Lava Maps Key to Future Development

Jul 11, 2018

Lava-flow hazards map
Credit U.S. Geological Survey

Lava continues to flow in the east rift zone of Kīlauea volcano, and several times a week there are new explosions at the summit. While the volcanic activity continues, some are already looking ahead to future development of the area near the volcano, and whether hazard zone maps from the U.S. Geological Survey can help.

Geophysicist Jim Kauahikaua has worked with Hawaiian Volcano Observatory for around 40 years. He says the United States Geological Survey started developing hazard zone maps to help guide development.

“Our lava flow hazard zone map deals with the long term hazard produced by lava flows. The summit and the rift zones where vents come up and where eruptions start are the highest hazard zone levels.

Lava zone one and lava zone two are the highest risk.

The original map was produced in the 70s and it reflected the volcanic structure of the volcanoes, the rift zones, the summits, and those areas downslope. All the volcanoes on the island of Hawai'i are represented. Kohala and Mauna Kea are less likely in the long term to host lava flows, Mauna Loa and Kīlauea are most likely. Hualālai is somewhere in the middle.  We were hoping to communicate these geologic ideas to planners, for example.  We thought that if we identified the highest hazard zone area, the one most likely to host eruptions in the future, that these would be perhaps utilized for different purposes other than residential areas.”

Kauahikaua’s research revealed there was a similar map created even earlier than the 1970s.

Fissure 8 and a full lava channel as seen during HVO's early morning overflight. The visible road is Nohea Street in the Leilani Estates subdivision. Steam generated from heated rain water rose from the tephra deposits and lava flows surrounding fissure 8.
Credit U.S. Geological Survey

“That map was referred to in a newspaper article in 1960, when people were wondering about the safety of developing Leilani Estates. But they weren’t able to give quantitative information because good carbon 14 dating wasn’t developed yet in the way that we’re using it now. The old map in the late 50s looks remarkably like the one today.”

Kauahikaua says the boundaries between zones are not narrow lines, but around a half mile. And despite eruptions over the past decades, he says the geologic picture has not changed enough to create new maps at this time.