The distructive power of a valcano is one of the most violent and deadly of all
natural forces. In a short period of time, these massive explosions of the
earths crust can shatter whole communities. Valcanoes are very distructive no
matter how big or how small they erupt at. They cause the highest amount of
deaths and the greatest amount of damage. Of the two major types of Volcanoes,
andestic and basaltic, the two typical volcanoes begin life when a mass of
low-density magma forces its way to the surface.
When the density of the rising
magma is the same as that of the surrounding rock, it gathers in a magma
chamber. Any rise in pressure in the chamber may now push the magma upwards
through cracks in the overlying rock. As the magma traveling up a crack
approaches the surface, the pressure from the overlying rocks reduces; gases are
released from the magma and expand so suddenly that an explosion rips open a
funnel shaped vent (called a diatreme) to the surface. The lava that blasts out
of the vent then cools, to form cinders, ash and dust – all referred to as
"Tephra". A ring of tephra collects around the vent and, as the
eruption subsides, this blocks up the diatreme. Volcanoes have erupted in many
different places.
Volcanoes have erupted in The Philippines, Java, Papua New
Guinea & Hawaii and many other places. "The Ring of Fire", located
around the Pacific Ocean, is 20 or so places with active volcanoes in them
joined by one big imaginary line that forms a circle (or "Ring") when
scaled down to the size on a map. Somewhere in the world an eruption occurs at
least once a month. Whether it be big or small it doesnt really matter at
all. If it kills 1 person or 1 000 people it is still counted as an eruption. In
some countries volcanoes are common and erupt frequently as in Hawaii.
But in
other countries like Australia there are no eruptions at all. That could be
because all the volcanoes are dormant or there are simply no volcanoes at all.
In 1815, the most devastating eruption ever recorded, killed approximately 92
000 people. 10 000 people died directly from the volcano and a further 82 000
died from famine. The volcano is located at Tambora, Sumbawa in Indonesia.
Recently a volcano erupted in Monserrat, West Indies.
It devastated farms,
houses and streets became rivers of lava.
Geography .
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