Mokuʻāweoweo Caldera

Moku’āweoweo Caldera is the summit caldera of Mauna Loa on the Island of Hawai’i, occupying the highest part of the volcano at roughly 4,170 m elevation. It is the principal summit feature of one of the world’s largest active volcanoes.

The caldera itself is an expansive summit depression that has hosted lava lakes and summit eruptions; views across the caldera show rugged lava terrain and volcanic vents. Access to the summit area is controlled and conditions can be harsh due to altitude and rapidly changing weather, so visits are typically by well-prepared hikers or guided scientific parties.

Large-scale scientific monitoring and observation equipment are concentrated in and near the summit area to record seismicity, gas emissions, and ground deformation. The site is a focus of volcanological study because Mauna Loa has frequent eruptive episodes and large-volume lava flows.

Moku’āweoweo has been the site of Mauna Loa summit eruptions recorded since the 19th century and earlier in oral histories. Over time the caldera has changed shape with successive eruptions and collapses, and it remains an active volcanic feature monitored by the Hawaiian Volcano Observatory.

Located near the center of the Island of Hawai’i, the caldera crowns Mauna Loa and lies inland from the island’s east and west coasts; the nearest population centers are Hilo to the northeast and Kona to the west, both many tens of kilometers from the summit.

• Elevation: Sits at the summit of Mauna Loa, whose peak reaches about 4,170 m above sea level, making it one of the highest points on the Island of Hawai’i.
• Volcanic significance: Part of one of the largest active volcanoes on Earth by volume; summit activity and lava flows have been recorded repeatedly over the 19th to 21st centuries.

What to See#

• Summit caldera: The summit caldera at the top of Mauna Loa, forming the highest point of the volcano and the site of long-term volcanic activity and summit eruptions.

Access roads to Mauna Loa’s summit start from the Saddle Road (Route 200) and from Hilo via Highway 11; much of the mountain is managed by the U.S. Forest Service and Hawaii Volcanoes National Park-check with both agencies for current road closures and permit requirements. The nearest major gateway towns are Hilo and Kona.

• If attempting access near the summit of Mauna Loa, prepare for altitude sickness and rapid weather changes.
• Check with Hawaii Volcanoes National Park and U.S. Forest Service for permits and road conditions-Mauna Loa access is often restricted.
• Layer clothing-temperatures at the caldera can drop well below freezing at night even when the coast is warm.