The 300m long crack, which opened with a deafening screech, is the 17th and one of the biggest fissures to have emerged since the volcano began erupting on 3 May.
Those living nearby said it continues to hurl 45kg chunks of lava and rock into the air while spewing smoke and steam and emitting a near-constant roar.
Hundreds of people living near the volcano have been ordered to evacuate the area and dozens of homes have been destroyed by explosions and slow moving lava.
But some residents are refusing to leave in spite of the danger.
“The situation down there remains dynamic and as we’ve been saying for days now the outbreaks can continue to occur both uprift and downrift of the existing fissure system, or the existing fissures could be reactivated,” Tina Neal, the scientist in charge of Hawaii’s volcano observatory, said.
With a lava lake inside the volcano falling, scientists are worried that it could be building up to a huge eruption or that lava could force its way through the ground in other neighbourhoods.
But the observatory added that developments along the fissure were not particularly vigorous, with a very small amount of lava, and the level of concern around the eruption remains unchanged by the crack.
Disruption to the lives of residents and damage to property, however, remains serious and the area’s volcano national park has been closed.
One lava bomb crashed through the roof of a nearby porch, officials have said, and holiday rentals have been forced to suspend operations to conserve water and resources for residents.
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Lava bombs, or volcanic bombs, are a mass of molten rock formed when a volcano ejects viscous fragments of lava. They cool into solid fragments before hitting the ground.
Geologists have warned that the summit of Kilauea could be an danger of a steam eruption that would hurl rocks and ash miles into the air.