Abstract
For centuries, people across different civilizations had been terrified by the display of power that volcanic eruptions present, and they interpreted them as a sign of wrath and vengeance of gods. Clearly, with the progress of the modern science, volcanoes have been demystified; particularly, the development of the plate tectonics theory in the 1960s has played a major role in helping people understand volcanoes. The purpose of the present paper is thus to analyze volcanoes as a natural phenomenon. The first section provides an overview of the features that define a volcano while the second part considers the processes that take place in the Earth’s surface and shape the planet’s volcanic activity. The third and the fourth sections identify the different scientific and popular classifications of volcanoes, and the final part of the paper considers the impact of eruptions both on humans and the environment. The main conclusion is that the processes that create volcanos are so grand and complex that people still have little power to control and mitigate the impact of volcanic eruptions.
Main
Volcanoes are arguably one of the most powerful and awe-inspiring naturally occurring phenomena. Even given the current advances in science and technology, people have little power and control over the volcanic eruptions, apart from the fact that they have learned how to predict them. The present paper analyzes the science behind volcanoes with the purpose of discovering what makes them so powerful over human activities and even lives.
Phenomenon of Volcanoes
Volcanoes are a naturally occurring phenomenon that are, essentially, a byproduct of the movement of the seventeen tectonic plates that make up the surface of the Earth (Environmental Literacy Council, 2007, p. 6). It is typical to think of volcanoes as cone-shaped mountains that have an opening – a crater – on top of it and that release fire, gas, and lava. In fact, the very name of this phenomenon comes from the name of the Roman god of fire, Vulcan (Lockwood & Hazlett, 2010). While conical volcanoes are, indeed, one of the most frequently occurring types, it is far from being the only one. Essentially, what defines a volcano is not its shape or even the fire and lava that come out of it, but its structural characteristics (Environmental Literacy Council, 2007, p. 6). Volcanoes are, first and foremost, ruptures on the surface of a planet, and, as such, they can take any forms, including that of flat fractures (Hone, Mahony, Sparks & Martin, 2007, p. 204). Moreover, volcanoes are typical not only for the Earth but also to other planetary bodies such as Venus, Mars, and the Earth’s and Jupiter’s moons (Lockwood & Hazlett, 2010). The second defining characteristic is the volcano’s ability to release the planet’s magma, which is essentially hot molten rock (Environmental Literacy Council, 2007, p. 6). This process is known as a volcano eruption.
Plate Tectonics and Volcanoes
The central concept related to understanding the phenomenon of volcanoes is the theory of plate tectonics (Gabrieli, Wilson & Lane, 2015). The surface of the Earth is made up of seventeen rigid tectonic plates. Even though the plates themselves are hard, they tend to move and float because they are situated on the Earth’s mantle – a hot and soft layer underneath the plates (Environmental Literacy Council, 2007, p. 6). As the tectonic plates move around, they tend to either converge or diverge, and it is precisely this process that leads to the appearance of volcanoes. On top of that, the Earth’s mantle, because of its extremely hot conditions, has the ability to melt rock and turn it into a thick yet fluid substance called magma (Environmental Literacy Council, 2007, p. 6). This substance is stored in the so-called magma chambers – large pools of magma underneath the Earth’s surface that have high internal pressure. However, as the tectonic plates slide and collide with one another, they disrupt the conditions within the magma chambers, causing the magma to rise and escape through the volcano’s crater (Environmental Literacy Council, 2007, p. 7).
Types of Volcanoes
While there is no one universally accepted typology of volcanoes, generally, they are classified on the basis of their size and morphological characteristics (Hone et al., 2007, p. 203). For instance, fissure vents and shield volcanoes have been identified, with the former being flat fractures in the Earth’s surface and the latter being broad-profiled volcanoes. Volcanic cones are arguably the most widely known type since this is the shape that is typically associated with volcanoes. While shield volcanoes are broad at base, stratovolcanoes are the exact opposite to them, as they represent tall cone-shaped structures that have been formed as a result of several eruptions (Lockwood & Hazlett, 2010). Thus, the primary difference between these three types is their shape and height. Another widely studied type is the super volcanoes with large-sized calderas. Because of their size, these volcanoes can produce devastating effects, even at a continental scale. An eruption of such a volcano can significantly impact the Earth’s atmosphere and cool down the planet’s average temperature (Lockwood & Hazlett, 2010). Another common type is the submarine volcanoes that, as their name suggests, can be found on the bottom of the oceans’ floor. In fact, most of the Earth’s volcanoes are located underneath the water’s surface, so submarine volcanoes are among the most frequently occurring kind. However, the list of types mentioned here is not exhaustive since different features can be used as the basis for classification.
