cool fact!

• The term “volcano” is from the Latin Volcanus or Vulcan, the Roman god of fire.

neat fact!

• The most formidable volcanoes are called supervolcanoes. A supervolcanic eruption can rain hellfire across thousands of miles and cause worldwide climatic changes, such as a drop in global temperature due to the release of tons of ash particles into the atmosphere. These monsters rear there ugly heads only ever few hundred thousand years, however. One of the biggest is in Yellowstone National Park, and scientists say it may be due for another eruption.

!wild fact!

• The largest volcanic eruption ever observed was of Mount Tambora, on the island of Sumbawa, in Indonesia. Its eruption in 1815 killed about 100,000 people. Indonesia is thought to have the largest number of historically active volcanoes – a total of 76, according to the U.S. Geological Survey.

weird fact’s

• Hundreds of years ago, the Aztecs of Mexico and the people of Nicaragua believed gods lived in lava lakes. They would sacrifice beautiful young girls to these powerful gods.

sad fact

• During the past 400 years, nearly a quarter of a million people have been killed as a direct result of volcanic eruptions. Indirect aftereffects such as famine, climate change, and disease most likely have tripled that number

What is a Volcano?

A Volcano is an opening (crack) in the crust where lava reaches the surface

How does it happen?

• Volcanoes are generally found where tectonic plates are diverging or converging

………………………..

Sidenote:

• (volcanoes are usually not created where two tectonic plates slide past one another…..this type of movement causes…..???)

Plate Tectonics & HotspotsDivergent plate

boundariesConvergent plate

boundariesHotspots

The pulling apart of plates, causing

molten

The pulling apart of plates, causing molten rock to

come to the top of the mantle.

Causes mainly submarine

volcanic activity and creates new oceanic crust.

rock to come to the top of the

mantle. Causes mainly submarine volcanic activity and creates new oceanic crust.

The c The collision of

plates, causing

The collision of plates, causing

Subduction or one plate to submerge beneath the other late to submerge beneath the

other plate to submerge

beneath the other ollision

of plates, causing

Subduction or.

Located away from tectonic plates, over

mantle plumes where pipes

vent magma. Volcanoes

formed over hotspot go

dormant and new ones are

formed when plates move overhead.

Divergent Plate Boundaries Most divergent plate boundaries are at the bottom of the

oceans, causing most of the volcanic activity to be under water, thus forming new seafloor.

Convergent Plate Boundaries• When two plates (usually an oceanic and continental

plate) collide, causing the one plate to submerge under the other plate (called subduction).

• In the case of oceanic-continental, a deep trench just off shore is formed.

• When the thick magma, reaches the surface, a volcano is formed.

• *This is what caused the typical Ring of Fire volcanoes.*

Oceanic - Oceanic convergenceContinental - Continental convergenceOceanic - Continental convergence

• In the theory of plate tectonics most of the geological characteristics are explained by tension (interaction) among plates. However, some of most spectacular formations are caused by "hot spots" which are situated far from the edges of tectonic plates.

HotspotsA hotspot is a place in the middle of a tectonic plate where hot magma rises

(called a mantle plume) until it reaches the crust. Magma then flows out.

Pacific Ring of Fire

• The Pacific Ring of Fire is an area of frequent earthquakes and volcanic eruptions circling the basin of the Pacific Ocean.

• Result of plate tectonics and the movement and hitting of crustal plates.

Ring of Fire

Area where large numbers of earthquakes and volcanic eruptions occur in a 40,000km horseshoe shape.Contains 452 volcanoes, with over 75% of worlds active and dormant volcanoes.

There are 3 types of Volcanoes

• Shield Volcano• Cinder Cone Volcano• Composite Volcano

Shield Volcano

Shield Volcano

• A gently-sloped volcano (large volcano but not very tall)

• built out of layers of lava from lots of little eruptions

Cinder Cone

• Most common• Steep sides• Made of cinders

(melted volcanic rock that has cooled down)

Composite Volcano

• A tall volcano made of many layers of cinders and hardened lava

What kind of volcano is this?

Diamond Head is an eroded Cinder Cone volcano

Early sailors mistakenly thought shining calcite crystals inside the rocks were diamonds, leading to the incorrect name. Diamond Head formed when hot magma rising up a tube hit ocean water, causing large explosions that threw exploded magma particles into a broad ring.

What kind of Volcano is this?

Mount Shasta is a composite volcano

Over the last 10,000 years, Mt. Shasta has erupted on average once every 800 years. During the 3,500 years the volcano has erupted about once every 300 years. The most recent eruption may have occurred in 1786 A.D.

California

What kind of volcano is this?

Kohala is a shield volcano.

• Kohala is the oldest of the subaerial volcanoes that make up the Island Of Hawaii. Kohala is considered to be extinct because it has not erupted for 60,000 years.

Hawaii