GR9 SCIENCE VOLCANOES

Topics about Volcanoes - Volcanoes based on Shape - Volcanoes based on Volcanic Activity - Types of Eruption - Plate Movements - Causes of Melting of Magma - Types of Magma - Relationships of Magma and Viscosity

Volcano

Volcano

A cone shaped mountain or hill often made u of lava and ash.

Magma Chamber

Where molten rocs is found deep below the Earth’s Surface and a basin for magma.

Ash and Dust

Fine Materials thrown out by a Volcano.

Magma

Molten rocks below the Earth’s Surface.

Lava

Molten rocks flows from the Crater of an Active Volcano.

Volcanic Bombs

Lava rocks fragments thrown out by an Erupting Volcano.

Ring of Fire

A Circle of Active Volcanoes found around the Edge of Pacific Ocean.

PHIVOLCS

Philippine Institute of Volcanology and Seismology

As the Magma Rises, Pressure?

Pressure decreases

Shield Volcano

• a type of Volcano formed by the accumulation of Lava that oozes out from the Volcano.

• Resembles a warrior’s shield

Cinder Volcano

• A type of Volcano that are built from ejected lava fragments.

• Most Abundant of the three major volcanoes.

• Have sleep slope, wide crater

Composite/Stratovolcanoes

• A type of Volcanoes that are nearly perfect slope structure formed from alternate solidification of both Lava and pyroclastic deposits.

Active Volcano

A type of Volcano that erupted within the last 600 years or within the last 10,000 years based on analysis of database materials.

Inactive Volcano

• A type of Volcano that have NOT erupted for the last 10,000 years of their existence.

• Their Physical form is being changed by agents of weathering and erosions of deep and long gullies.

Dormant Volcano

A type of Volcano that is expected to erupt again.

Extinct Volcano

A type of Volcano that will not erupt again.

Explosive

• A type of Eruption that involves in thick magma with large amounts of trapped gases.

• High Gases content, High Viscosity

Effusive

• A type of Eruption that involves in thin basaltic magma that flows perfectly with small amounts of trapped gases.

• Low Gases Content, Low Viscosity

Phreatic or Hydrothermal eruption

A type of Volcanic Eruption that occurs when magma heat around the surface of water.

Phreatomagmatic Eruption

• A type of Volcanic Eruption with an explosive magma-water interaction, large amounts of steam and magmatic gases are emitted.

• Large column of very fine ash and high speed sideways emission of pyroclastic called BASE SULGE are observed.

Strambolism

• A type of Volcanic Eruption named after “Stromboli”, an Italian Volcano

• Consists of ejection of incandcent cinder, lapili and lava bombs.

• Eruptions up to Tens to a Hundred meters

• Eruptions are small to medium

Volcanian Eruptions

• A type of Volcanic Eruption that is Explosive

• Occurs when the pressure of entrapped gases in a relatively viscous magma.

Plinian

A type of Volcanic Eruption that is excessively explosive of gas like Pinatubo Volcano in Zambales.

Convergent Plate Boundaries

A Plate Movement where tectonic plate converge

Divergent Plate Boundaries

A Plate Movement with locations where plate are moving away from one another.

Ignenous Rock

When lava cools and solidifies

Decompression

• A Causes of Melting of Magma due to lowering of the pressure.

• The rock in this section melts to form a magma

Heat Transfer Melting

• A Causes of Melting of Magma in which magma is created when hot liquid is forced to highly pressurized core to the crust.

• The liquid rock loses heat to the surrounding rock which also melts in the process.

Flex Melting

• A Causes of Melting of Magma that occurs when carbon dioxide and water is added to rocks.

• There 2 can significantly reduce to the melting point of rock resulting in this formation of magma.

How many elements are found in Magma and which has the highest Percentage?

8 Elements with Oxygen being at 46.6%

Basaltic Magma

• Temperature?

• Viscosity?

An Example of magma from a Shield Volcano

• Temperature = 1000C - 1200C

• Viscosity = Thin, Less Viscous

Andesitic Magma

• Temperature?

• Viscosity?

Example of a magma from a Composite Volcano

• Temperature = 800C - 1000C

• Viscosity = Moderate Viscous

Felsic or Rhyolitic Magma

Example of a magma from a Cinder Volcano

• Temperature = 650C - 800C

• Viscosity = Thick, High Viscous

Relationship of Temperature and Viscosity

As Temperature Increases, Viscosity Decreases

Relationship of Silica Content and Viscosity

As Silica Content Increases, the Viscosity Increases

Relationship of Gas Content and Viscosity

As Gas Content increases, Viscosity decreases