Volcanic eruption

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Description or situation

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Overview

There are about 1500 potentially active volcanoes worldwide, aside from the continuous belt of volcanoes on the ocean floor. Many of these are located along the Pacific Rim in what is known as the "Ring of Fire." According to the USGS there are almost 70 active volcanoes in the United States alone. This is far more than enough to justify concern. Volcanic activity is a natural occurring process which happens regularly on planet earth. This process occurs in such a way that it often goes unnoticed by the majority of earths inhabitants. It is a process of venting which occurs in areas that resemble cuts and tears in the earths crust. These cuts and tears are in locations that are typically hidden from exposing extreme levels of action or noticeable results. Volcanic activity is often minuscule in its entirety as a result of the frequency of venting and release of pressure from these areas. Materials spewed during volcanic activity is for the most part a slow process as long as this release of pressure is consistent. Just the same can be said for those areas around the edges of tectonic plates which allow adjustments for release of similar pressures.

Other areas of earth known to expel contents associated with volcanic activity are more evident and visible than the previously mentioned. They are commonly known as as "Volcanoes" and are apparent as large mountain peaks on the surface of the earth. They generally stand in view as a singular entity resembling a massive ant hill. During those times when the inner earths pressure is not being released on a regular basis the potential exists for pressure to build up resulting in an explosive event. Volcanoes are usually the place where this happens. Explosions as such have been known to devastate regions of earth often changing nearby geography and extinguishing life forms. Volcanoes have been known to destroy societies and populated regions within moments. The effects of an explosive super volcano is suspected as having the capability to reach across vast regions of the  planet impacting all life forms as well. These are often speculated as potential extinction level events.

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The following is intended to aid those seeking information related to the effects and consequences associated with "volcanic activity"

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What is volcanic eruption?

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A volcanic eruption for the most part is an overflowing or explosive event in which planetary gases, ash and molten rock are released out of an area originating from below the earths surface. In this reference a volcanic eruption pertains to a circumstance that is monumental in scope and size. It is an event which can most often be seen and experienced for hundreds of miles away from it's point of origin. It is typically a situation which humans should avoid being near when it occurs. Volcanic eruptions are suspected as having the potential to cause extinction level environments on plant earth.

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Types of eruptions

Several types of volcanic eruptions—during which lava, tephra (ash, lapilli, volcanic bombs and blocks), and assorted gases are expelled from a volcanic vent or fissure have been distinguished by volcanologists. These are often named after famous volcanoes where that type of behavior has been observed. Some volcanoes may exhibit only one characteristic type of eruption during a period of activity, while others may display an entire sequence of types all in one eruptive series.

There are three different types of eruptions. The most well-observed are magmatic eruptions, which involve the decompression of gas within magma that propels it forward. Phreatomagmatic eruptions are another type of volcanic eruption, driven by the compression of gas within magma, the direct opposite of the process powering magmatic activity. The third eruptive type is the phreatic eruption, which is driven by the super-heating of steam via contact with magma, these eruptive types often exhibit no magmatic release, instead causing the granulation of existing rock.

Within these wide-defining eruptive types are several sub-types. The weakest are Hawaiian and submarine, then Strombolian, followed by Vulcanian and Surtseyan. The stronger eruptive types are Pelean eruptions, followed by Plinian eruptions, the strongest eruptions are called "Ultra Plinian." Subglacial and phreatic eruptions are defined by their eruptive mechanism, and vary in strength. An important measure of eruptive strength is Volcanic Explosivity Index (VEI), an order of magnitude scale ranging from 0 to 8 that often correlates to eruptive types.  [Source]

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What causes a volcanic eruption?

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As rock inside the earth melts, its mass remains the same while its volume increases--producing a melt that is less dense than the surrounding rock. This lighter magma then rises toward the surface by virtue of its buoyancy. If the density of the magma between the zone of its generation and the surface is less than that of the surrounding and overlying rocks, the magma reaches the surface and erupts.

Magma of so-called andesitic and rhyolitic compositions also contain dissolved volatility's such as water, sulfur dioxide and carbon dioxide. Experiments have shown that the amount of a dissolved gas in magma (its solubility) at atmospheric pressure is zero, but rises with increasing pressure.

