Lava from Hawaii's Kilauea volcano — one of the most active in the world — is continuing to ooze across the Big Island, and there's no sign of it stopping anytime soon.

In the past 66 years, the volcano has erupted a shocking 34 times, though most of Kilauea's activity has been nonexplosive. Unlike other active volcanoes, Kilauea doesn't spew hot ash and lava straight into the sky.

Instead, miles below, the volcano is fed 2,000-degree molten rock from deep inside Earth that needs to find a way out. Rather than exploding, lava simply sits "at the surface," U.S. Geological Survey (USGS) volcano hazards coordinator Charles Mandeville told The Associated Press on May 7.

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The lava typically flows out through cracks in the ground, usually within the confines of the national park that surrounds Kilauea — but this time, the eruption is spreading lava miles from the summit.

So, what makes this eruption different than ones in the past? Here's a look at the science behind the volcano, and why this eruption is different than the others.

What caused Kilauea's most recent eruption?

A series of earthquakes rocked the Puna district of the Big Island toward the end of April, causing Kilauea's crater floor to collapse and triggering even more earthquakes which forced magma into new underground chambers.

The earthquakes, including the May 4 magnitude-6.9 one — Hawaii's largest in more than 40 years — drastically altered the "volcano's plumbing system," Mandeville said.

The magma escaped in "fire fountains" of lava shooting as high as 230 feet out of cracks in the ground, Mandeville said. The first fissure opened on May 3.

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A fissure is an opening or crack in the ground that's created by the volcano, allowing molten rock, toxic gas and steam to burst through the opening.

"On volcanoes, a fissure is an elongate fracture or crack at the surface from which lava erupts. Fissure eruptions typically dwindle to a central vent after a period of hours or days," the USGS explains on its website.

How long will the eruption last?

Officials in Hawaii say there is no way to predict how long this latest eruption on Kilauea volcano will last.

Asta Miklius, a geophysicist with the USGS Hawaiian Volcanoes Observatory, says how long it will last will depend on whether the summit magma reservoir gets involved.

Volcano experts predict it will take months before scientists will be able to see whether the lava spewing volcano has settled down.

However, USGS says, there have been signs earthquake activity may be slowing, which would help halt the lava leak.

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"Earthquake activity in the summit remains elevated but has decreased over the past few days," the USGS states in a May 7 news release. "Many of these earthquakes are related to the ongoing subsidence of the summit area and earthquakes beneath the south flank of the volcano."

Why do people (especially Hawaiians) need volcanoes?

We wouldn't exist without volcanoes, scientists say. Volcanic eruptions provide nutrients, like nitrogen, for soil and their gases, especially water vapor, helped form the atmosphere we now have.

The Hawaiian Islands, specifically, wouldn't exist without volcanoes.

The island's five volcanoes were created from "hot spots" of underground magma, which are mostly but not always underwater. The molten rock erupts on the sea floor, cools and forms a volcano. With each eruption, the volcano grows until it is big enough to push out of the water and form islands.

The Associated Press contributed to this report.