The Tokachi-Oki Earthquake in 2003, whose magnitude was 8.0, occurred at 4:50, September26, 2003 (Japan time) and caused a series of tsunamis. The tsunami struck the Pacific coasts in theHokkaido and Tohoku regions and caused coastal flood in low-lying areas, resulting in containersand cars floated, especially in the Hokkaido region. There was, however, little serious damage ofport facilities by tsunami attack. Victims by the tsunami were two people.
　Immediately after this earthquake, the Port and Airport Research Institute (PARI) dispatchedfield investigation teams to the southeast coast in the Hokkaido. The Storm Surge and TsunamiDivision in PARI investigated the characteristics of the tsunami run-up and damages, especially inport and harbor areas.
　This report described the characteristics of this tsunami based on the results of the fieldinvestigations. Numerical simulations of the tsunami were also conducted using the fault models ofthe earthquake proposed until now, to obtain overall feature of the tsunami in the Hokkaido andTohoku regions. Finally, we summarized the problems for disaster reduction and more detailedestimation of tsunami damage.