Active tsunami generation by tectonic seafloor deformations of arbitrary geometry considering rupture kinematics

Abstract

In this study, the propagation of surface water waves initially displaced by a tectonic seafloor deformation of arbitrary geometry was obtained considering the rupture kinematics. The developed solution was applied to a set of problems for wave generation by bottom motion with arbitrary spatiotemporal variations. First, a single bottom motion with different uplift speeds was considered; results showed that relatively fast uplift speed produces increased free surface elevation at the center of the movable bottom. For dual bottom motion with spatial and temporal intervals, the free surface elevation at the end of entire uplift motion has different maxima at different positions depending on their intervals. Then, the bottom motion subdivided into 10 sub-regions with rupture velocity and uplift speed was considered. The result implies that when the rupture process is introduced in the solution, the wave energy in the direction opposite to rupture decreases, while it is enhanced in the rupture direction with higher-frequency components. The solution was applied to the dual-Gaussian-shaped bottom motion with various rupture velocities and directions to demonstrate its prospective use in the numerical models for real tsunami events. Depending on the rupture direction, surface wave propagation exhibits distinct patterns.