Question:
•How are these
volcanoes in
Hawaii formed?
Trivia
• The Hawaiian Islands were
formed by a stationary
volcanic hotspot beneath the
Pacific Plate. As the plate
slowly moves northwest at
about 7–10 cm per year, the
hotspot keeps producing
magma in the same spot,
creating a chain of islands of
different ages—the youngest,
Hawaii (the Big Island), is still
growing today from active
volcanic eruptions.
Short Video Clip on Volcanic Hot spots
https://www.youtube.com/watch?v=AhSaE0omw9o
HOT SPOT
• An area in the mantle from which hot materials rise as a
thermal plume.
• High heat ad lower pressure at the base of the
lithosphere (tectonic plate) facilitates melting of the rock.
This melt, called magma, rises through the cracks and
erupts to form volcanoes.
• As the tectonic plate moves over the stationary hot spot,
the volcanoes are rafted away and new ones form in their
place. This results in the chains of volcanoes, such as the
Hawaiian Islands.
When extensive mapping of seafloor
volcanoes in the Pacific revealed a chain of
volcanic structures extending from the
Hawaiian Islands to Midway Islands. When
geologists determined the age of each
volcanic island through radiometric dating,
they noticed that the farther the volcano
from Hawaii is, the older and less active it is.
Scientists suggested that there is a source of molten
materials from the mantle called mantle plume that
formed the volcanic island chains. As the Pacific plate
moves, different parts of it will be on top of the mantle
plume to receive the molten materials, thus creating the
volcanic islands. Continuing plate movement eventually
carries the island beyond the hot spot, cutting it off from
the magma source, and volcanism ceases. As one island
volcano becomes extinct, another develops over the hot
spot, and the cycle is repeated. This process of volcano
growth and death, over many millions of years, has left a
long trail of volcanic islands and seamounts across the
Pacific Ocean floor.
• Consider this illustration in answering questions 1 to 5.
A. 1. Which volcano is the youngest?
2. Which volcano is the oldest?
3. Volcano B is ________________than volcano C.
4. The farther a volcano is from the mantle plume, the ___________ is the
age of the volcano.
5. The volcano on top of the mantle plume is the _______________.
B.6. (U – Relate hotspot with plate tectonic)
Which statement best describes the relationship between a hotspot and plate tectonics?
A. Hotspots occur only along plate boundaries where plates collide.
B. Hotspots remain stationary while tectonic plates move over them. C. Hotspots move
together with the tectonic plate.
D. Hotspots form only in subduction zones.
7. (U – Describe hotspot)
What is a hotspot?
A. A crack in the Earth’s crust that forms only during earthquakes.
B. A region in the mantle where rocks melt to form magma that rises to the surface.
C. A zone where two plates slide past each other.
D. An area on the ocean floor without any volcanic activity.
8. (U – Explain the formation of Hawaiian Islands)
How did the Hawaiian Islands form?
A. They were pushed up by colliding tectonic plates.
B. They formed from a hotspot while the Pacific Plate moved over it.
C. They appeared after an asteroid impact.
D. They are remnants of an ancient continental plate.
C 1. Explain in 3-5 sentences how a hotspot is formed.
