East Maui volcano, known as Haleakalā, has witnessed at least ten eruptions in the past 1,000 years, and numerous eruptions have occurred there in the past 10,000 years. The most recent eruptions occurred sometime between the years 1480 and 1600. East Maui's long eruptive history and recent activity indicate that the volcano will erupt in the future. East Maui's volume is about 30,000 km3 (7,200 mi3) with about 97% of the volume below sea level. Its area is 1,470 km2 (570 mi2. The volcano is considered to be in its post-shield stage.
The Hawaiian name Hale-a-k
The oldest lava flow exposed on East Maui is about 1.1 million years in age. It is part of a sequence of flows emplaced near the end of shield building on East Maui. The volcano began its growth about 2 million years ago.
Volcanism of the past 30,000 years on East Maui has been focused along the southwest and east rift zones. These two volcanic axes together form one gently curving arc that passes from La Perouse Bay (southwest flank of East Maui) through Haleakalā Crater to Hana on the east flank. The alignment continues east beneath the ocean as Haleakalā Ridge, one of the longest rift zones along the Hawaiian Islands volcanic chain. The on-land segment of this lengthy volcanic line of vents is the zone of greatest hazard for future lava flows and cindery ash.