Generation of tsunamis in the Okhotsk Sea caused by the 1994 great Kuril earthquake

The 1994 great Kuril earthquake generated an unusual tsunami that was obser ved at five tide gauges on the Hokkaido coast of the Okhotsk Sea. The tsuna mi arrived at tide gauges considerably earlier than the expected time, calc ulated on the assumption that the tsunami source area coincides with the af tershock area. Numerical simulation of the tsunami shows that the first wav e of the tsunami in the Okhotsk Sea was generated by the significant subsid ence north of the Kuril Islands. It is assumed that this subsidence is due to the earthquake. The coseismic deformation area of the ocean bottom exten ded over a vastly larger area than the aftershock area or the rupture area for the Kuril earthquake. The numerical simulation also shows that the tsun ami observed at Utoro during the first hour after the origin time of the ea rthquake was mainly generated by the horizontal movement of the sloping oce an bottom near the Shiretoko Peninsula.