Transcript volcanoes!!! - Schoolwires.net

VOLCANOES!
WHAT IS A VOLCANO?
Volcano

An opening in Earth’s crust through which
molten rock, rock fragments and hot gases
erupt.
 More than 1500 active volcanoes.
Products:
Rock Fragments:
 Ash
 Cinders
 Blocks
Volcanic Gases:
 Mixture of gases and
ash
 Volcanic gas + rock
fragments=
PYROCLASTIC FLOW
( a dense cloud of super
hot gases and rock
fragments and is very
dangerous)
Volcano according to Eruption Activity:
 Active: A volcano that is currently erupting or
is just about to erupt. Ex. Mt. Helens
The most active volcano…
Kilauea
Located in Hawaii
Erupting for centuries!
ICELAND
 Famous for
active
volcanoes
 Iceland is
known as the
“Land of fire
and ice”
 Dormant : A volcano that is not currently erupting,
but that has erupted in the recent past. Mt. Rainier
 Extinct: A volcano that has not erupted in recorded
history, and is unlikely to erupt again.
 Ex. Mt. Kilimanjaro
Parts of a Volcano:
Vent = an opening in a
volcano where magma flows
out through.
Crater = the steep-walled
depression around a
volcano’s vent
Volcanic cone - the pile of lava, dust, ashes,
and rock around the vent. It can be found in
different shapes!
Magma -hot molten rock inside the earth.
Lava - the flowing magma that pours from
the crater.
Types of Volcanoes:
Shield Volcano
Composite Volcano
Cinder Cone
Depends on:
 Quiet or explosive eruption
 Type of lava it is made of
(basaltic, granitic, andesitic)
Shield Volcano:
 Broad, Flat Dome shape
 Built up through many eruptions of thin layered lava
with low silica.
 Ex. Rangitoto in New Zealand
Cinder Cone:
 Steep, cone shaped hill.
 Formed on the sides of other types of volcanoes by
loose pile of volcanic rock fragments.
 Ex. Sunset Crater in Az.
Composite Volcano:
 Cone shaped volcano
 High in silica
 Built up of layers of hardened lava and fragments.
 Ex. Mt. Helens
Krakatau
This volcano erupted
with such great force
that the island
disappeared.
Most of the island
collapsed into the
emptied magma
chamber
Noise was so loud that it
woke up people in
Australia!!!
More than 36,000
people killed
Area around the volcano
was in completely dark
for about 24 hours.
Effects of Volcanic Eruptions
 Human impacts
- can cause lung disease
- forces people to abandon homes
 Environmental Impacts
- collapse buildings
- block roads
- acid rain (sulfurous gases mix with
water vapor)
- cities, towns and crops can be damaged
Bringing it all home…
37.5 miles away!
Baja California, Mexico
Cerro Prieto ("Dark Hill")
The last eruption at the volcano is unknown, but may be
within the past 10,000 years.
Home again…
Pinacate
Northwestern Sonora, Mexico
91 miles away
Composite volcanic mountains created over long periods of time by sequential eruptions from
evolving magma bodies are found in many of these fields; Pinacate has Volcan Santa Clara,
the only Trachyte Shield Volcano in North America (on the horizon). Magma interacted with
ground water in about a third of these fields to create steam explosion hydro-volcanoes.
Pinacate's steam explosion maar-calderas (Sykes Crater above) are the most spectacular
such craters outside of Africa.