Kilauea’s summit was inflating Friday, indicating that magma was accumulating, according to Hawaiian Volcano Observatory scientists, who said the on-again, off-again eruption that began before Christmas could resume by Monday.

An overflight Friday morning confirmed lava was visible within both recently active vents in Halemaumau Crater.

“It is not possible to forecast an exact outcome of this activity, but we are in a window where it is likely another fountaining episode may occur,” according to HVO.

Assuming the vents remain open and the inflation rate remains constant, it seems likely that a new episode could begin anytime by Monday, HVO scientists said.

The two vents are part of the most recent eruption of Kilauea, which began Dec. 23 and paused for the third time Jan. 3.

HVO geologists said the current eruption has had three separate episodes:

>> Dec. 23: 2:20 a.m. to 4 p.m., or over 14 hours of lava flow.

>> Dec. 24: 8 a.m. to Dec. 25 at 11 a.m. for 15 hours of lava flow.

>> Dec. 26: 8:30 p.m. to Jan. 3, or over eight days of lava.

“Episodes are marked by the onset of lava fountains and rapid deflation of the source magma chamber,” according to a Friday HVO update. “Pauses between fountain episodes are usually accompanied by reinflation of the summit. A new episode begins when the system builds up enough pressure to force magma to the surface again.”

The recent eruption has been confined to Halemaumau on Kilauea’s summit region within Hawai‘i Volcanoes National Park.

Scientists said there has been no unusual volcanic activity in the East Rift Zone or Southwest Rift Zone as part of the eruption.