Name _______________________________
VOLCANO VIDEO
Burning mountains and the human imagination are a powerful combination.
We still respect the Earth’s awesome forces, but when science replaced
_____________________, our understanding of the Earth grew.
A volcano isn’t an isolated explosion of a God’s fury. Instead, it’s a window on
a red hot world a few miles below; a living _______________ that involves the
entire planet.
We know that we ride on a thin skin called the __________. It floats above the
__________, a churning layer of molten rock. It’s here that __________ is born.
At the Earth’s core is a ball of molten _______________. The _______________ from
the core remains trapped from the insulating layer of the Earth’s exterior crust.
In the 1960’s scientists pieced together a new theory called
___________________. Earth is a jigsaw puzzled of __________ major plates.
When two plates spread apart magma rises to fill the gap. These zones are
usually found in the middle of the ___________ where they create new sea floor.
When two plates crash to together, one layer of the Earth gets folded under
the other, a ___________________ zone. The lower layer of crust is ______________
as it’s forced down into the heat. Then it burns and is forced back up through
the layer above creating explosive _________________. These areas surround
the Pacific Ocean in a string of the Earth’s most violent volcanoes called the
_____________________________.
There are __________ known volcanoes in the world. 500 are active; resulting in
about _________ major eruptions a year. A volcano can have a life span of
over a million years. Unpredictable they can lie ____________ for hundreds of
years then explode.
A volcano can threaten for millennia, but eventually it will die. When magma
no longer seeps into the chambers, the eruptions weaken and stop. The
______________ remains much longer, warming the ground water. Pools of
sulfur, mineral deposits, geysers and hot springs are the last reminders of the
volcanoes long forgotten power.
The last major eruption of Mount Vesuvius was in 1944. It sits over a
_________________ zone and ______ still dangerous.
A volcanoes origin determines its temperament. Many volcanoes develop
along subduction zones. Here the tectonic plates of the Earth’s surface push
against one another. Where one plate is rolled beneath another we find the
most ________________ volcanoes. They create large ___________ shaped
mountains. They have alternating layers of ash, cinders and lava. These
layered cones are called ___________________ volcanoes.
_________________ islands, like Hawaii, are created when a pool of magma
breaks through a ____________ spot in the crust. As it burns the plate moves
along 4 inches a year. One island cools as another island is _________________.
One the big island of Hawaii, Kileuea has been erupting since 1983 and is
showing no signs of stopping. This is an example of a ______________ volcano.
__________________ cones are another kind of volcano. Like composite
volcanoes they can be explosively violent. They burst forth with enormous
quantities of ash, cinders and lava fragments. They rapidly build volcanic
_____________________ but never as ____________ as shield volcanoes or as
________________ as composite volcanoes. The cinder cone shape is
determined by the size of the ejected material.
If we are to reduce the risk of volcanoes, we must learn to _______________
them.
The best way to predict a volcano may be to keep an ear to the ground.
___________________ devices can detect the earthquakes that accompany a
waking volcano.
___________________ offers new ways to watch the Earth’s imperceptible
movements. Lasers and satellites combine to measure the drift of plates and
the rise of mountains… inches per year. If movements pick up so might the risk.