Hawaii officials have had a busy month pleading with travelers to keep their plans even as dramatic images of natural disasters afflicting the islands have bombarded televisions and social media feeds. That kind of explosive eruption was last displayed by the volcano almost a century ago.
Workers have removed flammable pentane from a nearby geothermal plant.
Scientists fear that, as lava and superheated rocks meet the water table below ground, steam could accumulate and cause an explosion that hurls massive rocks into the sky.
If the volcano blows its stack, communities about 2 miles (3 kilometers) away could be showered with pea-size rocks or dusted with nontoxic ash, said Tina Neal, scientist-in-charge at the Hawaii Volcano Observatory.
As fissures opened up on Kilauea's slopes, geologists also watched as levels of the Halema'uma'u lava lake at the volcano's summit dropped nearly 1,000 feet. The Hawaii County Civil Defense Agency said a new fissure had opened near the Kilauea volcano, bringing the total number of vents in the area to 15.
The danger zone from such a blast could extend about 3 miles (5 kilometers) from the summit, land that all falls within the national park, Mandeville said. It's been sluggish and somewhat cooler as a result, she said. "You don't want to be underneath anything that weighs 10 tons when it's coming out at 120 miles per hour (193 kph)".
South of Leilani Estates, in the Kalapana-Seaview neighborhood, residents are on high alert as the air quality is low and there are very few ways out of the area if an evacuation is ordered.
Since the eruption started more than a week ago, 36 structures, including 27 homes, have been destroyed.More news: Khloe Kardashian shares first look at baby True
The Hawaii Volcanoes National Park around the summit was closed to visitors on Thursday, given risks of the first explosive eruptions in almost a century, which could launch refrigerator-sized "ballistic blocks" over half a mile (0.8 km) and send ash columns tens of thousands of feet into the atmosphere.
As long as people stay away, they will be safe, Johnson said, noting that residents are likely well aware of the potential dangers while tourists may be less so.
About 2,000 people have been evacuated from the neighborhoods were lava has oozed from the ground.
Hawaii's Kilauea volcano could soon send boulders and ash shooting out of its summit crater.
He says it would be "very hazardous" if a volcanic vent were to open under the facility where the fuel is stored.
What could happen is not an eruption of volcanic gases but mostly trapped steam from flash-heated groundwater released like in a kitchen pressure cooker, with rocks, said volcanologist Janine Krippner of Concord University in West Virginia. "This is three football fields going down", Mandeville said.
"We want to make sure that everybody is still working and people have jobs to go back to", Birch said.
People should also be cautious around the water: once lava interacts with saltwater, it produces hydrochloric acid, which is toxic.