A STUDY ON PALEO-TSUNAMI SOURCE ESTIMATION CONSIDERING SEDIMENT SOURCE OF TSUNAMI DEPOSITS

Abstract

 Tsunami source estimation is important for low-frequency giant tsunami risk assessment in the field of paleo-tsunami. There are many attempts in reconstructing inland inundation conditions using the layer thickness, grain size distribution and distribution of tsunami deposits as constraints so as to estimate the tsunami sources that satisfy the reconstructed inundation conditions. However, sediment source (sea or land) of the tsunami deposits has never been investigated so far. In this study, numerical simulations using sediment transport model were performed using three different tsunami sources model proposed for the 2011 tsunami to investigate whether information of the sediment source of the tsunami deposits can be an additional constraint for the tsunami source estimation. As a result, it was suggested that the source of sediment of the tsunami deposits was very different even if the tsunami source models showed similar inland inundation conditions. Although there are still some problems to be solved, it can be concluded that the information on the sediment source of the tsunami deposits is possibly used as a further constraint in addition to the conventional paleo-tsunami tsunami source estimation method.