Volcanoes
Reference Pack
WEBSITES
http://www.woodlands-junior.kent.sch.uk/homework/mountains/volcanoes.htm
http://www.weatherwizkids.com/weather-volcano.htm
http://www.volcanolive.com/eruptions.html
SHORT FILMS
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ARTICLES
The World’s Worst Volcanic
Eruptions
The World’s Worst Volcanic Eruptions
As Measured by Death Toll
This list of the world’s worst volcanic eruptions
includes only those whose death toll can be
reasonably documented. The death toll from some
of the worst eruptions in history can only be
guessed. The eruption of Santorini in Greece in
1650 BC destroyed competely destroyed entire
civilizations. Scientist also theorize that an eruption
of Tuba around 75,000 years ago caused a volcanic
winter that came close to wiping out mankind.
1.
Mt. Tambora, Indonesia
April 10 - 15, 1816
Death Toll: 92,000
The eruption of Tambora killed an estimated
92,000 people, including 10,000 from explosion
and ash fall, and 82,000 from other related causes.
The concussion from the explosion was felt as far
as a thousand miles away. Mt. Tambora, which was
more than 13,000 feet tall before the explosion was
reduced to 9,000 feet after ejecting more than 93
cubic miles of debris into the atmosphere.
The effects of the eruption were felt worldwide:
1816 became known as the “year without a
summer” because of the volcanic ash in the
atmosphere that lowered worldwide temperatures.
It snowed in New England that June, and crop
failures were common throughout Northern Europe
and North America. As many as 100,000 additional
deaths from starvation in these areas are thought to
be traced to the eruption.
2.
Mt. Pelee, West Indies
April 25 - May 8, 1902
Death Toll: 40,000
Thought to be dormant, Mt. Pelee began a series of
eruptions on April 25, 1902. The primary eruption,
on May 8 completely destroyed the city of St.
Pierre, killing 25,000. The only survivors were a
man held in a prison cell, and a man who lived on
the outskirts of the town. Several ships also were
destroyed with all hands.
3.
Mt. Krakatoa, Indonesia
August 26 - 28, 1883
Death Toll: 36,000
The August 1883 of Mt. Krakatoa (Krakatua)
destroyed 2/3 of the island, ejecting more than six
cubic miles of debris into the atmosphere. The
sound of the explosion was the loudest ever
documented, and was heard as far away as
Australia.
Interestingly, it’s probable that no one died in the
initial explosion. The casualties all came from the
resulting tsunami.
4.
Nevado del Ruiz, Columbia
November 13, 1985
Death Toll: 23,000
A small eruption of the Nevado del Ruiz volcano
melted part of the volcano’s ice cap, creating an
enormous mudslide that buried the city of Armero,
killing 23,000.
5.
Mt. Unzen, Japan
1792
Death Toll: 12,000 - 15,000
The eruption of Mt. Unzen was followed by an
earthquake, which collapsed the east flank of the
dome. The resulting avalance created a tsuanami
which killed 12,000 to 15,000 in nearby towns.
6.
Mt. Vesuvius, Italy
April 24, AD 79
Death Toll: 10,000+
In one of the most famous eruptions of all time, Mt.
Vesuvius erupted and completely destroyed the
Roman towns of Pompeii and Herculaneum. The
eruption, which is said to have lasted 19 hours,
buried Pompeii in ten feet of volcanic ash. The
intense heat—perhaps as much as 750 degrees—
carbonized much of the organic material in the
area. Many of the victims have been found with the
tops of their heads missing—their brains having
boiled and exploded.
7.
The Laki Volcanic System, Iceland
June 8, 1783 - February 1784
Death Toll: 9350
Nearly a year of constant eruptions created a dusty
volcanic haze that created massive food shortages.
Iceland suffered 9,350 deaths mostly due to
starvation.
8.
Mt. Vesuvius, Italy
December 1631
Death Toll: 6,000
The notorious Mt. Vesuvius has erupted more than
a dozen times since it destroyed the towns of
Pompeii and Herculaneum. The 1631 eruption
killed as many as 6,000 people when lava flows
consumed many of the surrounding towns. Boiling
water ejected from the volcanos added to the
destruction.
9.
