基于射线理论的海脊俘获波机制

虽然众多现场实测资料和数值模拟均表明海脊可以俘获海啸波并引导其传播至远场地区，带来严重的灾害，但少有研究阐述其产生机理。本文基于射线理论，推导了指数型海脊上波浪传播轨迹的理论解，并提出了震源位于海脊顶部的海啸被海脊完全俘获的条件。基于该俘获条件进一步给出了海脊对海啸俘获效率的表达式，用以评估海啸中被海脊俘获影响至远场的能量占海啸总能量的比例。

Mechanism of trapped wave over an ocean ridge based on the ray theory

Although many on-site measures and numerical simulations indicate that ocean ridges can trap tsunami waves and guide them toward the far-field area, causing serious disasters, few studies have elaborated its mechanism. Based on the ray theory, this paper derives analytical solutions of the ray trajectory for trapped waves over the exponential ocean ridge. Furthermore, the completely trapped condition for tsunamis generated at top of the ridge is proposed. Based on such critical condition, the formulation of the trapped efficiency is derived to evaluate the ratio of the energy trapped by the ocean ridge to the total tsunami energy.