Objectives

1
Objectives
Volcanoes of the Island of Hawaii Seven Shield
Volcanoes Types of Volcanoes Descriptions and
Images Eruption Update
Mahukona
Loihi
REGIONAL DISTRIBUTION
2
Shield Volcanoes of the Island of Hawaii
How and why volcanoes erupt
GG103 Nasir Gadzar
3
5 Shield Volcanoes 2 Submarine cones
Shield Volcanoes - Regional Distribution
4
(No Transcript)
5
REGIONAL DISTRIBUTION
Red recent volcanism on the ocean floor
Green Hawaiian islands
Hawaiian Islands
Pacific Ocean
6
Hawaii
7
Island of Hawaii The subaerial (rocky, above sea
level) portion of the Island of Hawaii is made of
five volcanoes. From oldest to youngest, they are
Kohala, Mauna Kea, Hualalai, Mauna Loa, and
Kilauea. Each volcano can be recognized by its
size, shape, and physical features. Two other
volcanoes, Mahukona and Loihi, add to the
submarine base of the Island.
Mahukona
Pacific Ocean
8
Volcanoes of the Island of Hawaii, elevation,
area.
9
Volcanoes are classified as Active - These are
erupting or keep erupting. Kilauea Dormant -
These are not erupting but could at any time.
Mauna Kea Extinct - These volcanoes are no
longer active and do not erupt. Diamond Head
Crater
10
??1500 volcanoes are potentially actives on
Earth ?? 70 are currently in eruption ?? 10
of the human population is directly exposed to
volcanic risk. Several large cities are located
close to an active or dormant volcano
11
Cinder Cones  - Cinder cones are the simplest
type of volcano. They are built from particles
and blobs of congealed lava ejected from a single
vent. As the gas-charged lava is blown violently
into the air, it breaks into small fragments that
solidify and fall as cinders around the vent to
form a circular or oval cone. Most cinder cones
have a bowl-shaped crater at the summit and
rarely rise more than a thousand feet or so above
their surroundings. Cinder cones are numerous in
Hawaii as well as throughout other volcanic
terrains of the world.
12
Shields - Another easily recognized volcano which
is familiar is the Shield volcano. This type of
volcano can be hundreds of miles across and many
tens of thousands of feet high. The individual
islands of the state of Hawaii are simply large
shield volcanoes. Mauna Loa, a shield volcano on
the  island of Hawaii, is the largest single
mountain in the world, rising over 30,000 feet
above the ocean floor and reaching almost 100
miles across at its base. Shield volcanoes have
low slopes and consist almost entirely of frozen
lavas
13
The animation shows the steps in the formation of
a caldera. The volcano usually shows signs of
erupting by producing earthquakes as the magma
rises in the volcano.
14
Calderas - Calderas, are simply circular
depressions, are found on the summits of many
volcanoes. "Giant" calderas are the largest of
these huge craters up to many tens of miles
across. Giant Calderas form by collapse (see
animation) in gigantic eruptions that spew
volcanic rocks out hundreds or even a thousand
miles in all directions. Sometimes the calderas
are so filled with lava and volcanic ash that
there is no recognizable depression at all.
15
After a huge ejection of lava there may be no
magma left in the chamber to fill the conduit and
crater. When this happens there is a hollow space
under the summit of the mountain where the magma
used to be. The top of the mountain then
collapses creating a caldera.
16
The caldera may fill with water creating a lake.
17
REGIONAL DISTRIBUTION
18
REGIONAL DISTRIBUTION
19
Shield Volcanoes of the Hawaiian Islands Shield
Volcanoes are enormous features built up only
from layers of lava. They produce lots of Aa and
Pahohoe lava flows but they tend not to erupt
violently.
Topographic Profile of Mauna Loa
Basaltic Lava Flow
10,000m
250 kilometer
20
Hawaiian Islands Palaeogeographical Location of
the various islands over the active volcanic
activity (hotspot red circle) at different times
21
Kilauea magma hiding from volcano scientists 
Scientists at Kilauea Volcano are pondering the
big question Where is 250,000 cubic yards of
magma going if it's not flowing each day to the
Pu'u 'O'o eruption? Magma that forced its way
into the upper East Rift Zone and caused hundreds
of earthquakes finally cracked the surface.
22
Beware of lava from Kilauea.
