1. Warm-Up: Fri 2/21 Write What You Know!
Write everything you know about the prompt below for five minutes, try for at least 3-4 complete sentences.
Describe how low-viscosity magmas behave differently than high-viscosity magmas. What does viscosity even mean?

2. Eruption Notes 2/21/2014 Major Key Term Key Term
definition in own words
Key Term
definition in own words
facts
pictures
Key Term

3. Volcanic Eruptions What makes volcano go boom?
Magma forms in asthenosphere (mantle)
Hot molten material naturally rises, and great pressure underground forces magma up through mantle and crust through cracks
Magma often gets trapped under layers of rock, forming a magma chamber
If magma finds a weak spot, it can burn through and form a volcano!

4. Wait, what about the actual *boom*?
gas pressure!!!
magma has many dissolved gases mixed in to its “recipe”
as magma rises through the surface, rock pressure decreases and gases expand
force of expanding gases causes the magma to erupt from volcano
magma minus escaped gases = lava

5. Types of Eruptions Quiet Eruption
Low silica, low water, low viscosity magma erupts “quietly”, like Mt. Kilauea
Gases in magma bubble out gently
Lava oozes and flows out slowly and can travel for many kilometers

6. Types of Eruptions Explosive Eruption:
High silica, high water, high viscosity erupts violently, like Mt. St. Helens
“sticky” magma builds up in volcano until enormous pressure of trapped gases causes the entire mountain to explode!
Pyroclastic Flow: a mixture of hot gases, ash, cinders, and bombs that explodes out of a volcano

7. Life Cycle of a Volcano
Active: a volcano that is erupting or shows signs it might erupt in the near future
Dormant: not currently active, but may “awaken” in the future
Extinct: a volcano unlikely to ever erupt again

8. Assignments Read Chapter 3.3: Volcanic Eruptions
Complete Review 3.3 Worksheet
Continue filling out “Properties of Magma” chart
And

9. Assignment: Volcano Anatomy
vent, crater, pipe, side vent, lava flow, magma chamber
(pg 93 in textbook)