In reality, volcanoes are vents in
the Earth’s surface from which
molten rock called lava is released.
There are around 1900 active
volcanoes around the world,
including those that have been
active in historical times. Ninety
percent (90%) of these are located
along what we call the “Ring of
Fire,” which is a band of volcanoes
circling the edges of the Pacific
Ocean.
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How Volcanoes are formed?
Most volcanoes are formed at the
Earth’s plate boundaries, areas
where huge slabs of rock meet in the
lithosphere, the planet’s outer
shell. As these land plates move and
interact, they trigger a gradual
series of events that can end with
explosions. These events can happen
slowly or really quick, and either
the volcano grows from inside or it
builds up as it adds layers of lava
and ash outside of the volcano.
How Volcanoes Erupts?
Volcanoes erupt when magma, the
molten rock deep in the Earth’s
crust, rises towards the surface
since its intense temperature
creates pressure on the magma to
push upwards. As magma comes out
halfway along the volcano’s vent, it
is called lava.
As lava rises,
dissolved gases and rocks are
collected along the way. Once the
lava reaches the top, it causes the
volcano to erupt, blasting lava,
rocks, and dust clouds across great
distances. The lava is so hot, it
burns everything that crosses its
path until it slowly cools and
hardens to become rocks or part of
the volcano.
Where do volcanoes occur?
Volcano and earthquake risk maps overlap
considerably. Along portions of the western
edge of North America, oceanic crust is
sliding under continental crust this
process is called as subduction. Volcanic
activity is common here, as is evident by
the volcanic mountains of the Cascade,
Sierra Nevada, and Coast Ranges. The western
states where these ranges are found,
including California, Oregon, Washington,
British Columbia, Yukon Territory, and
Alaska, are all at risk of volcanic
eruptions. In most of the areas, only one or
two volcanic eruptions are expected in any
century. Continuing south, volcanoes are
found along Baja California and western
Mexico.
In the rest of the world, three regions in
particular are at significant risk of
volcanic activity:
The Pacific Rim is also known
as the "Ring of Fire" due to its
extensive history of volcanic eruptions.
Many countries around the Rim are at great
risk of volcanic eruptions. In the east,
these include Japan, the Philippines,
Indonesia, New Guinea, New Zealand, and many
of the South Pacific Islands. In South
America, all west coast countries (Chile,
Peru, Ecuador, Columbia) lie in the shadow
of the explosive Andean Mountain Range
volcanoes.
The Mediterranean and Middle East
regions including the countries of Italy,
Greece, Turkey, Iran, Saudi Arabia, Yemen,
and Pakistan have been plagued by volcanic
eruptions throughout history.
The Great Rift Valley in eastern Africa
has many volcanoes found in the countries of
Ethiopia and Kenya.
The most active volcano in the World is
Stromboli, in the Mediterranean Sea, which
has been erupting almost continuously for
approximately 2000 years.
Can Volcanoes be predicted?
Like earthquakes, volcanic
eruptions cannot be predicted. Unlike
earthquakes, no structure can be made to be
"volcano-resistant." Some volcanoes are
almost continuously eruptive, which can
serve as a deterrent to living or working
near them. Other volcanoes are only active
over very long periods of time, at least on
human time scales. In areas where such
volcanoes are found, most people perceive
little or no threat from the volcanoes.
Here, mitigation is entirely dependent on
careful monitoring and warning systems to
alert people of an impending eruption. With
technologies such as tilt meters, strain
meters, and GPS, volcanic eruptions can
sometimes be predicted months in advance.
Although monitoring and warning systems can
save lives, they often cannot save property,
crops, or livestock.
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