Transcript Volcanoes in the United States

By Justin Lampert and Jenna
Macchione
• The United States ranks
third in the number of
historically active
volcanoes.
• Of the 1,500 volcanoes
that have erupted in the
past 10,000 years, 10
percent are located in the
United States.
Where do they exist?
• Hot spots for volcanoes in the U.S. are found in the Aleutian
Islands, the Alaska Peninsula, the Hawaiian Islands, and the
Cascade Range.
• The majority of active and inactive volcanoes are found in the
western part of the U.S. The eastern United States has been
isolated from volcanoes due to global plate tectonic features,
tectonic plate boundaries, and hot spots in the mantle, which
are the causes for volcanic activity
Hawaiian Volcanoes
• The islands of Hawaii were
formed by volcanoes. These
volcanoes are ideal for
scientific research because
they erupt frequently but
are generally non-explosive.
• Mauna Loa is one of the
world’s largest active
volcanoes. Since 1900, it has
erupted 15 times, with
eruptions lasting as long as
145 days to less than 1 day.
Cascade Volcanoes
•
The Cascade Range is a popular area
for volcanic activity. Although this
area has fewer eruptions compared
to the volcanic activity in Hawaii,
these volcanic explosions have been
more catastrophic due to the
behavior of the volcanoes and the
heavily populated areas in
Washington, Oregon, and California.
In 1980, the deadly eruption of
Mount St. Helens proves this point
•
Mount Rainier has not produced a
significant eruption in the past 500
years, but is considered by
scientists to be one of the most
hazardous volcanoes in the Cascades
Alaskan Volcanoes
Augustine, Cook Inlet, Alaska
March 27, 1986
• Alaskan volcanoes have
produced one or two
eruptions per year since
1900.
• The most recent
eruption was the
eruption of 1912 at
Novarupta in the Katmai
National Monument
• The biggest concern of
the people is eruptions
that could affect the
Cook Inlet Region which
is 60% of the Alaskan
Population
Restless Calderas
Medicine Lake, California
When large volume of magma is removed from beneath a
volcano, the ground subsides or collapses into the emptied space,
to form a huge depression called a caldera.
• Most caldera unrest does not lead to an eruption, however, the
possibility of the violent eruptions causes scientists to monitor
some of the active calderas today.
•
Most Recent Eruption
• 18 May, 1980 Mt St Helen’s, Southwest
Washington State
• Prior to eruption: Small craters
projecting steam explosions and ash
• After eruption: Magma and lava created
dome over the crater
The End