As Mauna Loa’s rumbling continues, the message to residents is simple: Be prepared

Scientists and emergency managers say those living below the world’s largest active volcano shouldn’t put their guards down. (Source: KHNL/KGMB)
Published: Oct. 27, 2022 at 5:13 PM HST|Updated: Oct. 28, 2022 at 7:59 AM HST
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PAHALA (HawaiiNewsNow) - While seismic activity on Mauna Loa has eased in recent days, scientists and emergency managers say those living below the world’s largest volcano shouldn’t put their guards down.

There were about 20 small quakes at the volcano over a 24-hour period ending Thursday morning ― all below magnitude 3. The Hawaiian Volcano Observatory said that the unrest “is most likely being driven by renewed input of magma two to miles” beneath the volcano’s summit. Officials stressed an eruption is not imminent.

On Thursday night, officials held a community meeting in Pahala to underscore the importance of vigilance.

Pahala resident Jandale Waltjen-Kuilipule was asked if she was concerned about an eruption.

“Very concerned, yes, very concerned,” she replied. “Because we didn’t have one for a very long time with Mauna Loa.”

The meeting comes on the heels of a gathering in Ocean View last week, where some residents questioned whether county officials had a good enough plan in the event of an eruption.

The USGS has Mauna Loa at a "yellow advisory" ― meaning be prepared. "Orange watch" means start moving.

People in the Ka’u district are especially at risk as Highway 11 is their only way out. If an eruption were to close that highway, evacuating some 20,000 people who call that area home would be extremely difficult.

“Sincere there’s just one main road, what is their plan for another mass exodus, because that is what will happen,” said Waiohinu resident Lynne Adams. “I mean, people are going to panic. That’s human nature.”

“Do I turn to the right when I hit the highway? Do I turn left when I hit the highway? That’s what you really want to know. But we can’t do that until we react to what the volcano is doing,” said Ken Hon, scientist in charge at the Hawaiian Volcano Observatory.

The USGS has Mauna Loa at a “yellow advisory” ― meaning be prepared.

USGS is monitoring Mauna Loa closely. Here’s how their color-coded advisory system works

“We would hope if Mauna Loa rocks that we would have ... days so that folks can be evacuated and notified,” said Dr. Andria Ellis, a geophysicist with USGS at the Hawaiian Volcano Observatory.

But Ellis said Mauna Loa’s structure could leave residents far less time to evacuate than they had when Kilauea erupted in 2018. “One of the challenges with Mauna Loa that makes that’s different than Kilauea is the way that it’s structured. It has flanks or sides that are really steep, and that depending on where lava emerges for at the surface, it could travel very quickly into places of residence and we might not have that day or more,” she said.

Hawaiian Volcano Observatory geologist Frank Trusdell has tracked Mauna Loa’s history. He said most of the eruptions start at the summit.

“Half of the eruptions start there and stay there,” he told the gathering. “All Mauna Loa eruptions in this period have started with a summit phase first.”

As for the earthquakes, Hon showed a map of the area, with dozens of white lines over the Ka’u District and the Pahala area.

“The white things are faults,” Hon said. “So these are mapped faults on the island of Hawaii. You’ll notice that you live inside the biggest nest of faults on the island of Hawaii.”

Hon said the earthquakes mostly are due to the weight of the mountain slowly sliding toward the ocean.

HVO also said earthquake activity remains elevated, but has eased in the last week or so.

“It’s kinda rounded off a little bit, which is important, but with this type of threat we need to take a cautious look at what may be coming, and at this point in time, like we always say, it’s better to be prepared and be ready,” said Luke Meyers, administrator of the Hawaii Emergency Management Agency.