Mauna Loa, the largest active volcano on the planet, is in a “state of heightened unrest,” but is not erupting and there are no signs of an imminent eruption, the Hawaiian Volcano Observatory said in an update Friday.
Earlier this week, Hawaiʻi Volcanoes National Park closed the Mauna Loa summit backcountry until further notice, calling it a “precautionary measure” amid “elevated seismic activity.”
The observatory said the heightened unrest began in mid-September, “as recorded by an increase in earthquakes below Mauna Loa summit.”
The volcano, which stands about 13,680 feet (4,170 meters) above sea level, last erupted in 1984, the observatory said. Since 1843, it has erupted 33 times, with the time between eruptions ranging from months to decades, according to the observatory.
The park's online portal says this is the volcano’s “longest quiet period since written records have been kept.”
“Mauna Loa will erupt again,” Ken Hon, scientist-in-charge at the Hawaiian Volcano Observatory, told the Honolulu Star-Advertiser. “As long as there is heightened unrest, it is more likely to erupt. But it could be weeks or months — or it could eventually die off.”
The latter happened the last time there was elevated seismic activity and summit expansion on Mauna Loa in early 2021.
Hon said scientists don’t have much information to determine what normal behavior for the volcano is. There have been just two eruptions since 1950.
The observatory in recent years has urged residents living on Mauna Loa's slopes to have a “go bag” with essentials and important documents in the event of any potential evacuation order. It is a readiness step local emergency managers also recommend.
Last year, state lawmakers directed the Hawaiʻi Emergency Management Agency to develop an evacuation plan for Hawaiʻi County in case of an eruption.
Hawaiʻi County Civil Defense Administrator Talmadge Magno said his office has been assisting with the plan. The first draft is due in January.
If the need were to arise before that, Magno said: “We’re ready to respond."
