SGER- Understanding the coastal impacts of Kuril Island 2006 tsunami

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Abstract:The 26 December 2004 Great Indian Ocean Tsunami cost the world community more than 230,000 lives. Additional DARTs have been planned and deployed in the Pacific Ocean to provide additional data and warning capabilities. However, on November 15, 2006 scientists and emergency workers in US were surprised by the tsunami generated by a large earthquake (Mw = 8.3) on the Kuril Islands subduction zone (Ledford, 2006). The earthquake generated a tsunami which was expected to reach Northern Japan in one hour and west coast of the United States in about 8 hours. Since the wave heights of this tsunami reaching Japan were, in general, less than 1 m, a large tsunami was not expected in Alaska or along the US west coast. Unfortunately, the tide gage data showed that the highest maximum wave heights on Oregon coast and Northern California were lager than 1m. Total damage in Crescent City, California is expected to be between $500,000 and $1,000,000. This research is aimed at understanding the behavior of the Kuril Islands tsunami. Based on the information and data collected in the proposed research activities, we intend to find the answers to the following scientific questions: 1. What is the cause of large tsunami wave heights along the US west coast? Why the wave heights are still relatively large there? Is it because of the strong wave reflection from the Aleutian Islands (trench)? Is it due to the reflection from the coast of North America or the trapped waves propagating along the coast (i.e., edge wave or stem wave)? Or is it a local phenomena (i.e., dominated by the local bathymetry)? 2. What is the reason that in many locations the maximum wave heights seem to occur 1.5 - 2 hours after the leading wave has arrived? Is the delay in occurrence caused by the harbor resonance? Is it strongly affected by the location of tide gage? Again, is it controlled by the local bathymetry? This project contributes to teaching by involving graduate and undergraduate students in the cross-disciplinary research. The research will shed light on the interactions of the Aleutian Islands (trench) and the continental shelf of Northern America with a distant tsunami and their effects on the tsunami heights along the Oregon and California coasts. The results will affect the protocol for issuing and canceling of tsunami warning for the US west coast. The research will also provide site specific information of the influence of local bathymetry on tide gage responses. Findings from the project will improve and update materials prepared for tsunami outreach and education programs.