Volcanoes

Sherlock HolmesVOLCANOES

Volcanoes are landforms on a planet that are either dormant, active or simply dead. When an active volcano erupts, lava, ash and rocks can be released. The Ring of Fire is filled with volcanoes both active and dormant.

VOLCANOES

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Info: http://en.wikipedia.org/wiki/Volcano

BC Science 7 Textbook

Krakatoa Erupting

When a volcano erupts, lava, ash and rocks can spew out of it. Volcanoes erupt because of a lot of reasons. One reason is because a plug has formed and pressure builds up. This usually leads to a very explosive eruption.

ERUPTIONS

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A dormant volcano is a volcano that doesn’t seem to show any volcanic activity. It is in between being active and being dead. A dead volcano shows very similar effects except they will never become active and erupt ever again. There was a volcano in Alaska that seemed to dead but erupted after 1500 years of being dormant.

DORMANT

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A Dormant Volcano

A vent is the place where the volcano spits out lava, ash and rocks spew out. It’s usually on top of the volcano in the centre of a crater.

VENT

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There are different types of volcanoes based on their shape and what they’re made of. There are Cinder Cone volcanoes, Shield Volcanoes and Composite Volcanoes.

TYPES OF VOLCANOES

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Shield Volcano

Composite Volcano Cinder ConeVolcano

Cinder cone volcanoes are cone shaped and it’s built from hardened magma. This type volcano isn’t known for it’s eruption because it doesn’t usually kill anyone.

CINDER CONE VOLCANOES

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Info: http://en.wikipedia.org/wiki/Cinder_coneBC Science 7 Textbook

Shield volcanoes are built from hardened lava flows. These volcanoes are named Shield Volcanoes because they are shaped like shields.

SHIELD VOLCANOES

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Info: http://en.wikipedia.org/wiki/Shield_volcanoesBC Science 7 Textbook

Hot spots are volcanic regions thought to be fed by mantle that is strangely hot compared to the mantle in other places.

HOT SPOTS

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Composite volcanoes are, like it’s name suggests, built of more than one material. They are formed by layers of lava and bits of rock. Composite volcanoes often end up exceeding over 2500m in height. Between eruptions, these giants are often so quiet, they seem extinct.

COMPOSITE VOLCANOES

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The Ring of Fire is an area in the pacific where volcanic and seismic activity is common. It’s because the Pacific plate is colliding with the other surrounding plates.

RING OF FIRE

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Info: http://geography.about.com/cs/earthquakes/a/ringoffire.htmBC Science 7 Textbook

PACIFIC RING OF FIRE MAP

Volcanoes effect people in a lot of ways. When a volcano erupts, ash is spewed out which can make it hard to breathe. Another thing that volcanoes spit out is lava. Lava is dangerous too but it’s slow and you could probably outrun it. The biggest problem of all is pyroclastic flow. It’s hot gas that’s extremely hot. To add to that, it’s really fast so running away isn’t an option. There are some good stuff too like fun hike if the volcano is dormant or dead and the ash is good for helping plants grow

VOLCANOES AND PEOPLE

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Info: http://volcano.oregonstate.edu/how-do-volcanoes-affect-peopleBC Science 7 Textbook

A volcano erupting near a city

The word intrusive means inside so Intrusive Volcanic Features are features inside the volcano. There are Volcanic Necks, Sills and Dikes.

INTRUSIVE VOLCANIC FEATURES

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A volcanic neck is a land form that is created magma hardens in a vent on an active volcano. When forming, the neck can cause a huge build-up of pressure and in the end, lead to a very explosive eruption.

VOLCANIC NECK

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A volcanic sill is a sheet of magma which is parallel to the nearby rocks. They store magma unlike dikes which transport magma.

SILL

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A dike is a sheet that stores magma. The thickness of dikes can range from a few cm to 1km. A single dike by itself could be over 10km in length.

DIKE

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http://www.decadevolcano.net/photos/keywords/dikes.htm BC Science 7

Textbook

There are lots of different types of energy from inside the Earth. Geothermal energy is energy from inside the earth.

ENERGY FROM INSIDE THE EARTH

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The word geothermal comes from 2 Greek words: ‘geo’ meaning inside, and ‘therme’ meaning hot. Geothermal is energy from inside the Earth. Scientists usually retrieve this energy near hot places such as volcanoes and hot springs. This form of energy is better for the environment than others like fossil fuels.

GEOTHERMAL ENERGY

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Info: http://iceland.ednet.ns.ca/schedule.htmBC Science 7 Textbook

Geothermal power plant

Relative age is the age of a rock compared to the other minerals that surround it.

THE RELATIVE AGE OF ROCKS

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This principle shows that every layer on the Earth has a special age. The layer above another layer is younger than the one below. This can help determine the age of the rocks.

THE PRINCIPLE OF SUPERPOSITION

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http://evolution.berkeley.edu/evosite/lines/IIIAchronology.shtmlhttp://evolution.berkeley.edu/evosite/lines/images/strat_column.gif

The Absolute age is the almost exact age of a rock or layer. Determining the absolute age includes having to go deep into the structure of the rock or layer. There is a special material inside rocks that eventually disappears over time. Scientists calculate how much of the material has disappeared to figure out the absolute age.

ABSOLUTE AGE

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The Geological Time Scale is a line of chronological events that are theorized to have happened. They are split into Eras to organise the time lines even more.

GEOLOGICAL TIME SCALE

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Info: http://en.wikipedia.org/wiki/Geologic_time_scaleBC Science 7 Textbook

Eras are events that have happened in the world. They are split up by major events such as the Dinosaurs extinction and the start of the rein of mammals.

ERAS

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Volcanoes