November 29, 1903 Tsunami: Hawaii, United States

Waves began on November 29 and continued through the 30th, making cargo unloading difficult. Cox (1984, p. 54) now considers the waves of the 29th probably an increase in the size of already large meteorological swells.

A tidal wave flooded the northern coast of the islands of Oahu and Molokai and was registered by the tide gauge at Honolulu. (Listed as possible tsunami). (Reference #415)

A local source seems less probable than a distant one. Landsliding might easily occur on the steep submarine slope north of Molokai. It seems unlikely, however, thatt a landslide-generated local tsunami could have accounted for waves of so long a period or persisting with the heights observed for so long a time as indicated in the reports. Even the tectonically-generated local tsunamis of April 1868 and November 1975 did not have wave periods so long or wave heights comparable with those of 1903 persisting over so long a time, and none of the contemporary accounts mention the occurrence of an earthquake at the time of the 1903 waves. Hence, we consider that the waves were those of a tsunami of probably distant origin in the north Pacific, although there i s no record of a tsunami on 29 November 1903 elsewhere than in Hawaii […] While submarine landslide generation is more likely in the case of the 29 November 1903 waves (they were too high to be storm waves, and there was no associated earthquake), their two-hour duration makes their identification as a distant tsunami in the North Pacific more probable. Lists uncertain cause of tsunami with possibility of landslide and earthquake. (reference #80)

Tidal wave at Honokohau, Maui, and at Halawa, Pelekunu, and Kalaupapa, Molokai. (In this report the term tidal wave will be used in its commonly used sense as including storm surges and tsunamis - waves or trains of wave that, like the astronomic tides may rise gradually against a coast or may convert to bores). Considering all of the evidence together, and the alternative interpretations that are possible of those part of the evidence suggesting the occurrence of a tsunami, although I earlier considered that the "tidal wave" of the 29th was probably a tsunami (Cox and Morgan, 1977; Cox 1978, I now consider that it more probably represented simply an increase in the size of the swell that was already unusually large an the 27th and 28th, rather than a tsunami. If there was a tsunami, it's source was more probably distant from Hawaii than local […] The waves responsible for the railroad track washout might have been the swell, and the location of the washout is uncertain. (reference #72)

Reference #12345 lists event as validity 2 (questionable tsunami), with meteorological source. (access August 2024)