GSA Annual Meeting in Denver, Colorado, USA - 2016

Paper No. 235-4
Presentation Time: 9:00 AM-6:30 PM

TSUFLIND-ENKF: INVERSION OF TSUNAMI FLOW DEPTH AND FLOW SPEED FROM DEPOSITS WITH QUANTIFIED UNCERTAINTIES


TANG, Hui1, WEISS, Robert1, WANG, Jianxun2 and XIAO, Heng2, (1)Department of Geosciences, Virginia Tech, Blacksburg, VA 24061, (2)Department of Aerospace and Ocean Engineering, Blacksburg, VA 24060, tanghui@vt.edu

Deciphering quantitative information from tsunami deposits is especially important for analyzing paleo-tsunami events in which deposits comprise the only leftover physical evidence. The physical meaning of the deciphered quantities depends on the assumptions that are applied. The aim of our study is to estimate the characteristics of tsunamis and quantify the errors and uncertainties that inherent within them. To achieve this goal, we apply the TSUFLIND-EnKF inversion model to study the deposition of an idealized deposit created by a single tsunami wave and one real case from 2004 Indian ocean tsunami. TSUFLIND-EnKF combines TSUFLIND for the deposition module with the Ensemble Kalman Filtering (EnKF) method. In our modeling, we assume that grain-size distribution and thickness from the idealized deposits at different depths can be used as an observational variable. Our tentative results indicate that sampling methods and sampling frequencies of tsunami deposits influence not only the magnitude of the inverted variables, but also their errors and uncertainties. An interesting result of our technique is that a larger number of samples from a given tsunami deposit does not automatically mean that the inversion results are more robust with smaller errors and decreased uncertainties.