Thursday, October 6, 2011

The Types of Volcanic Eruptions

Hawaiian: Hawaiian eruptions are characterized by lava-effusion (an eruption of lava which causes lava flows) more frequently, they cause "fountains" of lava, and this causes cones of fragments to form.
Strombolian eruptions: when lava is viscous (sticky or thick), gas that is trapped will rise intermittently to the surface and cause blocks & bombs to fall on the local environment. Lava flows & cinder cones are produced by these volcanic eruptions.


Vulcanian eruptions: These volcanoes burst to life after a extremely long period of time, These eruptions give off a large amount of ash, rock & gas that it seems to blot out the sun. because these are docile the build up a large amount of gas that cause quite an explosion.

Pelean eruptions: these are very calm eruptions that span decades between each one. these eruptions create domed volcanoes and a volcanic rock called Pele's (the Hawaiian volcano goddess) hair. It is created by lava streaming through the air.
Plinian eruptions are probably the most explosive and powerful of all. They often start suddenly and unexpectedly after a long quiet period.
Plinian eruptions occur when utmost viscus magma containing a lot of gas explodes in the depth of the volcano by which the crater pipe functions as the barrel of a shotgun. An enormous gas escape shoots upwards with a very high speed whereby an enormous ash cloud comes into existence.

Submarine Eruptions:Submarine eruptions occur under the sea chiefly emerging from vents aligned along fissures of mid-ocean ridges.
Because the volcano lies far beneath sea level the eruption probably won't even be noticed from the surface. Because of the pressure of the sea, gases and steam remain in solution which stifles any potential explosions. The lava will roll down off the slopes quietly in blocks, called pillow-lava.

Hydrovolcanic Eruptions: Surtseyan eruptions: These eruptions take place in shallow waters like a lake. because of this, the lava has little resistance from lack of pressure, but the cold water causes the lava rocks to shatter.

Phreatomagmatic Eruptions: Phreatomagmatic eruptions are characterized by violent steam explosions. Surface water may flow through fissures in the Earth's crust and interact with the rising magma causing the explosions. Country rocks, steam and shattered pieces magma are ejected.

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