Run-Up means the process of a Tsunami wave entering very shallow coastal waters and the propagation further inland. In this process, the wave may be subject to essential transformations, e. g. the shoaling of the wave to a multiple of the height in the open ocean. Eventually, the wave may break, and the water masses continue to propagate in the form of a bore. In the end, these transformations determine, besides the characteristics of the coastal area, how far inland and how fast the inundation occurs. This is of great importance for the planning of protective measures including the evacuation of population.
Some phenomena can’t be described by the set of nonlinear shallow water equations which is used in the open ocean modeling. To be able to simulate, for example, the disintegration of a single wave into waves of different frequencies or the generation of an undulated bore, it is necessary to use a different type of equations. A suitable choice is the set of Boussinesq equations containing additional terms of equal or higher order (see for example the model result of an artificial test case).
These kind of simulations are computational very expensive, in particular because of the additional requirement of a high spatial resolution (in the order of 100 m or less) to resolve coastal properties, bathymetric features, and the Tsunami signal itself. For this reason, the strategy developed by the participating institutions GKSS Research Center and DHI Water & Environment is to concentrate on a few selected areas characterized by high vulnerability, typical coastal geometries, water depths and bottom slopes. Different realistic model scenarios will be performed with the systems MIKE 21 HD and MIKE 21 BW, receiving boundary values from AWI’s ocean model FEOM.
The computational results of these scenarios will go into the decision support system of the warning center.
Likewise, differences of the results when using both types of equations will be identified and represented in terms of preferably simple parameters. In combination with parameters characterizing the coastal area, we thereby want to improve the prediction in similar coastal areas.