Promising developments in the Mauna Loa lava flow have given Daniel K. Inouye Highway a temporary reprieve, at a minimum, and might even signal the beginning of the end to an eruption entering its 10th day.
Or maybe not.
Hawaiian Volcano Observatory scientists are closely monitoring the status of the eruption following a major change early Thursday morning that saw lava being cut off from the main flow, leaving the leading edge stalled 1.7 miles away from the busy highway, also known as Saddle Road.
What’s more, lava production from Fissure 3, the eruption’s remaining active vent, appears to have been substantially reduced — a possible sign that the eruption is tapering off.
But that’s only one possible explanation for the reduced flow, according to scientists, who said the change may be temporary, lead to other changes or signal a transition in the type of lava flowing from the eruption.
David Phillips, deputy scientist-in-charge at the Hawaiian Volcano Observatory, said Fissure 3 continues to produce lava, but instead of feeding the channel of the main flow, the lava is moving in various directions in a “disorganized system of flows” nearer to the vent.
On Wednesday “there was a really well-established, rapidly moving river of lava,” Phillips told reporters. “You don’t see that this morning.” The flows from Fissure 3 on Thursday were overtopping channels close to the vent and flowing no more than 2.75 miles away and generally above Mauna Loa Observatory Road.
Below that point the lava channels appeared to be drained.
“That’s good news for us,” said Hawaii County Mayor Mitch Roth. “It gives us a little more time before anything gets down to Daniel K. Inouye Highway, hopefully.”
Both Roth and Hawaii County Civil Defense Administrator Talmadge Magno said they won’t stop preparing for the eventual possibility of lava encroaching on the key highway that connects the east and west sides of Hawaii island.
While the 12-mile-long flow is now inactive for most of its lower length, the half-mile flow front might appear to advance a little as it settles, officials said. Geologist Frank Trusdell, HVO’s Mauna Loa expert, said it’s unlikely the flow front will be reactivated as a threat now that it is cut off from its lava source.
“Essentially, we have to renew the entire flow field with (lava) supply directly from Fissure 3 to go all the way back down the entire distance to become a threat,” Trusdell said.
HVO scientists are also looking at what caused the Fissure 3 fountain to grow Wednesday night, shooting lava 200 to 500 feet above the vent in a spectacular display that was noticed all around the island.
Phillips said one explanation is that something was restricting the vent, in the same way one might put their thumb over the end of a water hose.
“We are still out there making observations and piecing together causes and effects, trying to understand the relationships of the things we’re seeing,” he said.
Ken Rubin, University of Hawaii professor of earth sciences, said it’s too early to tell whether the reduction in lava production signals the beginning of the end for the 2022 eruption.
If the eruption is in fact dying, scientists likely will see corresponding reductions in volcanic gases and earthquakes near the vent, plus measure deflation at the summit, Rubin said. “We’ll see what happens in the next 12 to 24 hours,” he said.
Rubin said news of Wednesday’s parallel breakout flow from the lava river may have been an early indicator that the main flow was starting to lose some of its lava supply.
If the end is near for the 2022 eruption, it will have matched a trend over the past couple of centuries that saw most modern-era Mauna Loa lava flows lasting one to three weeks, the professor said.
So far, more than 16.6 square miles of Hawaii island has been covered by lava in an eruption that largely has been confined to barren mountain landscape. The spectacular nighttime display has drawn more than 20,000 vehicles to a newly created safe viewing route that runs parallel to Saddle Road, officials said.
Meanwhile, three men were cited Wednesday for walking in the closed and active lava flow area off Daniel K. Inouye Highway. The area was closed shortly after the start of the eruption to protect people from risk of injury.
All three men, Kazakh nationals, are scheduled to appear in Hilo District Court on Jan. 20 on petty misdemeanor charges and could face fines of up to $500 and/or jail time of 30 days.
The state Division of Conservation and Resources Enforcement is also investigating people who have entered the closed area and posted photos on social media. Officials said some of those who have posted their unlawful actions online are receiving death threats.
“The Mauna Loa Forest Reserve and active lava zone is closed for a reason. Eruptive activity can seriously injure or kill people. There are hidden dangers and when someone enters a closed area they are also putting first responders at risk if they’re called for help,” DOCARE Chief Jason Redulla said in a news release.