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Hawaii hotspot

earth science Maturity 7-9 Next article →

The Hawaii hotspot is a significant volcanic feature located in the northern Pacific Ocean. It is responsible for the Hawaiian–Emperor seamount chain, which is a massive undersea volcanic mountain range. This chain extends from the island of Hawaii all the way to the Aleutian Trench near the eastern coast of Russia.

Bathymetry image of the Hawaiian archipelago
Bathymetry image of the Hawaiian archipelago

While most volcanoes form at the boundaries where tectonic plates meet, the Hawaii hotspot is located far from any plate boundaries. This makes it a unique area for scientists to study how magma reaches the Earth's surface. The hotspot has been active for at least 85 million years, producing a massive amount of rock during its history.

To understand how this works, we must look at the mantle plume. A mantle plume is a rising column of hot, buoyant rock from deep within the Earth. This plume may originate at a shallow interface in the lower mantle or at the D'' layer, which is a deep layer just above the core-mantle boundary.

Earth cutaway schematic-en
Earth cutaway schematic-en

As the mantle material is heated, it undergoes thermal expansion and becomes less dense. This causes it to rise toward the surface as a Rayleigh-Taylor instability. When the plume reaches the base of the lithosphere, it heats the rock and produces melt. This magma then travels upward to erupt as lava on the seafloor.

The creation of the islands follows a specific cycle driven by the Pacific Plate. According to the classic hotspot theory, the mantle plume remains relatively fixed in one position deep underground. However, the Pacific Plate moves steadily over this stationary source of heat.

WorldCrustalAge - Hawaii hotspot
WorldCrustalAge - Hawaii hotspot

As the plate slides, the plume creates a volcano in one spot. As the plate continues its journey, it carries that volcano away from the magma source. This process eventually cuts off the supply of lava to the volcano. Once the eruptions stop, the volcano becomes extinct and begins to erode.

This process creates a long trail of volcanic features that show the history of plate movement. Some volcanoes remain as large islands, while others erode and sink to become seamounts or atolls.

Coral atoll formation animation
Coral atoll formation animation

The Hawaiian–Emperor chain contains more than 123 volcanoes in total. Currently, four of these volcanoes are active, while two are dormant. The rest are extinct, with many preserved as undersea mountains. The age of the islands changes depending on their distance from the hotspot. For example, the rock on Hawaii Island is less than 0.7 million years old, whereas the rock on Kauai is about 5.5 million years old.

One of the most famous features of this chain is a sudden 60-degree bend. For many years, scientists used the classic hotspot theory to explain this shape. John Tuzo Wilson proposed in 1963 that this bend occurred because the Pacific Plate changed its direction of movement. This change might have been caused by different rates of subduction or drag forces from other plates. However, a 2003 study using lava samples from the Detroit Seamount suggested a different cause. This new research proposed a mobile hotspot hypothesis, suggesting the bend happened because the hotspot itself moved.

Modern science now considers a more complex view of how these hotspots behave. Some researchers suggest a three-stage model for the Hawaii hotspot. In the first stage, the hotspot may have interacted with a spreading ridge. The second stage involved mutual movements between the Pacific Plate and the moving hotspot.

Loa and Kea trends
Loa and Kea trends

During this time, the hotspot may have drifted several degrees to the south. Finally, the third stage involves the continued movement of the Pacific Plate while the hotspot becomes stagnant. This combination of ideas helps explain the complex paths seen in volcanic tracks.

Human observation of these volcanoes has a long history. Ancient Hawaiians recognized the changing state of the islands and included volcanic deities like Pele in their mythology. Formal scientific study began in the late 19th century with James Dwight Dana. Later, in 1912, Thomas Jaggar founded the Hawaiian Volcano Observatory to allow for constant monitoring.

East rift zone kilauea
East rift zone kilauea

Today, tools like tomographic imaging allow scientists to see the wide, deep structure of the plume. This helps us understand how these massive systems shape our planet over millions of years.

Puu Oo cropped
Puu Oo cropped
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🖼️ Images & Media (7)
File:WorldCrustalAge - Hawaii hotspot.png
WorldCrustalAge - Hawaii hotspot.png
File:Earth cutaway schematic-en.svg
Earth cutaway schematic-en.svg
File:Loa and Kea trends.svg
Loa and Kea trends.svg
File:Puu Oo cropped.jpg
Puu Oo cropped.jpg
File:Bathymetry image of the Hawaiian archipelago.png
Bathymetry image of the Hawaiian archipelago.png
File:East rift zone kilauea.jpg
East rift zone kilauea.jpg
File:Coral atoll formation animation.gif
Coral atoll formation animation.gif
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