Abstract
On March 11, 2011, huge tsunamis took place due to the Great East Japan Earthquake as large as Mw 9.0. It has been observed that an ocean bottom presimeter (OBP) and an ocean bottom seismometer (OBS) were sagged to the deep ocean by approximately 1 km, which suggests the possibility of the generation of a large scale line-source turbudity current taking place on the ocean floor off the coast of Tohoku. In this study, we reproduce the tsunami by the use of a tsunami simulation software, iRIC/ELIMO, evaluate the entrainment rate of suspended sediment, and estimate the source area of the turbidity current. It is found, from the results of the analysis, that a large amount of entrainment continuously took place from the north of Oshika Peninsula to the area within 40 km off the coast of Sendai Bay, which is assumed to be the source area of the turbidity current.
