Maui Volcanoes
West Maui Volcano (Iao Valley area is approximate location of the central caldera) - extinct volcano; last eruption: about 1 million years ago
East Maui Volcano (Haleakala Valley) - active volcano (considered active since the last eruption was within historical time) ; last eruption: 1790

Maui Volcano Exploration
Haleakala National Park