Officials not letting guard down despite reduced lava output, stalled flow front

Aerial image of the lava channel issuing from fissure 3, erupting high on the Northeast Rift Zone of Mauna Loa on Friday. The reduced lava output at Fissure 3 is evident in the low level of lava in the channel. Maunakea is visible in the background of the image. (USGS image by P. Dotray/Special to West Hawaii Today)

Aerial view of Fissure 3 erupting on the Northeast Rift Zone of Mauna Loa on Friday. The eruption continues but the vigor was greatly reduced over the past 24 hours. (USGS image by M. Patrick/Special to West Hawaii Today)

Although the Daniel K. Inouye Highway is not in imminent danger of being cut off by lava, Hawaii County officials aren’t letting their guard down.

On Friday, the lava output from the Fissure 3 vent on Mauna Loa was significantly reduced, and the inactive main flow that was threatening the highway earlier in the week was inactive and stalled about 1.7 miles away.


That news led Civil Defense Administrator Talmadge Magno to declare the highway was no longer at risk.

“I am happy to say that the threat to Daniel K. Inouye Highway is over,” Magno said Friday.

However, Mayor Mitch Roth said the county isn’t relaxing yet.

“Although right now it looks good, we’re still not sure at this point what’s going to happen,” Roth said Friday. “It’s possible that lava could come out from a new fissure elsewhere. It’s possible that it could start producing pahoehoe lava. So, we’re still in this situation.”

Roth said he is hopeful that the county will be spared the impacts of losing its primary transit corridor.

He said the county had a host of contingency plans, such as alternate routes for Environmental Management and Mass Transit vehicles, and finding alternate jobs for county workers so they wouldn’t have to commute from one side of the island. While he said no total cost estimate for those plans had been worked out, he guessed that the overtime costs alone would have been substantial.

“I’ve asked each county department to tally up their extra costs caused by this so far,” Roth said. “I’m sure if the highway was cut off, those costs would have been even higher.”

Roth said that some of the county’s emergency response expenses could be reimbursed by agencies like the Federal Emergency Management Agency or the U.S. Small Business Administration.

Roth and Magno both said the county is continuing to monitor the situation and is prepared in case the highway or other infrastructure is threatened.

“We’re very optimistic that we’ve dodged a bullet,” Roth said. “But we don’t know if the bullet could come back.”

HVO Scientist in Charge Ken Hon said Friday that between one-third and one-half of all Mauna Loa Northeast Rift Zone eruptions transition between a highly effusive phase and a longer, less effusive phase.

Hon said it seems clear that the highly effusive phase of this current eruption is winding down, but it is not yet clear whether a second phase will follow.

For now, effusion rates at Fissure 3 have diminished, and the buildup of cooled lava around the fissure may make it difficult for new lava to spread away from the fissure.

Email Michael Brestovansky at

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