hazards and lavas

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  • hazards and lavas
    • hazards
      • continental
        • sismic activity
          • rising magma can create volcainoes
      • oceanic
        • effusive submarine volcanic activity
          • creates effusive volcanoes on surface too can be phreatic though when mixes with ice
      • oceanic and continental
        • 80% of worlds volcainoes
          • rising magma exploits weaknesses in the plate
            • viscous magma can create explosive volcanoes like Pinatubo
      • continental and continental
        • shallow seismic activity
          • e.g. in Pakistan in 2005
      • oceanic and ocianic
        • 80% of worlds volcainoes
          • rising magma exploits weaknesses in the plate
            • viscous magma can create explosive volcanoes like Pinatubo
        • creates deep focused earthquakes like the chillie earthquake
    • lavas!
      • andesitic
        • from the oceanic plates
          • strata volcano
            • not usaually frequent eruptions
            • realeases ash and lava bombs
            • cone shaped
            • slopes built up of ash and lava
            • can form secondary cones
          • lava charachteristics
            • viscous thick  lava
            • formed on destructive boundary ocean-cont
      • rhyolitic
        • from the continental plates
          • lava forms...
            • ash and cinder cones
              • gas and ash explodes in which lava boms are created
              • explosive
              • made fro a build up of ash and cinder making a concade shape
            • acid dome volcainoes
              • has steep convex slopes
              • non frequent eruptions
              • violent eruptions with pyroclastic flows
          • lava charachteristics
            • thick and vicous
            • explosive as gas cannot escape through it
      • basaltic
        • from the mantle
          • lava forms...
            • shield volcainoes
              • gas easily escapes
              • frequent non violent eruptions
              • have gentle slopes and the lava travels long distance
            • occurs along constructive margins and hotspots.
          • lava charactheristics
            • runny low viscosity
            • low in silica
            • gas can easily escape
      • cakaderas
        • steep sided
        • no summit
        • a collapsed magma chamber cn fill with water
          • non frequent eruptions
    • hotspots
      • e.g. Hawaii and Iceland
        • a plume of a rising thermal current from the core rises to the athsenosphere
          • the oceanic lithosphere is thin and due to a fall in pressure magma is created
            • the rising magma burns through the crust
              • this creates submarine volcanoes that eventually form islands
                • due to plate movement these islands move away from the hot spot eventually becoming volcanically inactive
                  • the islands that have moved get eroded over time by the sea
                    • new island are created on the new area of the plate that has moved over the hotspot
    • examples of volcinoes
      • ash cylinder
        • Paricutin (mexico)
      • caladera
        • pinatubo
        • yelloestone
      • strata
        • etna scicilly
        • Untitled
      • acid dome
        • mount pele
      • fissure
        • moana loa
          • hawaii

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