Why the Hawaiian Islands Move: Plate Tectonics Over a Hotspot

The Hawaiian Islands ride the Pacific Plate as it drifts northwest (~3–4 inches/year) over a stationary mantle hotspot. The hotspot continuously feeds magma upward, creating volcanoes.

Lifecycle of an Island:

1. Seamount: Submarine volcano builds up.
2. Active Shield Volcano: Breaches surface (e.g., Kīlauea, Mauna Loa on the Big Island).
3. Erosion & Subsidence: As plate moves northwest, volcano dies, erodes, and sinks.
4. Atoll/Reef: Coral fringes remain (e.g., Midway, Kure).

The chain's age progression (youngest SE, oldest NW) proves plate motion. Loʻihi Seamount, SE of Hawaiʻi, is the next island forming.