Volcano Facts
Fun stuff!
Range of ashfall for volcanoes
Mt. St. Helens
Where did the term
"volcano" come from?
The word "volcano" comes from the
little island of Vulcano in the
Mediterranean Sea off Sicily.
Centuries ago, the people living in this
area believed that Vulcano was the
chimney of the forge of Vulcan -- the
blacksmith of the Roman gods.
Where did the term
"volcano" come from?
... They thought that the hot lava
fragments and clouds of dust erupting
from Vulcano came from Vulcan's forge
as he beat out thunderbolts for
Jupiter, king of the gods, and weapons
for Mars, the god of war.
How many active volcanoes
are there in the world?
About 500 active volcanoes are
known on Earth, not counting
those that lie beneath the sea.
What are some positive
products from volcanoes?
The Earth's crust, on which we live and
depend, is in large part the product of
millions of once-active volcanoes and
tremendous volumes of magma that did
not erupt but instead cooled below the
surface.
Volcanic ash can increase soil fertility
More positives ...
Heated groundwater can be tapped for
geothermal energy
Heated groundwater has concentrated
valuable minerals, including copper, tin,
gold, and silver, into deposits that are
mined throughout the world
What was the largest volcanic
eruption in the 20th century?
1912 at Novarupta on the Alaska
Peninsula. An estimated 15 cubic
kilometers of magma was explosively
erupted during 60 hours beginning on
June 6 -- (which is equivalent to 230
years of eruption at Kilauea (Hawaii) or,
about 30 times the volume erupted by
Mount St. Helens (Washington) in 1980.)
Where is the largest active
volcano in the world?
Mauna Loa (Hawaii) is the world's
largest active volcano, projecting 13,677
feet above sea level, its top being over
28,000 feet above the deep ocean
floor. From its base below sea level to
its summit, Mauna Loa is taller than
Mount Everest.
Cascade Range
Which Cascade Range volcano
erupted through a glacier?
Mount Garibaldi (British Columbia,
Canada) is a composite cone and domes
built on a glacier. It is one of the larger
volcanoes (6.5 cubic kilometers) in a
chain of small Quaternary volcanic piles
-- the Garibaldi Belt -- within the
southern Coast Mountains of British
Columbia.
How dangerous is Mount
Rainier?
Although Mount Rainier (Washington) has
not produced a significant eruption in the
past 500 years, it is potentially the most
dangerous volcano in the Cascade Range
because of its great height, frequent
earthquakes, active hydrothermal system,
and extensive glacier mantle. Mount Rainier
has 26 glaciers containing more than five
times as much snow and ice as all the other
Cascade volcanoes combined.
How would an eruption of Mount
Rainier compare to the 1980
eruption of Mount St. Helens?
Eruptions of Mount Rainier usually produce
much less volcanic ash than do eruptions at
Mount St. Helens. However, eruptiontriggered debris flows at Mount Rainier are
likely to be much larger -- and will travel a
greater distance -- than those at Mount St.
Helens in 1980. Furthermore, areas at risk
from debris flows from Mount Rainier are
more densely populated than similar areas
around Mount St. Helens.
How much ash was there from the
May 18, 1980 eruption of Mount St.
Helens?
During the 9 hours of vigorous eruptive
activity, about 540 million tons of ash fell
over an area of more than 22,000 square
miles. The total volume of the ash before its
compaction by rainfall was about 0.3 cubic
mile, equivalent to an area the size of a
football field piled about 150 miles high with
fluffy ash.
How often do Alaskan
volcanoes erupt?
Alaskan volcanoes have produced one or two
eruptions per year since 1900. At least 20
catastrophic caldera-forming eruptions have
occurred in the past 10,000 years
The awesome eruption of 1912 at Novarupta
in the Katmai National Monument is the most
recent. Scientists are particularly concerned
about the volcanoes whose eruptions can
affect the Cook Inlet region, where 60
percent of Alaska's population lives.