4TH QUARTER SCIENCE

• Mountain

  • a land formation without vent
• Volcano

  • a land formation with vent
  • any vent or built-up mountain where lava, pyroclastic materials, or gases erupt
• Primary Parts of a Volcano

  • Magma Chamber
  • Conduit
  • Crater
  • Flank
  • Base
• Secondary Parts of a Volcano

  • Sills
  • Dikes
  • Parasitic Cone
  • Caldera
• Magma Chamber

  • an open space where magma accumulates.
• Conduit

  • the pipe or vent where material wells up from beneath the surface.
• Crater

  • a circular depression around the vent where lava, ash, and rock erupt out of a volcano.
• Flanks

  • sides of a volcano which usually have fractures.
• Base

  • the bottom and foundation of the volcano.
• Sills

  • beds of rocks that form as a result of rock formation between layers of older materials
• Dikes

  • rock sheets that can form from magma when they seep into cracks in rocks.
• Parasitic Cone

  • cone-shaped accumulation of volcanic material not part of the central vent of a volcano.
• Caldera

  • a large circular depression with steep walls.
• Types of Volcano

  • Lava Dome
  • Shield Volcano
  • Stratovolcano
  • Pyroclastic Cone
  • Caldera
• In the Philippines, volcano monitoring is conducted by the Philippine Institute of Volcanology and Seismology (PHIVOLCS).
• Types of Volcanoes According to Activity

  • Active
  • Inactive
  • Potentially Active
• Active Volcano

  • Have eruptive histories or there has been recorded eruption in historical times.
  • Examples: Mt. Mayon, Mt. Taal, Mt. Kanlaon, Mt. Bulusan
  • PH has 23 active volcanoes
• Inactive Volcano

  • Have no eruptive histories, and will never erupt again.
  • Examples: My. Arayat, Seven Lakes of San Pablo
  • PH has 335 inactive volcanoes
• Mt. Mayon

  • Its last eruption was in 2018, with 52 historical eruptions.
  • The famous “perfect cone” signifies Mayon’s structure as a stratovolcano.
• Mt. Taal

  • Its last eruption was in 2020, with 34 historical eruptions.
  • Taal Lake represents a collapsed caldera covering 234 km2.
• Mt. Kanlaon

  • Its last eruption was in 2016, with 30 historical eruptions.
  • It’s the highest mountain in Visayas with several flank vents around the summit crater.
• Mt. Bulusan

  • Its last eruption was in 2017, with historical 18 eruptions.
  • It is part of the Irosin Caldera, a complex volcanic field spanning most of Sorsogon.
• Mt. Arayat

  • is an inactive volcano with hiking trails are well-known, and there is a rich history of folklore and superstition surrounding the mountain.
• Seven Lakes of Laguna

  • This is also known as the Seven Lakes of San Pablo. 
  • Lake Calibato, Lake Palakpakin, Lake Muhikap, Lake Sampaloc, Lake Yambo, Lake Pandin, and Lake Bunot
• Potentially Active Volcano

  • have no eruptive histories but in some instances present signs of activity or remnant heat.
  • PH has 26 potentially active volcanoes.
  • Example: Mt. Apo, Mt. Talinis, Mt. Isarog
• Mt. Apo

  • It is the country’s highest peak, which showcases sulfuric steam and hosts a geothermal plant.
  • It is a stratovolcano and is considered a national park.
• Mt. Talinis

  • It is also known as Cuernos de Negros.
  • This range exhibits areas of geothermal alteration and steaming, and will soon host a geothermal plant.
• Mt. Isarog

  • Mt. Isarog is located in Camarines Sur. 
  • It is a stratovolcano famous for its rich and unique biodiversity.
• Volcanic Eruptions

  • Classified according to their eruptive style: Effusive and Explosive.
• Effusive Eruptions

  • Considered effusive when they produce lava flows exclusively.
• Explosive Eruptions

  • Produce pyroclastic debris
• Classification according to their Eruptive style and Height of eruption

  • Magmatic
  • Phreatomagmatic
  • Phreatic
• Magmatic Eruptions

  • Driven by thermal expansion of dissolved gases in lava.
  • Plinian
  • Palean
  • Vulcanian
  • Surtseyan
  • Strombolian
  • Icelandic
  • Hawaiian
• Pelean Eruptions

  • Characterized by "glowing avalanches"
• Vulcanian Eruptions

  • Result from more viscous lava which builds up until it explodes.
• Plinian Eruption

  • Result from the extreme build up of gases in the magma chamber and conduit.
  • Eruption column higher than 10 km.
• Icelandic Eruptions

  • Sustained fissure eruptions
• Strombolian Eruptions

  • Result of the bursting of clumps of gas bubbles.
• Hawaiian Eruptions

  • Produce low-viscosity basaltic lava flows.
• Surtseyan Eruptions

  • Occurs in shallow bodies of water.