Science 9 3rd Grading

• a volcano is an elevated landform with an opening at the top
• the word volcano comes from Vulcan, the Roman god of fire
• crust is the outermost layer of the earth
• beneath the earth's crust is a region called the Mantle which is about 2890 km thick
• tectonic plates can move toward each other, drift away from each other, or override each other with the heavier tectonic plate sinking to the mantle and the lighter plate rising above it on a process called SUBDUCTION
• magma is a semi molten (not totally liquid) rock that tries to escape upward through spaces between plates
• once the magma reaches the crust it is called LAVA that flows over the surface, building layer upon layer until a volcano is formed
• summit is the highest point or the apex of a volcano
• a CRATER is a funnel-shaped opening at the top of the volcano
• a CALDERA is formed when a part of the wall collapse following an explosive eruption
• slope is the rising or falling surface of a volcano - it is a surface of which one end or side is at a higher level than another
• base is the lowest part if the volcano and it is the supporting layer
• the crater is the bowl-shaped depression at the top of the volcano where the vent is located
• vent is an opening where volcanic materials are released
• fissure is an elongated fracture or crack on earth's crust
• conduit is the passageway through which magma travels to reach earth's surface
• flank is the side of a volcano
• magma chamber or reservoir is the underground compartment where the magma is stored
• stratovolcano is formed by highly viscous or thick slow moving lava
• stratovolcano is also known as composite cone volcano
• stratovolcano are the most dangerous volcanoes
• the cinder cone volcano is also known as the scoria cone
• the cinder cone volcano is formed by fluid lava that is ejected because of high pressure that builds up in the magma chamber
• the shield volcano is by loose and fluid lava that flows over each other
• the shield volcano is usually low and broad, resembling a warrior's armored shield or a gigantic blob
• volcanic eruptions occur when magma rises to the surface and erupts through a vent in the earth's crust
• hawaiian eruptions are the least violent and non-explosive
• hawaiian eruptions form shield volcanoes
• Hawaiian eruptions are characterized by the effusive eruption of basaltic lava
• strombolian eruptions are characterized by frequent, small explosions that eject cinders, ash, and blobs of molten lava
• strombolian eruptions form cinder cone volcanoes
• vulcanian eruptions are more explosive than hawaiian and strombolian eruptions
• vulcanian eruptions are characterized by the ejection of a thick, viscous magma lows around the vent
• plinian eruptions are the most explosive type of volcanic eruptions
• Plinian eruptions are characterized by the eruption of large amounts of ash, gas, and pumice into the air, forming a mushroom-shaped cloud that can rise several tens of kilometers
• magma is a molten material that is stored under the earths surface
• magma forms when rock under the earths surface melt
• lava is a molten material that has reached the earth's surface through the volcanic vents
• lava hardens and solidifies forming an igneous rock
• lava and magma has the same composition