23
A tour boat had a sea view of lava from Kilauea
flowing into the ocean. Michael Marlin
24
Lava flows from Kilauea March 12, 2008
25
An abandoned pickup truck is engulfed in flames
after lava from Kilauea came into contact with
it.
26
A backyard swimming pool in the Royal Gardens
area of the Big Island that was once filled with
water is now filled with lava from Kilauea.
27
Stages of Growth of Volcanoes in Hawaii, 500,000
years ago
28
In order of growth, the volcanoes that make the
island and its submarine base are Mahukona,
Kohala, Mauna Kea, Hualalai, Mauna Loa, Kilauea,
and Loihi. Mahukona, Kohala, Mauna Kea, and
Hualalai have completed their shield-building
stage.
Mahukona slides into the sea
29
The island has grown at an average rate of 0.008
mi2/yr (5 acres 0.02 km2/yr) for the past
600,000 years. It is estimated that 600,000 years
was required for each volcano to grow from the
ocean floor to the end of its shield building
stage
30
Kohala Shield Volcano Extinct volcano Most
Recent Eruption(s)About 120,000 years ago
Number of Historical Eruptionsnone Oldest
Dated RocksAbout 460,000 years before present
46 ??? Estimated Age of KohalaEmerged above
sea level before 500,000 years ago Hawaiian
Volcano StageTransition between postshield and
erosional stage
Location20.08 N 155.70 WElev. Above Sea Level
1,670 m5,480 ft Area 606 km2235 mi2(5.8 of
Hawaii) Volume 14,000 km3, 3,400 cu mi3
31
Mauna Kea tallest volcanoe Most Recent
Eruption(s)At least 7 separate vents erupted
between about 6,000 and 4,000 years ago Number
of Historical Eruptionsnone Oldest Dated
Rocks237,000 31,000 years before present 23
??? Estimated Age of Mauna KeaAbout 1 million
years, 100 ??? Volcano StagePost-shield Stage
(transition from shield stage to post-shield
occurred before about 200,000 to 250,000 years
ago)
Location19.82 N 155.47 WElev. Above Sea
Level4,205 m13,796 ft Area2,380 km2920
mi2(22.8 of Hawaii) Volume30,000 km37,200
mi3
32
Mauna Loa Most Recent Eruption, March 24-April
15, 1984 Summit Caldera Name Mokuaweoweo,
"Moku" refers to a coastal land section or islet
"aweoweo" is a type of red Hawaiian fish.
Literal translation is fish section Dimension 3
x 5 km, elongated northeast-southwest Depth 183
m deep Age estimated to have collapsed 600-750
years ago Oldest Dated RocksBetween 100,000 and
200,000 years ago Estimated Age of Earliest
Subaerial EruptionsAbout 400,000 years ago
Estimated Age of First Eruption of Mauna
LoaBetween 1,000,000 and 700,000 years before
present Hawaiian Volcano Stage Shield-forming
stage
Location19.475 N 155.608 WElev. Above Sea
Level4,170 m13,680 ftArea5,271 km22,035
mi2(50.5 of Hawaii) Volume80,000 km319,000
mi3
33
Location19.69 N 155.87 WElev. Above Sea
Level2,521 m8,271 ft Area751 km2290
mi2(7.2 of Hawaii) Volume12,400 km32,975 mi3
Hualalai Most Recent Eruption(s) 1800 and 1801
34
Hawaiian Meaning The Hawaiian name "Kilauea"
means "spewing" or "much spreading," apparently
in reference to the lava flows that it erupts.
Most Recent EruptionContinuous since January 3,
1983 Number of Historical Eruptions61, not
counting the continuous lava-lake activity in
Halemaumau crater Summit Caldera The caldera
itself has no Hawaiian name other than Kilauea
but houses the famous crater, Halemaumau
"hale" is a house, "maumau" a type of fern.
