Abstract
To date, no attempt has been made to explore possible constraints on maximum water depths for tsunami-generated sedimentary structures of various sediment grain sizes, in terms of estimated wavelength and amplitude of potential bedforms. This paper explores some possible quantitative limits on threshold velocities for sediment movement at specified water depths, assuming Airy wave theory which treats tsunami waves as shallow-water, small- amplitude, long-wavelength waves. Such a treatment suggests that the passage of tsunami waves is unlikely to entrain sediment coarser than line sand to coarse silt in water depths in excess of 200 mm. Although fraught with theoretical difficulties and a lack of observations of modern sedimentary bedforms attributable to known tsunamis, this paper is presented to stimulate debate rather than provide definitive answers.
