Mauna Loa Volcano Erupts on Hawai‘i’s Big Island

On Monday, the world’s largest active volcano spewed waves of glowing orange lava and billowing ash, marking its first eruption in 38 years. Officials urged residents of Hawai‘i’s Big Island to prepare for potential worst-case scenarios.

While the eruption of Mauna Loa currently poses no immediate threat to nearby towns, the U.S. Geological Survey cautioned the approximately 200,000 residents of the Big Island that volcanic activity can be unpredictable, and lava flow paths may change quickly.

Authorities advised locals to be prepared for evacuation should lava flows begin approaching populated regions.

The eruption commenced late Sunday night, triggered by a series of significant earthquakes, according to Ken Hon, the scientist-in-charge at the Hawaiian Volcano Observatory.

The locations where lava is surfacing—the summit crater of the volcano and vents along its northeastern slope—are both situated far from residential areas and communities.

Officials have advised the public to avoid these areas due to the hazards posed by lava, which is erupting from three fissures and reaching heights of 100 to 200 feet (30 to 60 meters), extending approximately 1 to 2 miles (1.6 to 3.2 kilometers) long.

The volcanic gases escaping from the vents, mainly sulfur dioxide, also present health risks.

Currently, air quality on the Big Island is deemed good, but officials are keeping a close watch, according to Dr. Libby Char, the director of the state Department of Health.

Hon mentioned that air quality may worsen during the eruption, which scientists predict could last about one to two weeks, following historical trends.

Bobby Camara, a lifelong resident of Big Island living in Volcano Village, urged everyone on the island to stay informed about the eruption. Having witnessed three eruptions of Mauna Loa in his lifetime, he emphasized the importance of being alert.

“I believe everyone should be somewhat concerned,” he remarked. “We have no idea where the lava flow is headed or how long this will continue.”

Gunner Mench, an art gallery owner in Kamuela, said he woke up shortly after midnight to a notification on his phone regarding the eruption.

Mench and his wife, Ellie, went outside to capture footage of the strange red glow illuminating the island as they watched the lava cascade down the volcano’s slope.

“You could see it shooting up into the sky, over the edge of this crater,” Mench noted.

“At the moment, it’s just a spectacle, but the worry is” it might approach inhabited areas, he stated.

For many residents of the Big Island, witnessing Mauna Loa’s eruption is a novel experience, especially since the population has more than doubled from 92,000 in 1980.

Over one-third of the island's population resides in either Kailua-Kona, which is about 23,000 people to the west of the volcano, or Hilo, home to roughly 45,000 to the east. Officials are particularly concerned about several neighborhoods located about 30 miles (50 kilometers) south of the volcano, where around 5,000 people live.

A time-lapse video captured overnight showed lava illuminating an area, flowing across it like ocean waves.

According to the U.S. Geological Survey, the eruption has moved to a rift zone on the northeast side of the volcano. Rift zones are characterized by cracks in the mountain rock, which makes it easier for magma to escape.

According to Hon at a news conference, lava could potentially flow toward Hilo, the county seat, but this might take about a week.

Scientists are optimistic that the current lava flow will mirror the 1984 eruption, during which the lava was thicker and moved more slowly.

Mauna Loa features another rift zone on its southwest side. If the volcano were to erupt from this area, lava could reach nearby communities within hours or days. However, Hon noted that historically, Mauna Loa has never erupted from both rift zones at the same time.

“At this stage, we assume that all future activity will occur on the northeast rift zone of Mauna Loa, rather than the southeast rift zone,” he explained. “Therefore, residents in that area need not be concerned about lava flows.”

Hawai‘i County Civil Defense has announced the opening of shelters due to reports of people evacuating from the coast on their own accord.

The USGS advised residents who might be at risk from lava flows to revisit their eruption preparedness plans. Scientists had been monitoring the situation closely due to a recent increase in seismic activity at the volcano’s summit, which last erupted in 1984.

Certain areas of the Big Island were placed under an ashfall advisory by the National Weather Service in Honolulu, warning that some locations could see ash accumulation of up to a quarter-inch (0.6 centimeters).

Governor David Ige mentioned that “volcanic gas, along with fine ash and Pele’s hair, may be carried by the wind,” referring to the glass fibers created when hot lava erupts and cools quickly in the air. The wind elongates these fibers into strands resembling hair. “We advise individuals with respiratory sensitivities to take precautions to limit their exposure.”

Mauna Loa is one of five volcanoes that form the Big Island of Hawai‘i, which is the southernmost island in the Hawaiian chain.

Standing at 13,679 feet (4,169 meters) above sea level, Mauna Loa is significantly larger than its neighbor Kilauea, which erupted in a residential area and destroyed 700 homes in 2018. The slopes of Mauna Loa are much steeper than those of Kilauea, allowing lava to flow more rapidly during eruptions.

In a 1950 eruption, the lava from the mountain reached the ocean, covering 15 miles (24 kilometers) in less than three hours.

Mauna Loa's estimated volume is over 18,000 square miles (75,000 square kilometers), making it the largest volcano in the world when measured from its ocean floor base to its summit.

While tourism is the backbone of Hawai‘i's economy, Big Island Mayor Mitch Roth forecasted minimal disruptions for visitors during the eruption.

“It will be a stunning sight where it occurs, but the likelihood of it significantly affecting the tourism industry is extremely low,” he stated.

Tourism officials assured that no changes to travel plans on the Big Island should be necessary due to the eruption.

For some, the eruption could reduce travel time, even if it results in increased volcanic smog from higher sulfur-dioxide emissions.

“The advantage now is that you no longer have to drive from Kona to Hawai‘i Volcanoes National Park to witness an eruption,” Roth remarked. “You can simply look out your window at night and see Mauna Loa erupting.”