The front of the June 27 lava flow, stalled for a week near Pahoa Village Road, might not move another inch after cooling significantly, according to a Hawaiian Volcano Observatory geologist.
“That lower portion of the flow (below the Pahoa Cemetery) is very cool and it’s very unlikely that lava is now making its way into that part of the flow where it’s going to squirt out the leading edge,” said Steve Brantley, HVO acting scientist-in-charge.
But Brantley cautioned that doesn’t mean nearby residents are safe since a breakout upslope could still overtake the flow’s front.
When and where that would occur remains to be seen.
Activity on the flow remained weak Wednesday with breakouts mostly occurring mauka of Cemetery Road.
Brantley also noted it’s unclear if the lava tube just above that road will remain stable enough to continue feeding lava down slope without an uptick in activity.
“Once that cools enough, then the lava won’t be able to make it down to that lower point,” he said, “and that could force additional surface flows upslope. Where exactly? That depends on wherever the channel, where the tube is weakest.”
As of Wednesday, a small surface flow and inflation were seen near the cemetery, indicating the tube there remains active.
Overall, the amount of lava being fed to the flow from Puu Oo remains significantly below the peak rate seen in mid-September.
Brantley said about 100,000 cubic meters of lava is moving from the vent through the tube system each day, compared with about 350,000 cubic meters at its peak.
Regarding what the flow will do next, officials say it’s basically a matter of watching and waiting.
Pahoehoe flows like this one are known to be unpredictable and periods of calm can abruptly come to an end.
Darryl Oliveira, Hawaii County Civil Defense administrator, said Pahoa residents are getting “more time to breath,” but he assured that the county is maintaining its vigilance.
“We’ll continue to walk the flow … and watch any breakouts,” he said.
Warren Lee, county Public Works director, told reporters rough grading on the Chain of Craters alternate route finished Wednesday after crews working on both ends met.
The route, which rebuilds the Chain of Craters-Kalapana Road with a gravel surface, will become the only means of accessing lower Puna should the June 27 lava flow cut across Highway 130 and reach the sea.
About 7.74 miles of that roadway was covered by past lava flows and hasn’t been used as a through route in 28 years, according to the National Park Service. The emergency access route, anticipated to cost between $12 million and $15.5 million, is expected to be done in early December.
More than 5 miles of the buried roadway is within the park. On Tuesday, the park service announced it will receive comments on an environmental review of the project until Dec. 5.
Among the concerns highlighted in the review were the introduction of invasive species and a significant increase in vehicular traffic inside the park.
Currently, an average of 342 vehicles visit the end of the road within the park where the lava flows had cut off access.
According to the review, between 1,000 and 2,500 vehicles a day could travel the rebuilt roadway once other access routes to lower Puna are severed.
The document can be viewed at nps.gov/havo/parknews/20141104_pr_environmental_review.htm.
Meanwhile, officials at Puna Geothermal Venture said a small amount of pentane fluid leaked Wednesday at the plant near Pohoiki.
PGV alerted Hawaii County Civil Defense as a courtesy, but no workers or nearby residents were at risk and no emissions were released into the air, said Mike Kaleikini, director of Hawaiian Affairs for Ormat, PGV’s parent company.
Email Tom Callis at tcallis@hawaiitribune-herald.com.