Following weeks of elevated unrest, Kilauea sparked back to life early Monday morning in a remote area within Hawai‘i Volcanoes National Park, the first eruption outside the caldera in six years.

But 12 hours after it began, the fiery show fizzled, leaving behind a glowing crack in the ground and a stream of volcanic gas.

“(Seismic) activity indicates it might not be over,” Hawaiian Volcano Observatory geologist Katie Mulliken said late Monday afternoon.

Officials lowered the Kilauea Volcano alert warning level and aviation color code Monday from warning to watch and the aviation color code from red to orange.

The eruption, which began at about 12:30 a.m. Monday, was in an inaccessible region of the mountain, about 2.5 miles southwest of Kilauea caldera in an area that had been closed by the National Park Service since 2008 due to its location just downwind of the volatile summit region.

Officials said the flare-up never posed a threat to human life or critical infrastructure.

It was the first time in 50 years that an eruption had occurred in this remote stretch connected to Kilauea’s Southwest Rift Zone. In December 1974 the eruption there lasted only six hours. The previous time before that was 1971, when it lasted five days.

Mulliken said this time the eruption consisted of a series of four fissures more than a half-mile long. By the time scientists were able to get their first good look — during a 6 a.m. flyover — only one of the fissures was still erupting.

Fountaining was estimated to be 16 feet tall, she said, while emissions were estimated to be about 12,000 tons a day. By comparison, first-day fountaining in the summit area typically are twice the height and emissions are about 100,000 tons a day.

Earthquake activity Monday was concentrated near Maunaiki at the western end of the system of cracks that opened during the eruption.

Volcanic tremor, a signal associated with fluid movement and potential volatility, continued to be recorded on summit seismometers throughout the day, Mulliken said.

“While the current eruption may be over, it is equally likely that it might resume at or to the west of the last active fissure,” HVO wrote Monday afternoon in its volcano update.

HVO scientists Sunday reported an increase in seismic activity and ground movement near Kilauea’s summit starting around noon, a sign of the likely movement of magma underground.

Rates of seismicity and deformation at the summit increased further after 5 p.m., and HVO ended up raising the Kilauea volcano alert level for ground-based hazards from advisory to watch and the aviation color code from yellow to orange.

Scientists reported about 250 earthquakes beneath Kilauea’s summit over eight hours with some seismic activity occurring beneath the upper East Rift Zone. The largest earthquakes included a magnitude-4.1 temblor at 9:12 p.m. and a magnitude- 4.0 event at 7:07 p.m.

But late Sunday, about 45 minutes before the eruption, earthquake activity had decreased slightly, they said, though it remained elevated.

After the eruption flared up early Monday, a news release from Hawai‘i Volcanoes National Park described the setting:

“A beautiful red-orange lava glow was visible in the sky before dawn from overlooks along Crater Rim Trail including Uekahuna and Volcano House. Early risers witnessed the glowing evidence of Pele, the elemental force of Hawaiian volcanoes, return for the first time since September 2023. After daybreak, a wispy distant gas plume became visible from Uekahuna and other summit overlooks.”

HVO warned that the primary hazards would be airborne and related to gas emissions and tephra being blown downwind. Tephra is the general term for anything thrown into the air during a volcanic eruption.

State health officials said that even though the lava flow stopped, elevated volcanic gas emissions might continue. Officials said air quality levels were still slightly elevated at the Pahala and Naalehu air quality monitoring stations, and it’s possible that hazy and voggy conditions with sulfur dioxide could increase and fluctuate in various areas of the state.

Although all of the action Monday was in a closed area of Hawai‘i Volcanoes National Park, park officials announced these temporary closures to park visitors:

>> Hilina Pali Road from Chain of Craters Road intersection

>> Kulanaokuaiki Campground

>> Pepeiao Cabin

>> Ka‘aha Trail and campground

>> Ka‘u Desert Trail and pullout on Highway 11

>> Maunaiki Trail

Despite the lull in the eruption, the park was still likely to see an influx of visitors hoping to catch a glimpse of the latest vol­canic activity.

Park officials said to expect long waits for parking spaces at popular vantage points, and they urged people to stay on marked trails and overlooks and to avoid cliff edges and earth cracks that are unstable.

Park visitors, they said, are urged to check the park website for closure and hazard alerts at nps.gov/hawaii volcanoes. Live webcam images, Kilauea updates and more are available on the USGS HVO website.