Dimension 6 x 6 km (outermost faults), 3 x 5 km
(main depression) Depth 165 m deep Age
probably several incremental collapses 500-210
years ago Oldest Dated Rocks23,000 years old
Estimated Age of Earliest Subaerial
Eruptions50,000-100,000 years Estimated Age of
First Eruption of Kilauea300,000-600,000 years
before present Hawaiian Volcano Stage
Shield-forming stage
Location19.425 N 155.292 W Elev. Above Sea
Level1,277 m4,190 ft Area1,430 km2552
mi2(13.7 of Hawaii) Volume25,000-35,000
km36,000-8,500 mi3
35
Loihi Seamount depth 969 meters will reach
surface in about 30,000 years
36
Volcano Safety
Mahukona
Loihi
37
March 19, 2008 Explosive eruption in Halemaumau
Crater, Kilauea Volcano, is first since 1924
Volcanic gas escapes from a vent in the
Halemaumau Crater near the Jaggar Museum inside
Hawaii Volcanoes National Park. AP Photo/Marco
Garcia
38
The explosion scattered debris over an area of
about 75 acres (30 hectares), covering a portion
of Crater Rim Drive and damaging the Halemaumau
overlook. Rocks ejected by yesterdays explosion
at Kilauea volcano dug impact craters when they
hit. Finer-grained material was blown away during
the impact. Boulders and smaller rocks were
scattered over a large area of Hawaii Volcanoes
National Park, but no one was injured. March
19,2008.
39
Kilauea an explosive volcano in Hawaii
Explosive eruptions at Kilauea are thought to be
caused when water comes into contact with hot or
molten rock (magma) and flashes into steam. In
1924, this happened after the level of the lava
lake in Halema'uma'u Crater dropped below the
water table. The walls of the crater then
collapsed and blocked the opening down which the
lava had drained, allowing steam pressure to
build up and cause violent explosions.
40
Many of Kilauea's pre-1924 explosive eruptions
that produced significant ash deposits probably
happened when the volcano's summit crater was so
deep that its floor was below the water table,
letting ground water seep in to form a lake.
Whenever magma erupted into the lake water,
violent explosions of steam and volcanic gases
resulted, fragmenting the magma into tiny ash
particles and driving fast-moving, extremely hot
ash-laden steam clouds (pyroclastic surges) out
of the crater.
41
Kilauea eruption blasts rocks across landscape
March 19, 2008. The most recent explosive
eruptions before March 19, 2008 were in 1924 and
were much bigger than the latest event. Those
explosions killed a photographer, who ventured
too close and was hit by falling rocks and hot
mud. This explosive eruption at Kilauea on May
22, 1924, the cloud was 2 miles high and still
rising. Geologists now believe such explosions
were common in the past
42
Rocks litter the area around a wooden fence at
the Kilauea volcano overlook. The fence was
heavily damaged yesterday in the first explosive
eruption at Kilauea volcano in almost a century.
43
The largest boulder to be blasted out of
Halemaumau Caldera was almost about 3 feet wide.
It landed on the steel cable of the barrier
adjacent to the trail next to the Halemaumau
Overlook. The recent increase in hydrothermal or
gas sources had forced the explosive eruption,
the first since May 1924. No lava was found in
the area.
44
A near vertical view looks down into the
explosion crater. The crater is estimated at
roughly 100 feet across.
45
KAMEHAMEHA'S VOLCANIC VICTORY The most
significant Kilauea eruption ever documented may
have altered Hawai'i's history, according to
records at the Hawaiian Volcano Observatory.
Kamehameha I, before becoming king and uniting
the Islands, was locked in an indecisive war with
his rival, Keoua. In 1790, a sudden eruption of
searingly hot ash and gas exploded out of Kilauea
as a large group of Keoua's warriors and their
families passed nearby. At least 80 and perhaps
hundreds of people were killed in the deadliest
historical eruption to occur in what is now the
United States. That disaster helped tip the
rivalry in Kamehameha's favor.
46
Pu'u 'O'o on Kilauea's East Rift Zone has been
producing about 2,000 metric tons of sulfur
dioxide a day for years, but only about 200 tons
per day were being released at Halema'uma'u at
the summit. That changed late last year when
sulfur dioxide emissions from the summit began to
climb, and by March 13 had reached record levels
of 2,000 tons a day as a new vent opened in the
wall of the crater.
47
Debris avalancheDebris avalanches are moving
masses of rock, soil and snow that occur when the
flank of a mountain or volcano collapses and
slides downslope. As the moving debris rushes
down a volcano and into river valleys, it
incorporates water, snow, trees, bridges,
buildings, and anything else in the way. Debris
avalanches may travel several kilometers before
coming to rest, or they may transform into more
water-rich lahars, which travel many tens of
kilometers downstream
48
(No Transcript)
49
Composition of Hawaiian Volcanoes Igneous
Rock The term igneous'' comes from the Latin
word ignis or fire''. Igneous rocks are rocks
which form from cooling magma or lava.
