On the performance of sequential Bayesian update for database of diverse tsunami scenarios

TL;DR

This study evaluates the effectiveness of a Bayesian tsunami scenario detection framework using a diverse set of complex fault rupture scenarios, comparing it with scenario superposition and DTW methods across different observation windows.

Contribution

It introduces a comprehensive evaluation of Bayesian tsunami detection with complex fault scenarios and compares its performance to superposition and DTW methods.

Findings

Scenario superposition outperforms the previous most likely scenario detection.

Detection accuracy improves with longer observation windows.

Bayesian method shows robustness across diverse fault rupture patterns.

Abstract

Although the sequential tsunami scenario detection framework was validated in our previous work, several tasks remain to be resolved from a practical point of view. This study aims to evaluate the performance of the previous tsunami scenario detection framework using a diverse database consisting of complex fault rupture patterns with heterogeneous slip distributions. Specifically, we compare the effectiveness of scenario superposition to that of the previous most likely scenario detection method. Additionally, how the length of the observation time window influences the accuracy of both methods is analyzed. We utilize an existing database comprising 1771 tsunami scenarios targeting the city Westport (WA, U.S.), which includes synthetic wave height records and inundation distributions as the result of fault rupture in the Cascadia subduction zone. The heterogeneous patterns of slips used in the database increase the diversity of the scenarios and thus make it a proper database for evaluating the performance of scenario superposition. To assess the performance, we consider various observation time windows shorter than 15 minutes and divide the database into five testing and learning sets. The evaluation accuracy of the maximum offshore wave, inundation depth, and its distribution is analyzed to examine the advantages of the scenario superposition method over the previous method. We introduce the dynamic time warping (DTW) method as an additional benchmark and compare its results to that of the Bayesian scenario detection method.