An Analysis of Volcanoes: Formation, Eruption, and Global Hazards

This essay provides an overview of the nature of volcanoes, detailing their formation processes and eruption dynamics. Volcanoes are formed at geographical ruptures within the earth's crust due to hot temperatures and pressure, which drive magma out through vents. The earth's crust consists of tectonic plates, and volcanoes commonly form at their meeting points where friction causes rocks to melt into magma. This magma builds pressure, eventually finding its way to the surface as lava. While approximately 1500 volcanoes are active worldwide, most volcanic activity occurs at divergent plate boundaries at the bottom of the oceans or at subduction zones. The essay also includes a table with data on recognized volcanic eruptions, listing their dates, locations, and other details. The data includes information on the Pinatubo, Hudson Cerro, El Chicon, St Helens and Agung volcanoes.

NATURE OF VOLCANOES
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How Volcanoes are Built
A volcano refers to a geographical rupture within the interior of the crust of the earth that is
triggered by natural forces. The forces that are commonly involved include the hot temperatures
and pressure in the interior of the earth. These forces are known to have effects of driving the
gases and the hot liquid called magma out of the orifice of the volcanoes called vent(Sparks,
Biggs and Neuberg 2012).
Formation of volcanoes
The crust o the earth is made up of several sections of the rocks called tectonic plates. These
plates normally resemble the puzzle pieces that are known to be in constant motion towards each
other. The formation of the volcanoes is common on the meeting sections of these plates. The
crust of the earth undergoes melting as a result of the friction of the plates that are in contact.
This friction makes the rocks underneath to melt and change into the magma as a result of the
high temperatures.
Figure 1: Plate Tectonics extracted from (Sigurdsson, Houghton, McNutt, Rymer and Stix 2015)
The molten magma results into the increase in the pressure and as time go the pressure builds up.
The built-up pressure finally finds its way through the fractures of in the plates. Upon reaching

the surface of the earth, the magma is now called lava. Nearly 1500 volcanoes in the whole
world are considered active
Majority of the divergent boundaries of the plates are found at the bottom of the oceans. This
explains why most of the activities of volcanic eruption take place within the ocean. Also,
volcanoes may be formed at the zones of the subduction. A subduction refers to a meeting point
of a continental plate and an oceanic plate. In this case, the oceanic plate submerges below the
continental plate. The friction that is present generates magma. A volcano is formed upon this
magma reaching the surface.
Figure 2: Parts of a volcano extracted from(Bolt, Horn, MacDonald and Scott 2013)

Data on the recognized volcanic eruptions with their dates and locations
Volcano Location Date VEI Tephra(KM2)
Pinatubo Philippines 1991 6 11
Hudson Cerro Chile 1991 5 4.4
El Chicon Mexico 1982 5 2.3
St Helens Washington 1980 5 1.2
Agung Indonesia 1963 5 1
Table 1: Data on volcanoes extracted from (Burton, Sawyer and Granieri 2013)

REFERENCES
Bolt, B.A., Horn, W.L., MacDonald, G.A. and Scott, R.F., 2013. Geological Hazards:
Earthquakes-tsunamis-volcanoes-avalanches-landslides-floods. Springer Science & Business
Media.
Burton, M.R., Sawyer, G.M. and Granieri, D., 2013. Deep carbon emissions from
volcanoes. Reviews in Mineralogy and Geochemistry, 75(1), pp.323-354.
Sigurdsson, H., Houghton, B., McNutt, S., Rymer, H. and Stix, J. eds., 2015. The encyclopedia
of volcanoes. Elsevier.
Sparks, R.S.J., Biggs, J. and Neuberg, J.W., 2012. Monitoring volcanoes. Science, 335(6074),
pp.1310-1311.