Lava flows vs. fissures. What's the difference?

HAWAII (HawaiiNewsNow) - When it comes to terminology, there's a difference between a lava flow and a volcanic fissure.

On Hawaii Island, Leilani Estates in the Puna District has been plagued with now 10 fissures that have opened since Thursday.

This is different from previous lava flows that slowly wiped out Kalapana and damaged homes in Pahoa in 2014.

It's important to note how these fissures differ from lava flows to better understand what is happening.

According to the USGS, a volcanic fissure is an elongated fracture or crack in the earth's surface from which lava erupts.

"Fissure eruptions typically dwindle to a central vent after a period of hours or days. Occasionally, lava will flow back into the ground by pouring into a crack or an open eruptive fissure, a process called drainback; sometimes lava will flow back into the same fissure from which it erupted," the USGS says.

This is different from lava flows which are defined as the movement of overflowing lava out of a central point, such as an active volcano or crater.

Lava flows come in different widths, distances and speeds, making them slightly more predictable following an eruption.

It's almost impossible however to forecast when and where a fissure will appear.

Scientists on the Big Island know the general direction Kilauea's magma is traveling (beneath the Leilani Estates subdivision along the East-Rift Zone) but they do not know where fissures will form, or where the lava will erupt.

Which is what makes the situation unpredictable and dangerous.

Seismic activity and cracks in the ground are indicators a fissure may soon appear. Officials urge residents to stay away from the area to avoid being put in harm's way.

Lava Flow

Volcanic Fissure

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