Mauna Loa and Kilauea are very different ... and so are their eruptions

While there is no immediate threat to downslope communities, authorities are urging residents to remain vigilant.
Published: Nov. 28, 2022 at 3:18 PM HST|Updated: Nov. 28, 2022 at 5:49 PM HST
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HONOLULU (HawaiiNewsNow) - In 2018, the eruption of Kilauea sent residents in lower Puna scrambling for safety as fissures opened up in normally quiet subdivisions.

Sunday’s eruption of Mauna Loa is less alarming to authorities for several reasons, but mostly for the projected path of the flows.

So far, USGS officials said the lava is flowing in the northeast rift zone, and is not posing any immediate threat to communities.

“While the 2018 eruption was big, it went longer than we expect the Mauna Loa eruption to,” said Ken Hon, Hawaiian Volcano Observatory scientist-in-charge. “The average Mauna Loa eruption is really in the range of just a couple of weeks, so we don’t expect a long eruption.”

Previous activity is also a factor scientists are considering.

“Typically, Mauna Loa eruptions start off with their heaviest eruption first, and then after a few days, it starts to calm down a little bit,” Hon added.

“The difference between this and the lower east rift zone eruption is (with) Kilauea, most of the magma moves underground. And so it intersected that sluggish cooled stored magma. That slowed the original eruption down because it had to push all that out of the way.”

Mauna Loa’s eruption also is in a fairly isolated location, which would give people more time to evacuate if they needed to. The fissures spewing lava are located just off the caldera of the volcano.

“What’s the difference between the 2018 eruption? That happened in the middle of a subdivision,” community organizer Ikaika Marzo said. “And that’s when people were getting affected right at the moment it erupted. This is in a remote area where we can still prepare the people to evacuate at any given notice.”

Hon says the flow’s current path will mostly impact an area known as “the Saddle,” where the Mauna Loa Weather Observatory is located. The Pohakuloa Training Area is out of the projected path of lava.

“We’re hoping that it will parallel the 1984 eruption and become more viscous as time goes on,” Hon said.

“Only a couple of eruptions have made it into what is now the outskirts of Hilo.”

Map showing historical paths of lava flows.
Map showing historical paths of lava flows.(USGS / HVO)

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