Transcript Hot Spot Volcanoes

Hot Spot Volcanoes
Animation
Animation 2
Volcanic activity at mid-ocean ridge can form
ocean islands (e.g., Iceland).
Volcanic Activity at Tectonic Plate Boundaries
Source: USGS http://pubs.usgs.gov/gip/hawaii/page10.html
However Not all volcanoes occur at
plate boundaries.
HOT SPOTS: areas of volcanoes that
result from plumes of hot solid material
that have risen from deep within
Earth’s mantle.
Map of hot spots
http://www.math.montana.edu/~nmp/materials/ess/geosphere/advanced/activities/hotspots/index.html
Hawaiian Islands
Source: USGS http://pubs.usgs.gov/gip/hawaii/page05.html
Northwest Movement of Pacific Plate Over
Fixed Hawaiian Hot Spot
Source: USGS http://pubs.usgs.gov/gip/hawaii/page12.html
Ages of Hawaiian Islands
Source: http://volcano.und.edu/vwdocs/vwlessons/hotspots.html
Hot Spot Volcanism
All of the mountains in this
map of the floor of the
Pacific Ocean are
volcanoes
Note that there are several
long chains of volcanoes
But there are also many
individual volcanoes
None of these volcanoes
are formed along plate
boundaries
Hot Spot Volcanism
These isolated areas of
volcanic activity are not
associated with plate
boundaries
These volcanoes are
found both on continents
and out in the ocean
Hot Spot Volcanism
A plume of hot mantle
material rises up to the
bottom of the lithosphere
Melting occurs and
magma is created
These are called “hot
spots”
They can last for many
millions of years
Hot Spot Volcanism
The magma works its way
to the surface over the
hot spot and a volcano is
formed
Out in the ocean, the
volcano may or may not
reach the surface and
form an island
In fact, few oceanic
volcanoes reach the
surface
Hot Spot Volcanism
As the moving plate
carries the volcano away
from the hot spot, the
volcano dies out
With time, another
volcano may form
This cycle may repeat
many times, forming a
long chain of under sea
volcanoes and islands
Hot Spot Volcanism
The Hawaiian Islands are the classic
example of hot spot volcanism
Hot Spot Volcanism
Every island in the Hawaiian Island chain was
created by volcanic eruptions that occurred as
the Pacific Oceanic Plate crossed over a hot spot
Hot Spot Volcanism
In fact, the 7 main Hawaiian Islands are just the
southern most portion of two great undersea
mountain ranges, composed of hundreds of
volcanoes, that runs for 6000 kilometers (4000
miles) across the floor of the Pacific Ocean
Hot Spot Volcanism
The plate has
moved to the
northwest for
more than 65
million years
The big island
of Hawaii is
now over the
hot spot
Hot Spot Volcanism
The volcanoes that
formed the Hawaiian
islands are classified
as shield volcanoes
Hot Spot Volcanism
Shield volcanoes are characterized by broad,
gentle slopes built up from repeated basaltic
lava flows
Hot Spot Volcanism
Not all eruption create big islands
Molokini represents one eruption that
is slowly being reclaimed by the sea
Hot Spot Volcanism
Loihi Volcano, the youngest volcano of the
Hawaiian Island Chain, lies about 20 km off the
south coast of the Big Island
Currently it rises 3500 meters above the
surrounding sea floor and its summit is about
1000 meters beneath the surface
Fast and Slow Changes to
Earth’s Surface
http://www.pbs.org/wgbh/aso/tryit/tect
onics/shockwave-nojs.html
Changes due to Plate Tectonics
Fast: Earthquakes and volcanoes
Slow: Continental Drift
Fast Process: Volcanoes and
Hot Spots
http://www.youtube.com/watch?v=tfXG
bzgGJ74
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