science volcanos

• volcano 


  is a vent,hill, or mountain that erupts, releasing molten rocks, rock fragment, and gaseuous material,s onto the Earth's surface.
• it is where magma passes through from the magma chamber to reach the Earth's surface.

  main vent
• this is a large resorvoir that stores molten rock(magma) prior to eruption

  magma chamber
• it is a bowl shaped depression produced by volcanic activity and explosion

  crater
• this is the stream of molten rock flowing out of the crater

  lava flow
• this is an alternative smaller outlet where magma escapes to reach Earth's surface

  secondary vent
• this is formed when lava and ashes escape from smaller vents: it is also known as parasitic cones

  secondary cone
• are formed from pyroclastic fragments and volcanic ashes that form and solidify around the main vent to form a cone, which can be either circular or oval

  cinder cone
• composite volcanoes


  also known as stratovolcanoes are typically symmetrical cones that are steep and may rise as high as 2 400 meters (8 000 feet)
• shield volcanoes


  are formed from non-acidic basaltic lava flows of high viscosity producing broad sloping sides and shield like structures.
• active


  these volcanoes have erupted during historical times within the last 600 years
• these volcanoes are active but not erupting

  dormant
• these volcanoes have not had any eruptions in the past 10 000 years and are expected to not erupt anymore in the future.

  extinct
• preparation phase


  the magma chamber is being filled with magma.
• eruption phase


  the pressure will start to build up inside the magma chamber amd the energy starts to increase for eruption.
• ending phase


  the magma chamber is now empty.
• effusive eruptions 


  involve the outpouring of basaltic magma that is relatively low in viscosity and low in gas content
• explosive eruptions


  involve high viscosity and high gas content
• hawaiian type


  fluid basaltic lava is thrown into the air, creating a lava fountain or lava flows.
• strombolian type


  there is a burst of glowing lava due to the bursting of gas bubbles at the vent of the volcano.
• vulcanian type


  the eruption is short,eplosive, and violent.
• plinian 


  most violent among all types of volcanic eruptions
• phreatic 


  is a steam drivn explosion
• phreatomagmatic


  involves the eruption of magma that reacts to the external water.
• A mass of molten rocks that is larger than 64 mm in diameter

  Volcanic bombs
• A mixture of powder-sized rocks, minerals, and gas particles

  Volcanic ash