Lava returned to the remote Napau Crater in Hawaii Volcanoes National Park this week for the first time in nearly 30 years Tuesday as Kilauea’s latest eruption continues.
The current eruption started Sunday evening when fissures opened up just west of Napau Crater on Kilauea’s middle East Rift Zone.
Those fissures stopped erupting Monday morning. But by Monday evening, lava had resumed flowing, and by Tuesday morning it was emerging from the crater itself, with fountains as high as 30 feet.
Ken Hon, scientist-in-charge for the Hawaiian Volcano Observatory, said the most recent eruption at the crater took place in 1997 and was relatively brief, lasting only a few days.
“I think that’s probably what we’re going to see here, too,” Hon said, adding that the system of fissures opened so far only stretches about one kilometer (about 0.62 miles) and that there is no guarantee the fissures will continue to extend beyond the eastern bounds of the crater.
Hon said there also has been no indication of magma moving underground beyond Pu‘u‘o‘o to the east, suggesting that the eruptive activity could be confined to the area.
“Right now, this is where all the action is,” Hon said.
In response to increased seismic activity over the weekend, HVNP closed Chain of Craters Road to the public.
“For other eruptions, our safety policies have been more reactive,” said HVNP spokesman Ben Hayes. “But this time, since it’s so far away, it’s allowed us to be a bit more proactive, to prevent exposing people to hazards.”
Hayes said public access to the eruption site is effectively closed. The nearest usable parking lot is a nearly 10-mile hike away across closed trails. Hayes said park rangers will “maintain a presence” to ensure park users’ safety.
Hayes said the park is monitoring three specific eruption-related hazards.
The simplest hazard is the flow of the lava itself. Currently confined to the Napau Crater, Hayes said the lava is not expected to pose a threat to people or infrastructure for the foreseeable future. However, even though he said the lava is not believed to have impacted the nearby Napau campground, it may have damaged a historic pulu station, which was used in the past to collect and process the pulu fern.
The other two hazards are more volatile.
For one, wildland fires in the area can quickly spread and become destructive. Hayes said the eruption has ignited parts of the nearby forest, but those fires have, so far, been mitigated by wet conditions caused by frequent rainfall in the area.
The final hazard is the most insidious: air quality. An air-monitoring station at Kealakomo Overlook, roughly four miles to the south, recorded on Tuesday about five parts per million of toxic sulfur dioxide, which Hayes said would be grounds for evacuating the area if it wasn’t already so remote.
“It is pretty gassy,” confirmed Hon, although he added that it doesn’t appear to be unusually so.
While Hayes said the park could reopen Chain of Craters Road if it is determined to not be too hazardous for the public, the eruption’s distance from the road complicates that decision.
“If something happens and people need to leave quickly, they could be five, six miles away from the road,” Hayes said. “We don’t want to open the road if there’s a risk that we’ll have to rescue a lot of people.”
For now, both HVO and HVNP continue to monitor the situation. Chain of Craters Road remains closed, and HVO’s alert level for Kilauea remains at “Watch” and its aviation color code is set to “Orange.”
