The HVO warned the current eruption could become more violent as "ballistic projectiles may be produced should steam-driven explosions occur", but their impact would be limited to the area around the crater.
A number of earthquakes have also been registered, with the biggest tremors reaching magnitude 5.0.
The US Geological Survey (USGS) on Wednesday issued a red alert for the eruption of the Kilauea volcano in Hawaii, which led to the evacuation of hundreds of people from the area last week. The troops may be needed for emergency evacuations, search and rescue, clearing debris and other duties. The U.S. Geological Survey said a recent lowering of the lava lake at the volcano's Halemaumau crater has raised the potential for explosive eruptions at the volcano. "The plume, it's not near as ashy as it was yesterday, and it's rising more or less vertically over the summit region".
Because of the ash, USGS scientists operated from a backup command center at the University of Hawaii at Hilo.
Lava flows at a lava fissure in the aftermath of eruptions from the Kilauea volcano on Hawaii's Big Island, on 12 May, 2018 in Pahoa, Hawaii.
Geologists have warned that Kilauea's summit could have an explosive steam eruption that would hurl boulders and ash miles into the sky.
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"We're observing more or less continuous emission of ash now with intermittent, more energetic ash bursts or plumes", Steve Brantley, a deputy scientist in charge at the Hawaiian Volcano Observatory (HVO), said on a conference call with reporters.
"They're just in disarray and frantic", Adele Tripp, an employee at the Kilauea General Store, said of other residents.
"Things seem to be progressing largely as they have been, except for a shift in wind and less ash", Poland said.
Most of the Hawaii Volcanoes National Park remains closed due to ongoing seismic activity and the possibility of an explosion at the summit. But it's not certain when or if that might happen. For those on the ground near active lava vents, similar health warnings were issued because of risky volcanic gases.
An air-quality alert was in effect for an area near the Lanipuna Gardens subdivision. The volcano spewed ash and volcano smog, or vog, as it is known, in the latest activity since the eruption began 12 days ago.
With several fissures still posing a danger to many island residents, the sights of the phenomenon are incredible.