T50 Undergraduate Research Talks: The Next Step in Student Research Projects

Sunday, 25 September 2016
1:30 PM - 5:30 PM
Room 406

FINDING AOTEAROA: THE ROLE OF THE KAHAROA ERUPTION IN EARLY POLYNESIAN NAVIGATION AND PERCEPTION OF NEW ZEALAND AS “THE LAND OF THE LONG WHITE CLOUD”

Paper number: T50-11
Program: Technical Sessions
Time: 3:50 PM – 4:05 PM

Authors

Abstract

When Polynesians set foot on the North Island of Aotearoa (New Zealand) they claimed the world’s last uninhabited landmass between 1280 and 1300 AD. Also occurring at this time was the 4-5 year Kaharoa eruption sequence (1314 +/- 12) of the rhyolitic Tarawera Volcanic Complex. The almost coincident nature of this eruption with the postulated date for Polynesian arrival to Aotearoa raised the following questions; did early Polynesian voyagers and settlers observe these eruptions? Were the eruptive plumes large enough to be seen from significant distance, and if so, did these plumes provide a navigational tool in voyaging to Aotearoa? The likelihood of this occurrence was assessed using SketchUp and Google Earth to model the eruption plumes produced by a series of 11 plinian eruptions (≤26km high) that occurred within the 4-5 year Kaharoa eruption sequence. The model was based on data provided within previous Kaharoa eruption studies, defining column height, column radius as a function of height, visible dispersal, and wind direction. Analysis of this model utilises Pythagorean Theorem to assess the visibility of these plumes from significant locations within greater Polynesia.

The largest of the Kaharoa plinian eruptions produced a 26km high plume. From sea level, this plume would have been visible ~1115km from source, a significant distance but not one which would have been visible from the closest inhabited neighbouring Pacific Islands (i.e. Tonga, Raheti, and Nuie). Based on the relative dates of Polynesian arrival to New Zealand and the Kaharoa eruption, it is more likely that the Polynesians witnessed this eruption as newly established inhabitants of Aotearoa, or as they navigated to their destination. In either case, the Polynesian observation of this eruption may have had a greater impact than has previously been explored, and the term Aotearoa (“Land of the Long White Cloud") may be a reference to the extensive eruptive plumes produced by the Kaharoa eruption sequence.

Geological Society of America Abstracts with Programs. Vol. 48, No. 7

doi: 10.1130/abs/2016AM-284698

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