For example, in an andesitic magma saturated with water and six kilometers below the surface, about 5 percent of its weight is dissolved water. As this magma moves toward the surface, the solubility of the water in the magma decreases, and so the excess water separates from the magma in the form of bubbles. As the magma moves closer to the surface, more and more water exsolve's from the magma, thereby increasing the gas/magma ratio in the conduit. When the volume of bubbles reaches about 75 percent, the magma disintegrates to pyroclast's (partially molten and solid fragments) and erupts explosively.  [Source]

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What are the effects of a volcanic eruption?

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A volcano eruption is one of the most impressive and frightening events on the planet. The effects of volcanoes and their eruptions can often be felt as far away as other continents. The type of effects from volcanoes depends on the size of the eruption. Some volcanoes can erupt and not cause much damage while others are so massive that should they erupt they could trigger a world wide catastrophe. So what type of disturbances would we see if there were a massive eruption today? To answer that question we need to be clear about the type of volcano that we are talking about. Volcanic eruptions are measured in what is called (VEI) or Volcano Explosivity Index  which can reach the most powerful eruption of a VEI-8.

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Explosive Eruptions

If there were an explosive eruption in your area the effects could be devastating. During an explosive eruption type event a volcano will spew lava, magma and other materials which could travel several miles away from the point of origin. The explosiveness of the eruption could also cause pyroclastic flows which would destroy anything within its path. The ash emitted could cause damage to buildings and structures depending on the amount of ash. In addition property damage are those negative attributes associated with health concerns such as what happens when we breathe in volcanic ash. An explosive eruption is believed as having the potential to cause a blast wave similar to those associated with a nuclear detonation.

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Effects On Cities And Towns

Volcanic eruptions can have severe effects on populated regions and the supporting infrastructure associated with those areas. Most all life forms, ... which encompass just about everything, ... have a tendency to become displaced, ... experience health difficulties and/or perish as a result of nearby volcanic activity. This sort of calamity can be unfortunate for densely populated areas such as with cities, towns and villages built near the basin of a volcano.. The first set of conditions effecting areas as such is the blast itself and the pyroclastic flow racing down the mountain. Cities and towns built at or near the base of a volcanic mountain can certainly experience the effects similar to the detonation of a massive bomb. Explosive blasts from volcanoes have been known to wipe out entire cities and cultures. On some occasions these conditions are not as dramatic due to the direction of flow and primary path of the explosion. The majority of natural forces may occur on the other side of the mountain alleviating immediate risks to residence and businesses. In any case, ... the degree of destruction is contingent upon the category and explosive values.   [Explosive index]

Volcanic explosions have a tendency to rumble the ground like an earthquake which is yet another instant effect that can be experienced by local inhabitants. That in itself can cause damage and bodily injury due to items falling off shelves, ... breaking glass or collapsing structures. If a town and its inhabitants manage to survive the initial impacts of a volcanic explosion than they will most likely have to deal with a secondary set of issues and concerns.

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The secondary effects for populated regions are largely contingent upon how much and what types of material and debris is being ejected and the force behind the explosion. If a city or town survives an initial blast from a volcanic explosion it must often contend with some potential after effects such as falling ash, lava flow, poison gases & mud flows.

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»   Volcanic ash is generally abrasive and bad for populated regions. Due to its wide dispersal, ash can have a number of impacts on society, including human and animal health, disruption to aviation, disruption to critical infrastructure (e.g., electric power supply systems, telecommunications, water and waste-water networks, transportation), primary industries (e.g., agriculture), buildings and structures.Volcanic ash can fall from the sky such as with snow and may continue to fall until it immobilizes people, animals and machines. Combined with rain or water volcanic ash can become similar to cement.

»  Lava flow is another issue to contend with flowing an explosive event. Lava is a diverse material in which its characteristics of flow rate are largely dependent upon the actual composition of the material and it's temperature. Nothing survives the flow of molten rock. Lava flows have been know to destroy or divide cities and town in half. Lava eats steel, metal wood and all life forms and vaporizes water.

»  Volcanic gases also present a degree of hazards for most all life forms near an explosive event. Volcanic gases were directly responsible for approximately 3% of all volcano-related deaths of humans between 1900 and 1986. Some volcanic gases kill by acidic corrosion, others kill by asphyxiation. The greenhouse gas, carbon dioxide, is emitted from volcanoes, accounting for nearly 1% of the annual global total. Some volcanic gases including sulfur dioxide, hydrogen chloride, hydrogen sulfide and hydrogen fluoride react with other atmospheric particles to form aerosols.

