Transcript Volcanoes and Plate Tectonics

Volcanoes and Plate Tectonics (69)
What Are Volcanoes?
• A volcano is an
opening in Earth that
erupts gases, ash,
and lava.
• Volcanic mountains
form from layer of ash
and lava.
• Earth has approx 600
active volcanoes
Most Active Volcanoes
• Kilauea located in
Hawaii, is the world’s
most active volcano
• Eruptions from
Kilauea began
in January 1983
and still
continues.
Kilauea
• http://www.telegraph.co.uk/news/worldnew
s/australiaandthepacific/hawaii/8365606/H
awaiis-Kilauea-volcano-erupts.html
Iceland
• Land of fire and ice.
• Sits on a divergent plate
boundary.
• Lava flows destroy
everything in their path
• Falling volcanic ash can
collapse buildings, block
roads.
• http://www.bbc.co.uk/new
s/world-europe-15995845
Magma Forced Upwards
• Deep inside Earth,
heat and pressure
changes cause rock
to melt, forming liquid
rock or magma.
• Magma is less dense
than the rock around
it, so it is forced
slowly toward Earth’s
surface.
• Magma reaches
Earth’s surface and
flows out through an
opening called a
vent.
• Lava, cools quickly
solidifies, forming
igneous rock layers
around the vent.
• The steep walled
depression around a
volcano’s vent is the
crater
• Volcanoes form in
places where plates
are moving apart,
moving together, and
at locations called hot
spots.
• Example of a hot spot
is the formation of the
Hawaiian Islands.
Hot Spots
• Hawaiian Islands created
because of volcanic activity.
• Hot rock forced toward the
crust where it melts partially
to form a hot spot.
• Pacific Plate is moving over
a stationary hot spot.
• http://www.history.com/sho
ws/how-the-earth-wasmade/videos/how-washawaii-formed#how-washawaii-formed
• The opening in a volcano from which lava
flows is called the __________.
• A. plate
• B. shield
• C. tephra
• D. vent
The steep-walled depression around a
volcano’s vent is a __________.
• A. crater
• B. rift
• C. shield
• D. trough
• What is a hot spot?
Hot rock that is forced
toward the crust
partially melts,
forming what are
known as hot spots.
The Hawaiian Islands
sit on top of a hot spot
under the Pacific
Plate.