Unit Seven Notes

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Volcanoes
gvc1007.gvc10.virtualclassroom.org
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Volcano Terminology

• Volcano
• Fissure
• Hot spot
• Lava
• Pahoehoe
• Lapilli
• Pillow lava
• Volcanic ash

• Aa
• Cinder cone
• Magma
• Stratovolcano
• Vent
• Composite volcano
• Mafic lava
• Shield volcano

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Earth Science (4/24)

• Infinite Campus
• Seismic Map (10pts.)
• Seismic Waves packet (23pts.)
• Earthquake Quiz (22 pts.)
• Objectives
• Review earthquake quiz and study guide
• Earthquake Exam
• Read, annotate, and summarize volcano legends.

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What is a volcano?

• Annotate and summarize each Volcano Legend
• Which legend would you be more inclined to
  believe and why? (Lived during that time period)
• What do you think a volcano is? (Be specific)

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Earth Science (4/25)

• Due Today
• Volcano legend summaries
• Objectives
• What is a volcano.
• Origin of a volcano.
• Anatomy of a volcano.

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What is a volcano?

• Volcano
• an opening in the earths surface through which
  lava, hot gases, and rock fragments erupt.

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Origin of Volcanoes

1. Magma 80-160 km below the earths surface slowly
   begins to rise to the surface.
2. As the magma rises it melts gaps in the
   surrounding rock.
3. As more magma rises a large reservoir forms as
   close as 3.2 km below the surface (magma chamber).

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Origin of Volcanoes

• Pressure from the surrounding rock causes the
  magma to blast or melt a conduit (channel) to the
  surface where magma erupts onto the surface
  through a vent (opening)

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Origin of Volcanoes

• The magma, now called lava, builds up at the vent
  forming a volcano

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Origin of Volcanoes

• 6. Over time the volcanoes sides will be higher
  than the vent forming a depression called a
  crater.

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• Crater

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• Caldera
• an unusually large crater or the remains when
  the cone collapses into its own magma chamber

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Anatomy of a Volcano

• Cone
• the above ground structure built from lava or
  tephra.

Mt. Kilauea in Hawaii
gvc1007.gvc10.virtualclassroom.org
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• Conduit
• the path that magma takes from the magma chamber
  to the vent.

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• Magma Chamber
• the reservoir located under the volcano where
  magma collects and becomes the supply of
  magma/lava to build the volcano

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Lava

• Molten, solidified rock on the surface of the
  earth.
• Solidfied lava is called?

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• Parasitic Cone
• a smaller secondary volcano built on the side of
  or near the main volcano, but sharing the same
  conduit to the magma chamber

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• Vent opening of the volcano, through which lava,
  ash and gases flow

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• Fumarole
• a secondary vent that emits only gases

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• Fissure
• a long fissure (crack) from which lava flows

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Volcano Illustration

• Illustrate a volcano using these terms below.

• Cone
• Crust
• Mantle
• Magma
• Lava
• Magma Chamber
• Conduit
• Vent
• Fumarole

• Tephra
• Gases
• Parasitic Cone

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Volcano Illustration

• Illustrate a volcano using these terms below.

• Cone
• Crust
• Mantle
• Magma
• Lava
• Magma Chamber
• Conduit
• Vent
• Fumarole

• Tephra
• Gases
• Parasitic Cone

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Volcanoes (4/26)

• Objectives
• Complete volcano illustration.
• Distinguish between the 3 types of lava.
• Discuss and illustrate the classes of volcanic
  tephra.
• Identify the types of volcanic gases.
• Distinguish the difference between quiet and
  violent eruptions.

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Volcano Illustration

• Illustrate a volcano using these terms below.

