Volcano

• Parts of a volcano:

  • Summit: highest point or apex of the volcano
  • Vent: opening at the summit
  • Slopes: sides or flanks of a volcano radiating from the main or central vent
  • Base: lower outer part of the volcano
• Geologic features of a volcano:

  • Magma Chamber: region beneath the vent where molten rock or magma is stored before eruption
  • Main Vent: main opening on the surface emitting lava, gases, ash, or other volcanic materials
  • Conduit: underground tube-like structure connecting the magma chamber to the crater
  • Side Vent: smaller outlet for magma escape
  • Crater: funnel-shaped hollow at the top of the vent from where magma, ash, and gas come out
  • Lava: molten rock expelled onto the Earth's surface during an eruption
• • Ash and Gas Cloud: mixtures of rock, minerals, glass particles, and gases expelled during volcanic eruption
• Types of Volcanoes Based on Structure:

  • Cinder cone volcanoes: built from solidified lava ejected from a single vent, forming a circular or oval cone with a steep slope and wide crater
  • Phreatic or hydrothermal: stream-driven eruption due to hot rocks contacting water, characterized by ash columns
  • Shield volcanoes: large, broad volcanoes built of fluid lava flow, with tall and broad, flat, rounded shapes, relatively safe due to lack of pyroclastic materials
• Type of Volcanic Eruption:

  • Vulcanian: tall eruption columns reaching up to 20 km high with pyroclastic flow and ash fall, like Paricutin Volcano in Mexico
  • Plinian: excessively explosive eruption of gas and pyroclastic materials, like Pinatubo Volcano in Zambales
  • Phreatomagmatic: violent eruption due to water-magma contact, resulting in fine ash column and high-speed emission of pyroclastic materials
  • Strombolian: periodic, weak to violent eruption characterized by fountain lava, like Irazu Volcano in Costa Rica
• • Cinder cone volcanoes do not contain molten rock, it tends to be quiet and explosive, it's base is narrow and the crater is very visible

  • Composite volcanoes eruption alternate between lava and ash and that causes this volcano to have perfect or symmetrical shape. It is quiet and explosive.

  • Shield volcanoes is non-explosive and quiet, the magma is runny because of it's low silica. It can grow to 100km
• Volcanoes erupt when molten rock called magma rises to the surface
• Magma is formed when the earth's mantle melts
• Melting may happen when tectonic plates are pulling apart or when one plate is pushed under another
• Magma is lighter than the surrounding rocks, so it rises towards the Earth's surface
• As magma rises, bubbles of gas form inside it
• Running magma erupts through openings or vents in the Earth's crust before flowing onto its surface as lava
• If magma is thick, gas bubbles cannot easily escape
• Pressure builds up as the magma rises
• When the pressure is too much, an explosive eruption can happen, which can be dangerous and destructive
• Volcanoes erupt when molten rock called magma rises to the surface

  Magma rises towards the Earth's surface when tectonic plates are pulling apart or when plate is pushed down under another