1.2 million years ago the islands of Maui, Molokai, Lanai, and Kaho’olawe were part of one huge land mass, 40-50 percent larger than the Big Island of Hawai’i.
Maui is part of a large volcanic massif that includes the islands of Molokai, Lanai, and Kaho’olawe.
At times this massif was emergent as a single island with an area of about 2,000 square miles. Maui itself consists of two separate volcanoes. The West Maui volcano is probably the older of the two, but both may have been concurrently active over part of their histories. East Maui (Haleakala) was last active around 1790, while activity at West Maui is wholly pre-historic.
Although both Maui volcanoes may well have been concurrently active over part of their respective histories, they have evolved quite separately. Maui is blessed with two distinctive volcanic monuments. Together they typify Hawaiian volcanoes in general. But individually, they maintain their own unique characteristics – features that provide evidence for more fully understanding the origin and evolution of one of the most beautiful and facinating island chains in the world.