Energy flux as a tool in locating tsunami secondary sources

• Main Author: Zygmunt Kowalik
• Format: Article
• Language: English
• Published: Tsunami Society International 2008-01-01
• Series: Science of Tsunami Hazards
• Subjects: tsunami; tsunami travel time; computational methods; tsunami propagation; tsunami energy flus
• Online Access: http://tsunamisociety.org/273Kowalik.pdf

The sea levels recorded in the wake of Indian Ocean Tsunami of December 2004 and of the Kuril Island Tsunami of November 2006 show strong tsunami signal enhancement of the late arriving secondary waves. Using these tsunami eventswe demonstrate thatsudden changes caused by higher energy pulses in the intermittent tsunami wave trains can be assessed by energy fluxes. Therefore, to delineate the regions of tsunami wave amplification and travel time we propose to use energy flux.A series of numerical experimentsdefinedinexplicitwaythe bathymetric features which scatter tsunami signal towards ports, like Crescent City. Identification of the distant bathymetric featureswas achievable sincethe energy fluxvectordelineatedthe energy pathways that coupled distant bathymetric features to portslocated thousands of kilometers apart. Calculations of the energy flux vector involves simple formulas based on two components of velocity and sea level. The maximum of the energy flux (which has no directional properties) can be evaluated from the sea level amplitude, hence both observed and computed sea level can be used for this purpose. The main task of this paper is to suggest that tsunami warning and prediction services should use numerical-hydrodynamical models with wider scope of physical processes by incorporating the energy balance equation into presently used tools.