»   Mud and debris flows are some of the most frightening to imagine. The name given to such an event when associated with volcanic activity is called Lahar. A lahar is a volcanic mudflow or debris flow. Lahars have the consistency, viscosity and approximate density of wet concrete: fluid when moving, solid at rest. Lahars can be huge. The Osceola lahar produced by Mount Rainier, (Washington), some 5,600 years ago resulted in a wall of mud 140 meters (460 ft) deep in the White River canyon, which covered an area of over 330 square kilometers (130 sq mi), for a total volume of 2.3 cubic kilometers (0.55 cu mi). A lahar of sufficient size and intensity can erase virtually any structure in its path, and is capable of carving its own pathway, making the prediction of its course difficult. Conversely, a Lahar quickly loses force when it leaves the channel of its flow: even frail huts may remain standing, while at the same time being buried to the roof line in mud. A lahar's viscosity decreases with time, and can be further thinned by rain, but it nevertheless solidifies quickly when coming to a stop. Lahars vary in size and speed. Small lahars less than a few meters wide and several centimeters deep may flow a few meters per second. Large lahars hundreds of meters wide and tens of meters deep can flow several tens of meters per second (22 mph or more): much too fast for people to outrun.With the potential to flow at speeds up to 100 kilometers per hour (60 mph), and flow distances of more than 300 kilometers (190 mi), a lahar can cause catastrophic destruction in its path.

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Effects on humans and animal life

In addition to the previously mentioned there are effects associated with long term exposure to volcanic fumes which may create or aggravate existing respiratory problems. It may also cause headaches and fatigue in typically healthy people. Water supplies may become contaminated with various byproducts associated with volcanic activity result in adverse health conditions. Just the same applies to consumable vegetation and plant life which may absorb unwanted substances and materials which are also not conducive for a healthy existence to humans or animals.

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Effects on the environment

There are several aspects associated with the impacts that a volcano has on the environment. Even smaller eruptions can have a considerable impact. Surrounding environments can be effected by exposure to any of the known gases associated with volcanic activity which can be released during such events. Some of the gases which are released into the air include carbon monoxide, carbon dioxide, sulfur dioxide, fluorine, chlorine, hydrogen sulfide and more. This simply means that air may become saturated with chemicals which are known to harm people, animals and vegetation. Impact zones are contingent upon weather patterns and wind direction for disbursement of these gases and materials.

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 Impacts to aircraft, ocean transportation and machinery

Aircraft and planes

Aircraft are some of the things that are effected by explosive volcanoes. Plumes of volcanic ash near active volcanoes are an aviation safety hazard, especially for night flights. Volcanic ash is hard and abrasive, and can quickly cause significant wear to propellers and turbocompressor blades, and scratch cockpit windows, impairing visibility. The ash contaminates fuel and water systems, can jam gears, and make engines flameout. Its particles have low melting point, so they melt in the combustion chamber and the ceramic mass then sticks to turbine blades, fuel nozzles, and combustors which can lead to total engine failure. Ash can also contaminate the cabin and damage avionics.    [Source]

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Maritime impacts of volcanic eruptions

Until more recently public focus has mainly been on effects on aviation effects—ash, which can be undetectable, can cause an aircraft's engine to cut out with catastrophic potential. However, the July 2008 eruption of Okmok Volcano in Alaska triggered attention to the maritime effects. Employees at the National Weather Service Ocean Prediction Center's Ocean Applications Branch examined this event and partnered with the Alaska Volcano Observatory to compile information on the topic.

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Ash can affect marine transportation in many ways

Volcanic ash can clog air intake filters in a matter of minutes, crippling airflow to vital machinery. Ash particles are very abrasive and, if they get into an engine's moving parts, can cause severe damage very quickly. Water is the main component in volcanic eruptions; it is what makes them so explosive. Through chemical reactions, toxic gases that are released in eruptions can bond or adsorb to ash-fall particles. As the particles land on skin, metal, or other exposed shipboard equipment, they can begin to corrode. Certain types of volcanic ash do not dissolve easily in water. Instead, they clump on the surface of the ocean in pumice rafts. These rafts can clog salt water intake strainers very quickly, which can result in overheating of shipboard machinery dependent on sea water service cooling. Heavy amounts of volcanic ash reduce visibility to less than ½ mi, which is a hazard to navigation. This, combined with the above three other main impacts make sailing in the vicinity of volcanic ash very dangerous for mariners.  [Source]

