An ash advisory remains in effect Monday for Hawaii’s Big Island and surrounding waters until 6 a.m. HST (11 a.m. ET) after Mauna Loa, the world’s largest active volcano, began erupting in Hawaii Volcanoes National Park.
Parts of the island could get up to a quarter of an inch of ash.
“People with respiratory illnesses should stay indoors to avoid inhaling ash particles, and anyone outside should cover their mouth and nose with a mask or cloth,” the National Weather Service in Honolulu warned.
“Possible damage to crops and animals. Minor equipment and infrastructure damage. Reduced visibility. Extensive cleaning may be required,” it added.
The eruption does not pose a threat to slope communities or flights to Hawaii Island, the Hawaii Tourism Authority said Tweeted on Monday morning.
Lava flows are contained to the summit area and do not threaten slope communities, the Hawaiian Volcano Observatory said. Winds can carry volcanic gas and fine ash downwards.
“Based on past events, the early stages of a Mauna Loa eruption are very dynamic and the location and progression of lava flows can change rapidly,” the observatory said, adding, “If the eruption remains at Moku’owiio, lava flows will be largely confined within the caldera walls.
“However, if an erupting vent migrates outside its walls, the lava flows can move rapidly downward.”
According to the observatory, the eruption began at Moku’āweoweo, Mauna Loa’s summit caldera, around 11:30 pm HST (4:30 am ET Monday) Sunday.
Mauna Loa, which covers about half of the island of Hawaii, has erupted 33 times since 1843, according to the US Geological Survey, the volcano’s first “documented historic eruption.” It last erupted in 1984, making this long quiescent period the volcano’s longest in recorded history.
The volcano has recently been at a peak of unrest, according to the agency, which has increased seismic activity and increased seismicity rates since late last month.
Seismic activity has increased from five to 10 earthquakes per day since June 2022, with July and August averaging around 10 to 20 earthquakes per day, according to the US Geological Survey. CNN reported that peak numbers of more than 100 earthquakes per day were recorded on September 23 and September 29.
Increased activity prompted Hawaii Volcanoes National Park in October to close Mauna Loa’s summit to all backcountry hikers until further notice, although the US National Park Service said the main section of the park remains open.
Correction: An earlier version of this story misstated the ash fall advisory and the Eastern Time equivalent for the eruption.