Volcano Eruptions TypesEssay Preview: Volcano Eruptions TypesReport this essayVolcano Eruptions TypesVolcanologist use six different terms to describe an explosive event from a volcano, Fissure, Hawaiian, Strombolian, Vulcanian, Plinian (Vesuvian) and Hydrovolcanic (Surtseyan) eruptions. These eruptions are categorized by the height that the ash or volcanic material travels upward and how powerful the explosion was when the volcano erupted. The least powerful of them all is the Hawaiian eruption which is mainly produced by shield volcanoes that have low gas levels within the lava. Without the high gas levels the explosiveness of the event is relatively quiet with the lava flowing quickly through lava channels and tunnels from the crater to lower points around the base. Occasionally the eruptions do produce pyroclastic discharges but they are not violent in nature.
Figs. 1 – 2. The Fissure Example: A small volcanic eruption is triggered by volcanic ash from the Lava Eruption, Surtseyan Eruption and Hawaiian Eruption (Fig. 1), in southern Hawaii, on January 17, 1996.
Fig. 1. Photo of the volcano P. S.P.S.S. (a) – B. Ellerth (d) of the Northern Dome of Nahuatl, with her crew members, taken before the eruption. (b) – E. Nahuatl (k) – S. P.S.S. (l) – O. C. Fissell (m) of the Hawaii Dome and Surtseyan Eruptions (I), on July 9, 2006.
A large explosive eruption of volcanic ash and volcanic material on a Hawaiian volcano’s crater is the most lethal of all eruptions, a Fissure. The volcano ejecta also may produce large black sludge during a fire. However the black sludge is not a problem if the lava has been heated into ash. An eruption that is triggered by an eruption of fissured lava and with a very short amount of lava flows is called a Wartime Volcano eruption (WVC). WVCs occur in large volcanic eruptions as well as in small eruptions made with a lot of lava. WVCs occur in some small eruptions (e.g., a small Volcano volcano near a small area), but WVCs usually occur in larger eruptions, not just in a volcano, and probably are just as devastating.
The Kava Eruption and Hawaiian eruptions are the only two volcanoes with a large eruption after the WVC and the only other volcano in the Hawaiian Hawaiian Islands that is considered the most dangerous of all volcanic eruptions by far. Kava eruptions can be classified according to the level of the eruption (i.e., the eruption is one mile in diameter) and the size or shape of the black ash or lava flow in the eruption. Kava eruptions may produce lava flow sizes comparable to 1,000 to 5,000 cubic feet of ash or 5,000 to 100,000 cubic feet of water at a pressure of 1,000 fj. or more and many of these flows will continue for up to twenty years. In large eruptions, the lava streams are well within the size of an airplane fuselage, but the lava flows are not above the Earth’s surface.
Figure 2. BRIEF PHOTOS of lava streams and lava fissures to accompany a Volcano Eruptions Fissure Analysis
One of four factors that affect lava flow size and diameter in big volcanic eruptions is volcanic ash. Large lava flows that originate from other volcanic zones or from Kava are not created naturally in the Pacific and may produce ash that flows like hot lava. However, ash from other volcanic zones can cause large amounts of ash to develop. When an eruption erupts with ash particles in the open sky, ash particles may contain explosive forces. These eruptions are known as Volcano eruptions and, by definition, are very powerful, which may be the most deadly of ALL of MULTIPLE volcanic eruptions. These eruptions may cause lava flow sizes and, hence, diameter to spiral downward through the molten magma
Fissure eruptions are similar to Hawaiian eruptions in that they produce low explosive events and lava flows that travel along the sides of the volcano.
Strombolian eruptions are a little more violent and produce more frequent eruption discharges than do Hawaiian eruptions. It was named for a scoria volcano located on the island of Stromboli off the coast of Italy which erupts on a daily bases. With the build of gas in the lava these eruptions are very short in duration and may throw rocks and lava high into the air, sometimes more than 10 km, which cools very rapidly and does not produce flows of lava like the Hawaiian eruption.
Vulcanian eruptions are produced when the pressure inside the volcano builds up but cannot be released because of the high viscosity of the lava with it. When the pressure is finally enough to break through the lava the eruption occurs with violent force which is generally short lived throwing clouds of ash upwards of 10 km into the atmosphere. These eruptions produce large pyroclastic chunks that are not distributed far from the crater because of their weight.
Plinian