Volcanism and Volcano Formation Quiz

Vulcan Point

• The world's largest island within a lake, located on an island within a lake, which itself is on an island.
• Situated on Taal Volcano in the Philippines.

Pacific Ring of Fire

• A geological area characterized by frequent earthquakes and volcanic eruptions.
• The Philippines is located within this region.

Volcanism

• A phenomenon related to volcanoes and volcanic activity.
• The process of magma moving from the Earth's mantle to its surface.

Volcanoes

• Mountains with openings or vents that connect to a pool of molten rock beneath the surface.
• These openings allow magma, ash and gases to escape.
• Molten rock beneath the Earth's surface is called magma.
• When magma erupts at the surface it's called lava.
• Most volcanoes form due to geological activity along plate boundaries.

Volcano Formation

• Subduction Zone: Plates collide, one sinking into the mantle causing melting and subsequent magma rise through the other plate, resulting in a chain of volcanoes.
  • Example: Mount Fuji in Japan.
• Rift Zone: Plates pull apart, creating a rift where magma rises from the Earth's sea floor.
  • Example: Iceland, formed by the spreading boundary of the North American and Eurasian plates.
• Hot Spot: A rising column of superheated magma from deep within the mantle.
  • Example: Hawaiian Islands.

Parts of a Volcano

• Magma: Molten rock beneath the Earth's surface.
• Magma Chamber: The underground reservoir where magma is stored.
• Parasitic Cone: A smaller, cone-shaped volcano, formed by the accumulation of volcanic debris secondary to a larger volcano.
• Sill: A flat, sheet-like intrusion of solidified magma within a volcano's crack.
• Vent: The opening where volcanic materials escape.
• Crater: The bowl-shaped depression surrounding the vent at the summit of a volcano.
• Laccolith: A sheet-like intrusion of magma that hardens within or between sedimentary rock layers.
• Layers of Ash: Small fragments of lava or rock, less than two millimeters in size, ejected during volcanic explosions.
• Ash Cloud: A cloud of ash formed by volcanic eruptions.

Volcano Types

• Cinder Cone: Cones formed by the accumulation of volcanic cinder or congealed basaltic lava ejected from a single vent.
  • Example: Taal Volcano (Philippines) and Perikutan (Mexico).
• Composite: Volcanoes constructed by alternating layers of lava flows and ash.
  • Example: Mount Fuji (Japan) and Mount Mayon (Philippines).
• Shield: Large, broad, gently sloping volcanoes formed by the eruption of basaltic lava flows.
  • Example: Kilauea and Diamond Head (Hawaiian Islands).
• Lava Dome: Small, circular mounds formed by the accumulation of viscous lava around a vent.
  • Example: Chaitan Lava Dome (Chile) and Lassen Peak (Western United States).

Philippine Volcanoes

• The Philippines has more than 100 volcanoes.
• Philippine Institute of Volcanology and Seismology (PHIVOLCS) categorizes volcanoes as:
  • Active: Has erupted within the last 10,000 years.
    • Erupting: Currently erupting.
    • Dormant: Not currently erupting but expected to erupt again.
  • Inactive: Has not erupted in over 10,000 years; also known as extinct or sleeping.

Advantages and Disadvantages of Living Near Volcanoes

• Disadvantages:
  • Damage to land from volcanic materials.
  • Landslides.
  • Pollution.
  • Impacts on weather patterns.
• Advantages:
  • Volcanic soils are often fertile.
  • Volcanic materials have industrial and chemical uses.
  • Volcanic areas often attract tourists.

Key Concepts

• Volcanism is the process of magma moving from the Earth's mantle to its surface.
• Volcanic eruptions result from the release of pressure as magma rises to the surface.
• Different volcano types have distinct characteristics.
• Volcanoes range from active, erupting, dormant, to inactive stages.
• Living near volcanoes has both advantages and disadvantages.