Hawaii’s Big Island is on alert as a huge volcano rumbles

HONOLULU (AP) – Hawaii officials are warning Big Island residents that the world’s largest active volcano, Mauna Loa, is sending signals that it may erupt.

Scientists say an eruption is not imminent, but they are on high alert because of a recent increase in earthquakes at the volcano’s summit. Experts say it will only take a few hours for lava to reach homes closest to vents on the volcano, which last erupted in 1984.

The Hawaii Civil Defense Agency is holding meetings across the island to educate residents on how to prepare for a possible emergency. They recommend having a ″go″ bag of food, identifying a place to stay when leaving home, and making a plan for reunification with family members.

“Not to panic everyone, but they need to be aware that you live on the slopes of Mauna Loa. There is a potential for some kind of lava disaster,” said Talmadge Magno, administrator for Hawaii County Civil Defense.

The volcano makes up 51% of Hawaii Island’s land mass, so a large portion of the island has the potential to be affected by an eruption, Magno said.

There has been a flurry of development on the Big Island in recent decades — its population has more than doubled to 200,000 today from 92,000 in 1980 — and many newer residents weren’t around when Mauna Loa last erupted 38 years ago. All the more reason, Magno said, for officials to spread the word about the science of the volcano and urge people to be prepared.

Rising 13,679 feet (4,169 meters) above sea level, Mauna Loa is the much larger neighbor of the Kilauea volcano, which erupted in a residential area and destroyed 700 homes in 2018. Some of its slopes are much steeper than those of Kilauea, so when it erupts, its lava can flow much faster.

During an eruption in 1950, the mountain’s lava traveled 15 miles (24 kilometers) to the sea in less than three hours.

The Hawaiian Volcano Observatory, part of the US Geological Survey, said Mauna Loa has been in a state of “increased unrest” since the middle of last month, when the number of earthquakes on the summit jumped from 10 to 20 a day to 40 to 50 a day.

Scientists believe more earthquakes are occurring because more magma is flowing into Mauna Loa’s summit reservoir system from the hot spot beneath the Earth’s surface that feeds molten rock into Hawaii’s volcanoes.

The tremors have decreased in frequency in recent days, but may increase again.

More than 220 people attended a community meeting last weekend that county civil defense officials held in Ocean View, a neighborhood lava could reach in hours if molten rock erupts through vents on Mauna Loa’s southwest flank.

Bob Werner, an Ocean View resident who did not attend the meeting, said it’s wise to be aware of a possible outbreak, but not to fear it. He’s not worried that the neighborhood would be completely cut off if lava flows across the only road that connects it to the larger cities of Kailua-Kona and Hilo, where many people do their shopping.

The “bigger concern is that it will be extremely annoying to drive an extra hour or two hours to get the same things,” he said.

Ryan Williams, the owner of the Margarita Village bar in Hilo, said the volcanic unrest didn’t worry customers accustomed to warnings.

There may still be a heightened sense of urgency as officials have held town hall meetings and urged people to prepare.

“But everything I’ve read or heard, they’re kind of trying to reassure people that conditions haven’t changed,” Williams said. “There is no imminent outbreak, but just to be aware.”

Magno said his agency is talking to residents now because communities closest to vents likely wouldn’t have enough time to learn how to respond and prepare when the observatory raises its alert level to “watch,” meaning an eruption is imminent imminent.

The current alert level is “advisory,” meaning the volcano is showing signs of unrest, but there is no indication that an eruption is likely or certain.

Residents in other parts of the island would have more time to react.

Lava from Mauna Loa’s northeast flank can take days or weeks to reach residential communities. This is because the slopes of the mountain on that side are relatively gentle and because cities are further away from volcanic vents.

Frank Trusdell, research geologist at the Hawaiian Volcano Observatory, said all of Mauna Loa’s eruptions in recorded history have started in its summit crater. About half of them stayed there, while the other half later spewed lava from vents lower down the mountain.

Lava that erupts from the summit generally does not travel far enough to reach residential areas.

Mauna Loa has erupted 33 times since 1843. It last erupted in 1984, when lava flowed down its eastern flank only to stop 4.5 miles (7.2 kilometers) from Hilo, the Big Island’s most populous city.

Mauna Loa also has a history of engulfing massive amounts of lava.

In the 1950 eruption, which lasted 23 days, Mauna Loa released 1,000 cubic meters (1,307 cubic yards) of lava per second. In contrast, Kilauea released 300 cubic meters (392 cubic yards) per second in 2018.

The earthquakes could continue for some time before any eruption: increased seismic activity lasted for a year before an eruption in 1975 and a year and a half before the eruption in 1984. Alternatively, the tumbling may subside and Mauna Loa may not erupt this time.

Trusdell said residents should look at his agency’s maps and learn how quickly lava can appear in their neighborhood. He also urged people living in one of the short-notice areas to be aware if the summit turns red.

“All you have to do is look up there and see the glow. You grab your things, throw them in the car and drive. Go!” he said.

They can always go home after if the lava doesn’t end up flowing into their neighborhood, he said.

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Associated Press Writer Mark Thiessen contributed to this report from Anchorage, Alaska.

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