• Cone
• Crust
• Mantle
• Magma
• Lava
• Magma Chamber
• Conduit
• Vent
• Fumarole

• Tephra
• Gases
• Parasitic Cone

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Take a minute to label the parts on the diagram
(not all parts are shown)
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Crater
Ash Cloud/Gases
Vent
Parasitic Cone
Lava Flow
conduit
mantle
Magma chamber
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• Lava There are 3 kinds

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• Pahoehoe lava
• Hot, thin, fast flowing.
• Hardens with a relatively smooth surface
• Often has a ropy or wrinkled appearance

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• Pahoehoe lava

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• Aa lava
• Cooler, thicker, slow moving.
• Hardens with a rough, jagged, sharp edge surface.

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• Pillow Lava
• Lava suddenly cooled by water.
• Shows sack-like segments (stuffed pillows)

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Can you identify the kinds of lava from the
pictures?
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1
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2
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3
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4
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• Tephra
• (pyroclastic, rock fragments)
• Three Types of Tephra
• 1. Volcanic dust
• 2. Volcanic Ash
• 3. bombs

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• Types of Tephra
• Volcanic Dust
• Smallest particles and carried by atmosphere
  circulation.

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• types of Tephra
• Volcanic Ash
• 0.25-0.5 cm diameter
• Generally settles out within miles of the cone
  but can be carried greater distances by stronger
  winds.
• Forms a mudflow when mixed with water

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• Lahar (mudflow)
• mixture of ash, eroded land, and water flowing
  down river valleys.

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• Lahar (mudflow)

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• Types of Tephra
• Bomb
• Smaller bombs (gravel, pea size) are called
  cinders.
• Walnut size bombs are called lapilli.
• Larger fragments up to 4 feet in diameter are
  called bombs.

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• Types of Gases Expelled
• water vapor, carbon dioxide, nitrogen, sulfur
  dioxide, hydrogen sulfide, chlorine

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Volcanoes

• What is the difference between the following
• lava and magma
• fumarole and fissure
• Pahoehoe, Pillow, and Aa lava
• What is the following
• lahar b. tephra
• Identify the three classes of tephra.
• What type of gases are ejected from a volcano?

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Types of Volcanic Eruptions

• Volcanic eruptions can be explosive or quiet.
• What two factors determine the type of eruption
  a volcano can have?

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Types of Volcanic Eruptions

• What two factors determine type of eruptions?
• Amount of water vapor other gases in the magma.
  
• The chemical make-up of the magma.

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Explosive Eruptions

• Primarily caused by granitic magma
• Thick magma
• High water content
• What type of lava is associated with granitic
  magma?

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Explosive Eruptions
Mont Serrat An island located near Puerto Rico
and the Dominican Republic
Mt. Pinatubo Located on the island of Luzon
near the Philippine Islands
Mt. St. Helens Located in Washington State
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Quiet Eruptions

• Primarily caused by basaltic magma
• More fluid magma
• Low water content
• What type of lava is associated with basaltic
  magma?

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Quiet Eruptions
Mt. Kiluea in Hawaii
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Location of Volcanic Activity
From the diagram, where do most volcanic activity
occur?
scienceclarified.com
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Locations of Volcanoes

• Divergent Boundaries
• As the plates move apart, long cracks (rifts)
  form and lava builds up forming volcanoes.
• The long cracks are also called?

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• If the divergent boundary is on the ocean floor,
  volcanoes can grow tall enough to break the
  surface of the ocean and become islands (Iceland)

vulcan.wr.usgs.gov
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• Convergent Boundaries
• Places where plates are moving toward each other
  forming a subduction zone.
• One plate melts under the other and the magma
  moves upward to form volcanoes.

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• Example Cascade Volcanoes

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• Convergent Boundaries Volcanoes
• Example Pacific Ring of Fire

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Seismic Activity
blog.wolfram.com
58
In your notes, explain how the scientific
evidence belowestablishes a connection between
volcanic and earthquake activity.
blog.wolfram.com
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Hot Spots

• Magma that may originate in the mantle or outer
  core will move upward, breaking the surface and
  forming a volcano, they are independent of plate
  boundaries and a chain of volcanoes may form as
  the plate moves across a hot spot.

