Experts: Two volcanoes erupting in close proximity not unique to Big Island

Over the past two weeks, visitors to Hawaiʻi Volcanoes National Park on the Big Island have had the rare opportunity to view two eruptions. They can see molten rock spewing and degassing within the lava lake in Halemaʻumaʻu on Kīlauea; and about 18 miles away, the bright red/organge glow of lava can be seen down the slopes of Mauna Loa.

“This dual eruption in a once-in-a-lifetime event for many of us, to see Pele [the Goddess of volcanoes and fire] in two different places at once,” said Jessica Ferracane, Public Affairs Specialist for the popular national park.

The last time the volcanoes were erupting at the same time was in 1984, also the last time Mauna Loa erupted.

But already, the dual eruption has ended. On Sunday, scientists said the Kīlauea eruption within Halemaʻumaʻu crater paused, with all recent eruptive activity in the crater ceased, according to the Hawaiian Volcano Observatory. The Mauna Loa eruption is winding down with the flow from the active vent having stagnated.

In the 1800s, when Kīlauea was continuously active, dual eruptions on Hawaiʻi Island occurred more often.

“Over the last 200 years of Mauna Loa eruptions, I think it’s safe to say that when Mauna Loa erupted, Kīlauea was also erupting a majority of the time,” said Michael Poland, Scientist-in-Charge at Yellowstone Volcano Observatory for the U.S. Geological Survey. “They erupt together more often than not.”

There are always 40 to 50 volcanoes erupting at any given time in the world, according to the Smithsonian Institution Natural Museum of Natural History Global Volcanism Program. The Smithsonian group compiles this information online where information on volcanoes around the world is released.

The latest update for active volcanoes is from Oct. 28 and lists 47 eruptions. For the week of Nov. 30 to Dec. 6, the site lists eight new eruptions, including Mauna Loa, the worldʻs largest active volcano.

There are a number of pairs of volcanoes that are in close proximity around the world. Besides the Big Island volcanoes, the best example is in the Democratic Republic of Congo, where Nyiragongo and Nyamulagira frequently erupt at the same time.

As of July, the Smithsonian group reported both volcanoes had thermal anomalies from lava effusion in their respective crater floors.

Poland said Nyiragongo is a bit like Kīlauea because there is a lava lake that is usually active, while Nyamulagira is similar to Mauna Loa, with lava flow eruptions every few years. So whenever Nyamulagira erupts, that means both volcanoes in Congo are usually erupting at the same time.

“Those two volcanoes are located even closer together than Kilauea and Mauna Loa,” Poland said.

Also this month, Ferracane said, volcanoes Ibu and Dukono are erupting in tandem in Indonesia on the same island in the remote Maluku island chain.

Poland said it’s not that unique for two volcanoes to erupt at the same time in the same location. When speaking specifically about Mauna Loa and Kīlauea, Poland said both volcanoes have independent source areas in the mantle because they erupt in slightly different compositions.

“And there isn’t really a record of them impacting one another in a direct way,” he added.

Kīlauea and Mauna Loa are important volcanoes because they are well monitored, with Poland dubbing them “laboratory” volcanoes.

“We learn a lot from studying them, and then those lessons can be applied to other, less-well-understood volcanoes around the world,” he said. “In that sense, what we learn from eruptions like the current activity at Mauna Loa can have global implications, and help to mitigate volcanic hazards elsewhere.”

At Volcanoes National Park, Ferracane said visitation to the park has been robust as word has spread about the dual eruption. She expects a spike in park visitations when schools and colleges get out for their holiday breaks.

“It is never a dull moment in the park,” Ferracane said. “On Thursday, rangers and visitors marveled over being able to see huge fountains from fissure 3 visible from the Kīlauea Visitor Center parking lot and other vantage points along Kīlauea caldera rim.”

While the fountaining has diminished significantly, Ferracane said, visitors still marvel at the two eruptions.

There are various places within the national park where the two flows can be seen. Ferracane said she likes the Kūpinaʻi Pali overlook. It is a short, paved half-mile walk from Kīlauea Visitor Center where visitors can look out across Kaluapele [Kīlauea caldera], and see the lava lake and the glow from Mauna Loa in the distance.

Views can be seen at the Volcano House as well. The park created an eruption page on its website that explains these vantage points in detail. Click here for more information.

Ferracane said the lava is best viewed in the dark as molten lava is harder to see in daylight.