Transcript Volcanoes - Laconia School District

Volcanoes
By: Graham Nyhan and Cameron
Lyons
Part 1
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The science behind a volcano
What conditions can cause a volcano?
When, how and why a volcano occurs.
Definition of a volcano.
Where does a volcano occur?
A picture of a volcano.
Is a volcano related to another type of disaster?
Which one and why and how?
• Vocabulary of volcanic terms.
What conditions can cause a
volcano?
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A volcano begins as magma which rises from deep inside the earth toward
the surface. As the gas-filled magma rises, it melts gaps in the surrounding
rock and forms a large chamber. Pressure from the solid rock around it
forces the magma up to the surface through the channel in a weakened part
of the rock. The gas and melted rock blast out an opening called the central
vent.
When, how and why does a
volcano occur?
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A volcano occurs when molten rock becomes strong and pressure from
gases push the magma to the surface of the volcano. It then busts out of a
chamber called the central vent. Then the magma changes to lava as it
spills out of the volcano. A volcano occurs because of the plates shifting and
the pressure in the magma making it rise to the surface of a volcano.
Definition of a volcano
• The definition of a volcano is a large earth opening
that spills out lava, rocks and gasses.
Where does a volcano occur?
• They can occur all over the earth and even
underwater.
Is a volcano related to another type of
disaster? Which one, why and how
• A volcano is related to a
couple types of disasters and
they are the earthquake and
Tsunamis.
• They are related because
sometimes when a volcano
erupts, it can cause an
earthquake because of the
force of the eruption of the
volcano. It is related to a
tsunami because an
underwater volcano can
displace the land under the
water causing a Tsunami.
Vocabulary
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Magma- Molten mixture of rock- forming substances, gasses and water vapor.
Lava- When magma reaches the surface.
Lahars- A mudflow containing volcanic ash and rock.
Ring of fire- Major volcanic belt.
Island arc- Resulting volcanoes create a string of islands.
Hot spot- Area where magma from the mantel melts through the crust like a blow torch.
Magma chamber- A pocket of magma.
Pipe- Long tube in the ground that connects the magma chamber to earths surface.
Vent- Opening where molten rock and gas leave the volcano.
Lava flow- Area covered by lava as it pours out of a vent.
Crater- Bowl-shaped area that may form at the top of a volcano around the volcanoes
central vent.
Silica- A material that is formed the elements, oxygen and silicon.
Pahoehoe- Fast moving hot lava.
Aa- lava that is cooler and slower moving.
Pyroclastic flow- occurs when an explosive eruption hurls out ash, cinders and bombs as
well as gases.
Active- A live volcano.
Dormant- Sleeping or non-active volcano.
Vocabulary (cont.)
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Extinct- Dead volcano.
Hot spring- Forms when ground water, heated by a nearby body of magma, rises to
the surface and collects into a natural pool.
Geyser- A fountain of water and steam that erupts from the ground.
Geothermal energy- A clean reliable source in volcanic areas, where water is heated
by magma.
Shield volcano- Lava flows gradually build a wide, gently sloping mountain.
Cinder cone- A steep- cone shaped hill or mountain.
Composite volcanoes- Tall, cone- shaped mountains in which layers of lava alternate
with layers of ash.
Lava plateaus- High, level areas formed by eruptions of lava.
Caldera- The huge hole left by the collapse of a volcanic mountain.
Volcanic neck- Forms when magma hardens inside a volcanoes pipe.
Dike- Magma that forces itself across rock layers.
Sill- When magma squeezes between layers of rock.
Batholiths- A mass of rock formed when a large body of magma cools inside the
crust.
Dome mountains- Forms when rising magma is blocked by horizontal layers of rock.
Part 2
• History of Mount. St. Helens eruption in
1980.
Mt. St. Helens eruption- 1980
• Mount. St. Helens erupted on May 18, 1980.
• On May 18th, 1980 the eruption of Mount St. Helens in southwest
Washington state disrupted the lives of thousands and changed more than
200 square miles of forest into a grey, landscape. Now, more than twentysix years later, the land around the mountain is slowly getting more life to
it. Nature may be covering the evidence of the 1980 eruption, but many
people will never forget what happened that day.
Mount. St. Helens interesting fact.
• One interesting fact about Mount. St.
Helens is that it took 2 months for the
volcanic ash to travel 1,000 miles where it
was eventually all dropped to the surface
in North Dakota.
Pictures of the event before,
during and after
Inserted PowerPoint
• The following slides contain a PowerPoint
of Mount. St. Helens From google.com.
October 24, 1980 a new dome started growing.
This October dome was 112ft high and 985 feet
wide making it taller than a nine-story building
and wider than the length of three football fields
USGS Scientist Explore Pumice
Blocks from a Pyroclastc flow
October 17, 1980
Geologists install a seismic
station near the dome.
An increase in seismicity is often the first
precursor to an approaching eruption
Measuring magnetic field in crater
6/18/84
Geologist measured the strength of the magnetic
field surrounding the dome. The strength of the field
increased as the dome cooled and magnetic
minerals formed. During the eruptions, the strength
usually changed rapidly as magma heated and
deformed the dome
USGS scientists survey the
dome 5/26-84
April 18, 1988 USGS
Deformation Monitoring on the
Dome
Mt. St. Helens, Sept. 1994
Aerial View of Mt. St. Helens
2002
Mt.St Helens night shot of
Dome 10-22-86
Mt.St Helens Spirit Lake before
The May1980 Eruption
USGS Scientist Explore Pumice
Blocks from a Pyroclastc flow
October 17, 1980
Geologists install a seismic
station near the dome.
An increase in seismicity is often the first
precursor to an approaching eruption
5/19/82- Plume from Harry's
Ridge
Plumes of steam, gas, and ash often occurred at
Mt. St. Helens in the early 1980’s. On clear days,
they could be seen from Portland Oregon, 50 miles
to the south
Harry's Ridge Was Named After
Harry Truman of Spirit Lake
Measuring magnetic field in crater
6/18/84
Geologist measured the strength of the magnetic
field surrounding the dome. The strength of the field
increased as the dome cooled and magnetic
minerals formed. During the eruptions, the strength
usually changed rapidly as magma heated and
deformed the dome
USGS scientists survey the
dome 5/26-84
April 18, 1988 USGS
Deformation Monitoring on the
Dome
Mt. St. Helens, Sept. 1994
Aerial View of Mt. St. Helens
2002
Mt.St Helens night shot of
Dome 10-22-86
Mt.St Helens Spirit Lake before
The May1980 Eruption
Mt.St. Helens Lake ReflectionAfter the Eruption
Picture taken May 19, 1982
Part 3
• Safety precautions we should take in the situation
of a volcano occurring.
• What you should do if you are present during a
volcano.
• What you should do after a volcano.
Safety precautions we should
take if a volcano occurs
• If a volcano occurs you should evacuate
the area and leave the presence of that
eruption.
• If you can’t leave then close all of the
windows and doors and stay inside.
• Wear long-sleeve shirts and pants and
other protective wear to protect yourself
from the harmful gases and rock.
What you should do after a Volcano
occurs
• Clear roofs of debris
and ash fall.
• Stay out of the
damaged areas and
use simple
precautions until you
receive help.
Bibliography
• Google.com
• Youtube.com
• Ask.com