Development of a Numerical Algorithm Considering Tide-Tsunami Interaction

The perimeter of the Pacific Ocean Basin, known as the Ring of Fire, has several sources that can produce strong earthquakes of magnitude >= 7.0. The earthquake of magnitude 9.0-9.1, occurred in 2011 off the Pacific coast of Tohoku, produced a devastating tsunami that affected the Pacific Basin. The lead time before the subsequent tsunami of such an earthquake reaches the coastal areas of the Korean peninsula varies. A tsunami from a distant location like Chile or California, USA, will take 12 h or more to reach the Korean peninsula, while that from Japan or the Ryuku Trench will take only 1-4 h. The tide-tsunami interaction may be strengthened significantly in some regions with very strong tides and could be used to predict tsunami hazards in Korea. Therefore, to develop a plan for mitigating tsunami hazards around the Korean peninsula, the tide-tsunami interaction that occurs during the propagation of a tsunami over regions with strong tides and tidal currents should be properly evaluated and its impact on a local community should be considered during numerical simulations. We developed a new numerical algorithm that includes tide-tsunami interactions for the national tsunami forecasting system. Numerical experiments using this tsunami forecasting algorithm were conducted to investigate the impact of tide-tsunami interactions as the tsunami propagates toward coastal areas of the Korean peninsula.