
erupt lava and the volcano grows.
Mt St. Helens and the other volcanoes in this area are
a part of the "Ring of Fire," the geologically active area of
volcanoes that encircles the Pacific Ocean. First graders do not have to
understand why they occur in this ring. They need to understand that
volcanoes can cause damage.
PROCEDURE:
- Show the Mt. St. Helens slides within the Volcano Slideshow to your
students. Locate Mt. St. Helens on a map of the United States. Most of
the other slides in the set show other volcanic hazards. Tell your
students that Mt. St. Helens erupted in 1980 and is still active.
- Have the students cut out the active and dormant volcano figures on
one of the worksheet. Using the list below, review which volcanoes are
active and which are dormant. Have the students cut out the volcano
figures. You may want to use "cotton balls" for the active
volcanoes. Instruct them to paste the pictures on the appropriate
volcano. Here are the volcanoes to review:
Mt. Rainier (dormant)
Mt. St. Helens (active)
Mt. Hood (dormant)
Mt. Baker (dormant)
Glacier Peak (dormant)
Mt. Adams (dormant)
Mt. Shasta (dormant)
Mt. McLoughlin (dormant)
Mt. Lassen (dormant)
- All of these volcanoes are either active or dormant. Ask the students
if this might be a hazardous area. The answer is "yes" because
all of these volcanoes have the potential for eruption. Ask the students
if people should build big cities near these volcanoes. The answer is
"no," because it might endanger people if the volcanoes decide
to erupt.
