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Dispersion and nonlinear effects in the 2011 Tohoku‐Oki earthquake tsunami
Author(s) -
Saito Tatsuhiko,
Inazu Daisuke,
Miyoshi Takayuki,
Hino Ryota
Publication year - 2014
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1002/2014jc009971
Subject(s) - dispersion (optics) , geology , seismology , nonlinear system , waveform , submarine pipeline , tsunami earthquake , amplitude , dissipation , geotechnical engineering , physics , quantum mechanics , optics , thermodynamics , voltage
This study reveals the roles of the wave dispersion and nonlinear effects for the 2011 Tohoku‐Oki earthquake tsunami. We conducted tsunami simulations based on the nonlinear dispersive equations with a high‐resolution source model. The simulations successfully reproduced the waveforms recorded in the offshore, deep sea, and focal areas. The calculated inundation area coincided well with the actual inundation for the Sendai Plain, which was the widest inundation area during this event. By conducting sets of simulations with different tsunami equations, we obtained the followings insights into the wave dispersion, nonlinear effects, and energy dissipation for this event. Although the wave dispersion was neglected in most studies, the maximum amplitude was significantly overestimated in the deep sea if the dispersion was not included. The waveform observed at the station with the largest tsunami height (∼2 m) among the deep‐ocean stations also verified the necessity of the dispersion. It is well known that the nonlinear effects play an important role for the propagation of a tsunami into bays and harbors. Additionally, nonlinear effects need to be considered to accurately model later waves, even for offshore stations. In particular, including nonlinear terms rather than the inundation was more important when precisely modeling the waves reflected from the coast.