Restless Kilauea

Halemaumau Crater inside Kilauea's caldera.

Kilauea lies on the southeastern slopes of Mauna Loa. One of five volcanoes on the Big Island, it is the most active. The caldera itself is one of the centerpieces of Hawai’i Volcanoes National Park. It is an oval depression, a few miles across, its floor paved with twisted dark grey barren lava. Calderas form as the summit of the volcano collapses. At the west side of the caldera is the steaming depression of Halemaumau, visible only from a distance. During the day steam and sulfurous gases billow up and are blown to the west by the trade winds. At night the basin glows a fiery orange.   

The caldera area is active with steaming vents, and lush forests grow up the slopes of the volcano to the rim. There are many more craters along the slopes of the volcano, some visible from Chain of Craters Road.

Repeated lava flows down the slopes of Kilauea over the decades are recorded in the mosaic of forest and barren rock across the landscape of the Park. The majority of surface rocks on Kilauea are less than 500 years old, making these among the youngest rocks on earth. The lava consists of a variety of forms, from braided twisted rock to large plates that have cracked. The Hawaiian names for two main classes of cooled lava are a’a and pahoehoe. The a’a lava is jagged rubble, lying in heaps on the landscape. The smoother pahoehoe is more common. Until these new deposits erode to form soils, there is little space for plants to colonize.

Kilauea volcano on the Big Island. Map from USGS, Hawaiian Volcano Observatory.

Halemaumau crater glowing at night.

Steaming vents in vegetation on the northern side of the Kilauea caldera. Halemaumau crater is to the left.

Lava flows down Kilauea as seen from Chain of Craters
Rd. The a'a is dark grey; pahoehoe is lighter grey. The
Pacific Ocean is visible in the distance.

Click here for a USGS thermal webcam view into the lava caldron of Halemaumau Crater.

References

Holcomb RT 1987. Eruptive history and long-term behavior of Kilauea Volcano. Chapter 12. USGS Professional Paper 1350.

National Park Service. 2008. Hawai’iVolcanoes National Park Business Plan.