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Welcome ToThe Geological Hazards Of Hawaii

Volcanoes

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What causes the volcanoes?

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Puu Oo Cone, Kilauea.Hawaii.

National Parks Active Volcano

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.

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
volcano-eruption.gif

 
 
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.