The southern coast of West Java suffered damage from 2 – 8 m height tsunamis generated by the 2006 Java earthquake. In this study we validated the tsunami modellings for the 2006 tsunami, which can be applied for the tsunami hazard assessment of future tsunamis. We assumed 27 output points from the tsunami field survey data as coastal points in tsunami computations in order to understand the tsunami phenomena in the target areas. We adopted four tsunami source models: Model 1, uniform slip of 8 m; Model 2, two sub faults with slips of 12 m and 8 m; Model 3, 10 sub faults from tsunami waveform inversion; and Model 4, uniform slip of 15 m. Shallow water theory in the spherical coordinate system was applied in the computation to evaluate the tsunami heights and inundation in the target areas. We applied a nesting grid system with two-four layers in the computation.
The preferable source model (Model 4, Mw = 8.1) produced tsunami heights around 2.7 – 6.9 m along the coastal areas and maximum tsunami heights exceeded 10 m at some offshore areas. Such tsunami heights were only reproduced by the source model which has the slip amount of 15 m. The tsunami travel time for reaching the coastal areas was around 60 min after the main shock, which was agreeable with the tsunami travel time reported by numerous reliable eyewitness accounts. Inundation depths of around 3 – 5 m from the field survey data were almost reproduced by the computation. The result from the numerical computation seems to be reliable because the patterns of tsunami heights from computation results agreed well with that from the field survey. Some of the results which do not quantitatively agree with the field survey data may be due to poor bathymetry or topography data of the coastal area. The magnitude of the preferable source model (Mw 8.1) was larger than the one from seismic data (Mw 7.8). This may indicate that another phenomena rather than fault slip may have happened. Proper bathymetry and topography data with finer spatial grid size than the current resolution should be used for further studies.