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GG103
Nasir Gadzar
http://pubs.usgs.gov/gip/hazards/mauna-loa.html
http://pubs.usgs.gov/gip/hazards/maunakea-kohala.html
http://pubs.usgs.gov/gip/hazards/hualalai.html
http://pubs.usgs.gov/gip/hazards/kilauea.html
Mahukona
Loihihi
• Volcanoes Defined
• Types of Volcanoes
• Volcanoes of the island of
Hawaii
–Descriptions
–Images
• Presentation Summary
Volcanoes Defined
• vol·ca·no n. pl., vol·ca·noes or
vol·ca·nos. Abbr. vol.
• 1. a. An opening in the earth's crust
through which molten lava, ash, and gases
are ejected. b. A similar opening on the
surface of another planet.
• 2. A mountain formed by the materials
ejected from a volcano.
Types of Volcanoes
• Geologist categorize volcanoes into four
groups.
1)Composite
2)Cinder
3)Shield
4)Lava domes
Composite Volcanoes
• Called “composite” because they are made of
alternating layers of lava and rock.
• Oftentimes called “Stratovolcanoes”
• Physical Characteristics
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–
–
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Steep
Symmetrical cone shaped
Often have snowcapped tops
Explosive eruptions
Examples of Composite volcanoes
Mount Ranier, Washington, USA
Mount Fuji, Honshu, Japan
Cinder Volcanoes
• Simplest type of volcano
• Built from particles globs of coagulated
lava expelled from a solitary vent which
then falls and solidifies around the vent to
form a circular cone.
• Physical Characteristics
– Bowl shaped crater
– Size is usually about 1000ft. The size of a hill.
– Single vent
Example of Cinder cone volcanoe
Parícutin volocano, Mexico
Lava domes
• Also known as “volcanic domes”
• Usually occur on flanks of composite volcanoes
• Formed by bulbous masses of lava too viscous
to flow any great distance, eventually piles
around vent and dome becomes bigger from
acitivity within.
• Physical Characteristics
– Rounded
– Steep sided
Example of Lava dome
Unzen lava dome, Japan
Shield Volcano
• Built almost entirely of fluid lava flows. Flow
pours out in all directions from a central summit
vent, or group of vents, building a broad, gently
sloping cone of flat, domical shape, that profiles
a warrior shield.
• built up slowly by the accretion of thousands of
highly fluid lava flows called basalt lava that
spread widely over great distances, and then
cool as thin, gently dipping sheets. Lavas also
commonly erupt from vents along fractures (rift
zones) that develop on the flanks of the cone.
Shield Volcano facts
• 3-4 miles in diameter but heights of 1500-2000
feet.
• The Hawaiian Islands are composed of linear
chains of these volcanoes.
• Shield Volcanoes of the Island of Hawaii
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Kilauea
Mauna Loa
Mauna Kea
Hualalai
Kohala
• Southernmost shield volcano on the Big
Island.
• Predominantly erupts basaltic lava in
profuse eruptions.
• Kilauea stands just under 4200 feet tall at
it's highest point.
• Kilauea has a 165m deep circular caldera
at its summit that measures 3x5km.
• At 60 miles long and 30 miles wide, it
makes up half of the entire island.
• Mauna Loa is the largest active volcano in
the world.
• The thickness of its lava pile from the
center of the volcano from is 56,080 ft
(17,170 m).
• Tallest volcano on the Island of Hawaii.
• Tallest mountain in the world.
• From sea floor to summit it towers more
than 5.6 miles (9 km).
• Mauna Kea is the only Hawaiian volcano
known to be glaciated.
• The most recent eruption was about 3,500
years ago. Mauna Kea is considered a
dormant volcano.
Cinder cone on top of Mauna Kea
• The summit of Hualalai rises to an elevation of
2523m (8271ft) above sea level.
• Hualalai is well-known in Hawaii as a good
source for mantle xenoliths.
• The surface of Hualalai is entirely composed of
post-shield alkalic basalts.
• The last historical eruption at Hualalai ended in
1801. This eruption produced very fluid, high
velocity lava flows that entered the ocean off
western Hawaii.
• Presently, the volcano is mantled by alkalic lavas
erupted during the post-shield stage of
volcanism.
• Summit elevation of 1700 m (5577ft.)
• Kohala is considered to be extinct
because it has not erupted for 60,000
years.
• Kohala is the oldest of the sub-aerial
volcanoes that make the Island Of Hawaii.
• Volcanoes are openings in the earth's crust
through which molten lava, ash, and gases are
ejected.
• There are four categories of volcanoes
1) Composite
2) Cinder
3) Lava dome
4) Shield
• Volcanoes found in the island of Hawaii are
Shield volcanoes, these volcanoes names are:
Kilauea, Mauna Loa, Mauna Kea, Hualalai, and
Kohala. Mahukona is a seamount in west.