Transcript Unit 1.5- Volcanoes - Aspen View Academy

Unit 1.5- Volcanoes
Introduction to Volcanoes
•Forces of Nature- National Geographic
Video
Latitude and Longitude Review
• Latitudes are imaginary lines to the north
and south of the equator (x- axis)
• Longitudes are imaginary lines to the east
and west of the Prime Meridian (y-axis)
Example: Plot the following Points
(1, 4), (2, 3), and (5, 2)
Earthquake Locations
• Where did most of the Volcanoes occur?
• How is this similar to where earthquakes occur?
• How does plate tectonic movement effect the location of volcanoes?
Ring of Fire
• The volcanoes belt that
circles the Pacific Ocean is
called the Ring of Fire
Volcanoes at Subduction Zones
• Volcanoes Form at Subduction Zones Video
• At CONVERGENT BOUNDARIES the denser
plate subducts below the less dense plate to
form a trench. As this dense plate gets pulled
into the mantle, it begins to melt
• This melted rock rises toward the crust and
forms a volcano
How do Volcanoes form in the middle of a plate?
• Volcanoes that do not form on plate boundaries
form over Hot Spots
• Hot Spots Video
• Hot magma from the core rises through the
mantle and heats the earth’s crust until it breaks
through the crust.
• As it breaks through the crust, lava is spewed
into the ocean and hardens into an island.
• The oceanic crust moves like a conveyer belt and
forms a string of islands like the Hawaiian
islands.
Anatomy of a Volcano
• Can we go inside a volcano and see what it looks like?
• How could we learn what the inside of a volcano is like?
What does the inside of a volcano look like?
• In your notes, draw and label a picture of what you think the inside of
a volcano looks like.
Anatomy of a Volcano Vocabulary
• Magma- Molten rock beneath the
surface
• Lava- Molten rock on the surface
• Magma Chamber- as magma rises to
the surface, it forms a large pocket
beneath the surface that holds the
magma
• Pipe: a narrow crack in the crust
through which magma flows
• Vent- central opening that allows the
flow of magma to the surface (where
magma leaves the pipe)
• Crater- the bowl-like depression over
the vent at the summit of the cone
Types of Volcanoes
• Cinder Cone
• Shield
• Composite
Cinder Cone Volcano
• A small, steep- sided volcano
• Made mostly of cinders with lava flow
intermixed
• Eruptions are small and often do not cause
damage
Shield Volcano
•
•
•
•
Usually wider than it is tall
Made entirely of lava
Near oceans or on oceanic crust
Eruptions are quiet, but lava
causes significant damage
Composite Volcano
• A large, steep-sided volcano
• Made of alternating layers of lava flow and pyroclastic debris
• Pyroclastic Debris: ash, lava and hot volcanic gas
• Erupt explosively or quietly
Life Cycle of Volcanoes
1. Active Volcanoes: a volcano that is erupting now, has erupted
in the recent past, and shows signs of erupting in the near
future
2. Dormant Volcano: a volcano that has not erupted recently, but
has during recorded history. It is expected to erupt again in the
future.
3. Extinct Volcano: has not erupted in recorded history and will
not likely erupt again.