The world’s largest active volcano has erupted in Hawaii for the first time in nearly four decades, officials said.
Mauna Loa erupted at 11:30 p.m. local time on Sunday (4:30 a.m. ET Monday), the US Geological Survey said. It was the first eruption since 1984, according to the Hawaii Volcano Observatory’s daily update.
The eruption began in Moku’āweoweo, Mauna Loa’s summit caldera, in Hawaii Volcanoes National Park, the agency said as it upgraded the volcano’s alert level from advisory to warning.
“At this point, lava flows are contained in the summit area and do not threaten hillside communities,” the agency said in a release. “Winds can carry volcanic gas and possibly fine ash and Pele’s hair downwind,” it said, referring to a type of lava.
Residents threatened by Mauna Loa lava flows have been advised to “assess readiness and contact Hawai’i County Civil Protection information for further guidance.”
“Based on past events, the early stages of a Mauna Loa eruption can be very dynamic, and the location and encroachment of lava flows can change rapidly,” the agency warned. It said that if the eruption stays in Moku’āweoweo, the lava flows would most likely be contained. “However, if the vents travel outside their walls, lava flows can move down the slope rapidly,” she said.
The latest eruption follows weeks of warnings from officials that an eruption is possible given a recent earthquake spike at the volcano’s summit and that Big Island residents should be prepared for an evacuation, Hawaii-based NBC affiliate KHNL reported.
The USGS said “increased civil unrest” began in mid-September when earthquakes increased below the peak of 10-20 per day to 40-50 per day. That unrest prompted Hawaii Volcanoes National Park to close the summit’s backcountry until further notice, KHNL reported.
Ken Hon of the Hawaiian Volcano Observatory said the earthquakes were mainly due to the weight of the mountain slowly sliding toward the ocean, KHNL reported.
The volcano, whose name means “Long Mountain,” covers half of the island, according to the US Geological Survey. Before its last eruption, it erupted 33 times from 1843, making it one of the most active volcanoes in the world. According to the US Geological Survey, it is one of six volcanoes in the state of Hawaii.
About half of these past eruptions stayed in the summit region — which rises about 55,700 feet above its base according to the US Geological Survey — and most others migrated from the summit into one of the rift zones, producing lava flows that covered large regions of the volcano’s lower slopes, according to USGS.
“Hawaiian lava flows have rarely caused human deaths, but they can cause great damage by covering, burning and crushing anything in their paths, or starting secondary fires,” according to the USGS, adding that water-lava interactions “can also do so.” can sometimes be explosive in coastal environments.”
When the volcano’s northeast flank erupted in 1984, residents had time to prepare because the eruption occurred in a “higher slope area” and it took longer for the lava to flow toward the city of Hilo — the city on the island’s northeast and home to Hilo International Airport — Former Hawaii County Mayor Harry Kim, who was the civil defense administrator at the time, told KHNL. This eruption lasted three weeks, according to the US Geological Survey.