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Volcanoes, a beautiful site to see, but dangerous at times. Looking at plate tectonics we can describe
why these volcanoes can be dangerous. Plate tectonics is were the continents are drifting from place to place breaking
apart, colliding, and sliding past eachother creating volcanic activity. It is the building of mountain ranges caused by the
stress of the continents crashing into eachother. The Plate Tectonic Theory describes how earth came to be and creating zones
of volcanic and earthquake activity.
The reason why Hawaii is significant to this information is becasue Hawaii lies right in the middle of the
Pacific plate, this is a spot where there is one of the most spectacular volcanic island chains in the world.
In Hawaii, there are alot of events that are caused by volcanic activity. These activities can
be dangerous to both life and property. These natural and dangerous hazards include, lava flows, lahars, ash falls, debris
avalanches and pyroclastic density curents.
While volcanoes are erupting they tend to emit some gases. Even when the volcanoe doesn't erupt it
is still releasing gases through cracks in the ground. Water vapor , carbon dioxide, hydrogen sulfied, and hydrogen are the
most common gases released. Sulfur dioxide is dangerous for vegetation because it mixes with water droplets in the atmosphere
falling after as acid rain, were as carbon dioxide is heavier and can cause people and animals to suffocate. Gases are not
the only dangerous effects of the volcanoes, it is the Lava we have to worry about.
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LAVA ON OF THE MAIN INGREDIENTS!
Lava is described as molten rock , or magma which pours onto the earth's surface. If the silica's content
is higher it is more viscous and slow moving, where as low-silica basalt can flow alot quicker.
An example of a dangerous basalt lava flow is the eruption of Kilauea volcanoe, which is
on the big Island of Hawaii between 1983 and 1993. "The eruption destroyed nearly 200 houses and destroying the coast highway
along the volcanoes south flank. The major hazards of these flows are that they bury, crush, cover and burn everything
in their path",( http://www.to-hawaii.com/natural-disasters.php).
Lava flows can dam rivers to form lakes that might overflow or break their dams causing floods. Their are
ways of contolling lava paths by constructing barriers and diversion channels, cooling advancing front with water, or disrupting
the source with explosives, but these preventions don't stop the lava it just slows it down.
| Here is a diagram showing how a Volcano works |
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This is what happens when we think of a volcano eruption.The Magma underground is heated up
while overtop a hot spot, pushed up from pressure of heat and moves all the way up to the surface of the earth. When the magma
reaches the surface is explodes through the surface as hot lava. After the Lava is released it travels down the slop of the
volcano spreading around the landscape burning, and bury everything in its way, again it may reach far depending on the Silica
of the magma.
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