When is a tsunami a mega-tsunami?
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Date
2014-01-12
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American Geophysical Union
Abstract
The 2004 Indian Ocean Tsunami is commonly called a mega-tsunami, and this attribute has also been linked to the 2011 Tohoku-oki tsunami. However, since this term was first coined in the early 1990's there have been very few attempts to define it. As such it has been applied in a rather arbitrary fashion to a number of tsunami characteristics, such as wave height or amplitude at both the source and at distant locations, run-up height, geographical extent and impact. The first use of the term is related to a tsunami generated by a large bolide impact and indeed it seems entirely appropriate that the term should be used for such rare events on geological timescales. However, probably as a result of media-driven hyperbole, scientists have used this term at least twice in the last decade, which is hardly a significant portion of the geological timescale. It therefore seems reasonable to suggest that these recent unexpectedly large events do not fall in the category of mega-tsunami but into a category of exceptional events within historical experience and local perspective. The use of the term mega-tsunami over the past 14 years is discussed and a definition is provided that marks the relative uniqueness of these events and a new term, appropriately Japanese in origin, namely that of souteigai-tsunami, is proposed. Examples of these tsunamis will be provided.
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Keywords
Seas, Tsunamis, Geology, Impact strength, Japan, Geology
Citation
Chagué-Goff, C., Goff, J., Terry, J. P., & Goto, K. (2014). When is a tsunami a mega-tsunami? Paper presented at the AGU Fall Meeting 15-19 December 2014, San Francisco, America.