The diagram illustrates how the Hawaiian island chain forms in the central Pacific Ocean. It also shows the locations of the main islands in the chain.
Overall, the islands develop through repeated volcanic eruptions. As the Pacific tectonic plate moves, older volcanoes are carried away from the area of volcanic activity, while new volcanoes continue to form. This gradual process produces a chain of islands.
The eruption process begins approximately 2,883 kilometres below the surface, beneath a layer of solid, dense rock. Magma rises from this depth towards a fixed hot spot beneath the Pacific plate. Through numerous eruptions, volcanic material gradually builds up a volcano above the hot spot. The youngest volcano develops in this area.
The Pacific tectonic plate shifts at a rate of 7 to 9 centimetres per year, carrying existing volcanoes away from the fixed hot spot. As volcanic activity continues at that location, further volcanoes form in succession. Over millions of years, these volcanoes become part of the Hawaiian island chain. The oldest volcano shown dates back around 80 million years. The accompanying map identifies major islands, including Kauai, Oahu, Maui and Hawaii.