Mt. Kelut, Indonesia
May 19, 1919
Death Toll: 5,110
Most of the casualties apparently were the result of
mudslides.
10.
Mt. Galunggung, Java, Indonesia
1882
Death Toll: 4,011
Source:
http://www.epicdisasters.com/index.php/site
/comments/the_worlds_worst_volcanic_erup
tions/
Effects of Volcanoes
Volcanic eruptions are one of the most
destructive natural disasters, which endanger
human life and cause significant changes in
the atmosphere. To find out more about the
disastrous effects, read on.
A volcano is actually an opening or a fissure,
in the earth' crust , through which lava or
molten rocks, ash and toxic gases present
below the surface of Earth, are discharged by
a sudden, violent eruption. Sometimes, it can
be a mountain like structure with a bowlshaped depression at the top, through which
these substances are expelled. The term
volcano, is derived from the name of the
Roman God of fire, Vulcan. Volcanic
structures are usually formed at places where
the tectonic plates are either converging or
diverging. A stretching or thinning of the
Earth's crust, can also lead to the formation
of volcanoes. They are often classified into
three types, on the basis of their frequency
of eruptions, i.e. active, dormant and extinct.
The active volcanoes are characterized by
regular eruptions, while the dormant
volcanoes are those that erupted in the past,
but are silent now. On the other hand, an
extinct volcano is the one that erupted in the
remote past and is unlikely to erupt again.
Volcanic Eruptions
Volcanoes are notorious for their devastating
effects, not only on human life but also on
the global environment. Lava, emission of
toxic gases, ash fall, lahars and landslides
are some of the most dangerous hazards of
volcanic eruptions.
Lava
The mention of the name, volcano, brings to
mind the red hot lava, destroying and
burning everything that comes in its way.
But, lava flow is only a part of the hazards
created by volcanoes. There are many more
hazards of volcanic eruptions and some of
them are potentially more dangerous than
lava. Lava flows are usually slow and
therefore, people can easily escape them.
However, they can cause extensive economic
loss by burning and burying buildings and
crops.
Gas
Volcanic eruptions usually contain a number
of harmful gases like carbon dioxide, sulfur
dioxide, water vapor, hydrogen sulfide,
hydrogen fluoride, hydrogen chloride, carbon
monoxide, halocarbon and metal chlorides
that can create a lot of changes in the Earth's
atmosphere. The violent eruptions of
volcanoes, insert these gases and
compounds into the stratosphere, where the
sulfur oxide converts to sulfuric acid. The
sulfuric acid in turn condenses to sulfur
aerosols, which are responsible for cooling
the lower atmosphere, known as
troposphere, by increasing the reflection of
radiation from the Sun, back into space. On
the other hand, they increase the
temperature of the stratosphere by absorbing
the heat radiated by the Earth.
The hydrogen chloride and hydrogen fluoride
present in volcanic eruptions are important
contributors to acid rain. These compounds
get dissolved in water droplets, present in
clouds and then fall back on Earth as acid
rain.
Landslides and Lahars
Volcanic eruptions are generally accompanied
by dreadful vibrations in the surrounding
areas, which causes landslides. In the past,
such landslides were responsible for burying
surrounding cities.
Lahar or mud flow, is another danger posed
by volcanoes. Lahars contain rocks, mud and
water and can travel long distances at great
speeds. They destroy almost everything in
their way.
Ash Fall
Volcanic ash mainly consists of small and
sharp rock particles formed from the
breakdown of magma. The explosive
eruptions of volcanoes can throw such ash
particles over a long distance. Ash rains can
cover a vast area and hence cause huge
economic losses.
A volcanic eruption is a natural calamity,
which besides causing loss of human life and
property, can cause a lot of environmental
changes by contributing to acid rain and
global warming. Though we cannot prevent
the occurrence of such eruptions, we can
reduce their devastating effects. Movement
of magma, changes in the quantity and
quality of gases emitted by the volcanoes
and small earthquakes can serve as signals
of volcanic eruptions. So proper monitoring
of these signals, ready disaster management
techniques and creating awareness among
the general public about the hazards of
volcanic eruptions, can play an important
role in minimizing the losses and saving
human lives.
By Chandramita Bora
Source:
http://www.buzzle.com/articles/effects-ofvolcanoes.html