Popular Classification of Volcanoes
The present section is dedicated to exploring one of the most commonly used classifications of volcanoes that is based on their level of volcanic activity. According to this classification, volcanoes can be grouped into active, dormant, and extinct (Lockwood & Hazlett, 2010). While this classification is quite popular, especially in the wider circles, it is considered to be rather problematic in the scientific community. Assigning a certain volcano into one of these categories requires an assessment of the frequency of its eruption. However, the processes that create volcanoes and make them erupt are so complex and grand that it is meaningless to measure them against the lifespan of not only individual humans but even the humankind in general. The least controversial of these categories is the extinct volcanoes because they are defined as such on a comparatively objective basis. Extinct volcanoes are highly unlikely to erupt again because they have exhausted their magma supply (Lockwood & Hazlett, 2010). However, distinguishing between active and dormant volcanoes is a much more difficult task, mainly because the life cycle of a volcano can span across thousands and even millions of years. The prevalent rule is that a volcano is considered dormant if there are no written records of its activity.
Effects of Volcanic Eruptions
Volcanic eruptions present quite a spectacle that, given their devastating capacity, few people would like to witness first-hand. However, the negative effects of volcanic eruptions can also extend far beyond their physical impact. First of all, being tectonic creations, volcanoes are closely linked to earthquakes because of their mechanism of occurrence (Gabrieli, Wilson & Lane, 2015). Apart from that, volcanic eruptions result in the emissions of several gases, such as carbon dioxide, sulfur dioxide, and hydrogen sulfide, to name a few. A high concentration of such gases can have a devastating impact on the agriculture and farming. Moreover, it can also cause acid rains in the affected areas. Secondly, most volcanic eruptions are accompanied with ash plumes resulting from the extremely hot temperatures in and around the volcanoes. Consequently, eruptions may cause a major disturbance in the air traffic as flying under such conditions clearly becomes impossible (Picquout et al., 2013). A moderate amount of ashes can, in fact, be beneficial to the environment because of the problem of climate change: the resulting dust may help mitigate global warming by enhancing the Earth’s albedo potential (Adam, 2010). However, in other cases, ash plumes can be dangerous, and they even have the potential to lead to a volcanic winter.
Conclusion
People have certainly come a long way as far as their ability to comprehend natural phenomena is concerned. Volcanic eruptions, just like tsunamis and earthquakes, tend to be significantly devastating to humans, yet scientific knowledge reveals that there is little that people can do to mitigate their impact. These days, people know that volcanic eruptions are not an act of wrath committed by an angry god; nevertheless, the processes behind volcanoes are so grand that, in comparison to the human lifespan, they may as well be deemed supernatural.
References
Adam, D. (2010). Volcanic eruptions and ash clouds explained. Web.
Environmental Literacy Council. (2007). Earthquakes, volcanoes, and tsunamis. Web.
Gabrieli, A., Wilson, L., & Lane, S. (2015). Volcano–tectonic interactions as triggers of volcanic eruptions. Proceedings of the Geologists’ Association, 126(6), 675-682.
Hone, D. W., E., Mahony, S. H., Sparks, R. S., J., & Martin, K. T. (2007). Cladistic analysis applied to the classification of volcanoes. Bulletin of Volcanology, 70(2), 203-220.
Lockwood, J.P., & Hazlett, R.W. (2010). Volcanoes: Global perspectives. Hoboken, NJ: John Wiley and Sons.
Picquout, A., Lavigne, F., Mei, E.T.W., Grancher, D., Noer, C., Vidal, C.M., & Hadmoko, D.S. (2013). Air traffic disturbance due to the 2010 Merapi volcano eruption. Journal of Volcanology and Geothermal Research, 261, 366-375.