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Get Ready for an ERUPTION!!!
Three Types of Volcanos Shield Cinder Cone Composite
Shield Volcano Created by hot
spots Gently sloping
Cinder Volcano Steep Cone-shaped hill/
mountain Composite Volcano
Tall, cone-shaped mountain Alternating layers of ash and lava
http://www.earthonlinemedia.com/images/lithosphere/volcanism/shield_volcano_2.gif
http://www.earthonlinemedia.com/images/lithosphere/volcanism/shield_volcano_2.gif
Ecuador volcanoes, Guagua Pichincha volcano
Ash cinder and bombs erupt explosively to form a cone shaped
hill http://www.youtube.com/watch?v=aS_xl3nu_mY&NR=1&feature=endscreen
http://www.youtube.com/watch?v=1u1Ys4m5zY4
Quiet eruptions alternate with explosive forming layers of lava ash.
http://facweb.stvincent.edu/academics/pathways/science/volcanoes.htm
A weak spot in the crust where molten material, or magma, comes to the surface
Magma- molten mixture of rock-forming substances, gases & water from the mantle
Lava- Magma that reaches the surface
Volcanoes can be found: Diverging Plate boundaries
(mid-ocean ridge)
Converging plates with subduction zones Oceanic plate vs. oceanic plate Oceanic Plate vs. Continental plate
Hot Spots Area where magma from deep within the mantle
melts through the crust like a blow torch Example: Hawaiian Islands
Ring of Fire
A circular pattern located around the pacific ocean along the plate boundaries where volcanoes are more common
Are constructive: add new rock to existing land form new islands
Can be destructive explosive eruptions changes the
landscape of and around the volcano
Why do volcanoes erupt? Less dense magma seeps upward through
cracks and creates volcanoes Gas in the magma is trapped and builds
pressure Closer it gets to surface the less pressure it
has and the gases separate (bubbles) Gases dissolve on the surface and magma is
carried out
2 types: Quiet
Lava moves steadily and easily
Explosive Thick, sticky lava plugs vent like a cork and
builds up pressure Explodes and releases pyroclastic flow
Volcanic ash: fine, rock particles Cinders: pebble sized particles Bombs: baseball to car sized particles
Shield Volcano Created by hot spots Gently sloping
Cinder Volcano Steep Cone-shaped hill/mountain
Composite Volcano Tall, cone-shaped mountain Alternating layers of ash and lava
http://www.earthonlinemedia.com/images/lithosphere/volcanism/shield_volcano_2.gif
Ecuador volcanoes, Guagua Pichincha volcano
Ash cinder and bombs erupt explosively to form a cone shaped
hill http://www.youtube.com/watch?v=aS_xl3nu_mY&NR=1&feature=endscreen
http://www.youtube.com/watch?v=1u1Ys4m5zY4
Quiet eruptions alternate with explosive forming layers of lava ash.
http://facweb.stvincent.edu/academics/pathways/science/volcanoes.htm
Volcanoes can be found: Diverging Plate boundaries (mid-ocean ridge) Converging plates with subduction zones
Oceanic plate vs. oceanic plate
Hot Spots Area where magma from deep within the mantle
melts through the crust like a blow torch Example: Hawaiian Islands
Type of lava produces different types of rocks
Slower Flowing, Thicker, sticky, lighter colored
Rhyolite, Pumice, obsidian flows readily, dark colored
basalt
High Silica – thicker, sticky, lighter colored
Rhyolite, Pumice, Obsidian
Low silica lava flows readily, dark colored
Basalt
Quiet vs. Explosive – determined by
Percentage (amount) of silica (material made from the elements oxygen and silicon)
Active: (live) erupting or has shown signs that it may erupt In the near future
Dormant: (Sleeping) is not currently erupting but may/can erupt in the future
Extinct: (dead) unlikely to erupt again
Hot springs Groundwater is
heated by near by magma rising to the surface and collects in natural pools
Geyser Rising hot water
and steam that gets trapped underground and builds pressure until it sprays to the surface
http://w4.nkcsd.k12.mo.us/~mkurbin/ptrevgms.htm
Lava Plateaus Lava moves far from the volcano before
cooling which forms high plateaus
Calderas Huge hole left by the collapse of a volcanic
mountain All magma has been emptied leaving a hollow
shell that collapses
Volcanic Neck: magma hardens in the volcanoes pipes and the soft rock wears away
Dike: magma that was forced across rock layers hardens and the soft rock wears away
Sill: magma that squeezed between rock layers hardens and the soft rock wears away
Batholith Mass of rock formed when a large body of
magma cools in the crust
Dome Mountains Rising magma is blocked by horizontal rock
layers and forces the rock layers to bend upward into a dome shape and then the soft rock wears away
TYPES -- Shield - layers of lava- gradual hill - quiet -- Composite – Quiet/Explosive – layers ash and lava -- Cinder Cone – Quick Formation - Explosive
LOCATION (s) -- Hot Spots -- Ring of Fire (Convergent Boundary) -- Divergent Boundary (MOR-Mid Oceanic Ridge) --Island Arc (Convergent oceanic oceanic boundary)
ROCKS FORMED/LAVA FLOW -- Pyroclastic Flow – Cinder, Ash, Rock, Pumice, gases -- Pahoehoe – fast – low silica- low viscosity -- Aa – slow moving, high silica – high viscosity -- Pumice – Light and airy- from explosive eruptions -- Obsidian – more dense and smooth -- Basalt – low silica lava flow
FLOW & What determines it? --
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PARTS OF A VOLCANO -- -- -- -- -- -- --