The Ka Lua o Lapa eruption

Cape Kīna‘u

La Pérouse Bay

By John Sinton, G&G

The only eruption on Maui for which there exist “historical” accounts is the one from Ka Lua o Lapa. These accounts were collected by Lorrin A. Thurston and published in the Honolulu Advertiser in 1924

“I asked the natives if they knew when that flow occurred, and they told me that their grandparents saw it. They also told me that a woman and child were surrounded by the flow, but escaped after it cooled.”

- account of Father Bailey, told to J. D. Dana about 1841

Thurston reasoned that the eruption must have occurred 99 years prior to 1841, or about 1742 A.D., assuming 33 years for the length of a generation and an age of ~33 years for the natives who told the story.

In 1906, Thurston was camped on Haleakalā when he encountered a cowboy named Charlie Ako. Ako told Thurston:

“I married a woman from Honua‘ula, and my father-in-law, of Honua‘ula, who died last year, at the age of 92 years, told me that when the flow at Keone‘ō‘io ran out, his grandfather saw it, and that, at that time, he (the grandfather) said he was old enough to carry two coconuts from the sea to the upper road.”

From this, Thurston reasoned that the eruption occurred about 1757 A.D.

Ako’s father-in-law was 92 in 1905, and hence was born in 1813. His father, perhaps born 33 years earlier in 1780, was the father of the boy who carried the coconuts. A boy old enough to carry coconuts “from the sea to the upper road” must have been at least 10 years old at that time.

Keone‘ō‘io

Stearns and Macdonald (1942) questioned Thurston’s use of 33 years as the length of a generation for Hawaiians of the time, and suggested that 23 years might be a better approximation.

A shorter generation length makes the flow even younger, perhaps around 1770 instead of 1750.

Oostdam (1965) compared maps made by early western explorers to look for possible changes in the shoreline

Oostdam concluded that the flow that makes Cape Kīna‘u must have been erupted in 1790 ± 3 A.D.

Map drawn by Bernizet from the expedition of the La Boussole and L’Astrolabe under the command of Captain Jean François de Galaup Comte de La Pérouse

1786

Map drawn by Joseph Baker from the cruise led by Captain George Vancouver

1792

Cape Kīna‘u seems clearly to have been present in 1792.

Whether or not it existed in 1786 is hard to tell.

14C ages for selected lavas

hkol: 390 ± 50; 460 ± 50

hkan: 910 ± 40; 950 ± 40

hhan: 820 ±170; 920 ± 70

Geologic Map of Honua‘ula

Charcoal dating (consistent with paleomagnetic pole determinations) suggest emplacement of Ka Lua o Lapa lava in the period 1425-1613 A.D. (about 500 yrs ago)

From oldest to youngest, Pīmoe, Hanamanioa, and Kanaloa lavas were all erupted about 800-1000 yrs ago.

pau