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Hot Spots

• (Examples Hawaiian Islands and Yellowstone
  National Park)

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Earth Science (5/1)

• Infinite Campus Upadate
• Earthquake Exam (51pts.)
• Hotspot Worksheet (10pts.)
• Volcano Illustrations (10pts.)
• Types of Volcanoes (9pts)
• Objectives
• Identify types of volcanoes.
• Discuss activity levels of volcanoes (active,
  dormant, extinct)
• Quiz tomorrow over volcanoes
• Volcano Exam Friday

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Types of Volcano Mountains

• Cinder Cones
• Small base, steep-sided, loosely consolidated.
• Commonly built from gravel size lava rock
  fragments called cinders.
• Has violent eruptions and granitic lava sticks
  rather than flows.
• Up to 1000 feet tall
• Life span of a few years.

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Types of VolcanoEs

• Cinder Cone Illustration

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Cinder Cone Volcanoes
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Sketch a Cinder Cone Volcano
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Types of Volcano Mountains

• Shield Volcanoes
• Large base, gentle slope, lava rock layers
• A few miles high
• Life span of a million years or more
• The lava is hot, thin, very fluid, often
  basaltic.
• Example Hawaiian Islands

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Shield Volcanoes
Take a look at these examples http//ww.volcano.s
i.edu/world/tpgallery.cfm?categoryShield20Volcan
oes
The Mauna Loa volcano in Hawaiithe largest
volcano on Earthhas the broad expanse
characteristic of shield volcanoes. It spreads
across half the island of Hawaii.
Shield volcano on Mars Taken from space
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• Shield Volcanoes

Mauna Kea
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Sketch a sheild Volcano
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Types of Volcano Mountains

• Composite (strato) Volcanoes
• Alternates between tephra and lava eruptions.
• Tephra adds height to the volcano and lava
  cements the tephra together and adds to the base.
  
• Located mostly in subduction zones
• Known to have violent eruptions.
• Life span of million years or more.
• Large mountain volcano often snow capped, a few
  miles high
• Examples Mt Rainier, Mt Fuji, Mt Kilimanjaro

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• Composite (strato) Volcanoes

Mt. Fuji Honshu Island of Japan
Mt. Rainier Seattle, WA
Mt. Kilimanjaro Tanzania in Africa
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Sketch a composite Volcano
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Types of volcanoes
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Volcano Activity Levels (Stages)

• Active (awake)
• Has erupted within the last 10,000 yrs.
  (historical time).
• Pre-eruption activities
• Increase in earthquake activity under the cone.
• Increase in temperature of cone
• Melting of ice/snow in the crater
• Swelling of the cone
• Steam eruptions
• Minor ash eruptions

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Mt St. Helens, Washington State Erupted in May of
1980
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• Dormant (sleeping)
• Eruptions have occurred in the last 10,000
  years, but little to any activity is recently
  detected under the cone.
• Can become active and erupt again after a wake
  up period.
• Example Mt. Rainier Mt. Vesuvius

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• Mount Rainier
• The most dangerous volcano in the US
• Primary danger is the formation of lahars
  traveling down river valleys at a speed of 25mph
  and destroying everything in its path
• 100,000 people live on the solidified mudflows of
  previous eruptions
• Erupted 4xs in the last 4,000 yrs.

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Mount Vesuvius

• Erupted Last 79 A.D.

Naples, Italy
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• Extinct
• No eruption within recorded history.
• Not expected to ever erupt again.
• No magma supply detected.
• Example Mount Kohala in Hawaii Mount Mazama
  (Crater Lake), in Oregon.

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Mt. Kohala in Hawaii

• Has not erupted in a million years.
• No signs of volcanic activity under the cone.
• One of the five largest volcanoes in Hawaii.

http//en.wikipedia.org/wiki/Kohala_28mountain29
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Multiple Extinct Volcanoes comprising the Hawaii
Islands
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Crater Lake
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Super Volcanoes

• Volcanoes video clip addressing the super
  volcano under Yellowstone National Park

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(No Transcript)
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