2 quakes rattle Hawaii Island, prompt preparedness message as Mauna Loa unrest continues

HONOLULU (HawaiiNewsNow) - A 5.0-magnitude shook Hawaii Island on Friday morning, causing minor property damage in some areas and triggering a series of aftershocks that officials say could continue for days.

The Hawaiian Volcano Observatory said the larger quake came just 24 seconds after a 4.6-magnitude quake.

Both were centered south of Pahala ― near the southeastern flank of Mauna Loa ― with the larger one at a depth of 4.6 miles. Hundreds of people as far away as Oahu reported feeling the strong temblors.

And in Pahala, authorities confirmed some minor damage.

Talmadge Magno, administrator of Hawaii County Civil Defense, said part of the ceiling collapsed at Pahala’s Herkes Gym while rocks fell onto Highway 11.

“It shook pretty well to the point that we’re finding that there is damage, you know, minor damage at this point to public facilities as well as private facilities,” he said.

“I heard the earthquake coming, and then all of a sudden everything started shaking, so I had to hold on. I had to hold the walls,” said Duane Santiago, an employee at the Mizuno Superette in Pahala, where items were tossed off the grocery shelves.

A generator powered the store after electricity went out in the area.

“Power’s out, the store was closed because we had a lot of broken stuff that fell off the shelves and broke, and everybody’s just cleaning up,” said another employee who gave just her first name, Laurie.

Scientists say it’s still unclear if the quakes are directly related to ongoing unrest on Mauna Loa, but they say residents should update their evacuation plans.

“The two earthquakes occurred so close together that they felt like one with several different bumps in it to people,” said Ken Hon, HVO scientist-in-charge. :And so there was a much longer duration of shaking than we would normally feel during an earthquake of those magnitudes.”

At Kau High and Pahala Elementary School, Principal Sharon Beck said the quakes were powerful.

“Drawers opened, book shelves came down, binders came down, clocks came down, computer screens broke,” she said, adding they evacuated students out of their classrooms into the school yard for safety.

The two larger quakes triggered a series of aftershocks, most of which have been small.

The biggest came in at a magnitude-4.0, and officials warned they could continue for days and possibly weeks.

Hawaiian Volcano Observatory scientists said the tremors appear to be related to readjustments along the southeast flank of Mauna Loa, and come as authorities have been monitoring increased seismic activity.

“It’s very difficult to tell if these are magma driven, or just something driven basically by time and loading of the volcano so that we’re seeing the flank move a little bit,” said Hon.

Mauna Loa last erupted in 1984, sending lava within a few miles of the Kaumana area of Hilo. During that eruption, residents had time to prepare.

“It was in a higher slope area, and it was estimated that it would take days, not hours, before any part of Hilo is threatened,” said former Hawaii County Mayor Harry Kim, who was the civil defense administrator at the time of the eruption.

The U.S. Geological Survey says flows from Mauna Loa’s northeast flank, where the 1984 eruption occurred, would take weeks to reach the Hilo area.

However, if a vent opened on the southwest rift zone, it would take just a few hours or lava to reach the ocean. A flow in 1950 that covered the village of Pahoeho made it to the ocean in just three hours.

Last week, the elevated seismic activity prompted the precautionary closure of Mauna Loa summit backcountry. HVO said the area would be closed until further notice.

Mayor Mitch Roth said it’s not the time to panic. “But if you live in an area where the lava can go from the summit to the ocean in four hours, it’s important to know what you have around and to be prepared for that.”

For the Hawaii County Civil Defense volcano hazard page, click here.

For more information on the Hawaiian Volcano Observatory’s latest status report, click here.

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