The Worst-Case Scenario of Mauna Loa Eruption: 'Extremely Destructive'

The worst-case scenario of the Mauna Loa eruption could be "extremely destructive," an expert has told Newsweek.

Mauna Loa, one of the five volcanoes that make up the island of Hawaii, rises 13,000 feet above sea level. It is the largest volcano on earth.

The eruption—which began at 11.30 p.m on November 27, following months of unrest—is so far mostly confined to the summit, and not threatening any nearby communities. But this could change quickly.

'Extremely destructive'

Despite its large size, Mauna Loa eruptions do not tend to be as explosive when compared to other volcanoes on the island, such as Kilauea. Past eruptions have mostly been confined to the crater.

But the worst-case scenario could occur if lava migrates from the summit to any of the rift zones, which are home to several communities.

Jessica Johnson, an associate professor in Solid Earth Geophysics at the School of Environmental Sciences at the University of East Anglia in the U.K., told Newsweek: "Eruptions from Mauna Loa have the capability of sending Lava flows toward Hilo or Kona, which is the other main population center and tourism hotspot...If the vents (where the lava is coming out of the ground) should migrate to rift zones outside of the caldera, then voluminous lava flows could threaten towns on the island. These lava flows rarely present a risk to life, but they can be extremely destructive to infrastructure."

Mauna Loa last erupted between March 25 and April 15, 1984, following nearly two years of increased seismic activity. Nobody was hurt in this eruption, but lava flow blocked roads and caused damage to power lines.

"At the moment, the [Hawaiian Volcano Observatory] is monitoring the eruption closely for signs of changes in activity. It is likely that restrictions to access of Mauna Loa's summit have been put in place, and warnings about volcanic gases reaching populations has been issued. These gases can be irritants, and can be a problem for people with existing breathing problems. Should there be signs of changes in the eruptive activity, communities likely to be affected will be notified," Johnson said.

Lava has already been seen flowing from the summit. Pictures posted to Twitter of the ongoing eruption show the summit ablaze with bright orange lava.

"What happens next is anyone's guess," James Hickey, senior lecturer in Geophysics & Volcanology at the U.K.'s University of Exeter, told Newsweek. "Past eruptions have varied wildly in duration; days to months, so it could fizzle out or it could go on for a while. Either way, chances are it'll persist with what we call an 'effusive' eruption style, where the main hazard is lava flows."

Mauna Loa began showing signs of heightened unrest in mid-September. Since then, concern has been reported by residents living in nearby communities. The USGS has held information meetings over the past few weeks to prepare them for a potential eruption.

Rajeev Nair, earth science professor at the University of Calgary, told Newsweek that he hopes the eruption stays contained within the summit, as if it does not, it could prove a threat.

"It looks like the eruption is currently at the summit caldera and contained within it. As long as it remains contained the threat to communities is low. Primary concern now would be ashfall downwind of the summit. If eruption centers develop outside of the caldera, which is quite possible, the situation can become more problematic," Nair said.

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