Kilauea continued its spectacular Halemaumau lava show Friday with at least one fountain reaching 50 feet in the air and lava steadily rising in the caldera, though not as rapidly as in Wednesday’s opening phases of the eruption.

While there are no signs yet of the volcano tapering off, a research geologist with the Hawaiian Volcano Observatory said he would not be surprised if the eruption lasted for only a few weeks to a few months.

Drew Downs said the volcano could be transitioning into a new phase that will see relatively short-term eruptions confined to the caldera over at least a few years and maybe as long as a decade or more.

Downs said samples taken from chunks of tephra lava thrown from the volcano during the opening hours of the eruption on Wednesday were found to have a chemical makeup similar to the December 2020 eruption that was confined to the caldera for five months.

The finding suggests this could be another caldera-only eruption as Kilauea continues to re-pressurize and reestablish magma pathways after the 2018 eruption, he said.

“It could be getting back into the normal cycle of things,” Downs said. “It could be the start of a period where we see a summit eruption every couple of years.”

The new lava is filling the crater that collapsed in 2018 and is creating a new lava lake on top of the older one. Similar lava lakes frequently formed after collapses in Halemaumau in the 1800s, according to HVO, and eruptions were confined to the summit in the 1950s and 1960s and in the 1920s and the 1910s.

Downs said there is no indication that anything is going to happen in the volcano’s rift zones. “There are no earthquakes, and tiltmeters are not seeing any deformation (ground movement),” he said.

Volcanologist Ken Rubin, a University of Hawaii-Manoa professor and chairman of the Department of Geology and Geophysics, agreed that Kilauea could be entering a new phase — or rather returning to an old pattern.

But it is premature to make any definitive declaration, he said.

“Over most of the 20th century, there have not been a lot of short eruptions separated by a few months,” Rubin said.

The volcano seems to go in and out of various periods of behavior. From the mid-1950s to 2018, there was a pattern in which summit eruptions were followed by rift zone eruptions. From the mid-1800s to the early 1950s, there were often summit eruptions with generally no rift zone action. And for several hundred years, ending in 1790, there was an explosive phase.

“We’ll just see what happens next,” Rubin said. “It’s an exciting time. It’s great when people pay attention to be aware of what’s happening.”

Bruce Houghton, a UH colleague of Rubin’s, said he too isn’t ready to declare that the volcano is entering a phase of exclusive caldera eruptions.

“Every time we think we can define what is normal, it confounds us and Pele throws us a curve,” he said.

On the other hand, it could easily fall back into the caldera-only pattern, he said.

Houghton, a volcanology professor, said the latest eruption is rather small, especially in comparison with the 2018 eruption that produced 1,000 times the amount of material and plowed over large parts of Lower Puna.

The current eruption is also small in comparison with other caldera eruptions, he said, including ones in 1959, 1969 and from 1983 to 1986. While the current eruption is sending lava into the air as high as a five-story building, the 1959 eruptions saw fountains as high as 1,500 feet, he said.

The downside to caldera eruptions, Houghton said, is that they tend to produce a lot of vog.

HVO estimated sulfur dioxide emission rates at about 85,000 tons per day just after the eruption started. Those rates fell Thursday to 20,000 tons and were holding steady Friday.

In total, the lava lake surface has risen about 26 yards since the eruption started, HVO scientists reported Friday morning, although the lake had risen only about 4-1/2 yards in the previous 24 hours.

Meanwhile, thousands of visitors continued to visit Halemaumau within Hawai‘i Volcanoes National Park on Friday in hopes of viewing the fountains and lava lake.

But some were disappointed when they had to settle for a glimpse of the volcano’s glow within the crater at night or the billowing volcanic steam and gas during the day.

Park spokeswoman Jessica Ferracane said spectacular images and video of the new lava lake eruption are going viral, but they do not represent what visitors can safely see when they visit the park. The rim of the crater is off-limits to the public.

What can visitors expect to see? It depends on what time they arrive and the weather, Ferracane said.

At night “a magnificent reddish orange glow” fills the dark sky above the newly formed 127-acre lava lake, she said, reflecting into the plume of gas emanating from the crater and onto any clouds above. Jagged crater walls are lit up, revealing the scars from the 2018 summit collapse.

In the daytime, volcanic gas and steam billow out of the summit caldera, which is largely visible.

The best viewpoints, she said, day or night, are along Crater Rim Trail, and include Uekahuna, Kilauea Overlook, Wahinekapu (Steaming Bluff), Kupinai Pali (Waldron Ledge), Keanakakoi and other overlooks.

“Last night our rangers reported seeing the rising lava lake at times,” Ferracane said.