The USGS said, Depending on weather conditions, that the ash might fall as far as Hilo, 30 miles to the northeast. Geologists predicted such a blast would mostly release trapped steam from flash-heated groundwater.
On Thursday, a 21st fissure also opened in Leilani Estates while other fissures reactivated with lava, the Hawaii Civil Defense said in an alert.
In a video, you can see ash plumes and flying debris clearly visible in the early morning skies.
Residents of the Big Island were warned to take shelter from the ash as toxic gas levels spiked in a small southeast area where lava has burst from the ground during the two-week eruption.
She said it was a "real dynamic situation up there" on the summit, and that similar explosive events are still possible.
On Thursday, the volcano spewed ash almost six miles (9km) into the sky.
Hawaii's Kilauea volcano has been spewing lava since Thursday, May 3, and has destroyed 26 homes since then.More news: Netanyahu again defends response to Gaza protests, blames Hamas
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The volcanic eruptions on Hawaii's Big Island have been escalating for about two weeks, severely damaging nearby residential neighborhoods. People have been warned to protect themselves from ash fallout.
In another news conference Thursday, the deputy scientist in charge of the Hawaii Volcano Observatory, Steve Brantley, said the lava flows in the east rift zone have slowed in recent days.
The US Geological Survey had warned that an explosive eruption at Kilauea was becoming more likely as the volcano's lava lake was lowering. Experts say the explosive ballistic displays could continue for weeks, and they don't know when it's going to stop. "I mean, I expected there would at least be one of the bigger earthquakes just before, or a boom or something".
"This morning it smelled like sulfur so we had to close all the windows", Ms Magnani said.
In Pahoa, schools and the post office have been closed due to elevated levels of sulfur dioxide.
Coincidentally, Thursday's explosive event comes one day before the 94th anniversary of that death and on the 38th anniversary of the 1980 eruption of Mount St. Helens in Washington state. More than 1,000 people have been evacuated so far.
It is one of the most active in the world and has been erupting continuously, though not explosively, for more than 30 years.