Download 13-2 Notes

13-2 Notes
There are 2 main types of magma. They are:
1. Mafic
2. Felsic
Composition
Color
Make up
Viscosity
Texture
Gases
Produces
Magnesium and Iron
Feldspar and Silica
Dark in Color
Light in Color
Oceanic Crust
Continental Crust
Low Viscosity
High Viscosity
Runny Lava
Sticky Lava
Easily Escapes
Trapped: Water Vapor and
Carbon Dioxide
Quiet Eruption
Explosive Eruptions sending
molten and solid particles
shooting into the air.
Examples
Lava Flow, Hawaii
Pahoehoe
Aa
Pyroclastic Material
Volcanic dust < 0.25mm
Volcanic Ash < 2mm
Lapilli or
“Little Stones”< 64mm
Volcanic Bombs = BIG
Volcanic Blocks = BIGGER
3 main types of volcanoes:
1) Shield
2) Cinder Cone
Slope
Area Covered
Type of eruption
Layers
Gently sloping
sides
Steep, close to
40o
Not as steep as
cinder cones
Wide area
Quiet eruption
Mafic lava
Smaller area
explosive
Pyroclastic
material
3)Composite
Larger than a
Quiet and
Mafic lava and
cinder cone
explosive
Pyroclastic
eruptions
material
Craters: The funnel-shaped pit at the top of a volcanic vent is known as a crater.
Calderas: When the magma chamber below a volcano empties, the volcanic cone
may collapse and leave a large, basin-shaped depression called a caldera.
Predicting: Warning signals of volcanic eruptions:
1. An increase in the strength and frequency of earthquakes.
2. Temperature changes within the rock.
3. Fracturing of the rock around a volcano.
Links:
Pahoehoe Lava Flow:
http://www.youtube.com/watch?v=HURs_JxnKdg&NR=1
http://www.youtube.com/watch?v=qiVVvQ9SVfc&feature=relate
d
http://www.youtube.com/watch?v=xsJn8izcKtg&feature=related
http://www.youtube.com/watch?v=Ff9DpZIDWFs&NR=1
Aa Lava Flow:
http://www.youtube.com/watch?v=iyIV5fd1Aww
Felsic Eruption:
http://www.youtube.com/watch?v=vBJ9xZws7ro&feature=PlayLis
t&p=C4472E8C9A54D3CD&index=14
http://www.youtube.com/watch?v=I07WBMUH7Ns&feature=relat
ed