[A-OS14] Physical Oceanography (General)

[AOS14-P05] Leading Wave Patterns of Tsunamis: A Theoretical Study

*Chi-Min Liu¹ (1.Chienkuo Technology University)

Keywords:leading waves, tsunami

This study is extended from the earlier paper “Analytical solutions of tsunamis generated by underwater earthquakes” (Wave Motion, 93, 102489, 2020) to examine tsunami leading-wave patterns in the propagation stage. Two leading-wave features, which include (1) whether the leading wave is always the largest, and (2) the determination of the leading-wave type (elevation- or depression), are analyzed. Fundamental as well as specific seabed deformations are considered to generate tsunamis. Results show that the behavior of amplitude density at or around the longest wave component determines leading-wave characteristics. First, for tsunamis generated by some seabed movements, the leading-wave amplitudes are not the biggest. Second, a leading-depression or leading-elevation tsunami is determined by the sign of the second derivative of amplitude density at or around the longest wave component. These characteristics which can be decided by simply examining the topographic characteristics of seabed deformations improve an understanding of leading-wave patterns.