Variety in the volcano

Variety in the volcano
Based on the history of the activity done by Volcano
 Active-These volcanoes are currently errupting or exhibiting unrest through earthquakes and other gas emissions.
 Dormant-These volcanoes are inactive, but have not been so long enough to be declared extinct.
 Extinct-These volcanoes have been inactive in all of therecorded history.

Based on the shape Volcanoes are

 Volcanic cone-These are among the simplest volcanic formations. These are built up of ejected materials around a volcanic cones are differentiated into cinder cones, spatter cones, ash cones and tuff cones. Cinder cones(Scoria cones) are built almost entirely of loose volcanic fragments called cinders. Hot fluid lava clots are called spatter. When spewed spatter falls back to the earth the clots weld together and solidify, forming steep-sided spatter cones. Fallen ash forms ash cone, which becomes a”tuff cone” or “tuff ring” once the loose ash particles weld together.
 Shield Volcano- Shield volcanoes are formed by easily flowing lava that has low viscosity. Their heights are typically about 1/20th of their widths. The lower slopes are gentle but the middle slopes become steeper and then flatten at the summit. Many of the largest volcanoes on Earth are shield volcanoes. The Mauna Loa(Hawaii) is the world’s largest shield volcano.
 Strato volcano- This is a tall, conical volcano with gentle lower slopes that rises steeply near the summit. The summit usually has a small crater. Many of the most dangerous and explosive volcanoes are stratovolcanoes. For example; Mt. Fuji (Japan), Mt. Mayon(Phillipines) and Mt. Agua(Guatemala).
Volcanic Erruptions
An erruptions begins when pressure on a magma chamber forces magma up and out the volcano’s vents. Of course, sideways- directed volcanic explosions(lateral blasts) can shoot ejected material at very high speeds for quite a distance. When magma reaches the Earht’s surface, it is called Lava. Lava may flows as gentle streams called lava flows or it may erupt violently into the air along with the lava are called pyroclastic rocks. This type of eruptions depends somewhat on the amount of gases and silica in the magma. The amount of Silica determines the viscosity of the magma. Steam is what powers the explosion.