SCIENCE - VOLCANOES 4th Quarter

• Volcanism - pertains to all volcanic activities and phenomena

  
  

  - part of the process of bringing material from the deep

  interior of the planet
• Volcanoes - mountains, hills, or any vent or opening on the earth's

  crust which hot materials are expelled
• Ash - gasses released by volcano with a high content of sulfur and dust
• Vent - where magma flows out
• Main Vent - the main pathway of magma during volcanic eruption
• Crater - an opening in the top of volcano
• Secondary vent - because of the extreme heat and pressure during volcanic eruption some magma find another way out and it is where it is formed
• Magma Chamber - a large underground pool of melted rocks
• Magma - molten rocks beneath the Earth's surface

  - a layer of semi-liquid rock and dissolved gasses
• Lava - a magma that has escaped to the Earth's surface
• Volcanic Eruption - occurs when the pressure inside the magma chamber builds up, causing magma to be pushed out of a volcano
• Active Volcano - is one that has erupted 10 000 years ago

  * often shows signs of unrest, whish means that it may erupt again in the near future
• Dormant Volcano - are those that have not erupted for more that 10 000 year
• Extinct Volcano - are those that do not have shown signs of eruption and are not expected to erupt in the future
• PHILVOLCS - is the government agency that studies and monitors volcanic activities and earthquakes in the country
• Shield Volcano - extrudes highly fluid lava and forms a broad, doomed structure
• Mauna Loa - in Hawaii, worlds largest volcano
• Cinder cone - also known as scoria cone

  - most familiar kind of volcano

  - symmetrical cone-shaped, have steep slopes and cluster around larger volcanoes
• Parasitic cones - (single volcanoes or as secondary volcanoes) on the sides stratovolcanoes or shield volcano
• Tephra - airborne fragments of lava
• Stratovolcano - composite volcano

  - layers built by alternating lava flow, ash and unmelted

  blocks of stone

  - bigger that cinder cones

  - can erupt violently
• Icelandic - characterized by effusions of molten basaltic lava
• Hawaiian - fluid lava flows from summit and radial fissures to from shield volcano
• Strombolian - moderate bursts of expanding gases that eject clots of incandescent lava in cyclical or nearly continuous small eruptions
• Vulcanian -exhibits moderate explosions of gas laden with volcanic ash
• Pelean - associated with explosive outbursts that generate dense mixtures of hot volcanic fragments and gas
• Plinian - intensely violent kind of volcanic eruption exemplified by the outburst of Mt. Vesuvius