Hawaii’s Mauna Loa, the world’s largest active volcano, is beginning to erupt for the first time in nearly four decades

The world’s largest active volcano, Hawaii’s Mauna Loa, has begun to erupt for the first time in nearly four decades, causing volcanic ash and debris to fall nearby, authorities said Monday.

The eruption began around 11:30 p.m. Sunday at Moku’?weoweo, the summit caldera of Mauna Loa volcano, in Hawai’i Volcanoes National Park on the Big Island.

As of 2:43 a.m. local time, “the eruption at the summit of Mauna Loa is continuing,” according to the latest status report from the US Geological Survey’s (USGS) Hawaiian Volcano Observatory. “All ventilation openings remain restricted to the summit area,” the report states. “However, lava flows in the summit region are visible from Kona. There is currently no evidence of migration of the eruption into a rift zone.”

A rift zone is where the mountain is splitting open, the rock is fractured and relatively weak, and magma is more easily expelled, according to The Associated Press.


“The volcano alert level and aviation color code for Mauna Loa remain WARNING/RED,” the update added. “HVO continues to monitor the Conditions closely and will issue additional notices as necessary.”

The USGS warned that residents threatened by Mauna Loa lava flows should review their eruption preparations. Scientists have been on alert for a recent earthquake spike at the volcano’s summit, which last erupted in 1984.

Parts of the Big Island were under an ashfall advisory issued by the National Weather Service in Honolulu, which said ash could accumulate as much as a quarter of an inch in some areas.

This image provided by the USGS Hawaiian Volcano Observatory shows a view from a research camera of the north rim of Mauna Loa volcano’s summit caldera, Monday, November 28, 2022. The eruption began late Sunday night into the volcano’s summit caldera on the Big Island, according to the US Geological Survey.
(USGS Hawaiian Volcano Observatory via AP)

Mauna Loa is one of five volcanoes that together make up the Big Island of Hawaii, which is the southernmost island in the Hawaiian archipelago.

Mauna Loa is viewed from the Gilbert Kahele Recreation Area off Saddle Road on the Big Island of Hawaii on October 27, 2022. The ground at Mauna Loa, the world’s largest active volcano, is shaking and swelling, suggesting it could erupt.
(AP Photo/Megan Moseley)

Rising 13,679 feet above sea level, Mauna Loa is the much taller neighbor of Kilauea Volcano, which erupted in a residential area in 2018 and destroyed 700 homes. Some of its slopes are much steeper than Kilauea’s, allowing lava to flow much faster when it erupts.

During an eruption in 1950, the mountain’s lava traveled 15 miles to the ocean in less than three hours.


Mauna Loa last erupted for twenty days between March and April 1984. That means the new eruption, which began Sunday night, ended the volcano’s longest quiet period in recorded history.

“Based on past events, the early stages of a Mauna Loa eruption can be very dynamic, and the location and advance of lava flows can change rapidly,” the USGS said Sunday night. “If the eruption stays in Moku’?weoweo, lava flows will most likely be trapped within the caldera walls. However, if the vents migrate outside their walls, lava flows can flow rapidly down the slope.”

The Associated Press contributed to this report.