Why Two Volcanoes in Hawaii Are So Close, but So Different

SCIENCE

Mauna Kea and Mauna Loa, two volcanoes which have beguiled millions of tourists visiting the Hawaiian islands, have also intrigued scientists with a long-running mystery: If they are so close together, how did they develop in two parallel tracks over the same hot spot—and why are their chemical compositions so different? (New York Times)

Why are there volcanoes in Hawaii?

Teachers, scroll down for a quick list of key resources in our Teachers Toolkit.

The dormant volcano Mauna Kea is nothing less than the world’s tallest mountain … and its cinder cones make excellent ski slopes.
Photograph by Robert Madden, National Geographic

Mauna Loa, just 35 miles away, is one of the most active volcanoes on Earth, and less of a destination for ski bunnies.
Photograph by Robert Madden, National Geographic

This bathymetric map beautifully illustrates the double-track volcanism exhibited by Kea and Loa. The dashed lines are an estimate of the future projection of these trends based on the most recent research.
Illustration courtesy T. D. Jones, D. R. Davies, I.H. Campbell, G. Iaffaldano, G. Yaxley, S.C. Kramer, and C. R. Wilson. “The concurrent emergence and causes of double volcanic hotspot tracks on the Pacific plate.” Adapted by permission from Macmillan Publishers Ltd: Nature 3 May copyright 2017, doi:10.1038/nature2205

Discussion Ideas

 

  • Scientists have known about the the double-track volcanism of Mauna Kea and Mauna Loa since 1849. How did volcanologists know the volcanoes were on different tracks?

 

This diagram shows the tilted Hawaiian plume, the overlying Pacific plate and the distinct volcanism associated with Mauna Kea and Mauna Loa.
Illustration courtesy T. D. Jones, D. R. Davies, I.H. Campbell, G. Iaffaldano, G. Yaxley, S.C. Kramer, and C. R. Wilson. “The concurrent emergence and causes of double volcanic hotspot tracks on the Pacific plate.” Adapted by permission from Macmillan Publishers Ltd: Nature 3 May copyright 2017, doi:10.1038/nature2205

 

 

  • Can geologists observe and test their theory of double-track volcanism on other volcanoes or volcanic island chains?
    • Yes, scientists are looking forward to modeling and analyzing the chemistry of volcanoes that are part of the Hawaiian-Emperor seamount chain, and elsewhere in the Pacific.
      • Hawaii-Emperor seamount. The chemistry of Hawaii’s older volcanoes, on the northwestern islands of Kauai and Oahu, have both Kea and Loa chemistries. The Pacific plate’s shift in direction dramatically impacted the younger volcanoes on Molokai (which exhibits Kea volcanism), Lanai (which exhibits Loa volcanism), and even other volcanoes on the “Big Island” of Hawaii itself. The active volcano Hualalai exhibits Loa-type volcanism, while the active volcano Kilauea exhibits Kea-type volcanism. The infant Loihi Seamount, the next great Hawaiian volcano, exhibits Loa-type volcanism.
      • elsewhere in the Pacific. According to the research, “all volcanic chains on the Pacific plate that have displayed persistent volcanism for the past 5 million years show this trend.” For example, double-track volcanism exists over hot spots below the Galapagos, Samoan, Society, Easter, and Marquesas islands.

 

TEACHERS TOOLKIT

New York Times: Why Two Volcanoes in Hawaii Are So Close, but So Different

Nat Geo: What is the mantle? reference

Nat Geo: What is a hot spot? reference

Nat Geo: What is a volcano? reference

(extra credit!) Nature: The concurrent emergence and causes of double volcanic hotspot tracks on the Pacific plate

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