Transcript Volcanoes Notes 5 of 5

#17: Plate Boundaries Bellringer
1. Sketch the diagram below
2. Label: two convergent boundaries, divergent boundary, transform boundary, and a rift
valley
3. Below your sketch, describe the following:
- What is a convergent boundary?
- What is a divergent boundary?
- What is a transform boundary?
- What is a rift valley?
V. Volcanoes:
What, Where, & Why
Krakatoa Eruption
A. What is Volcanic Activity?
Ring of Fire and Volcanoes
1. An opening in Earth’s
crust through which
molten rock, ash and
gasses erupt.
2. The landform that
develops around the
opening.
3. A way for Earth to
release heat energy
from the interior due
to radioactive decay.
D. Peebles
B. Types of Volcanoes
1. Composite
2. Shield
G. Vaughn
USGS
Mt. St. Helens, WA
Mauna Loa, HW
3. Cinder
A. Heisey
Sunset Crater, AZ
C. How Do Volcanoes Differ?
1. Size
2. Shape
3. Composition
4. Location
Tarbuck & Lutgens
Questions 1 & 2
• Which type of volcano is the widest?
A. Cinder B. Composite C. Shield
• What type of volcano typically produces
the largest crater when forming?
A. Cinder
B. Composite C. Shield
D. Composition
1. Magma viscosity: fluid thickness
– Silica content: more = thicker
(most explosive)
– Temperature: higher= thinner
Kilauea, HW
2. Mafic
– Little silica
3. Felsic
– Lots of silica
D. Peebles, USGS
4. Pyroclastic- explosive eruption
with a mixture of gases, ash,
cinders (pebble sized lava
particles), & bombs (large lava
particles)
Mt. St. Helens,
WA
D. Weintraub
Questions 3
•
Which variable determines how
explosive a volcanic eruption will be?
A. Gases
B. Silica
C. Temperature
E. Types of Lava Flow
1. Flow types: depend
on temperature
– Pahoehoe: fast
moving, hot lava, low
viscosity
Aa Flow
J.D. Griggs, USGS
Pahoehoe Flow
– http://www.youtube.com/watch?v=
KGmLMbw_1CE&feature=related
J.D. Griggs, USGS
– Aa: slow moving,
cooler, high viscosity
– http://www.youtube.com/wa
tch?v=iyIV5fd1Aww
D. Peebles, USGS
J. Judd, USGS
F. Shield Volcanoes
1. Mafic lava (fluid)
– nonexplosive eruptions, slow
build up
– Hot spots
2. Structure
– Low angle slope
– http://www.youtube.com/watch
?v=byJp5o49IF4
Tarbuck & Lutgens
Questions 5, 6 & 7
•
Shield volcanoes are composed of what
type of lavas?
A. Mafic
•
B. Felsic
C. Andesitic
The shape of a shield volcano is due to
A. fluid, low viscosity lavas B. high viscosity lavas
C. pyroclastics
D. gases
•
Shield volcanoes are usually associated
with what landform feature/s or processes?
A. pyroclastic flows
C. steep sided cones
B. explosive eruptions
D. Gentle sloped cones
G. Cinder Cones
1. Felsic lavas
– Large amt. pyroclastics
– Gentle & explosive
– High viscosity
2. Structure
– High slope
A. Heisey
3. Deep crater
http://www.youtube.com/watch
?v=aS_xl3nu_mY
Tarbuck & Lutgens
Example: Paricutin
• West of Mexico City
• 1943 eruption began
• Cornfield of Dionisio
Pulido
• Earthquakes
• 1st day 130 feet
• 5th day +330 feet
• Lava flows from base
• Nine years of eruption
T. Nichols
Cinder Cones
Pelee’s Cinder Cone, HI
Fire Fountain=Pyroclastics
USGS G. Lewis
USGS G. Lewis
USGS G. Lewis
Parasitic Cone
Questions 8
•
Cinder cones are composed of -?- lavas
A. Mafic
B. Felsic
C. Andesitic
H. Composite Volcanoes
• Felsic lavas
– Large amt. pyroclastics
– Viscous lavas
– Explosive / catastrophic
eruptions
– Subduction boundaries
• Structure
– Symmetrical cone
– Medium to high slope
• Ring of Fire
http://www.youtube.com/watch?v=1
u1Ys4m5zY4
M. Giannechini
Pomerape & Parinacota, Chile
Cascade Range
• 50+ eruptions in U.S.
