Development and validation of a tsunami amplitude forecast system covering the whole Pacific Ocean

Abstract

Based on linear shallow water equation and tsunami amplitude Green's law, a rapid earthquake induced tsunami amplitude forecast system covering the Pacific Ocean is developed. Thirty-two hour tsunami propagation simulation and amplitude forecast for Chinese coast can be completed within 90 s by using GPU parallel method. The system is validated by 9 major historical tsunamis induced by submarine earthquakes with M w more than 8.0 in the Pacific region since 2006 with abundant observations. The results indicate that the linear shallow water model is capable of simulating the tsunami propagation in the ocean. And the Green's law basically can be used for amplitude estimation in the coastal region under the condition of slow-varying topography and open coastline with no complex geometry. Forecasting accuracy of threat levels is acceptable in terms of tsunami warning purpose, with 80% of results falling into the corresponding levels. The evaluation also confirms that the forecasting system can meet the requirement of tsunami warning in Chinese coastal areas. Note that near-field amplitude may have large deviations because of its sensitivity to tsunami source. In order to further improve the accuracy of quantitative warning of tsunami amplitude, we need to strengthen the research and operational practice from the following aspects:one is to improve the precision of the tsunami source by using method of multiple-data joint inversion; the second is to validate the feasibility of Green's law, or to construct refined and high-efficiency tsunami forecast model in coastal regions.