Volcano Types Quiz

Volcanoes

• A volcano is a natural opening in the Earth's surface where molten rocks, hot gases, smoke, and ash are ejected.
• Volcanoes are classified based on their records of eruption or activity, cone shape, and style of eruption.

Volcanoes in the Philippines

• The Philippines has around 300 volcanoes, with 23 identified as active and the rest as inactive or dormant.
• The Philippine Institute of Volcanology and Seismology (PHIVOLCS) system classifies volcanoes based on their records of eruption.
• Volcanoes with a record of eruption within the last 600 years or that erupted 10,000 years ago are considered active.
• Volcanoes with no record of eruption or that have not erupted for the last 10,000 years and are being changed by weathering and erosion are considered inactive.
• The six most active volcanoes in the Philippines are Mayon, Hibok-hibok, Pinatubo, Taal, Kanlaon, and Bulusan.

Types of Volcanic Cones

• Shield volcanoes are formed by the accumulation of lava that oozes out from the volcano, resulting in a broad, slightly domed structure.
• Examples of shield volcanoes include Mauna Loa Volcano in Hawaii and Mount Amorong in the Philippines.
• Cinder cones are built from ejected lava fragments and have a steep slope, wide crater, and are the most abundant of the three major volcano types.
• Examples of cinder cones include Smith or Babuyan, and Mount Mayabobo in the Philippines.
• Composite cones or stratovolcanoes are formed from alternate solidification of both lava and pyroclastic deposits, resulting in a large, nearly perfect sloped structure.
• Examples of composite cones include Mayon Volcano, Mount Pinatubo, Kanlaon, Mount Hibok-hibok, and Mount Apo.

Viscosity of Magma

• Viscosity is the ability of a material to resist flow, and is an important property in determining the eruptive behavior of magma.
• The viscosity of magma is controlled by its chemical composition, temperature, and gas content.
• Magma with high viscosity is thick and sticky, while magma with low viscosity is thin and fluid.

Types of Volcanic Eruptions

• Phreatomagmatic eruptions are violent and occur due to the contact between water and magma.
• Strombolian eruptions are periodic and weak to violent, characterized by fountain lava.
• Vulcanian eruptions are characterized by tall eruption columns that reach up to 20 km high with pyroclastics flow and ashfall.
• Plinian eruptions are excessively explosive and characterized by a large amount of gas and pyroclastics.
• Icelandic eruptions are characterized by effusions of molten basaltic lava that flow from long, parallel fissures.
• Hawaiian eruptions are gentle and low-level, characterized by lava flows from the vent.
• Pelean eruptions are associated with an explosive outburst that generates pyroclastic flows, dense mixtures of hot volcanic fragments, and gas.