shield volcano- broad, gently sloping volcano formed by quiet eruptions of basaltic lava. composite...
TRANSCRIPT
Volcanos – Book F Chapter 6
• Shield Volcano- broad, gently sloping volcano formed by quiet eruptions of basaltic lava.
• Composite Volcano-volcano built by alternating explosive and quiet eruptions that produce layers of tephra and lava; found mostly where Earth’s plates come together and one plate sinks below the other.
• Cinder Cone- steep –sided, loosely packed volcano formed when tephra falls to the ground.
Types of Volcanos Found on Earth
broad, gently sloping volcano formed by
quiet eruptions of basaltic lava.• Kilauea (Hawaii)
• Mauna Loa (Hawaii)
• Etna (Sicily)
• Piton de la Fournaise (Reunion)
• Erta Ale (Ethiopia)
• Fernandina and all Galapagos volcanoes
• Nyamuragira (Congo)
• Karthala (Indian Ocean)
• Savai’i (Samoa)
• Aoba (Vanuatu)
Shield Volcano
Volcano built by alternating explosive and quiet
eruptions that produce layers of tephra and
lava; found mostly where Earth’s plates come
together and one plate sinks below the other.
• Mount Fuji-Japan
• Mount Cotopaxi- Ecuador
• Mount Hood- Oregon
• Mount Rainier and Mount St.
Helens- Washington
Composite Volcano
steep –sided, loosely packed volcano
formed when tephra falls to the
ground.• California Cinder Cones
• Cerro Negro, Nicaragua
• Lava Butte, Oregon
• Newberry Caldera Vicinity, Oregon
• New Mexico Cinder Cones
• Paricutin, Mexico
• Portland Vicinity, Oregon
• Sunset Crater, Arizona
• Wizard Island, Crater Lake, Oregon
Cinder Cone
The reason volcanoes occur is
because when the Earth’s plates
pull apart they cause magma to
rise to the surface. Volcanoes
can also occur above hotspots
and where one plate goes
beneath another, forcing the
magma to rise above the
surface.
Why do volcanoes occur?
Volcanic eruptions occur in certain place
and don’t randomly occur. The reason for
this is because the Earth’s outermost
shell. (The lithosphere) is broken into a
series of slabs known as lithospheric or
tectonic plates. These plates are rigid,
but they float on the hotter, softer layer
in the Earth’s mantle.
Where do volcanoes usually occur?
The hot temperatures inside the
Earth’s mantle can melt rock;
creating magma.
• Magma can reach up to 700 and
1300 degrees Celsius depending
on the chemical composition of
the rocks.
• All igneous rock found on the
Earth was originally formed as
magma.
Magma
is the molten rock that comes out of
volcanoes during eruptions
• Lava can range in temperature from
about 750 degrees C to more than
1100 C.
• The temperature of the lava actually
depends on the composition of the
minerals in it. Some contain large
amounts of aluminum, potassium and
calcium, while others have iron and
magnesium.
Lava
• Magma is a liquid rock inside
a volcano
• Lava is a liquid rock (magma)
that flows out of a volcano.
What is the difference between lava and magma?
• Igneous rocks are formed from the molten
liquid minerals that lie below the earth’s
crust. They’re formed from magma that
cools beneath the earth’s surface or from
lava that cools upon the earth’s surface.
• Lava cools quickly and forms rocks with
small crystals. They are called extrusive
igneous rocks. Basalt is an example of this
type of rock. Obsidian is an example of
another extrusive igneous rock that cooled
so fast that it has no crystals and looks
like shiny, black glass.
Types of rocks formed when magma and lava cool and how.
• Extrusive (volcanic) - produced when magma
flows on the earth's surface
• Intrusive (plutonic) - produced when magma
solidifies at depth beneath the earth.
• Silica
• Obsidian
• Feldspar
• Quarts
• Amphiboles
• Pyroxenes
• Olivine
• Mica
• Basalt Granite
Types of Igneous Rock features formed from volcanic activity.
• Location- East Antarctica
• Summit - 3,794/ 12,447
• Hazards/Damage- Lava flows, some minor
explosions from Strombolian-style eruptions,
tephra/ash fall.
• Last known eruption- Start Date- December
1972 (on or before) Stop Date- 2011 (in or
after) January 14th, 2011 but is erupting as an
open vent system. Persistent current activity.
• The volcano always has hot gas and lava ,
creating surreal caves and towers. Has ice
caves and a pool of lava (one of the few of its
kind)
Mount Erebus