Mauna Loa Lava Flow Eruption Map as Active Volcano Bursts to Life

Mauna Loa, the world's largest active volcano, has erupted for the first time in decades, and an interactive hazard map created by the County of Hawaii is providing real-time updates about the event.

Mauna Loa, which makes up more than 50 percent of Hawaii's Big Island, began erupting at approximately 11:30 p.m. Hawaii Standard Time (HST) on November 27, the U.S. Geological Survey's (USGS) Hawaiian Volcano Observatory (HVO) reported.

The eruption began in Moku'āweoweo, the volcano's summit caldera, authorities said. Currently, lava flows are contained within this area and are not threatening downslope communities, although volcanic ash and debris has started to fall nearby.

Scientists know from past events that the early stages of a Mauna Loa eruption can be very dynamic, with both the location and direction of lava flows capable of changing at very short notice.

The HVO said lava flows will most likely be confined within the walls of the caldera if the eruption remains at the summit. But if the eruption migrates to areas outside the summit, as has occurred during previous events, there is a chance that lava could start flowing downslope.

In the past few hours, the USGS has recorded more than 60 earthquakes in the Mauna Loa area at the time of writing, with the largest of these measuring 4.2 in magnitude.

The map created by the County of Hawaii, which covers the Big Island, is providing updates about the eruption, including information about lava flows, ashfall and road closures.

Is Mauna Loa active?

Mauna Loa is among Earth's most active volcanoes, having erupted more than 30 times since its first well-documented eruption in 1843. This is an average of one eruption every five years over this period.

It is the largest active volcano on Earth, standing at 13,681 feet above sea level, and 30,000 feet above the bottom of the ocean—greater than the height of Mount Everest.

Mauna Loa eruptions usually involve high-volume lava flows that are capable of traveling long distances. The Mauna Loa eruption map below created by the National Park Service shows the direction of lava flows resulting from previous eruptive events since 1843.

While Mauna Loa is considered an active volcano, prior to yesterday, it had not erupted since 1984—its longest quiet period since written records have been kept.

There were signs that an eruption may have been brewing given that the volcano had been experiencing several changes over the past few months.

Rebecca Williams, a volcanologist and Earth scientist at the University of Hull in the U.K., told Newsweek: "Mauna Loa has been in a state of heightened unrest since mid-September. There had been an increase in earthquakes recorded, and an increase in inflation (ground swelling). This indicated movement of magma beneath the surface, but quite deep. There wasn't any change in the gases being released or significant tilting of the ground that suggested the magma was making its way to the surface.

"This unrest meant that the volcano was being very closely watched. But, an eruption was not certain. Sometimes these periods of unrest settle down and nothing happens. Sometimes, as in this case, an eruption happens," she said.