Volcano

• Volcano


  It is an opening in the earth's crust through which lava, volcanic ash, and gases escape. Beneath a volcano, liquid magma containing dissolved gases rises through cracks in the Earth's crust
• Types of volcanic features

  • Crater
  • Caldera
• Crater

  A volcanic crater is a circular depression in the ground caused by volcanic activity. It is typically a basin, circular in form within which occurs a vent from which magma erupts as gases, and lava
• Caldera


  A caldera is a large depression formed when a volcano erupts and collapses. During a volcanic eruption, magma present in the magma chamber underneath the volcano is expelled, often forcefully. Formed by the collapse of the roof of a magma chamber
• Magma


  Magma is extremely hot liquid and semi-liquid rock located under Earth's surface
• Lava


  Lava is magma that reaches the surface of our planet through a volcano vent
• Volcanoes in the Philippines

  • Taal Volcano is a large caldera filled by Taal Lake in the Philippines. Mayon Volcano, active volcano, southeastern Luzon, Philippines
• Taal Volcano in the Philippines is one of the most active volcanoes in the country, with 34 recorded historical eruptions concentrated on Volcano Island, near the middle of Taal Lake
• Mayon Volcano in the Philippines has had more than 30 eruptions recorded since 1616. An eruption in 1993 caused 79 deaths
• Parts of a Volcano

  • Summit
  • Slope
  • Base
• Vulcan Point in the Philippines is the world's largest island within a lake that is situated on an island located in a lake within an island. Vulcan Point is one of the cones of the active Taal Volcano
• The Philippines is known for its diverse natural resources and scenic views like mountains and volcanoes due to being situated in the Pacific Ring of Fire, characterized by frequent earthquakes and volcanic eruptions
• Volcanism is a phenomenon connected with volcanoes and their volcanic activity
• Volcano

  A mountain that opens downward to a pool of molten rock below the surface of the earth
• Magma


  Hot liquid rock under the earth's surface
• Volcanic eruption


  Magma rises and pushes through vents and fissures, forcing its way out through the earth's surface, known as lava
• Most volcanoes are formed along plate boundaries in the Ring of Fire


  Volcanoes are formed in the subduction zone when two plates collide, with one plate sinking into the mantle and melting, resulting in magma rising through the other plate above it to form a chain of volcanoes
• Some volcanoes are formed along the rift of two plates being pulled apart

  Magma rises out of the rift from the sea floor as the sea floor spreads, forming underwater volcanoes
• Some volcanoes are formed at the center of a plate by plumes


  A rising column of super hot magma from some places in the mantle burns a hole into the plate above, forming a volcano
• Hot spot volcanoes

  Formed by a hot spot occurring in the middle of a plate, with the plate moving over the hot spot to form a string of islands
• Parts of a volcano

  • Magma
  • Magma chamber
  • Parasitic cone
  • Sill
  • Vent
  • Crater
  • Laccolith
  • Layers of ash
  • Ash cloud
• Shapes of volcanoes

  • Cinder cone
  • Composite
  • Shield
  • Lava dome
• Cinder cone volcano


  • Forms when volcanic cinder or blobs of congealed lava of basaltic composition come out from one vent, with explosive eruptions caused by gas rapidly expanding and escaping from the molten lava, leaving a crater at the summit
• Composite volcano


  • Also known as a stratovolcano, composed of an alternating layer of lava flow, can have a cluster of vents with lava breaking
• Composite volcano

  • Also known as a stratovolcano
  • Includes a number of the world's grandest mountains
  • Composed of an alternating layer of lava flow which justifies the name composite volcano
  • Can have a cluster of vents with lava breaking through walls or issuing from fissures in the perimeters of the mountain
  • Eruptions are extremely explosive and dangerous
  • Can be up to 100 to 3500 meters high
• Composite volcanoes

  • Mount Fuji in Japan
  • Mount Mayon in the Philippines
• Shield volcano


  • Huge gently sloped volcanoes that exclusively erupt basaltic lava
  • Built by many layers of low viscous lava flows
  • Eruptions don't seem to be explosive
  • Can be as high as 9000 meters from the bottom
• Shield volcanoes

  • Kilauea and Diamond Head in the Hawaiian Islands
• Lava dome


  • Also referred to as volcanic dome
  • Relatively small circular mounds formed because the lava is too viscous to flow
  • Found within the crater or in the edges of enormous composite volcanoes
• Lava domes

  • Chaitan lava dome in Chile
  • Lassen Peak in Western United States
• The Philippines has more than 100 volcanoes as of 2013
• Classification of volcanoes by Philippine Institute of Volcanology and Seismology (PHIVOLCS)


  • Active erupting
  • Active dormant
  • Inactive
• An active volcano is a volcano that has had at least one eruption during the past 10,000 years
• An erupting volcano is an active volcano that is having an eruption
• A dormant volcano is an active volcano that is not erupting but is supposed to erupt again
• There are 24 active volcanoes in the Philippines
• An inactive volcano is one that could erupt but has not erupted for more than 10,000 years
• Inactive volcanoes are also called extinct or sleeping volcanoes
• Volcanoes with no record of eruptions are considered as extinct or inactive
• Volcanism is a phenomenon connected with volcanoes and its volcanic activity such as the movement of magma from the mantle to the surface of the earth