MARINE AND TERRESTRIAL SIGNALS IN TSUNAMI DEPOSITS

Tsunami deposits from paleo-events contained a wealth of information about paleo-tsunamis. The decryptions of this information become extremely important when quantifiable observations were not available. Tsunami deposit can be eroded and transported from both marine and terrestrial environment. An interesting question will be how marine-terrestrial signal can be applied to reconstruct paleo-tsunami events. In this contribution, we employ a state-of-the-art tsunami sediment transport model, GeoClaw-STIRCHE, to carry a parameter study. In this parameter study, we change the onshore slope, the initial wave amplitude, and the grain size in sediment source to study the marine-terrestrial signals in the tsunami deposit. We define the normalized location where the marine sediment becomes easily recognizable (> 5%) to characterize the distribution of the marine-terrestrial signal. Meanwhile, the normalized location can be used as a quantitative tool to estimate maximum inundation from the spatial distribution of tsunami deposits. Based on the parameter study, both the initial wave amplitude and the grain size in sediment source significantly influence the marine-terrestrial signal in the tsunami deposit. Our method successfully estimates the offshore wave amplitudes for the 2010 Chile tsunami in Las Ca\~{n}as area. Based on the data from Goff et al., 2015 and our parameter study, the normalized wave amplitude ranges from 0.03 to 0.04, which is consistent with simulation results.