Hot spot research

Diamond Head at sunset. Photo © J.B. Paduan, 2006

Life-cycle of Hawaiian hot spot volcanoes

The Hawaiian Islands and Emperor Seamount chain of volcanoes are the product of a mantle hot spot in the middle of the Pacific Plate. The hot spot’s current activity is underneath the southern end of the island of Hawaii and the next volcano in the chain, Lo’ihi Seamount, is forming on the sea floor just to the south of Hawaii and should emerge in another 200,000 years. (See maps of the entire chain.)

The volcanoes undergo a progression of eruption styles and chemistries as they age, from pre-shield stage (e.g., Lo’ihi), through the major shield-building stage (e.g., Kilauea), to post-shield (e.g., Haleakala) and rejuvenated stages (such as Diamond Head on Oahu when it erupted). As the enormous mountains build on top of the ocean crust, the crust flexes downward and the islands slowly sink. Coral reefs grow around the islands when sea level changes slowly enough for them to keep up with the sinking of the islands, and the reefs drown or are exposed if sea level rises or drops too quickly. Erosion takes an enormous toll on the islands: giant landslides have occurred off all the islands, and some of the debris has traveled hundreds of kilometers offshore.

Once the volcanoes are extinct, the islands continue to erode until they slip below sea level. The Emperor Seamount chain was once over the hot spot and probably looked much like the modern Hawaiian Islands, but the volcanoes have since submerged. The Pacific Plate is carrying the entire chain of islands and seamounts to the northwest as it drifts slowly to the Aleutian Trench and its ultimate subduction.

The following pages highlight our research on hot spot volcanoes: