Thermal images taken Wednesday over the June 27 lava flow showed that its tube remained hot enough to transport lava even as the system showed no signs of activity near Pahoa.
“There’s definitely heat there,” said Janet Babb, Hawaiian Volcano Observatory spokeswoman. “Whether lava is still in there, or the rock inside the tube is remaining hot, it’s hard to say.”
Surface activity remained limited to breakouts within a few miles of the Pu‘u ‘O‘o vent on Kilauea’s East Rift Zone.
While it’s possible that the tube could be reoccupied with lava, the chances of that occurring diminish each day that it cools.
“As the days pass, if it continues the trend we are on now … things may be different this time next week,” Babb said.
Meanwhile, scientists continue to study why the flow has struggled to get farther than 14 miles from the vent and, almost miraculously, stopped several times short of Highway 130 and Pahoa Village Road.
Terrain and the flow’s volume, temperature, viscosity and chemical composition are all being looked at as factors, Babb said.
“It’s quite a topic of interest,” she said. “This is one of the few places in the world where you have basaltic flows traveling these kinds of distances.”
Pu‘u ‘O‘o has been erupting since 1983, but flows were heading south into the ocean almost that entire time, leaving scientists without much to compare the current activity, at least in recent history.
The earlier flows that destroyed Kalapana and Royal Gardens traveled about 7 to 9 miles before getting cut off by the Pacific, Babb said. This flow, which started June 27, traveled nearly 14 miles to the northeast.
But scientists do know that Kilauea flows have traveled much farther, including a 60-year eruption that covered what is now Hawaiian Paradise Park in the 1400s.
Compared to that flow, the ongoing activity appears to be slightly cooler, by about 10 degrees Celsius, Ken Hon, a University of Hawaii at Hilo volcanologist, said during a lecture on this subject in January.
“The lava has been cooling,” he said in the video published online by Big Island Video News. “There’s definitely something going on here.”
Babb said the temperature of the lava hasn’t changed since lava entered Kalapana in the late 1980s.
Hon said volume could be a major factor for the flow’s stubbornness.
“We appear to be bumping up against the minimum amount of lava that it takes to advance,” he said. “Instead of advancing, they just sit there and bleed at the edges and get wider. If the lava supply was to pick up, I think this thing would start moving forward again.”
Even if the flow is starting again near the vent, Babb said it’s important to remember that the eruption hasn’t stopped and that lava could again make its way downslope.
This time, it could follow a different path since the flow has altered the terrain.
“If the flow begins to go downslope, that particular path of steepest descent is now changed,” she said.
Email Tom Callis at tcallis@hawaiitribune-herald.com.