The volcano has sputtered lava for a week, forcing around 2,000 residents to evacuate, and destroying some two dozen homes and threatening a geothermal plant.
"What will take a turn for the worse in terms of hazard is if hotter, fresher magma makes it to the surface, and that could be what is coming", Neal said on a conference call.
"What we've already been seeing is that chunks of the surrounding vents are just dropping off into the lava and that's why we're getting these small explosions", said Jessica Johnson, a volcanologist at the University of East Anglia in the United Kingdom.
Kilauea, however, is a shield volcano, where basaltic lava flows nearly continuously out of a summit crater and other vents, building a flat dome.
She says that's why the lava has been cool and has been moving a little sluggishly.
Rachel Smigelski-Theiss is among those who have changed their plans.
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Janet Coney, office manager of the Kilauea Lodge, an inn and restaurant, said officials told her lodge employees probably won't have to worry about rocks raining down on them but might experience falling ash. "But we also don't want to be stupid", said Cindy Hartman, 68, who lives in the Kalapana-Seaview neighborhood.
However, even if Kilauea does begin an explosive eruption, geologists say it will not be an event like Mount Saint Helens or other major eruptions.
The Hawaii volcano could blow its top in the coming days and cause a widespread disaster on the island, according to the latest from USA officials. "When you start seeing ferns go brown overnight, it's like, 'Wow, I gotta get out of here, '" said Peters, sitting at a Red Cross evacuation center at a sports center in nearby Pahoa.
The Kilauea volcano on Hawaii's Big Island is continuing to blow off toxic steam and release lava, but scientists now say there are signs it could be about to explode in a once-in-a-century eruption. Szigeti noted that the Big Island is "immense" and there are large parts of the island unaffected by the volcano.
"We have unbelievable Realtors with a fantastic work ethic and community spirit", said Kehaulani Costa, executive director of the Hawaii Island Realtors. "We know it is a distinct possibility".
The disaster declaration means that federal assistance will be available for public facilities such as roads, public parks, schools and waterpipes damaged or destroyed by the Kilauea volcanic eruption and earthquakes.