Analysis of the Mahuika comet impact tsunami hypothesis

A comet impact on February 13, 1491 AD, 250 km SW of New Zealand, named “Mahuika”, has been proposed as the tsunamigenic source for an alleged large 15th century tsunami along the New Zealand and east Australian coastlines. This hypothesis has been based on astronomic and atmospheric evidence and data from near the putative impact site, but the underpinning documentation has never been fully presented. We outline the current Mahuika comet impact tsunami hypothesis and analyse the original data sources. Geophysical evidence for a crater has never been documented; tektites are widespread in south Pacific sediments and provide no indication of the event age, and far-field evidence for any comet impact in the 15th century is unconvincing. All the evidence reviewed indicates that no comet, “Mahuika” or otherwise, struck the Earth on February 13, 1491 AD. Based upon our reassessment, the origin of apparent tsunami deposits along the coasts of New Zealand and east Australia needs to be reassessed — they are not tsunami deposits. The Mahuika comet impact tsunami hypothesis should be treated with extreme caution until stronger evidence is presented.