The world’s largest active volcano has erupted in Hawaii for the first time in nearly four decades, authorities said.
Mauna Loa erupted at 11:30 p.m. local time Sunday (4:30 a.m. ET Monday), the US Geological Survey said. It was the first eruption since 1984, according to their Hawaii Volcano Observatory Daily update.
The eruption began at Moku’āweoweo, the caldera atop Mauna Loa, inside Hawaii Volcanoes National Park, the agency said, raising the volcano’s alert level from a “warning” to an “advisory.”
“At this time, the lava flows are contained within the summit area and do not threaten communities downslope,” the agency said in a news release. “The winds can carry volcanic gas and possibly fine ash and Pele’s hair downwind,” she said, referring to a type of lava.
Residents at risk from Mauna Loa lava flows were advised to “review preparedness and consult Hawaii County Civil Defense information for further guidance.”
“Based on past events, the early stages of a Mauna Loa eruption can be highly dynamic and the location and advancement of lava flows can change rapidly,” the agency warned. He said that if the eruption remains in Moku’āweoweo, the lava flows will most likely be contained. “However, if eruptive vents migrate out of their walls, lava flows can move rapidly downhill,” he said.
The most recent eruption followed weeks of warnings from officials that an eruption was possible due to a recent increase in earthquakes atop the volcano and that Big Island residents should be prepared to evacuate, NBC affiliate KHNL of Hawaii reported.
The USGS said the “greatest unrest” began in mid-September, when earthquakes below the summit increased from 10 to 20 a day to 40 to 50 a day. That unrest prompted Hawaii Volcanoes National Park to close the summit backcountry until further notice. KHNL reported.
Ken Hon of the Hawaii Volcano Observatory said the quakes occurred mainly due to the weight of the mountain slowly sliding into the ocean, KHNL reported.
The volcano, whose name means “long mountain,” covers half the island, according to the US Geological Survey. Before its most recent eruption, it erupted 33 times, starting in 1843, making it one of the most active volcanoes in the world. It is one of six volcanoes in the state of Hawaii, according to the US Geological Survey..
About half of those past eruptions stayed in the summit region, which rises about 55,700 feet above its base, according to the US Geological Survey, and the lower slopes of the volcano, according to the USGS.
“Hawaiian lava flows have rarely caused human fatalities, but they can cause extensive damage by blanketing, burning, and crushing anything in their path, or starting secondary fires,” according to the USGS, adding that water-soil interactions lava “can also sometimes be explosive in coastal environments.”
When the volcano’s northeast flank erupted in 1984, residents had time to prepare, as the eruption occurred in a “higher slope area” and it took longer for lava to travel to the city of thread – the city located in the northeast region of the island and home to Hilo International Airport – former Hawaii County Mayor Harry Kim, who was the civil defense administrator at the time, told KHNL. That eruption lasted for three weeks, according to the US Geological Survey.