Lesson 1: Volcano
Volcano
Volcano in the Philippines
Parts of the Outer Volcano
Outer Volcano | Description |
Summit | highest point or the apex of the volcano |
Slope | middle side part of the volcano |
Base | lower outer part of the volcano |
Parts of the Inner Volcano
Inner Volcano | Description |
Crater | mouth of the volcano |
Main Vent | main opening of the volcano. |
Side Vent | smaller opening of the volcano |
Conduit | underground central-tube that connects the crater and magma chamber |
Magma Chamber | region below the surface where magma is stored |
Magma | hot molten rocks located below the surface |
Lava | magma released on the surface |
Ash | particles of rock and natural glass produced in the air in the eruption |
Classification of Volcano
Structure | Description | Structure | Built | Viscosity |
Cinder Cone Volcano | most abundant volcano simplest volcano | steep slope wide crater small cone | ejected lava particles | moderate viscosity |
Composite/Stratovolcano | almost to perfect sloped | steep slope narrow crater symmetrical cone | alternate solidification of lava and pyroclastic | high viscosity |
Shield Volcano | warrior’s shield | flat slope wide crater broad and round | repeated eruptions of lava | low viscosity |
Activity | Description |
Active Volcano | currently erupting or expected to erupt in the future erupted in the last 600 years |
Dormant Volcano | not currently erupting but expected to erupt in the future |
Extinct/Inactive Volcano | considered dead and not to erupt in the future not erupted in the last 10,000 years |
How is Magma Formed Inside the Earth?
Composition of Magma
Viscosity
Factors that Affects Viscosity in Magma
1. Temperature
2. Composition
3. Amount of Dissolved Gas
Types of Magma
1. Basaltic Magma
2. Andesitic Magma
3. Rhyolitic Magma
Types of Volcanic Eruption
Eruption | Description | Magma |
Phreatic/Hydrothermal | steam-driven eruption | flowing basaltic magma |
Phreatomagmatic | violent eruption due to contact of water and magma | flowing basaltic magma |
Strombolian | periodic, weak to violent fountain lava eruption | basaltic to andesitic magma |
Vulcanian | tall eruption columns | solidified or highly viscous andesite or rhyolite magma |
Plinian | most explosive eruption | andesitic to rhyolitic magma |
Types of Volcanic Material
Type of Material | Description |
Volcanic Gas | volcanic gas emissions (water vapor, carbon dioxide, sulfur dioxide, hydrogen dioxide) |
Lava | ejected magma |
Pyroclastic Material 1. Tephra 2. Pyroclasts a. Volcanic Ash b. Lapilli c. Block d. Bomb |
unconsolidated debris classified according to size particle less than 2 mm fragment between 2 mm and 64 mm solid fragment greater than 64 mm with angular shape and sharp edges solid fragment greater than 64 mm with streamlined shape |