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Eruptions under Glaciers

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  • Eruptions under Glaciers

    The top of Mauna Kea has no visible central caldera.
    The last time Mauna Kea erupted was about 3600 years ago
    The phonolite rock near the top was the last fluid flow .
    Many years earlier.
    The flanks may issue some more surprises at some point in time.

  • #2
    Re: Eruptions under Glaciers

    Geophysical events give us more surprises than any other natural phenomenon. We are a long way from being able to predict. Haleakala, Maui is said to have had a breakout about just 220 years ago! As the 'Pacific Hot Spot' keeps moving to the South East (or more accurately, as the Pacific Plate moves Northwest over the hot spot), we will have fewer events on the inhabited islands, but don't hold your breath. Mauna Kea can still erupt, Maunaloa last erupted in 1984. We are lucky they are pyroclastic flows, not like that recent eruption last week in Sakurajima volcano in S. Japan that flung boulders 1.5 feet in diameter over a mile from the summit crater.

    Uh, is there a glacier atop Mauna Kea???? I don't think so.
    Be Yourself. Everyone Else Is Taken!
    ~ ~
    Kaʻonohiʻulaʻokahōkūmiomioʻehiku
    Spreading the virus of ALOHA.
    Oh Chu. If only you could have seen what I've seen, with your eyes.

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    • #3
      Re: Eruptions under Glaciers

      Wasn't there a glacier on top of Mount St. Helens before the 1980 eruption?

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      • #4
        Re: Eruptions under Glaciers

        The last eruptions of Mauna Kea were later outbursts.
        Some of the earlier eruptions certainly did emerge from
        beneath glaciers now gone.
        The chants of Hawaii preserve some of that history.

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        • #5
          Re: Eruptions under Glaciers

          Originally posted by helen View Post
          Wasn't there a glacier on top of Mount St. Helens before the 1980 eruption?
          Yes, there were several.

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          • #6
            Re: Eruptions under Glaciers

            Originally posted by Kaonohi View Post
            Uh, is there a glacier atop Mauna Kea???? I don't think so.
            At present, no.
            Originally posted by lensperson View Post
            Some of the earlier eruptions certainly did emerge from beneath glaciers now gone.
            Dating suggests that the Pohakuloa glaciation occurred during the interval between approx. 150,000 and 100,000 years ago and that the Waihu glaciation occurred later than about 80,000 to 100,000 years ago; some have claimed evidence of glaciation on Mauna Kea possibly as recently as 9,200 years ago. The latest glacial stage was designated the Makanaka.

            Sources include:
            Mauna Kea Summit & South Flank
            Field Trip Guide Book
            by Edward W. Wolfe
            U.S. Geological Survey, 1987

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