Volcanoes

• Volcano is an opening in the Earth's crust through which rocks, gases, and ash erupt. It is formed from the emission of lava forms.
• Magma is a hot liquid rock in the Earth. Lava is magma reaching the Earth's surface.
• A crater is a funnel-shaped pit or depression.

  A caldera is a collapsed crater.
• Lava plateau is a landform produced by repated eruptions of basaltic lava.
• Step 2: Magma is subjected to high heat and pressure making it less dense than other rocks.

  Step 4: explosive eruption of lava, ash, and rocks

  Step 1: Magma forms in crust and upper mantle when rocks partially melt.

  Step 3: explosion
• Volcanoes erupt in order to release pressure and heat.
• Rhyolitic lava is rich in Mg, Fe, and Si; light-colored lava. Produces rhyolite rocks.
• Basaltic lava is dark and has water, rich in Mg and Fe. It produce Basalt.
• Andesetic has mafic and felsic similarities, produces andesite rocks.
• Mafic means dark, felsic means light.
• Cinder cones are the smallest and simpliest form of volcano.
• Shield volcanoes are broad and sloping. This is formed by basalt. Examples are Mt. Mauna Loa and Mauna Kea.
• Composite volcanoes are the largest and most violent type of volcano. Example is Mt. Mayon.
• Active volcanoes erupt regularly. They have a record of explosion in the past 10,000 years according to PHIVOLCS.
• PHIVOLCS mean Philippine Institute of Volcanology and Seismology.
• Potentially active volcanoes are young looking volcanoes without any record of eruption.
• Dormant volcanoes are inactive, they are capable of erupting in the future, though.
• Extinct volcanoes have no significant seismic activities, and have a long record of inactivity based on erosion patterns.
• The Circum-Pacific Belt is a path along an ocean which is classified by active volcanoes. It is called as the Pacific Ring of Fire.
• The Alpine-Himalayan Belt is the collision of the African plate and Info-Australian plate.
• Geothermal energy is heat from the Earth.
• Hot Springs are for bathing and swimming, has high mineral content, and water rises to the surface when heated.
• Geysers eject water. Geysers are the source of geothermal energy.