The 1958 Lituya Bay tsunami – pre-event bathymetry reconstruction and 3D numerical modelling utilising the computational fluid dynamics software Flow-3D
2020
Abstract. This study aims to test the capacity of Flow-3D regarding
the simulation of a rockslide-generated impulse wave by evaluating the
influences of the extent of the computational domain, the grid
resolution, and the corresponding computation times on the accuracy of
modelling results. A detailed analysis of the Lituya Bay tsunami event
(1958, Alaska, maximum recorded run-up of 524 m a.s.l.) is presented. A
focus is put on the tsunami formation and run-up in the impact area. Several
simulations with a simplified bay geometry are performed in order to test
the concept of a ???denser fluid???, compared to the seawater in the bay, for
the impacting rockslide material. Further, topographic and bathymetric
surfaces of the impact area are set up. The observed maximum run-up can be
reproduced using a uniform grid resolution of 5 m, where the wave overtops
the hill crest facing the slide source and then flows diagonally down the slope.
The model is extended along the entire bay to simulate the wave propagation.
The tsunami trimline is well recreated when using (a) a uniform mesh size of
20 m or (b) a non-uniform mesh size of 15 m ?? 15 m ?? 10 m with a relative roughness of 2 m for the topographic surface. The trimline mainly results from the primary
wave, and in some locations it also results from reflected waves. The denser fluid is a
suitable and simple concept to recreate a sliding mass impacting a waterbody,
in this case with maximum impact speed of ???93 m s ???1 . The
tsunami event and the related trimline are well reproduced using the
3D modelling approach with the density evaluation model available in
Flow-3D.
Keywords:
- Correction
- Source
- Cite
- Save
- Machine Reading By IdeaReader
37
References
4
Citations
NaN
KQI