抄録
The soil and structure interaction effects were clearly observed in the records at the Kushiro District Meteorological Observatory. The two-dimensional interaction model, in which the soil behaved nonlinearly and the structure behaved linearly, exactly expressed the dip at a period of 0.2 second and the peaks at periods of 0.1and 0.3 second, that were observed in the weak earthquake motions. The same model expressed the periods of 0.15 and 0.5 second of the peaks, that were observed in the strong earthquake motions from the 1993 Kushiro-Oki earthquake of M 7.8. However, the calculated amplitude of the peaks was a half of the observed one.
