Modes and degrees of the damages caused by the Onikobe earthquake (M=4.9) of July 5, 1976 were investigated in special reference to the predominant direction of the ground motion. The directions of falling and slip of gravestones near the focal region were restricted to a narrow range of directions and these data were found useful for estimating the predominant direction of the ground motion. On the basis of the seismological data such as the hypocenter location, the focal mechanism and aftershock distribution, various dynamicsource models were tested if they could explain the predominant direction near the focal region. As a result, precise determination of the hypocenter location became possible, and the finally selected model explained the systematic pattern of the predominant directions observed near and around the focal region.

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