Download The Hawaiian Islands

The Hawaiian Islands
• The Hawaiian Islands are not on any plate
boundary.
• They are in the middle of the pacific plate
• There are a few theories as to how they go
there…
Theory 1
• Intensive radioactivity creates a huge upwelling
of lava, known as a “plume”.
• The plume of plastic rock from the asthenosphere
pushes upwards.
• This lies at a fixed position under the Tectonic
Plate. As the plate moves over this “hot spot”,
volcanoes are formed. As the crust and part of
the plate are thinned.
• These domes or plumes of plastic rock can be up
to 1,000 km across.
Theory 2
-proposed in 2003 by G. Foulger.
• She proposed that all plates have scars and
fissures from collisions or divergence and that
some large plates like the Pacific are
“stretched” as their edges subduct.
• These more vulnerable parts of the crust pass
over slabs of previously subducted material
that melt easily lowered pressure, so hot spots
are formed.
Scheme of a Hawaiian eruption.
1. Ash plume
2. Lava fountain
3. Crater
4. Lava lake
5. Fumaroles
6. Lava flow
7. Layers of lava and ash
8. Stratum
9. Sill
10. Magma conduit
11. Magma chamber
12. Dike
Hazards
• Kilauea Volcano on the island of Hawaii is
extremely active right now.
• The toxic gasses being released have increased
each month since the beginning of the 2008
• This resulted in parts of the island being declared
a disaster area in 2009
• Some towns are becoming uninhabitable and the
county has notified island residents that they
should not wait for an alert if they feel ill from
the volcanic activity.
Kilauea Volcano
The volcano spews
toxic gasses. The
volcano releases
Sulphur Dioxide,
which acts as an
atmospheric
coolant. This lowers
the temperature of
the sun rays.