Waves and Currents in Hawaiian Waters Induced by the Dispersive 2011 Tohoku Tsunami

摘要

This study focuses on the effects of frequency dispersion on tsunami-induced coastal water waves and currents, exemplified by the 2011 Tohoku tsunami event. The investigation relies on numerical simulations. We start from a tsunami source constrained through the inversion algorithm of NOAA's tsunami inundation forecast system. The trans-Pacific propagation and the hydrodynamic processes in the Hawaiian Islands region are simulated with a weakly dispersive Boussinesq model and a shallowwater model that neglects dispersion effects. From these modeling results, boundary conditions are derived to force the high-resolution simulations in the coastal waters in the Hawaiian Islands region through MOST, a tsunami simulating code based on the shallow-water theory. We note that the dispersion effects generally lower the amplitudes of leading waves. Trailing waves of short wavelengths and high amplitudes can develop in coastal waters. A model neglecting dispersion effects could under-predict the wave heights and current speeds at the trailing waves.