A new study reveals that Hawai‘i’s two most active volcanoes, Kīlauea and Maunaloa, share the same source of magma deep within the Earth.
For years, scientists believed these volcanoes had completely separate magma pathways, but researchers from the University of Hawai‘i at Mānoa have shown that this is not the case.
Their findings, recently published in the Journal of Petrology, provide new insights into how these volcanoes interact.
Using nearly 200 years of lava chemistry data, researchers discovered that magma from a shared mantle source in the Hawaiian plume alternates between the two volcanoes over decades.
When Maunaloa is more active, Kīlauea becomes less active, and vice versa.
Maunaloa, the world’s largest active volcano, erupted in 2022 after 38 years of dormancy.
This quiet period coincided with Kīlauea’s intense activity during the 35-year-long Puʻuʻōʻō eruption, which ended in 2018 with massive lava flows and a dramatic summit collapse.
The study’s lead author, Aaron Pietruszka, explained that the distinct lava chemistry during these periods reflects how magma is diverted.
For example, when Maunaloa was more active in the late 19th century, Kīlauea’s lava chemistry became more unique, indicating less influence from the shared magma source.
In contrast, during the mid-20th century, when Kīlauea was highly active, its lava chemistry became more similar to Maunaloa’s.
Since 2010, researchers have observed changes in Kīlauea’s lava chemistry, suggesting that magma from the shared source is shifting back to Maunaloa. This could mean Maunaloa is entering another active period.
Scientists believe that tracking lava chemistry over time could help forecast long-term volcanic activity. Pietruszka noted, “Monitoring lava chemistry might allow us to predict eruption rates and frequencies for these volcanoes over decades.”
The connection between Kīlauea and Maunaloa highlights the complex dynamics of the Hawaiian plume. Understanding how magma flows between these volcanoes can improve eruption forecasts and help communities prepare for future activity.
The research team plans to continue monitoring Kīlauea’s lava chemistry to see if their predictions about Maunaloa’s future activity hold true.
This study not only deepens our understanding of volcanic processes but also offers a new tool for predicting eruptions in one of the world’s most volcanically active regions.
