Volcano FactsHot! Fire! Destruction! These are words that mostpeople associate with volcanoes. But some good effects cancome out of volcanoes.
Volcanoes also have their ownspecial mythology associated with them. A lot of volcanoeshave some general characteristics in common. There are manyvolcanoes around the world and some have specialcharacteristics. So come along and take a trip with me intothe wonderful and exciting world of volcanoes.Over 550 volcanoes have erupted on the surface of theEarth since human kind has been able to record history. Their destructiveness has claimed the lives of over 200,000people during the last 500 years with 26,000 deaths between1980 and 1990 alone. They have also cause an innumerableamount of property damage.
The biggest eruption of the twentieth century was theeruption of Novarupta on the peninsula of Alaska. Theamount of lava that erupted measured to roughly 15 cubickilometers! All of the lava erupted equaled to the amountof 30 times the amount of lava that came from Mount SaintHelens and it is also the equivalent of 230 years oferuptions at Mount Kilauea. The eruption lasted for 60hours on June 6, 1920.
The biggest eruption, despite its size, was not themost destructive, for the most destructive was the eruptionof Mount Saint Helens in Oregon during the week of May 18th,1980. This eruption mainly caused just loss of property,because many people didnt expect the volcano to erupt. Although some people did die, this volcano was kind of weakcompared to the size of the eruption and amount of liveslost in other eruptions like Tambora, Indonesia in 1815where 92,000 people died.Despite all of these bad effects, some life stillshines through these tragedies. For example the ash that avolcano spews out covers many square miles of plants andtrees. This holds in water and waters plants. The ash alsocontains many nutrients that plants use.
A little more than80 percent of the Earths surface is volcanic in origin,meaning that most of the Earths surface was formed byvolcanoes. Also, magma deposits heat water undergroundwhich produces geothermal energy.The word volcano comes from an island off of the coastof Sicily called Vulcano. The people of Sicily thought thatthe clouds of dust and spurts of lava were made from Vulcan,the blacksmith for the Roman Gods. They believed thatVulcan forged thunderbolts for Zeus and weapons for Mars onthat island.Out of the 550 of the worlds active volcanoes, theworlds largest active volcano is Mauna Loa, it is one ofthe Hawaiian islands.
The island protrudes around 13,677feet above sea level; while the whole island was formed byan underwater volcano, this brings it 28,000 feet above theocean floor where it started. From the base underwater tothe summit above water, this volcano stands higher thanMount Everest.There are two main types of volcanoes out there in theworld today, the first is felsic, and the second is mafic. Felsic volcanoes have a high silica content and a lightcolor to the lava. The second, mafic, has just theopposite, a low silica content and a darker color.
Then there are underwater volcanoes and above groundvolcanoes. The underwater volcanoes are less known aboutthan above ground for the obvious reason that they are seenwhen they are above ground. Underwater volcanoes producesome things called black smokers, they are basically justash as well as black smoke that combine and heat up water toboiling temperatures. An interesting fact about underwatervolcanoes is that some islands have been formed by lavaeruptions building up year after year. An island chain thatis very well known that has been formed by this process isthe chain of the Hawaiian Island chain.
This chain alsoincludes the worlds largest volcano, Mauna Lao, which, whenyou count the amount underwater and the amount above wateris taller than Mount Everest.Some volcanoes have been found in our solar system thatare not on the planet Earth. One volcano, which is thelargest one in our solar system, is Mount Olympus Mons onthe planet Mars. This is the only volcano found on theplanet mars. There are also numerous volcanoes found on Io,a moon of the planet Jupiter. These volcanoes also showthat some plate tectonics on Io, even though no platetectonics is believed to have occurred on Mars.Volcanoes form when magma, melted rock underground (itis called lava when it reaches the surface) (most of itforms around 50 to 100 miles underground), when the magmamixes with gas and rises, pressure builds against thesurface, the magma breaks through and you get a volcano.
Shield volcanoes form when a lot of lava spills out ofa vent and goes in a broad, flatter area. Another type ofdifferent volcano is a cinder cone. Cinder cones are madewhen tephra, thick globs of magma, erupts from a vent in theground and comes back down then accumulates.
A famous oneis Paricutn in western Mexico. It started to form in 1943in the middle of a farmers corn field, then it started tostop in 1952. When it was finished, the cinder cone was1,345 feet higher than the base. Then there are compositevolcanoes which form when tephra and lava erupt from thesame vent. One example of this is Pompeii and Japans MountFuji.When all of the magma is drained out of the chambers ofthe volcanoes, called magma chambers, sometimes the volcanocant support itself and collapses, this leaves a cratercalled a caldera.
So, I hope that you have learned about some specificvolcanoes as well as the properties that go along with them(even if they are bad). I also hope that you found out thatvolcanoes arent all that bad.Sources:World Book Encyclopedia, Book U-V, pg.462-pg.467Internethttp://vulcan.wr.usgs.gov/LinvingWithVolcanoes/Facts/misc_volcanic_facts.htmlhttp://volcano.und.edu/vwdocs/vw_hyperexchange/deadly_volcs.htmlhttp://volcano.und.edu/vwdocs/eruption_scale.htmlhttp://infoplease.lycos.com/ipa/A0001746.html