1. Mantle Plume: A plume of exceptionally hot magma rises from deep within the Earth's mantle.
2. Volcanic Activity: As the plume reaches the Earth's crust, it melts the overlying rock, creating a pool of magma. This magma erupts through the ocean floor, forming volcanoes.
3. Plate Movement: The Pacific tectonic plate moves slowly over the stationary hotspot. As the plate moves, the volcano is carried away from the hotspot and becomes extinct. A new volcano then forms over the hotspot, creating another island.
4. Chain Formation: This process continues over millions of years, creating a chain of volcanic islands. The oldest islands are the furthest from the hotspot, while the youngest islands are located directly above the hotspot (which is why the Big Island of Hawaii is still volcanically active).
Here's a simple analogy: Imagine a conveyor belt moving over a stationary candle. The conveyor belt represents the Pacific plate, and the candle represents the hotspot. As the conveyor belt moves, the heat from the candle melts the surface of the belt, creating a trail of burn marks. These burn marks are like the islands in the Hawaiian chain, formed by the heat of the hotspot.
Key points:
* The Hawaiian islands are not formed by plate boundaries, but by a stationary hotspot.
* The Pacific plate is moving northwest, which explains the northwest-trending chain of islands.
* The hotspot is still active, which is why the Big Island of Hawaii is still growing.