Haleakalā
Active shield volcano forming over 75% of Maui.
Haleakalā, also known as the East Maui Volcano, is a massive, active shield volcano that forms more than 75% of the Hawaiian Island of Maui. Its tallest peak, Puu Ulaula, rises to a significant elevation, and from this summit, a vast depression stretches across the landscape, measuring a considerable distance in width and depth, with steep surrounding walls and a mostly barren interior dotted with volcanic cones. The name Haleakalā, meaning "house of the sun," was applied by early Hawaiians to the general mountain and is also the name of a specific peak. In Hawaiian folklore, the summit depression was home to the grandmother of the demigod Māui, who helped him capture the sun to slow its journey across the sky.
Geologically, Haleakalā began forming around two million years ago, building a massive shield volcano along three rift zones. It is currently in a rejuvenated stage of volcanism, having produced numerous eruptions in the last 30,000 years, including ten in the past 1,000 years and at least one within the last 400 to 600 years, making it Maui’s only active volcano. Its volcanic activity occurs along two primary rift zones—southwest and east—which form an arc from La Perouse Bay through the crater to Hāna. The east rift zone continues underwater as Haleakalā Ridge, creating one of the longest combined rift zones in the Hawaiian chain. In its prime, the volcano may have reached a much greater height before erosion carved two large river valleys into its rim, which eventually merged to form the crater-like basin. A third rift zone trending north-northwest has seen no recent activity.
The depression at the summit is not volcanic in origin; it formed when the headwalls of two large erosional valleys, Koolau on the north and Kaupō on the south, merged. The volcano was previously thought to have last erupted around 1790, but radiocarbon dating later indicated the most recent eruption likely occurred between 1480 and 1600, producing the lava deposits of the Ahihi Kina‘u and La Perouse Bay area. Hazard assessments rate the summit and southwest rift zone as relatively high risk, based on eruption frequency—three eruptions in roughly the last 900 years—though its lava flow coverage rate is far lower than that of more active Hawaiian volcanoes. The volcano’s alert level is designated as normal. Haleakalā is also home to endangered species, including the nēnē bir
- type
- Active shield volcano
- location
- Maui, Hawaiian Islands
- peak
- Puʻu ʻUlaʻula (Red Hill)
- hazard_zone
- Summit and southwest rift zone rated Hazard Zone 3
Lore & Background
Early Hawaiians applied the name Haleakalā ("house of the sun") to the general mountain. In Hawaiian folklore, the depression at the summit was home to the grandmother of the demigod Māui, who helped him capture the sun and force it to slow its journey across the sky to lengthen the day. Haleakalā started forming 2 million years ago and built a massive shield volcano along three rift zones, though the crater itself is not volcanic in origin—it formed when the headwalls of two large erosional valleys merged at the summit. The volcano, also called East Maui Volcano, is active and makes up more than 75% of the island of Maui. Its tallest peak, Puu Ulaula (Red Hill), rises to 10,023 feet. From the summit, a vast depression stretches roughly 11.25 miles across, 3.2 miles wide, and nearly 800 meters deep, with steep surrounding walls and a mostly barren interior dotted with volcanic cones. Haleakalā is currently in the Rejuvenated Stage of Volcanism, with eruptions in the last 30,000 years, including ten in the past 1,000 years and at least one between 1480 and 1600. Its two active rift zones—southwest and east—form an arc from La Perouse Bay through the crater to Hāna, extending underwater as Haleakalā Ridge. The volcano may have once reached 12,000 feet before erosion carved two large river valleys that eventually merged into the summit basin. The nēnē bird, an endangered species, and the rare silversword plant, which lives only on Haleakalā’s slopes, are notable inhabitants.
Reader's Guide
Haleakalā is a key geological and cultural landmark. The volcano's two active rift zones—southwest and east—form one of the longest combined rift zones in the Hawaiian Islands chain. The U.S. Geological Survey rates the summit and southwest rift zone as Hazard Zone 3, based on eruption frequency and lava flow coverage. Haleakalā National Park, encompassing the summit depression and surrounding areas, is a popular destination for sunrise viewing and hiking, though trails can be challenging due to altitude and descent. The park also hosts endangered species such as the nēnē bird and the endemic Haleakalā silversword plant, which faces threats from climate change and herbivores. Conservation efforts include mosquito control using the incompatible insect technique to protect native forest birds like the kiwikiu and 'ākohekohe.
Did You Know?
- Haleakalā's crater is not volcanic in origin but formed when two large erosional valleys merged at the summit.
- The Haleakalā silversword plant grows nowhere else on Earth.
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