By Derrick Bryson Taylor
The world’s largest active volcano, Mauna Loa on the Big Island of Hawaii, erupted for the first time in 38 years late Sunday, following a series of spectacular eruptions of the smaller Kilauea volcano, also on the island, over the last five years.
At 11:30 p.m. local time, an eruption began at Mauna Loa’s summit, inside Hawaii Volcanoes National Park, according to the U.S. Geological Survey. Lava flowing from the volcano was confined to the summit area, and officials said there was no immediate threat to the public, but they warned that winds could carry volcanic gas, fine ash and thin glass fibers known as Pele’s hair downwind.
The Hawaii County Civil Defense Agency raised the volcano alert level to a warning from an advisory. Mitch Roth, mayor of Hawaii County, which has a population of about 200,000, said in a statement on Facebook early Monday that there were no evacuation orders or threats to the community. Two shelters were opened along the South Kona coast for people who voluntarily left their homes, officials said.
Roth did not respond to a request for comment Monday about how Hawaii County was preparing and guiding its residents.
The location and direction of lava flow can quickly change, officials said. Residents who are at risk were advised to review their preparedness plans.
Officials said they planned to conduct an aerial survey of the eruption and assess any hazards.
A period of heightened unrest began in mid-September when the number of earthquakes below Mauna Loa’s summit increased to between 40 and 50 per day from 10 to 20 per day, officials said.
In mid-October, the Hawaii County Civil Defense Agency reported a 5.0 magnitude earthquake on Mauna Loa’s southeastern flank, setting off near-daily updates on the volcano’s status and the number of earthquakes detected in a 24-hour period.
Before the eruption was reported Sunday night, officials said on Twitter that Mauna Loa was not erupting and that there were no signs of an imminent eruption. Twenty-four earthquakes, all below 3.0 magnitude, were also detected in the previous 24 hours.
Mauna Loa, which encompasses more than half of the Big Island of Hawaii and rises more than 13,600 feet above the Pacific Ocean, has erupted 33 times since 1843, averaging one eruption every five years. A majority of the eruptions occurred before 1950; since then, there have been only two — a summit eruption in 1975 and an eruption in 1984, when lava flow approached the city of Hilo.
That last eruption caused volcanic air pollution across the state and prompted authorities to close Highway 200 as lava flows destroyed utility poles and power lines. Heat released during the eruption also caused local thunderstorms and snowfall in certain regions.
While Mauna Loa has been largely dormant for 38 years, Kilauea, in the southeast corner of the Big Island, is considered one of the most active volcanoes in the world. It has been a site of continuous volcanic activity over a period of decades, punctuated by sequences of spectacular eruptions.
A monthslong eruption in 2018 produced 320,000 Olympic-sized swimming pools’ worth of lava that transformed the landscape around Kilauea and was blamed for the destruction of around 700 homes.