When volcanoes erupt different materials spew out. Each volcano has their very own style of eruption. The reason volcanoes have different eruptions is the result of the difference in magma that the volcanoes contain. The magma is low in gas and silica (silicon dioxide, a compund found widely in rocks and minerals) yields a gentle flow of thin, quickly spreading lava. Magma that is rich in gas and silica will cause a violent explosion; the thick, tarlike magma may plug up the volcanic vent, blocking the upward movement of the magma until built-up pressure which blows away the overlying rock. There are four main forms or phases that geologists classify volcanic eruptions and they are: Hawaiian, Strombolian, Vulcanian, and Peleean.
Hawaiian Phase
In this phase, runny lava gushes out in a fountain without any explosive eruptions.
Strombolian Phase
In this phase (which got its name after Stromboli volcano on an island north of Sicily), thich lava is emitted in a continuous but mild explosion. The lava arcs and steam-driven clouds of ash shower the dome with molten drizzle.
Vulcanian Phase
In this phase it occurs when the magma plug has blocked the volcanic vent. The explosion erupts and hurls tons of almost solid magma into the sky, and a vapor cloud will form over the crater.
Peleean Phase
This is the most violent eruption of a volcano. Fine ash, thick lava, and glowing, gas-charged clouds are emitted, traveling downhill at a high rate of speed. Fierce rains often accompany eruptions because of the release of steam from the volcano, which will then condense on the atmosphere to form clouds. Volatile gases and magma will fly into the atmosphere when the eruption takes place. The gases that are released include hydrogen sulfide, fluorine, carbon dioxide, and radon. After the gases are released a dense wave of ash, superheated gases, and rock will move the fluid from the volcano, which is known as a pyroclastic flow. This type of flow traves at a high speed and reaches more than 60 miles per hour, which causes the valleys to fill with the fluid mixture. This material will deflate as it cools down. Ignimbrite which is the rock formation that is a result of the eruption, and the rocks that fuse together are called tuff. Ignimbrites can cover hundreds of square miles.
Hawaiian Phase
In this phase, runny lava gushes out in a fountain without any explosive eruptions.
Strombolian Phase
In this phase (which got its name after Stromboli volcano on an island north of Sicily), thich lava is emitted in a continuous but mild explosion. The lava arcs and steam-driven clouds of ash shower the dome with molten drizzle.
Vulcanian Phase
In this phase it occurs when the magma plug has blocked the volcanic vent. The explosion erupts and hurls tons of almost solid magma into the sky, and a vapor cloud will form over the crater.
Peleean Phase
This is the most violent eruption of a volcano. Fine ash, thick lava, and glowing, gas-charged clouds are emitted, traveling downhill at a high rate of speed. Fierce rains often accompany eruptions because of the release of steam from the volcano, which will then condense on the atmosphere to form clouds. Volatile gases and magma will fly into the atmosphere when the eruption takes place. The gases that are released include hydrogen sulfide, fluorine, carbon dioxide, and radon. After the gases are released a dense wave of ash, superheated gases, and rock will move the fluid from the volcano, which is known as a pyroclastic flow. This type of flow traves at a high speed and reaches more than 60 miles per hour, which causes the valleys to fill with the fluid mixture. This material will deflate as it cools down. Ignimbrite which is the rock formation that is a result of the eruption, and the rocks that fuse together are called tuff. Ignimbrites can cover hundreds of square miles.