Welcome to Science 10/21
• Answer the following questions on your sheet of
paper:
• 1. What is the title of Ch. 9 ?
• 2. What is the title of Ch. 9 Sec. 3?
• 3. What were the terms to learn for Ch. 9 Sec. 3?
• 4. In a short paragraph, describe the main idea of
Ch. 9 Sec. 3.
Volcanoes and Plate Tectonics
Section 1
What do you know?
Question of the Day
• Pictured below is a map of the world’s volcanoes
and plate boundaries. What relationship between
volcanoes and plate boundaries can be drawn
from observing this map?
• Plate boundaries and volcanoes are found in close
proximity. The movement of Earth’s plates
creates volcanic mountains.
I. What is a
volcano?
• Volcano-weak spot in
the crust where molten
material comes to the
surface.
• Magma- a molten
mixture of rock-forming
substances, gases, and
water from the mantle.
• Lava- magma that
reaches Earth’s surface.
II. Where are most volcanoes found?
• Volcanic Belts- areas along plate boundaries where
there are many volcanoes.
• Ring of Fire- major volcanic belt formed by the
many volcanoes that rim the Pacific Ocean.
III. The Ring of Fire
75% of the world’s volcanoes are found in the Ring of Fire. 90% of the
world’s EQs happens in the Ring of Fire.
Why?
The movements
of the Pacific Plate.
•
IV. Volcanoes and Diverging Boundaries
• Volcanoes form at mid-ocean ridges and rift
valleys, which are diverging plate boundaries.
• rift valley volcano
V. Volcanoes and Converging Boundaries
• These volcanoes form in 2 ways.
• Volcanoes can form when two oceanic plates
collide or when an oceanic plate collides with a
continental plate.
VI. Island Arc Volcano
Tectonic Settings and Volcanic Activity
• Form when 2 oceanic plates collide. The
subducting plate melts to create magma. This
magma rises up through the ocean floor to form
volcanic islands.
VII.Continental Arc Volcano
Tectonic Settings and Volcanic Activity
• Form when an oceanic plate & a cont. plate
collide. The oceanic plate is subducted under
the cont. plate causing it to melt into magma.
The magma rises through the continent to form
volcanoes.
VIII. Hot Spot Volcanoes
• Hot spot- is an area where material from deep
within the mantle rises and then melts forming
magma.
• Hot spot can be near plate boundaries or in the
middle of a plate.
IX. Hot Spot
Tectonic Settings and Volcanic ActivityAnimation
• A volcano forms above a hot spot when magma
erupts through the crust and reaches the surface.
• As the plate moves, new volcanoes will form over
the Hot Spot.
TrackStar Activity
• TrackStar