1. Section 9.2
Volcanic Eruptions

2. “the Scream” by Edvard Munsch is about volcanoes and the ash it emiited into the atmosphere that traveled for thousands of miles and months

3. What FACTORS determine if a volcano erupts violently or quietly?

4. Quiet eruptions Hawaii & Iceland

5. Explosive, violent eruption

6. Felsic magma Mafec* magma
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Felsic magma Mafec* magma
Feldspar, silica magnesium and iron
Expolsivity depends on the amount of silica and gas in the magma.

7. Which has a HIGH viscosity?
Resistance to flow
honey
The more Viscous the magma, the more it resists flowing out of the volcano, the more explosive the eruption
water

8. FELSIC magma HIGH viscosity MAFIC magma LOW viscosity
Light colored minerals:
Quartz, orthoclase Feldspar
More than 60% silica
HIGH viscosity
MAFIC magma
Dark colored minerals:
Magnesium and iron Fe
Olivine, pyroxene,
Hornblende, augite, biotite
Less than 50% silica
LOW viscosity

9. Geode CD-ROM Lesson 1. Nature of Volcanic Eruptions And
Lesson 2. Materials Extruded During
Volcanic Eruptions

10. Bell-work Pyroclastics consist of …… - Cinders Lapillii Glass Pumice
Ash
Cinders
Lapillii
Glass
Pumice
Bombs
Blocks
Tuff (welded ash)

11. Bell-work 4. What is 1 difference and 1 similarity between a …
Pyroclastic flow and a Lahar

12. Volcanic Explosivity Index
How to measure a volcanic eruption
There is the Fajita scale for tornadoes, the Safiir-Simpson scale for hurricanes, Richter scale for earthquakes, and the VEI scale for volcanoes

13. Paroxysmal a sudden outburst of a violent eruption
an increase of periodic eruptions
An eruption with a (V.E.I.) Volcanic Explosivity Index of 5 (on a scale of 0-8)

14. Lava Vocabulary Quiz 9.2 pyroclastic
Hot, erupted glass, ash, and rock fragments. ________________
All lava flows are this type of rock. _____________________
3. A basaltic lava that results in smooth, ropelike surfaces: ____________
Magma has a high viscosity because it contains over 70% of ________
If the magma has a high gas content, the eruptions tend to be ________
Because of their high silica content, this rock is light colored. ________
viscosity lava aa pahoehoe
pillow lava pyroclastic ash silica
cinders igneous metamorphic sedimentary
non-explosive mafic explosive felsic
igneous
pahoehoe
silica
explosive
felsic

15. Before the 1980 eruption After the VIOLENT eruption
The summit and side has been blown away.

16. A portion of the side of the mountain was “blown away” leaving the mountain less steep. Flatter terrain then before.
*Construct the profile activity

19. “I was walking along a path with two friends – the sun was setting - suddenly the sky turned blood red I paused, feeling exhausted, and leaned on the fence - there was blood and tongues of fire above the blue-black fjord and the city my friends walked on, and I stood there trembling with anxiety - and I sensed an infinite scream passing through nature."
Edvard Munch

20. An agonized figure wails against a blood red Norwegian skyline in Edvard Munch's “The Scream” (1893) in the National Gallery, Oslo, Norway
The 1883 eruption of the volcano Krakatoa in Indonesia put so much ash into the atmosphere, it caused unusually intense sunsets throughout Europe in the winter of , which Munch captured in his painting.

21. Based upon the description…
What type of volcano was this?
shield, stratovolcano, cinder cone
2. What type of magma erupted?
mafic or felsic
What type of plate boundary does this volcano lie on? Convergent, divergent, transform
What would the eruption be on the V.E.I.