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Effects of super volcanoes

Lets face it, .... The eruption of what is referred to as a "Super Volcano" is one of those situations that is suspected of having the potential to become an extinction level event. (ELE).  [Source 1] , [Source 2] , [Source 3] , [Source 4]

Topping the Volcanic Explosivity Index at level 8, super-volcanoes are exceptionally violent, ejecting volumes of ash, magma and rock tens to hundreds of times larger than what mankind has ever experienced. Worryingly, there is a super-volcano that is alive and well in Yellowstone National Park in the United States. Since 2004, the pool of magma below Yellowstone has been swelling, pushing up the land by 25 cm and triggering 900 small earthquakes in 2008/9, although that activity has since slowed down.

What if the Yellowstone super-volcano explodes? Expect total devastation. The last Yellowstone eruption, roughly 640,000 years ago, was 1,000 times more explosive than the 1980 eruption of Mount St Helens in the US state of Washington. Whole ecosystems would be destroyed, not to mention most of North America’s crops and livestock.

Some human lives would be saved through successful evacuation, but the evacuation area would have to span the continent. Global food prices would skyrocket. In the days following a Yellowstone eruption, expect entire sections of the US and Canada blanketed in ash; ash that smothers the soil, causes buildings and infrastructure to collapse, clogs engines and machinery, and creates an epidemic of respiratory disease.

If Yellowstone erupted, global temperatures could drop 3-5°C and stay low for years. A prolonged volcanic winter, similar to the concept of a nuclear winter, could set in, devastating harvests and ecosystems the world over. As over 7 billion people begin to fight for survival, security and the rule of law would in all likelihood break down, and the human condition could once again become nasty, brutish and short.

Could this really happen? Yes. Scientists calculate that super-volcanoes erupt every 50,000 years, with the last known event at Lake Toba in Indonesia occurring 74,000 years ago. Such big figures quell some concerns, but bear in mind that there is also a 10% chance of a Tambora-scale event occurring in the next 40 years. To put this into perspective, the devastating eruption at Tambora Mountain in 1815 may not even have counted as a super-volcano, but its blast killed 71,000 people and was 16 times more explosive than the largest hydrogen bomb ever tested. Its ash plume stretched 43 km into the stratosphere, compared with a measly 9 km for Iceland’s volcano. If something on this scale exploded, it would make the eruption of Eyjafjallajokull in 2010 look like a child playing with firecrackers.  [Source]

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Volcanic eruptions in history

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This is a sortable summary of the pages Timetable of major worldwide volcanic eruptions, List of Quaternary volcanic eruptions, and Large volume volcanic eruptions in the Basin and Range Province. Uncertainties as to dates and tephra volumes are not restated, and references are not repeated. Volcanic Explosivity Index (VEI) values for events in the Miocene epoch sometimes lack references. They are given as VEI-equivalent, as orientation of the erupted tephra volume.

See lists of volcanic eruptions  ⇒  [Source 1] , [Source 2] , [Source 3]

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Find "Solutions to volcanic eruptions"

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Videos

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[Volcano Eruptions - National Geographic]

[Top 10 Deadliest Volcanic Eruptions in History]

[Biggest Volcanic Eruption Ever in the World - Supervolcano]

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References

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https://en.wikipedia.org/wiki/Lava

https://en.wikipedia.org/wiki/Lahar

Health risks of volcanic ash on humans

https://en.wikipedia.org/wiki/Volcanic_ash

https://en.wikipedia.org/wiki/Volcanic_gas

Effects of volcanic eruptions [BASIC PLANET]

http://www.usgs.gov/faq/categories/9819/2689

https://en.wikipedia.org/wiki/Types_of_volcanic_eruptions

https://en.wikipedia.org/wiki/List_of_large_volcanic_eruptions

https://en.wikipedia.org/wiki/Timeline_of_volcanism_on_Earth

https://en.wikipedia.org/wiki/Volcanic_ash_and_aviation_safety

https://en.wikipedia.org/wiki/List_of_largest_volcanic_eruptions

http://www.scientificamerican.com/article/what-causes-a-volcano-to/

https://en.wikipedia.org/wiki/Maritime_impacts_of_volcanic_eruptions

http://www.weforum.org/agenda/2012/01/global-risks-2012-what-if-a-supervolcano-erupted/

Volcanic eruption