What is a Volcano? A volcano is
a mountain, the top of which bursts out. Fire-ashes and lava come out
of it.
How many active volcanoes are there in the
world? About 850, of which many
are submarine.
How was the name 'volcano'
formed? The name volcano is
derived from the now dormant Vulcano island (from the God of fire Vulcanus)
in the Mediterranean.
Which explosion is thought to be the
strongest? The volcanic eruption
of Krakatoa, an island between Jawa and Sumatra, in Indonesia on 27th
Aug. 1883. The island was destroyed completly.
Which is the highest active
Volcano? Volcano Antofalla (6450
m) in Argentina.
Which Volcano is considered to be a holy one and is
worshipped? Mount Fujiyama of
Japan is the holy volcano worshipped.
What is a dormant Volcano? The
dormant Volcano is a Volcano that does not burst out for a long time but
could burst out any time.
What is a dead Volcano? A
Volcano from which no molten metal or life comes out as they are
exhausted inside the mountain is called a dead Volcano.
How are Volcanoes formed? As we
go into the interior of the Earth the temperature increases. At a depth of
about 30 km, the temperature is so high that it melts rocks. The
molten rocks get expanded. It starts coming up the openings on the
Earth's crust. Where the crust is weak, the molten rock exerts
pressure and the crust burst out. Hot gases, molten metals, fire and
rocks come out. This is called the volcanic eruption. Generally
this eruption occurs on the top of mountains. These mountains are
called Volcanoes.
What are the different kinds of Volcanic
eruptions? Three different kinds
of volcanic eruptions are the explosive type (krakatova in Indonesia and
Mount Pelee in the West Indies) the Quiet eruption. (like the Hawaian
eruptions) and the fissure eruption (like that which the Deccan
Plateau).
What is an earth quake? How is it
formed? An earth quake occurs when
the structure of the Earth shifts and moves. One of the causes is due
to the movement of the molten rock down in the earth's crust. The rocks
become soft when they are exposed to the great heat of the interior of the
Earth, and this change makes them move. Because of this movement
beneath, we on the surface, feel that the ground is shaking. It is called an
earthquake. The volcanic eruptions also cause earth quakes.
How is the earth quake measured?
By using the Richter Scale and Mercalli Scale.
What is Richter scale? Richter
scale is used to measure the total energy released during the earthquake.
What is Mercalli Scale? Mercalli
scale (devised in 1902) is used to assess the efforts of a quake at a
particular place, rather than to measure the over all power.
Which is the worst earthquake disaster ever recorded so
far? In the Shensi, Shansi, and
Honan provinces of China on Feb. 2, 1556. which is estimated to have killed
more than 830,000 people
