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Volcanic Eruption

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by

Karen Kwok

on 4 October 2013

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Transcript of Volcanic Eruption

Volcanic Eruption
Presented by:

KRISTEN & KAREN
Thanks for watching!
Mount Sinabug
-Mount Sinabug in Medan, Indonesia
-erupted on September 15, 2013
-caused 6,200 people to evacuate from their villages
-5 people were hospitalized
-5 people were having difficulty breathing after inhaling volcanic ash
-no damage was caused
Where?
-Cordillera Region
-it contains the coast mountains and the Rocky mountain
What Causes Eruptions?
- 3 predominate: the buoyancy of the magma, the pressure from the exsolved gases in the magma and the injection of a new batch of magma into an already filled magma chamber
- rock inside the earth melts (same mass but volume increases, producing a melt that is less dense than the surrounding rock)
- lighter magma rises toward the surface by virtue of its buoyancy, when the magma reaches the surface, it erupts
- the dissolved gas in magma at atmospheric pressure is zero but rises with increasing pressure and the pressure causes an eruption
PROS
- dramatic scenery created by the eruptions attract tourists, brings income to an area
- the lava and ash deposited during an eruption breaks down to provide valuable nutrients for the soil. This creates very fertile soil which is good for agriculture
- high level of heat and activity inside the earth, close to a volcano, can provide opportunities for generating geothermal energy

CONS
- many lives can be lost
- if the ash and mud from an eruption mix with rain, water, or melting snow, fast moving mudflows are created called lahars
- lava flows and lahars can destroy many homes, settlements and clear areas of woodland and agriculture
- human and natural landscapes can be destroyed forever

Effects of the World
- causes a lot of rain, lightning and thunder because the ash particles are good at attracting water droplets
Interesting Fact
- said to be the main theory of the extinction of dinosaurs
The word “volcano” was taking from the Italian word “wulcano” and from the Latin “vulcanus” meaning “burning mountain”.
In ancient Roman mythology, the God of fire went by the Vulcan.
The Latin words for lighting are fulgar, fulgere, and fulmen, this in turn became connected to flames.

Effects on People
- affected in good ways and bad ways
- homes get covered with ashes
- lava is too slow to run over people but can always run over their houses
- lava that are a mixture of hot gas and ash runs quickly down and hill and can kill you
- gasses released by volcano are hazardous

Types of Volcanic Eruption
- The most common type of eruption is when the magma is released from a volcanic vent
Hawaiian Eruption
- this phenomenon is known as fire fountaining lava flows may also come from vents at the same time as fountaining occurs
- it can last for hours or even days
- the bits of hot lava falling out of the fountain can melt together and form lava flows or build hills called spatter cones
- because these flows are very fluid like, they can travel miles before they cool and harden

Stombolian Eruption
- the explosions usually occure every few minutes at intervals
- the explosion of lava, which can reach heights of hundreds of meters, are caused by the bursting of large bubbles of gas, which travels upward in the magma filled conduit until they reach open air
- varies in different forms of eruptive products: spatter, harderned globs of glassy lave, scoria (chuncks of lava), ash or small lava flows
- one of the least violent of the explosive eruptions, still dangerous though
- usually occurs at night when the lava glows brightly

Vulcanian Eruption
- can create powerful explosions in which material can travel faster than 350 meters per second and rise several kilometers into the air
- produces ash clouds and pyroclastic density currents which are clouds of hot ash, gas and rock that flow almost like fluids
- eruption may be repetitive and go on for days, months or years or may also precede to even larger explosive eruptions

Plinian Eruption
-release enormous amounts of energy and create eruption columns of gas and ash that can rise up to 50 km high at speeds of hundred of meters persecond
- largest and most violent of all the types of volcanic eruptions
- caused by fragmentation of gassy magma
- ash from the eruption can be blown hundreds or thousands of miles away from the volcano
- extremely destructive and can even demolish the entire top of a mountain
- can produce falls of ash, scoria and lava bombs miles away from the volcano
- climatic
- volcano with a magma chamber emptied by a large Plinian eruption may subsequently enter a period of inactivity


Surtseyan Eruption
-a kind of hydromagmatic eruptions where magma interacts explosively with water
- occurs when an undersea volcano has finally grown large enough to break the water’s surface
- because water expands when it turns to steam, water that comes into contact with hot lave explosed and creates plumes of ash, steam and scoria

Volcanic Eruption
Mount Merapi
- took place in Yogyakarta, Indonesia
- spewed smoke and ash and unleashed a column of dark red volcanic material 1,000 m into the air
- ash made the rain thick and muddy in several villages
- the sound was heard 30 km away
- one of the most recent deadly volcanic eruptions
- people living within a 20 km zone were told to evacuate
- evacuation orders affected at least 19,000 people
- about 500 volcanic earthquakes had been recorded on the mountain over the weekend of 23-24 October, 2010
- magma had risen to about 1 km below the surface
- lava began flowing down the Gendol River (signalling the likelihood of an imminent eruption
- on November 10, 2010, 153 people were reported to have been killed and by November 18 the death toll increased to 275
- about 800 people suffering from minor to severe psychological problems
- by December 3 the death toll had rised to 353
- Alert Level 2 (September 20, 2010)
- Alert Level 4 (October 25, 2010)
- Alert Level lowered to 3 (December 3, 2010)
- destroys over a wide area of plants
- volcanic soil is, very rich, so after an eruption, plants can grow better and once again
- lots of mammals die
- can also kill sea life because they are affected by the acidity, the turbidity and the change in temperature.
- can also cause early bird migration

Effects on plants and animals
A very spectacular scene to watch.
Full transcript