Puu Oo

Puu Oo Puu Oo was a long-lived volcanic vent and cone on Hawaii Island associated with the East rift zone of Kīlauea. The vent produced one of the most prodigious basaltic eruptions of the late 20th and early 21st centuries, generating extensive lava flow fields, reshaping coastal geography and prompting sustained scientific study by institutions including the United States Geological Survey and the University of Hawaii at Manoa. Its activity influenced hazard response by agencies such as the National Park Service and local governments including the County of Hawaii.

Geology and Formation

Puu Oo occupied an eruptive site on the East rift zone of Kīlauea, itself a flank of the Hawaiian–Emperor seamount chain formed over the Hawaii hotspot. The cone developed atop a crust of pāhoehoe and ʻaʻā flows derived from recurrent basaltic eruptions, interacting with structures such as the Puʻu ʻŌʻō-Kupaianaha complex and nearby Kilauea caldera faults. Magma supply beneath the vent was fed from the magma chamber system linked to the Hilina Pali escarpment and modulated by dike intrusions along the rift, comparable to processes observed at Mauna Loa and other Hawaiian volcanoes. The morphology of the cone and its associated pit crater evolved through episodic lava fountaining, spatter accumulation, and collapse events analogous to those recorded at Mokuʻāweoweo and Halemaʻumaʻu.

Eruptive History

Puu Oo initiated an eruptive episode in 1983 that continued intermittently for decades, contemporaneous with eruptive phases at Puʻu ʻŌʻō-Kupaianaha and episodes recorded in the historical chronology of Kīlauea dating to the 19th century. Major eruptive styles included high fountaining comparable to eruptions at Ulawun and Mount Etna in terms of fountain-fed flow emplacement, prolonged effusive lava output reminiscent of older Mauna Ulu activity, and episodic collapse events like those that affected Mount St. Helens crater structures. Episodes produced lava flows that traveled along the rift zone, occasionally entering populated areas and changing eruption dynamics in response to dike propagation observed in studies by the United States Geological Survey and researchers at the Hawaii Institute of Geophysics and Planetology.

Lava Flows and Hazard Impact

Lava flows from Puu Oo covered large tracts of Puna District and reached the Pacific Ocean multiple times, creating new land and hazardous laze plumes akin to volcanic hazards documented at Sakurajima and Krakatoa. Flows destroyed infrastructure including portions of Chain of Craters Road, residential subdivisions such as Kalapana and access roads maintained by the County of Hawaii, prompting evacuations coordinated with the Hawaii Emergency Management Agency and civil defense organizations. Hazard mapping by the USGS Hawaiian Volcano Observatory and mitigation strategies developed with NOAA and the National Park Service informed land-use decisions and influenced insurance and recovery policy in the State of Hawaii.

Monitoring and Research

Continuous monitoring of Puu Oo involved seismic networks operated by the USGS, ground deformation measurements using GPS stations and InSAR conducted by the Jet Propulsion Laboratory and the University of Hawaii, and gas flux measurements by teams from the Smithsonian Institution’s Global Volcanism Program and the USGS. Research integrated petrology and geochemistry studies performed at laboratories including Caltech and the University of Cambridge to characterize basalt composition, volatile content, and magma plumbing system behavior. Collaborative projects with institutions such as NASA and the National Science Foundation advanced models of rift intrusion, lava rheology, and eruption forecasting that informed operational protocols at the Hawaiian Volcano Observatory.

Cultural and Environmental Effects

The sustained eruptions had cultural significance for Native Hawaiian communities, intersecting with practices and beliefs associated with Pele and sacred sites in the Kīpuka and Puna regions, discussed by cultural practitioners, the Office of Hawaiian Affairs, and local historians. Environmental impacts included alteration of coastal ecosystems, colonization of new lava substrate by pioneer species studied by researchers at the Hawaii Natural History Museum and Parker Ranch ecologists, and air quality issues from volcanic emissions monitored by the Environmental Protection Agency and Hawaii Department of Health. The interplay of scientific, cultural, and management responses involved stakeholders such as the Hilo community, Honolulu-based policymakers, and conservation groups including The Nature Conservancy.

Category:Kīlauea Category:Volcanoes of Hawaii (island) Category:Volcanic cones