Offshore Tsunami Observation by the Kuril Islands Earthquake of 15 November 2006

Tsunami from the mega-thrust earthquake off the Kuril islands on 15 November 2006 was observed by the offshore permanent observatory off Hokkaido, Japan. About one hour later, a series of the tsunami signal was observed by three bottom pressure sensors, two of them are permanent observatories and the other is temporarily deployed. Tsunami amplitudes observed offshore were approximately 5 cm, while those observed at the coast were a few tens of centimeters. An acoustic Doppler current profiler (ADCP) at the ocean-bottom, however, could not record any current anomaly by the tsunami propagation. This is because a particle velocity by the tsunami propagation is very slow (< 1 cm/s), whereas a phase velocity is more than 100 km/h. In the present study, the tsunami computation has been also done, and its results have been compared to the observations.