New evidence from the world’s largest active volcano could improve eruption predictions

Scientists studying the 2022 eruption of Mauna Loa on the Big Island of Hawaii say new evidence reveals ways future eruptions might be predicted.

Mauna Loa is known to be the world’s largest active volcano. It blew its top in November 2022 “following a 2-month period of sustained magma intrusion” deep beneath the summit, a new study now finds.

The team behind the new study said they reached this conclusion after a complex analysis of seismic data, gas plume measurements, studies on how the ground at the volcano deformed, and the type of minerals formed in the eruption. Advanced computer modeling also played a role in their overall assessment.

Lead author Kendra Lynn told Public Parks that she’s confident their methodology could be utilized to help monitor and even potentially predict eruptions at other volcanoes. That includes shield volcanoes of the sort found in Hawaii and stratovolcanoes formed where continental plates collide.

“Our study is certainly applicable at other volcanoes around the globe that are monitored for activity,” Lynn said. “It would be the same approach but using slightly different tools.”

One key difference, she explained, is that this study pertaining to Mauna Loa relied on the mineral olivine. The presence of olivine helped them to determine how deep the magma intrusion was.

Other minerals would have to be used for chemical analysis when monitoring activity at different volcanoes.

“The good news is many minerals found in volcanic rocks can be used in the way we used our olivine,” Lynn explained, “where you can measure chemical changes in the crystals to extract time related to when the magmas were moving through the system prior to eruption.”

The Mauna Loa eruption of two years ago was notable as it was the first time lava spewed from the volcano after a 38-year-quiet period. The eruption started on November 27, 2022, around the American Thanksgiving Day holiday. It continued for 13 days.

Lynn said her team’s detailed study of the conditions that led to the eruption indicated that a large well of underground magma rose to a relatively shallower depth just below an existing magma pool. The resultant pressure destabilized this overlying magma chamber, resulting in the eruption.

“We interpret that magma from 3 to 5 km beneath the summit rose up to about 1 km under the summit, causing pressurization until the rocks failed and the eruption began,” Lynn told Public Parks. “We know that magma from the 3 to 5 km depth storage region erupted at the surface because olivine crystals that fingerprint that depth were found in the lava and tephra samples.”

The greatest takeaway from this study, Lynn said, was the discovery of at least two magma chambers existing beneath Mauna Loa.

This knowledge, plus more sensitive and advanced volcano monitoring equipment installed on Mauna Loa after the last eruption 38 years ago, could improve surveillance of the volcano and help scientists send earlier warnings of when the volcano is about to erupt. 

“Now, when we study Mauna Loa’s other eruptions, we can consider how, where, and when magmas rise through the volcano with better context and look for patterns in this behavior over time,” Lynn said.

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