IASPEI - Picture Gallery

IUGG XXIV General Assembly July 2-13, 2007 Perugia, Italy
(S) - IASPEI - International Association of Seismology and Physics of the Earth's
Interior
JSS002 Poster presentation 1818
The implications of non-linearity and dispersion in a tsunami scenario
database
Mr. Arthur Simanjuntak
Australian Bureau of Meteorology Research Centre Australian Bureau of Meteorology
Diana J.M. Greenslade
The Australian Bureau of Meteorology has developed a 1st generation operational model-based tsunami
prediction system (T1) as a component of the Australian Tsunami Warning System. The T1 system is
based on a database of pre-computed tsunami scenarios. For each earthquake source location, the T1
system provides solutions from four different earthquake magnitudes and chooses the closest scenario.
A natural extension of this system would be to provide an interpolation of these scenarios to obtain the
solution for a specific intermediate earthquake magnitude. Implicit in this is the assumption of wave
linearity, which has been shown to hold in the open ocean but unlikely to be accurate in shallow water.
Furthermore, since the ruptures for each earthquake magnitude differ from each other not only in the
amount of slip but also width and length, the initial conditions would have different horizontal
wavelengths from each other. This will have implications as the waves disperse and encounter
bathymetric features. The importance of dispersion is proportional to the distance travelled by the
waves and inversely proportional to depth. In this presentation, the potential for scenario interpolation
will be investigated by means of numerical experiments and simple scaling arguments. The assumption
of linearity and the effect of dispersion will be investigated separately. Specifically, we will explore some
non-dimensional parameter space beyond which the non-linearity and dispersive effects start to
dominate and therefore render simple magnitude interpolation inappropriate.
Keywords: linearity, dispersion, simulation