in past 200 years
(mainly in Alaska)
• Pyroclastic Flows
• Lahars
USGS
USGS
Pre 1980 Eruption
Post 1980 Eruption
Mt. Saint Helens
May 18, 1980
Questions 11, 12, 13, & 14
•
Composite volcanoes are composed of -?lavas
A. Mafic
•
B. Felsic
The volcano with the steepest slope is a
A. Shield cone
•
C. Andesitic
B. Cinder cone
C. Composite cone
Volcanoes of the Cascade Range are
mainly
A. Shield
B. Cinder
C. Composite
Filmed in Wallace, Idaho
CBA: Volcano Types Review
1. Draw a detailed sketch of each type (pg.
218 red textbook)
-
composite, cinder, shield
Label all of the parts
Color magma/lava red & cinder brown
2. Include:
-
Type of lava (mafic, felsic, or both)
Type of eruption (quiet, explosive, or both)
Basic shape
Slope
I. Volcanoes Locations
1. Located along plate boundaries
2. “Ring of Fire”- major volcanic belt, formed
around the Pacific Ocean.
3. Hot spots-stationary plume of magma continually rising through the
crust from the athenosphere. Can occur in the middle of a plate.
Craters of the moon (Hotspot)
#19: Google Earth Field Trip
-We are taking a trip around the globe.
-You will be keeping a “field journal” of our
trip and recording details about each stop.
HERE WE GO!
#19 (continued)
• Please complete the following practice
questions in your composition notebook.
• Use the answer to check your completed
practice test.
Volcano Lab
1. Draw a detailed sketch of each type (pg.
218 Red textbook)
-
composite, cinder, shield
Label all of the parts
Color magma/lava red & cinder brown
2. Pg. 266 (Blk textbook)
-
Copy chart on back of graph paper
Complete volcanic chart & graph
Answer Conclusion questions 1-7 on separate
sheet of paper & staple to graph paper.
I. Calderas
Long Valley, CA
1. Huge hole left by the
collapse of a whole
mountain.
Crater Lake, OR
USGS G. Lewis
USGS G. Lewis
Mauna Loa, HW
J. Other Volcanic Structures
1. Plateaus- flat area
caused by lava flow.
2. Volcanic necksmagma left in vent,
extinct volcano
3. Dikes- molten
material that vertically
cut across rock layers
4. Sill- molten material
that horizontally cut
across rock layers
Tarbuck & Luntgens
5. Batholiths- large rock
structure, magma cools
inside crust
6. Active- erupting or will
erupt soon.
7. Dormant- erupt in the
future.
8. extinct- unlikely to erupt
again
Other Volcanic Features
Rift Eruption
G. Vaughn
Lava Plateaus
G.
J. Vaughn
Shelton
D. Falconer
T. Bean
Lava Dome
Volcanic Neck
Check Your Volcano Knowledge
• What purpose do volcanoes
serve on Earth?
• What is magma?
• List three factors that
determine the nature of a
volcanic eruption.
• What are the major gases
released in volcanic eruptions?
• What does Pahoehoe and Aa
refer to?
• What are the three types of
volcanoes? Describe each
one.
• What type of materials make
up pyroclastic flows?
• Generally, where are
volcanoes located on Earth?
• How does a caldera form?
• What are Lahars and what
type of volcano are they
usually associated with?
• Which type of volcano is the
most explosive?
• Name and describe three other
igneous features.