Volcanic Hazards Primary and Secondary

Volcanic Hazards

Hazards

Tephra: Air borne materials that if they are hot enough they could clump together to form pyroclastic material or tuffs.

Effects: -Covers crops and plants and cause them to die

-Stays in the stratosphere for some time and can    stop air traffic

- Large amounts of it can fall onto building, causing the building to collapse under it immense weight

Lahar: A rushing flow of volcanic ash mixed with water, lahar’s are common in snow or glacier capped mountains.

They are very desne and move extremely quickly

Effects:

-It’s speed and weight can destroy buildings and other objects

-Humans can get swept away or drown

-Riverbanks will overflow and crops by riverbanks will be destroyed

Lava bombs: Smooth, glassy blobs of basaltic lava which cool as they fly through the air, they come in many shapes and sizes, some even as big as boulders

Effects:

-Could crash into building an damage them severely

-May hit people and cause serious injury or death

Pyroclastic flow: Extremely hot gases, ash and rock that move down the volcano and lighting speed. The boulders that follow the pyroclastic flows have highly destructive force and can flatten objects.

Effects:

-The superheated pyroclastic flow can kill people and wildlife in its path

-The boulders that follow can flatten trees, destroy buildings and pose a risk to human life.

Lava flow: A flowing river of molten rock known as lava, lava can be divided into two categories basaltic and acidic, basaltic lava is usually found in gentle eruptions while the latter is found in explosive eruptions.

Effects:

-       The molten lava can start fires in trees, houses and buildings.

-       The fires poses a threat to human life

Landslides: A large amount of dirt, soil and debris movement under the force of gravity, in volcanic landslides, they can move very fast and sizes vary from small to enormous.

Effects:

-Can flatten trees, buildings or any other object in their path

-Humans and wildlife are usually killed in the path of a volcanic landslide.

Volcanic ash: Old lava and rock that are pulverized by violent eruptions, it are a jagged and glassy feel and look and can travel for miles on end

Effects:

-Airborne volcanic ash can stop air travel due to bad visibility

-Large amount of it can collapse a building due to the immense weight.

- Can cover vast areas of cars, buildings, objects, crops with volcanic ash that cause damage and loss

Success Criteria (9/1/12) Volcanic Hazards

Success Criteria

• I can classify at least 4 hazards
• I can make at least 4 links
• I can understand what is a good comparison case study

Hotspot Volcano Charecteristics

Hotspot Volcano

Characteristics	Description
Formation	A magma plume rises from the core and is forced up into the lithosphere, the magma then rises to the crust and forms a volcano, but since the crust is moving away, the plume is cut off and the volcano becomes extinct, this process is repeated as the magma plume rises and is cut off by the moving crust
Plate Boundary	Either conservative or destructive
Features	-Produces mainly lava -Very viscous lava - A shield like volcano -Magma is basaltic  -Very little pyroclastic material is erupted
Nature of eruption	Gentle oozing
Named Example	Mauna Loa, Hawaii

Success Criteria (5/1/12) Hotspot volcano/Hazards

Success Criteria

• I can explain the characteristic+formation  of hotspot volcanoes
• I can explain at least 4 volcanic hazards
• I can use what I know so far to better understand what I am doing this lesson

MEDC Comparison Case Study- (Mount. Etna)

MEDC Case Study-  Mount. Etna, Italy

Diagram explanation of the cause of Mount Etna eruptions.

Diagram	Stages
	The denser Eurasian plate is subducted under the lighter African plate, forming a subduction zone
	The denser Eurasian plate is destroyed under the immense heat and pressure turning it into lava
	The magma rises through fissures in the ground and a a a large swell occurs
	Finally, the magma erupts form Mount Etna, this volcano has frequent eruptions.

Fact Zone

Year: 1971

-Mount Etna erupts and the lava destroyed ski slopes, cable car station and observatories.

Year: 1983

-Millions of tonnes of lava gushed out from the side of Mount Etna, engulfing several buildings, the lava travelled up to speeds of 15 km an hour

Year: 27 Oct 2002

-       A short period of seismic activity was felt

-       -Lava was ejected from two fissures

-       The hot lava stated forest fires ad destroyed wildlife

Year: 2003

-Mount Etna seemed to be dormant, until the next eruption that took place in 2005

Diagram of location of Mount Etna

What were the…

Primary effects?

-Buildings, crops and land were destroyed or ruined by the lava and ash

-Communication and public services were halted

Secondary effects?

-Ash, dust and smoke would block and clog the air

-Wildfires from the flying burning debris and lava

-People had to be moved from their homes

Short-term responses?

-Economic problem due to rebuilding efforts

-Possible shortages of shelter for people affected by the volcano

-Limited movement, people could not get around

Long-term responses

-The government may have to pay compensation to the people affected by the volcano

Why did so few people die?

-Early warning system, people were alerted soon enough to escape safely

-Efficient rescue service, they were able to deal with the after effects of the volcano quickly and efficiently

Comparison

Mount Etna	Traits	Montserrat Eruption
The subduction of the denser Eurasian plate and forms magma that is forced upwards.	Cause?	Frequent earthquakes causes magma to be forced upwards
Mostly property and wildlife damage	Major Effects?	Property, wildlife and human lives were taken
Very violent and frequent eruptions	Volcano’s Characteristics	Eruptions were violent but volcano eventually became dormant
Plants and wildlife were destroyed	Physical Geographical Effects?	Plants and wildlife were destroyed
Property was destroyed	Human Geographical Effects?	Human lives were taken and property destroyed
-Early warning system -Efficient rescue and healthcare	Why were the effects so?	-Poor warning system -Late rescue and bad healthcare services -Bad infrastructure

Completed diagrams version is located in Geo notebook

LEDC Country Volcano Case Study- Montseratt Eruption

Find In Geo Book- LEDC case study (Montserrat Case Study)