丘陵地の卓越周期に関する解析的検討

抄録

It is well known that the alluvial has its natural period in relation to its depth, and makes the earthquake motion large. On the other hand, the hill also has its natural period in relation to its height. I this paper, the natural period of a hill is calculated in consideration of its sectional shape. As a result, The height and the sectional shape of a hill influences its natural period. But the natural period is proportional to the height of a hill. The mode analysis of the hill at Aobayama Campus of Tohoku University shows that the natural periods (from 1st till 4th) by 3D model are about 1.0 sec. The natural period by 2D model is also 0.92 sec. There are many predominant periods under the 1st natural period of 3D model in the calculated response spectra. And there is no tendency among response spectrum at each point on the 3D model.