A Guide to the Different Types of Volcanoes and Eruptions

Back in the 90s, you may remember Queen of Alternative Radio, Liz Phair, singing a song containing lyrics directed toward some unidentified person that suggested this person engaged in fornication that was analogous to a volcano.

Certainly, Phair was being kind. Do you have any idea of the power of a volcano?

The eruption of a volcano is the result of several very powerful forces of nature. You’ve got gravity, exceptionally heavy rocks, extraordinary amounts of dirt, fluctuations in temperature and pressure even greater than that experienced by a Florida politician facing the possibility of taking the state’s FCAT standardized test as a means of evaluating the ability of such an invention to accurately measure academic performance.

That pressure faced down in the volcano is placed upon parts of the earth that have been kneaded and rolled like a piece of dough for eons and eons. This material down inside the volcano is constantly folding, bending, sinking and pushing upward. The latter effect causes mountains. This terrain undergoes something akin to an earthquake which results in fissures forming way down below. The key to a volcano erupting is the molten rock down there which expands and begins flowing through those cracks. The molten material starts its journey from the crust or upper mantle of the earth and makes a trek toward the surface of the earth high above.

BOOOOOOOOOOOOOOOOOOOOM!

An interesting element in the formation of a volcano is the cinder cone. A cinder cone can most effectively be described as a small volcano created from the debris of lava and other explosive material that has built up around the vent of a volcano following every eruption. Fearful symmetry is the keystone of the cinder cone. Prepare for aching bones if you plan on climbing up the steep slope of a cinder cone as you can potentially be directing your path toward an angle that can reach 30 degrees. As you might expect from the name, the construction of these cones is made from loose cinders, but they don’t typically fall apart like the end of a cigarette left alone to burn too long. The cone shape of these structures are capable of being held in place partly as a result of rainfall submerging into the cone instead of dribbling down the side and causing erosion. One of the most famous examples of a cinder cone volcano is Sunset Crater in Arizona.

Another type of volcano cone is described as composite. A composite cone is constructed as a result of each layer of lava flow building up on top of the previous layer. In addition to lava, these layers contain ash and even cinders. The composite cone type of volcano can tower over the surrounding countryside like Jack Nicholson towering over his fellow actors in “The Departed.” Some composite cones reach as high as 8000 feet. The next time you see a perfectly formed mountain capped with snow, check it out to see if it qualifies as a composite cone volcano.


When Liz was singing about her lover doing the nasty like a volcano, she may have been referring to a Pelean eruption, or a Vulcanian eruption or a Hawaii type eruption. Or maybe she was referring to a Strombolian type of eruption. Perhaps Phair actually mean to describe an Icelandic type eruption? You might not have realized that not all volcanoes erupt in the same manner. I won’t bore you with all the details and, besides, I’m ready to bring this article an end, but here are a few of the differences. The Pelean eruption is the one that dramatically fires the innards of the volcano into a high, heated cloud. A vertical column of pumice and ash describes the look of a Vulcanian eruption. The Strombolian eruption looks like an Italian turnover. No, seriously, the Strombolian eruption features a series of mildly powerful explosions that produce thick lumpy lava and white steam. The Hawaii type of eruption means long, dense streams of lava flowing quickly down the sides. Icelandic eruptions spews out molten material from a series of cracks and fissures that may extend for miles.


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