MagmaMolten or partially molten rock material
and dissolved gases. Magma is molten rock
beneath Earth's surface. LavaMolten or
partially molten rock material and dissolved
gases. Lava is molten rock which has erupted at
Earth's surface.
50
Volcanic steam was rising yesterday from the MLK
vent that has deepened on Kilauea
51
Hawaii Volcanoes National Park firefighter Sean
Grossman, with hose, filled a 5,000-gallon "frog
pond" in the park June 21, 2007. The plastic pool
was one of five set up by the park to have water
ready in case fire flares up from lava flows
52
Volcanic gases and vapors produce VOG - Volcanic
fog, LAZE- Lava haze, and acid rain. These air
pollutants cause health related problems, water
pollution and damage to crops. When sulfur
dioxide concentrations greater than 1 ppm (equal
to 1,000 parts per billion) are measured, then
the volcanic air pollution is common.
53
Slump fissure at edge of Alae crater has split
Chain of Craters Road. Kilauea east rift. Hawaii
Volcanoes National Park.
54
Giant landslides surrounding the Hawaiian Islands
are among the largest known on Earth, and most
have occurred within the past four million years.
The youngest is thought to have occurred only one
hundred thousand years ago, and there is evidence
today that large blocks of land on the island of
Hawaii are beginning to slide, generating large
earthquakes in the process. Each slide has
resulted in huge land losses to the islands and
resulted in large waves that have carried rocks
and sediments as high as 1000 ft above sea level.
The giant Hawaiian landslides are important to
study because, although they occur infrequently,
they have potential for enormous loss of life,
property, and resources. Much of the existing
topography in Hawaii, both on land and on the
seafloor, owes its origin to these landslides,
55
Kilauea has been erupting nearly continuously
since Jan. 3, 1983, sending lava from the Pu'u
O'o cone through a system of tubes to the ocean,
where it forms new land over time. In Hawaiian
tradition, Kilauea is home to Pele, the volcano
goddess. Lava is said to be her physical
representation
56
Kilauea Volcano 'Something's got to give' June
19, 2007 Watch Video at Honolulu Advertiser
Kilauea lava flows putting on showy
display  What to know about Kilauea  Kilauea's
recent activity hints at eruption pattern Magma
pumping into Kilauea volcano's upper East Rift
Zone has buried under lava or scorched nearly
seven acres of rainforest, with heat and gases
wilting and sickening trees, ferns and other
plants around two large cracks that opened this
week as the rift expanded Magma Chamber is half
filled.
57
Interior Tube
(After Harter Harter, 1979)
58
(After Harter Harter, 1979)
Surface Trench
59
(After Harter Harter, 1979)
Semi Trench
60
(After Harter Harter, 1979)
True Trench
61
Rift Tube - Pre-Flow
(After Macdonald, 1965)
62
Rift Tube - Flow 1
(After Macdonald, 1965)
63
Rift Tube - Flow 2
(After Macdonald, 1965)
64
Rift Tube - Flow 3
(After Macdonald, 1965)
65
Rift Tube - Flow 4
(After Macdonald, 1965)
66
Rift Tube - Flow 5
(After Macdonald, 1965)
67
Volcanic Lava Tube Forms
68
(No Transcript)
69
(No Transcript)
70
Kilauea "skylight" April 23, 2008 - where a
roof section of a lava tube collapsed and then
poured into the skylight, producing a brief
surface flow on its way downslope to the ocean.
71
Water Fills Tube
72
Lava flowing underground created this _____
_____, large enough to walk through.
lava
tube
73
(No Transcript)
74
Volcanoes Review

• Fast-moving clouds of gas, ash, and other tephra
  are called ____________ _
• Large, rounded tephra are called __________ .
• Iceland and Hawaii have ______ volcanoes.
• A wall-shaped igneous intrusion is a
  ______________.

pyroclastic flows
volcanic bombs
shield
dike
75
There are three types of volcanic cones
Cinder cones

• ______ explosive eruptions, small but steep
  slopes, pyroclastics
• _______ nonexplosive eruptions, fluid basaltic
  lava, gentle broad slopes
• _________ alternating between lava and
  pyroclastics, explosive and non-explosive
  eruptions, steep and tall towering

Shield
Composite
76
Kilauea on Hawaii is a good example of a _______
volcano, with some explosive eruptions and less
viscous lava.
shield